Tuesday, May 25, 2010

Sunshine of Your Love Part 3: What is e-D-ible?

This is the third installment in our series about the sun.  For context, please read 
Sunshine of Your Love Part 1: Safely Getting What You Need and 
Sunshine of Your Love Part 2: The D Factor.  

After our last discussion of the inherent problems with getting your vitamin D from the sun alone, we were left with the question: So where can we get the vitamin D we need?  Today, let's talk food.  

Getting Your Vitamin D From Food

The vitamin D humans (and all animals) produce from a chemical reaction in our skin under UVB rays is D3, in the form of cholecalciferol, the most readily usable form by our bodies.  If we eat animals, we get the same form of vitamin D that we make ourselves.  Another form, vitamin D2, is produced by plants and fungi, but you're unlikely to ingest much of it when you eat the plant or fungus.  Special treatment of plants and fungus can extract the vitamin D for use in fortified foods and supplementation.  However,  since plants and animals are vastly different creatures down to the cellular level, their form of vitamin D isn't an equivalent to ours.  That is why if you are outsourcing your vitamin D needs, you must choose vitamin D from animal sources.  We'll discuss this more below under Fortified Foods: The Right Stuff.  Thus, our sources for vitamin D from food are: animals or fortified foods.

Fortified Foods: Frankenfoods

You've seen them before.  Cartons of milk and orange juice, containers of yogurt and margarine, and boxes of breakfast cereal all telling us they are a source of vitamin D.  On the surface, the game plan seems solid.  These are foods built from the ground up, combining numerous distilled ingredients to craft a whole new food novel to any creature in existence.  In theory, you would think the builders have your best interests in mind: they have the power to create super-nutritious super-foods.

For example, Total Cereal tells us they offer "100% Nutrition" by giving us 100% of the Daily Value of 12 vitamins and minerals.  How responsible of them!  One hitch: sugar is their number two ingredient and corn syrup, number three.  In each 3/4 cup serving, I repeat: 3/4 cup serving, there are 5 grams of sugar, or just over one teaspoon or sugar packet.  Exactly how does that contribute to total nutrition?

Unfortunately, the arms race in the processed food industry isn't to create a more nutritious product giving lasting health benefits; it's for profit and convenience (which leads to more profit).  The old saying rings true once more: 'You can have it cheap, you can have it good, or you can have it fast.  Choose two.'  Unfortunately, high quality, nutritional "goodness" has been sacrificed for cheap, fast food.

Just browsing through your average supermarket would make our ancestors weep.  Where the hell is the real food?  Oh yeah, tucked away on the periphery are the meats, fruit, and veggies, outliers of the industrial complex.  Even these aren't immune to commodification as we reconfigure and patent genetic codes creating genetically modified organisms, industrialize even "organic" farming, and feed waste products and surplus into animal "products" through CAFOs (Concentrated Animal Feeding Operations, also known as factory farms) producing meat instead of raising animals.  Food is being redefined away from its biological roots and into products that can be produced, refined, and commodified.    

Processed foods, a multitude of refined parts compressed into one whole, are less than ideal for many reasons.  One, they're made to sell.  Profit comes before any altruistic desires for the betterment of human health.  Perhaps this isn't true for every product out there, but certainly most.  Tell me how these products were created to nourish us: pancake batter in an aerosol can, fruit-flavored products without any real fruit, or meat substitutes with ingredient lists longer and more unpronounceable than those of beauty products, just to name a few.  To show just how abhorrent the whole creation of a food marketed as "healthy" really is, take the following passage from The Omnivore's Dilemma by Michael Pollan.  Let's play, What Am I?
...four cents' worth of commodity corn (or some other equally cheap grain) transformed into four dollars' worth of processed food.  What an alchemy!  Yet it is performed straightforwardly enough: by taking several of the output streams issuing from a wet mill (corn meal, corn starch, corn sweetener, as well as a handful of tinier chemical fractions) and then assembling them into an attractively novel form.  Further value is added in the form of color and taste, then branding and packaging.  Oh yes, and vitamins and minerals, which are added to give the product a sheen of healthfulness and to replace the nutrients that are lost whenever whole foods are processed.
So, what am I?  See the answer at the end of this post.  And even if you are okay with the whole frankenfood thing, there are other pitfalls to fortified foods.  Does it even give you what you need?  Is it even worth it?  Let's explore dairy, next.    

Fortified Foods: Does Milk Really Do a Body Good?

What about dairy products?  Although processed, they are closer to the source--their ingredient lists are short.  Can't I get my vitamin D from milk like the ads tell me?  No, because:
1.  Milk and dairy products aren't for everyone.  You can be healthy without them in your diet.
2.  Milk alone doesn't have the amount of vitamin D you need even when it's fortified.
3.  Skim milk doesn't have the fat you need to absorb vitamin D.  
4.  The trans fat in margarine totally gunks up the process of utilizing vitamin D.    

One, dairy may not "do a body good," at least not for every body.  There is definitely some debate about the healthiness of milk.  See Mark's Daily Apple for a good summary.  We'll hit that one another day, but for now, read up on why The Paleo Diet doesn't like dairy.  For more depth, check out founder Dr. Loren Cordain's argument at his website.  For as many opponents, there are just as many proponents of full-fat dairy like PaNu, The Weston A. Price Foundation,  The Heart Scan Blog, and Whole Health Source, to only name a few.  For me, I'll probably continue to partake in high fat dairy like butter and cream and try to mininmize my dairy that isn't full fat, raw, and grassfed.  Although I know dairy has many benefits, it also has some detriments I've seen firsthand in my N=1 experiments: I get plegmy, wake up congested, get a runny nose, and sometimes get a sore throat.  And that is dairy alone--no grains to confound these results.  The severity depends on the quantity, source, and form of dairy.  Definitely something is at work here.  And remember, on a paleo-style diet you are absorbing your calcium from your veggies (because a clean digestive system is an efficient one) and your vitamin D from other sources we'll discuss below.  So no one NEEDS milk to survive, except breastfeeding babies.  Just saying.

Okay, dairy is a personal choice, but as our second problem can it even provide the vitamin D you need?  This discussion of Vitamin D and Milk from a UC Riverside professor that we cited in our first installment is a good resource to answer this question.
Milk from all lactating animals, including humans, contains vitamin D3 that has been produced photochemically from 7-dehydrocholesterol present in the skin. In cow's milk it has been determined that the concentration of vitamin D3 in milk provided by the cow is roughly 35-70 International Units per quart as determined via biological assay and approximately 50-80 International Units as determined by modern chemical mass spectrometric procedures. However these are rather low levels of vitamin D3 from the perspective of providing the 200-400 IU per day as recommended by the Food and Nutrition Board of the Institute of Medicine. 
And remember, that 200-400 IU recommendation is way below that suggested by The Vitamin D Council to achieve 50-80 ng/mL blood levels.  They say to take 5k daily and recheck in 2-3 months.  Since milk isn't a great source for vitamin D naturally, it's fortified.  According to the article cited above, every quart is fortified with 400 IU of vitamin D.  So to drink your 5K a day, that would be 12 and a half quarts a day.  Even a more conservative dosage of 1k a day would be two and a half quarts.  Thirsty?  

Another problem, we've been told fat is bad for us, so we switched to heart-healthy skim.  But on this blog we've time and again taken skim milk to task for not containing the healthiest part: the fat!  Fat is where the vitamin D and other vitamins, essential fatty acids, and important constituents reside.  Fat is necessary for absorption of fat soluble vitamins like...say it with me now...Vitamin D!  And other forms of commercial milk aren't off the hook even if they DO contain fat because they are pasteurized and homogenized.  There is a LOT to say about these processes and how they destroy everything sacred about milk, so read the Weston Price Foundation's treatise: Milk: It Does a Body Good?  

Does that mean our precious, fortified, non-butter, saving-us-from-the-evils-of-saturated-fat spread (also known as margarine) is out too?  Um, YES.  Besides being a processed product made from an array of chemicals, margarine is mostly trans fat (trans fatty acids are made from the hydrogenation of vegetable oils and there is little argument about them NOT being the least bit healthy).  And why is trans fat a problem specifically with vitamin D fortification?  It interferes with the conversion of vitamin D into calcidiol in the liver.  Maybe the producers know it screws up the process, so they are just hedging their bets and dumping more vitamin D in there to hopefully balance it all out.  And you would think that with all the effort we put into refining and producing products based on their constituent parts that we could actually craft healthy products.  Silly me, it's a sci-fi pipe dream to think that food production is out to meet our nutritional needs.  Guess I'll have to wait for Asimov's yeast products and Star Trek's replicators.... Sigh.  

Fortified Foods: The Right Stuff

But other foods are fortified besides dairy, you say?  How about heart-healthy OJ fortified with calcium and vitamin D?  Even if everything seems "right" with vitamin D-fortified foods, other problems emerge.  Take that fortified OJ.  According to Minute Maid, it's just juice, calcium sources, and vitamin D3 (good for them!).  What's the problem?  The juice.  What's wrong with juice?  The fact that in 250ml or ONE cup there are 120 calories, 28g of carbohydrate (25 of which is sugar), and NO satiating fiber.  That's three Zone blocks right there and it's certainly NOT a low glycemic food.  One cup of orange juice is over 50 times the calories of an orange.  While it is difficult to overeat fruit because of their fibrous bulk, it's effortless to down a big glass of OJ and feel like you are doing your body good.  And good luck feeling full; without significant protein, any fat, or any fiber, you're just fanning the flames.  The worst part?  That sugar load, calories and all, isn't so different from soda.  In fact, 240ml of Coca-Cola Classic is only 96 calories and 27g of carbohydrate/sugar.  Are those vitamins and minerals in fortified OJ really enough to make it healthier?  For more on why juice is a no-go, please read my article: Just Say No...to Juice?

Another pitfall?  Fortification with vitamin D often involves the form vitamin D2, which comes from plants or fungi.  One catch, plants/fungi are entirely different beings than animals.  Our bodies are wired very differently, down to the cellular level (cell walls in plants and cell membranes in animals are quite different).  Plant vitamin D, D2, is not the same as our vitamin D, D3, so it is much less efficient to use the plant form to get what we need.  This study calls for an end to vitamin D2 fortification and supplementation because it is NOT an equivalent to D3.  The authors state that vitamin D2 is NOT as effective at raising vitamin D levels, has a shorter shelf life, may lead to incorrect circulating vitamin D measurements, and is metabolized differently, thereby it doesn't assume the same functions as vitamin D3.  Dr. Davis from The Heart Scan Blog concurs.  He discusses how D2 is a cheaper supplement than D3, but it pales in comparison to the effectiveness of D3 in the body.  

Insult to injury?  Even if producers fortify foods with the most bioavailable form of vitamin D, D3, the source is up for grabs.  Just because they are fortifying cow's milk, doesn't mean that added D3 is from a cow.  It could be from any animal used to make that source.  There are NO requirements to identify the source of ingredients like vitamin D.  Isn't that a little disturbing?

Animal Sources of Vitamin D

So where can you get natural animal sources of vitamin D?  Fish, for one.  Salmon, sardines, and shrimp are very good to excellent sources according to The World's Healthiest Foods (a nutritional database) and eggs follow close behind (and yes, you have to eat the yolk, which contains all the nutritional goodness like the vitamin D!).  That website also lists vitamin D-fortified cow's milk as a very good source, but we are going for whole foods, not processed, and I already discussed it's detriments above.  

Meat quality matters.  Wild-caught fish has significantly more vitamin D than non-organic farm-raised, which lends more evidence to support our preference for sustainable wild-caught, grass-fed, and pasture-raised sources of meat.  For more information on sustainable fish, check out the Monterey Bay Aquarium's Seafood Watch list.  The Weston Price Foundation article further elaborates that the plankton and other fish in the diets of the fish we eat provide their vitamin D (that they cannot synthesize it from the sun themselves).  Thus, farm-raised fish on a processed (usually grain-based) diet are not getting the dietary vitamin D to become as rich a source as their wild brethren.  Unless, of course, we fortify their grain-based diet, which leads us back around to the argument above: we CANNOT make better foods than those found in nature.  The Weston Price Foundation article also mentions that we aren't even exploiting the real WHOLE foods that contain the most vitamin D, like the organ meats, skin, fat, and insects that are uncommon modern foods. 

Unfortunately, getting the vitamin D you need is NOT as simple as just eating your fill of fish.  The quantity of vitamin D in different foods varies.  It even varies for the SAME foods!  Argh!  For instance, mackerel cooked 3 to 3.5oz is 388 IU here (for 3oz) and 345 IU here (for 3.5oz).  Either way, even the best food sources (one 3-4 oz serving of salmon with up to 794 IU, although most charts have it closer to 400 IU) are a drop in the bucket for what you need.  And if what I have read is right, we do NOT want to listen to the daily recommended values given on those sites (400 IU a day, are you serious?).  Remember, we are shooting for 5000 IU a day according to The Vitamin D Council.  But the real number you need depends entirely upon your own vitamin D level, so get checked!  The Vitamin D Council recommends 50–80 ng/mL (or 125–200 nM/L) year-round.  Taking the average 400IU in 4oz of the best food source (salmon), that would take 12 and half servings a day.  Hungry?

Additionally, there is also a whole can of worms to explore with vitamin D's cofactors (read more about them at the Vitamin D Council): those vitamins and minerals necessary for it to do it's many jobs.  Any deficiencies and you're screwed.  This is more detail than we can handle today, so it suffices to say that you should eat REAL FOOD and make sure your diet is full of variety and rich sources of vitamins and minerals, including sustainable wild-caught fish, pasture-raised poultry and eggs, grass-fed meat, and local and seasonal vegetables, fruit, and nuts.  

And what about getting the vitamin D you need?  Well, that question has not been answered yet.  I guess it's to be continued:

Sunshine of Your Love Part 4: Supplementation

General references used extensively (in addition to those cited above):
The Omnivore's Dilemma by Michael Pollan
The World's Healthiest Foods: Vitamin D
Weston Price Foundation's article: The Miracle of Vitamin D and Milk: It Does a Body Good?

Answer to What Am I: breakfast cereal.  Still think it's a healthy start to your day? 

Thursday, May 20, 2010

Sunshine of Your Love Part 2: The D Factor

Sunshining sea lion soaking up some vitamin D.

This is the second installment in our series about the sun.  For context, please read Sunshine of Your Love Part 1: Safely Getting What You Need.

So today, let's talk vitamin D.  We all know about vitamin D.  It's in the milk ads, in the news, and in steadfast nutritional pillars of our society: breakfast cereal, milk, margarine, and orange juice.  According to The Washington Post:
Vitamin D is shaping up to be the nutrient of the year, if not the decade.
This vitamin is common dinner table and water cooler conversation.  When the sun kisses your face, you likely think of it and then think of sunburn.  Vitamin D is the puffy white cotton candy cloud top, while it's alter ego, sunburn, is the thunderous underbelly, a raging tempest.  And with such mixed consensus about the sun, fortified foods, and supplementation, vitamin D sits right in the middle, teetering on the seesaw between nourishment and harm.

There are a lot of questions about vitamin D and today is it's time in the sun ;)

1.  What is it?

Short answer: a fat soluble, essential vitamin that acts as a hormone.

2.  Why do you need it?

Short answer: it has a multitude of roles to play and protects against cancer.

3.  Where do you get it?

Short answer: from the sun on your skin, from certain foods with animal origin, and from supplementation.  But whether or not any of these sources alone can meet your needs requires further discussion.

Now for the elaboration.  Why?  I don't want to provide Just Because kinds of answers--I want you to learn something and understand it so that you can discuss the subject intelligently.  For example, how do you respond when someone says that they get all the vitamin D they need from their fortified skim milk and from their sunscreen-lathered sunbathing?  Curious?  Read on.

What is Vitamin D?

Vitamin D is classified as a vitamin, but also as a hormone, or "pro-hormone," since it is synthesized by body tissues like a hormone as well as ingested through the diet like most other vitamins.  As a hormone, vitamin D regulates growth, development, and metabolism, whereas most other vitamins play bit parts in these processes.  Vitamin D enters the body either through synthesis in our skin cells or through foods (and supplements) we eat (for more see Where Do You Get Vitamin D? below).  Whatever the source, it must be transported to the liver where it is hydroxylated and circulated as hydroxyvitamin (which is the substance we measure to obtain vitamin D levels), called calcidiol.  Calcidiol is the storage form of vitamin D in your body and it is used to make calcitriol either in the kidneys or, if any is left over, directly in the cells.  This form enters cells and regulates gene expression.  As a hormone, vitamin D transports signals and messages; cells even have receptors for it just like they do for cortisol.  Hence, with vitamin D there is definitely more than meets the eye (did you say that in your mind with a robotic voice?  Yeah, I thought so :) ).  Vitamin D plays a host of roles, discussed in the next section.

Why Do You Need Vitamin D?

One of the most important jobs of vitamin D in the body is to maintain calcium levels.  It does this by reclaiming circulating calcium and increasing calcium absorption in the small intestine or, if dietary calcium is insufficient, by leaching calcium from the bones (ever hear of osteoporosis?).  That is why vitamin D and calcium fortification go together--you need adequate dietary calcium or vitamin D will get it by any means necessary.  This is a Clear and Present Danger sort of situation.  We'll go into just when this "no holds barred" presidential order is issued in a future installment on exactly how much vitamin D is adequate (that's a whole 'nother can of worms).  In addition to maintaining healthy bones, vitamin D also plays a role in insulin secretion, muscle health, metabolism, immunity, and blood pressure regulation.  Bottom line: it earns it's title as Essential.

An additional benefit of vitamin D is that it protects against cancer.  Vitamin D increases cellular differentiation, the specialization of cells to their specific functions, at the cost of decreasing cellular proliferation, the creation of new cells.  How does this relate to cancer?  Well, the chances of error (mutation) increase the more copies are made of any one thing.  Ever play the Telephone Game?  Then, you know of what I speak.  Cell proliferation increases the chance of mutation, thus, the formation of cancerous cells, a possible outcome of mutation.  Proliferation also makes matters worse once cancer cells are formed because it rapidly spreads them.  So the more vitamin D, the better your chance not to develop or to spread cancerous cells (to a point--we'll discuss toxicity concerns another day).  Interested in more about vitamin D's protective role?  Free the Animal summarized an incredible study on the Dose-Response of Vitamin D and a Mechanism for Prevention of Cancer.  Check out the charts to visualize it.

Without adequate vitamin D, infants and children can develop rickets, a bone growth impairment leading to deformity (softened bones bow out during development).  Surprisingly, even with vitamin D fortification of foods, rickets is still being reported in cities.  That is why our next section is so critical.  Other signs of deficiency are increased fractures, bone pain, and muscle pain and weakness.  Sounds fun!

Where Do You Get Vitamin D?

There are three main places to get vitamin D when you live paleo-style: one is through your skin, another through your food, and the third is through supplementation.  I would rather get my vitamin D from my skin and from whole foods, but there is debate about whether the sun or whole foods can supply us with the amount we need, thus, the need for supplementation.  Of course, if you eat processed foods, many are fortified with the vitamins and minerals you need despite the fact that the are ALSO full of everything you do NOT need, like ubiquitous grains, vegetable oils, sugars, and chemicals.  You can't make up for nutrient-poor foods, their constituent parts striped of any nutritional value during refining, by pumping them full of refined vitamins and minerals.  Processed foods do NOT do a body good.  In our evolutionary past, eating vitamin D-rich foods and spending ample time exposed to the sun allowed us to get what we needed, but in today's 9-5 world, getting sun is limited, and getting it from whole foods is difficult, if not impossible.

From The Sun

So how does your body synthesize vitamin D?  The ultraviolet radiation from the sun hits your skin in two main wavelengths: UVA and UVB (there is a third wavelength, UVC, that is mostly absorbed by the ozone and is actually given off by artificial lighting like fluorescent and halogen bulbs, so be wary).  UVA is the kind that penetrates into deep skin layers and creates free radicals.  According to the Weston Price Foundation's The Miracle of Vitamin D article, UVA leads to tanning, but not burning unless excessive, while UVB readily leads to burning (which is a flush of blood to the surface of the skin to repair damaged cells).  UVB also provides the necessary cue for our skin's production of vitamin D, but it too is harmful and can cause skin damage.

So how is vitamin D actually made?  UVB rays activate vitamin D synthesis by turning a certain cholesterol in our skin cells into cholecalciferol, or vitamin D3 (See? ALL cholesterol is NOT bad!  We make and need our own!).  Since the vitamin D needs to be absorbed from the oils on the surface of your skin, you shouldn't bathe or swim within one hour of sun exposure if you are trying to get your vitamin D primarily from the sun.  Thus, you need UVB to synthesize vitamin D in your skin, but not too much that you damage cells and increase your risk of skin cancer.  Talk about a balancing act!

What could make this even worse?  How about not only do you have to be careful not to burn, but the amount of vitamin D you can synthesize from the sun varies tremendously by time of day, time of year, latitude, age, skin exposure and duration, and skin color?  Let me explain.
  • Time of Day
UVB (the one leading to vitamin D AND sunburn AND skin cancer) is most intense at midday, but UVA (the tanning one that also contributes to skin cancer) is equally intense throughout the day--and both are even present on light cloudy days (hence my mom always telling me to wear sunscreen even when it's cloudy, which I thought was just being mean.  I think parents get a perverse enjoyment out of slathering sunscreen on wiggly children who pucker their faces with annoyance and can't believe the audacity of their parents to delay their play.  It's a ritual.).  So you have to get your vitamin D from sunbathing at midday, the time that ALSO puts you at the most risk.  Great.
  • Latitude and Time of Year
The further you are from equatorial regions, the less intense the UVB rays.  You need a UV index of 3 or more to kickstart your vitamin D synthesis, and while that is daily in the tropics, it's only daily in the the spring and summer in temperate regions, and almost never in the arctic.  According to Weston Price Foundation's article on The Miracle of Vitamin D:
Latitude and altitude determine the intensity of UV light. UV-B is stronger at higher altitudes. Latitudes higher than 30° (both north and south) have insufficient UV-B sunlight two to six months of the year, even at midday. Latitudes higher than 40° have insufficient sunlight to achieve optimum levels of D during six to eight months of the year. In much of the US, which is between 30° and 45° latitude, six months or more during each year have insufficient UV-B sunlight to produce optimal D levels. In far northern or southern locations, latitudes 45° and higher, even summer sun is too weak to provide optimum levels of vitamin D. 
  • Age
The older you are, the less efficient your vitamin D synthesis, so you need to stay in the sun longer to generate vitamin D.  But older skin is also more susceptible to burning, so it's a wash.
  • Skin Exposure and Duration
Weston Price Foundation's article on The Miracle of Vitamin D says that the current prescription of 10 minutes of midday sun exposure a day is not enough.  And remember, you can't wash your skin, bathe, or swim for at least an hour if you want to absorb that vitamin D.  
The current suggested exposure of hands, face and arms for 10-20 minutes, three times a week, provides only 200-400 IU of vitamin D each time or an average of 100-200 IU per day during the summer months. In order to achieve optimal levels of vitamin D, 85 percent of body surface needs exposure to prime midday sun. (About 100-200 IU of vitamin D is produced for each 5 percent of body surface exposed, we want 4,000 iu.) Light skinned people need 10-20 minutes of exposure while dark skinned people need 90-120 minutes.
  • Skin Color
 The lighter your pigmentation, the more quickly you'll burn.  We'll discuss this more in our final chapter:

Hey Chorles?  

Okay, Chucky D, so if the sun KILLS us, how the hell did we survive this long?  If it is that dangerous, wouldn't our ancestors all have had skin cancer and never have survived?  The evolutionary answer is skin pigmentation.  Melanin, the pigment in the skin, protects us by absorbing UV rays and disbursing them as harmless heat.  The more melanin, the darker the skin, and the more UV protection.  However, this UV protection comes at the cost of less vitamin D synthesis since it relies upon those UV rays to kickstart the process.  Accordingly, the distribution of skin pigmentation before modern transportation generally followed latitude: darker where the sun is brighter to protect the skin from the more intense rays, lighter where the sun is less bright and more intermittent, so that any sun exposure can get vitamin D synthesis activated post-haste.  Tanning is a second defense and one that depends on environmental cues.  It can be both adaptive and detrimental.  When UV rays damage your skin, they trigger more production of melanin to protect it from further assault.  So while it is a good thing to have more melanin to protect your skin if you are often out in the sun, also keep in mind that tanning shows damage already done and slows vitamin D synthesis, since the melanin is absorbing the UV before it can activate vitamin D synthesis.  See, even the biological world lives in shades of grey and defies a good/bad dichotomy.     

It's a trade-off: the evolution of darker skin pigmentation around equatorial regions allowed for more sun exposure before burning, but resulted in slower vitamin D production and required longer duration of exposure.  And vice versa: lighter skin pigmentation evolved farther from the equator to allow for quick vitamin D synthesis where there was reduced solar intensity, but came with the cost of greater susceptibility to sunburn.  You're damned if you do and if you don't.  Interestingly, there are a few exceptions to the generality, such as the Eskimo, who have darker skin than expected at such a sunlight-poor latitude.  How were they not vitamin D deficient?  Fish.  They ate lots of fish, which have the vitamin D they needed to survive.  

While skin pigment gradation by latitude was once useful, since we have migrated, it has become an issue.  Today, those with darker pigmentation are more likely to be vitamin D deficient without ample sun exposure, which is difficult to achieve at any latitude in today's working 9-5 world.  Between melanin levels, all the factors associated with sun exposure, and our prodigious use of sunscreen, it is highly unlikely that we are meeting our vitamin D needs through the sun alone.

All of these confounding factors add up, which is why many are deficient even in sun-soaked regions.  This study from sunny Florida, and this one from Hawaii show that even where there is adequate sunlight, people are still deficient.  So we're still left with the question: where can we get the vitamin D we need?

And that, my friends, is a tale for another day.  This story is NOT over yet!

Here is our next installment: Sunshine of Your Love Part 3: What is e-D-ible?


General references used extensively:
Micronutrient Information Center at the Linus Pauling Institute of Oregon State University
The World's Healthiest Foods: Vitamin D
Weston Price Foundation's article: The Miracle of Vitamin D
The Vitamin D Council, especially vitamin D physiology
Ultraviolet Radiation from The University of Minnesota School of Public Health
Wikipedia entries on Vitamin D and Melanin and Ultraviolet

Thursday, May 13, 2010

Sunshine of Your Love Part 1: Safely Getting What You Need

The sun is here again, hopefully to stay.  My cats, eternal sun worshipers, show their devotion as they migrate room to room chasing its rays throughout the day.  Nothing quite mimics that swaddling warmth of the sun.

A la Monty Python and the Holy Grail: "Winter changed into spring, spring changed into summer, summer changed back into winter, and winter gave spring and summer a miss and went straight on into autumn... until one day... " the sun came back and Summer-Spring was here.  The days are sunny and warm flitting back and forth between spring chilly and summer hot.  And with the sun comes CANCER, or so I have been taught.

Okay, knee-deep in research and trying to craft a post scrolling out to book length, I decided to attack this topic in parts.  One part is NEVER enough to say what I want to say and really educate you or my own self about nutrition issues as important as this.  So I'll save you the reading and try to make this as user-friendly and as concise as possible.

Today, let's give the meat: what you need to do to protect yourself from CANCER while still getting what you need, precious vitamin D, a vitamin-hormone essential to your inner workings and protective against cancer.  I'll go into specifics another day, but suffices to say it's IMPORTANT STUFF.  Even if cancer doesn't fall from the sky, those pesky cancer-causing UV rays do, who on one hand they activate your skin cells to synthesize vitamin D while on the other they damage your DNA, which spawns its own two hands: on one DNA damage causes your skin cells to produce more protective melanin to absorb the harmful UV and on the other hand it produces free radicals and oxidative damage that increases risk of cancer.  So as this four-armed creature we've created illustrates, it's complicated.

But I am really curious about what I should do about all this, as I imagine you are too unless you know everything about everything.

From my research, here are my friendly suggestions (and remember I am no Nurse Jane Fuzzy Wuzzy, so this is just my two cents):
take 5,000 IU per day for 2–3 months, then obtain a 25-hydroxyvitamin D test. Adjust your dosage so that blood levels are between 50–80 ng/mL (or 125–200 nM/L) year-round.
  • Find "natural" sunscreens that DON'T contain these harmful (if not toxic) chemicals:  
octyl methoxycinnamate (OMC)
butyl methoxydibenzoylmethane
para amino benzoic acid
octyl salicyclate
padimate O
menthyl anthranilate
trolamine salicyclate
titanium dioxide  
4-Aminobenzoic acid (also known as para-aminobenzoic acid or PABA) 
  • Use sunscreen with zinc oxide, which seems like a safe ingredient.  Rules: Apply 15-30 minutes before sun exposure, then reapply after 15-30 minutes of sun exposure.  Afterwards, only reapply as needed due to sweating, swimming, rubbing it off.  
  • If you do have to use commercial sunscreen, wash it off with soap as soon as possible after sun exposure.  The chemicals can leach into your skin and produce free radicals with exposure to the sun.  So, in fact, the sunscreen supposedly protecting you from skin cancer can actually lead to skin cancer itself.  Great!
  • If trying to synthesize vitamin D from the midday sun: expose as much of your skin as possible.   Cover up your skin after you've had only enough exposure to turn pink (NOT red).  And DON'T wash your skin or go swimming until at least an hour after exposure to absorb the vitamin D.  DON'T rely on this as the only way to get your vitamin D unless you validate that assumption with a vitamin D test.  Note: the UVB rays you need to synthesize vitamin D are most intense at midday and vary by time of year and latitude, so don't go sunbathing at 8am in the winter and expect to get your vitamin D!
  • Avoid overexposure during the midday sun.  Even with "protection" this is dancing-around-in-your-underwear-and-pink-dress-shirt kind of Risky Business.  While some types of skin cancer are clearly blocked by UVB-blocking sunscreen, melanoma (the Big Bad) confounds researchers by showing up in those who have used adequate sunscreen or who avoid UVB rays.  Even "broad spectrum" sunscreen may not block enough.  
  • Use high SPF and follow the directions for recommended amount.  SPF provides a multiplier for how much time it takes you to burn.  Me?  I'm a zero to 15 sort of girl ;) so I shoot for high numbers and usually try to find baby sunscreen that won't sting in my eyes and is supposedly more "gentle."  You'll be happy to know that many paleo/primal eaters (like this one) have seen an increase in the time it takes them to burn now that they are on clean fuel.  According to Mark's Daily Apple, the difference between SPF diminishes with higher numbers so that while an SPF of 30 is blocking 96.7% of UVB radiation, an SPF 50 is blocking 98% and an SPF 100 is blocking 99% (so keep that in mind when you price-shop).  And if you don't apply the required amount, you don't get the protection: using half of what is recommended does not mean you get half the protection--in fact you get much less.  In reality, there are so many factors to take into account that the higher the better (to a point), but don't bank on that number actually panning out.   
  • Eat plenty of veggies (and some fruit is okay too, especially berries) for antioxidants that decrease free radicals and their damage.  Specifically, there is evidence of carotenoids protecting against sunburn, especially with vitamin E (found in nuts).  
  • For dietary sources of vitamin D, eat plenty of fish, especially oily fish and salt water fish.  Eat whole eggs--the vitamin D (along with all the other nutrients) are in the yolk.  If your diet includes dairy, enjoy full fat dairy from pastured, grass-fed animals--preferably raw. 
  • Take a vitamin D3 supplement from an animal source (NO D2 is NOT the same thing and you can't get D3 from a vegan source) and have it with fat.  How much D3 do you need to take?  Get tested (and see our first bullet point).  One caveat, and one I am wrestling with myself, is that we are trying to get away from processed foods and supplementation introduces another processed food into our diet.  Is it a necessary evil?  Looks like you can get vitamin D3 from fish oil and from sheep's wool.  Either way it is processed and unfortunately my fish oil brand doesn't tell me the vitamin D content, so I use a separate D3 supplement from sheep's wool.  An article entitled "Vitamin D and Milk" by Professor Norman at UC Riverside (emphasis mine) explains the production process:
The commercial production of vitamin D3 is completely dependent on the availability of either 7-dehydrocholesterol or cholesterol. 7-Dehydrocholesterol can be obtained via organic solvent extraction of animal skins (cow, pig or sheep) followed by an extensive purification. Cholesterol typically is extracted from the lanolin of sheep wool and after thorough purification and crystallization can be converted via a laborious chemical synthesis into 7-dehydrocholesterol. It should be appreciated that once chemically pure, crystalline 7-dehydrocholesterol has been obtained, it is impossible to use any chemical or biological tests or procedures to determine the original source (sheep lanolin, pig skin, cow skin, etc.) of the cholesterol or 7-dehydrocholesterol.
Next the crystalline 7-dehydrocholesterol is dissolved in an organic solvent and irradiated with ultraviolet light to carry out the transformation (similar to that which occurs in human and animal skin) to produce vitamin D3. This vitamin D3 is then purified and crystallized further before it is formulated for use in dairy milk and animal feed supplementation. The exact details of the chemical conversion of cholesterol to 7-dehydrocholesterol and the method of large-scale ultraviolet light conversion into vitamin D3 and subsequent purification are closely held topics for which there have been many patents issued (2).
So there you have it.  Nice and neat.  This discussion is not over, but I encourage you to ask if you have questions and seek out more information through the links given above and below.  Happy sunshining!

Resources used: 
Dr. Mercola's sunscreen information (NOTE: he is trying to sell sunscreen and bug spray, so there is definitely a "pitch," but I tried to fact check everything I used.)
Weston Price Foundation's The Miracle of Vitamin D article

Wednesday, May 5, 2010

The Study Everyone Talks About: Part 2: The Ravaging Reviews

The China Study

Yes, you have heard of it before.

Here is our first post about it: The Study Everyone Talks About Part 1: Correlation is NOT Causation

Quick review: The China Study spearheaded by Dr. T. Colin Campbell incorporates meta-analysis from studies on 65 counties in China and 8000 statistically significant correlations to conclude that animal-based diets lead to more chronic disease than plant-based diets.  Thus, the authors conclude that people should be vegans.

My Intent

My intent is NOT to review The China Study.  That has been done sufficiently by many before me.  My intent is NOT to provide a balanced sampling of reviews.  That would be exhausting to both of us.  My intent is to present an online literature review of the arguments against The China Study.  I want to be able to confidently talk about why I DON'T believe the book is a convincing argument to give up meat and become a vegan.  Thus, I am looking into the arguments critically analyzing the book for my own personal benefit and highlighting them for your perusal.  My intent is to be a resource for your conversations about The China Study and provide a stepping stone for further research into these sources.

Last time in Part 1 we talked about how correlation does NOT mean causation, a topic that The China Study addresses and warns against, but ultimately commits itself when leaping from correlation to generalization (an animal protein-based diet leads to disease) and dietary prescription (recommendation of a vegan diet).  Don't get me wrong: While it is very useful to look at commonalities amongst those inflicted with a medical malady, not everything that correlates is meaningful or stands up to further testing.  And further testing is the NECESSARY next step to validate hypotheses gathered from the correlations.  It is that leap from correlation to dietary prescription without testing and validation that provides the fatal hiccup for The China Study.    

So what are the arguments against The China Study?

Wow, where to begin?  I am going to make this a two-parter since there is a lot to digest and I think it is worth digesting every morsel so that you have a foundation to draw upon next time someone pops the question to you, "So what about that China Study I've heard so much about?" Today, we'll discuss main flaws (lumped by topic) and leave the deficiencies of the vegan dietary prescription for another day.  Okay, let's dive in!

The Study Itself

One of the prominent reviewers of the The China Study is Chris Masterjohn, a writer and PhD student whose review was published in the quarterly journal of The Weston A. Price Foundation and sparked an animated discourse between The China Study author T. Colin Campbell and the reviewer.  Masterjohn exposes some limitations of the original China Study, the study that provides the basis for the book (which is named after the study).  The data collection occurred over 3 days in the autumn of 1983 and canvassed 65 rural counties, considered 367 variables, and included 6,500 individuals.  Why these people?  Their genetic background was very similar, yet their rate of disease showed significant variation.  Something was up.  Despite the large data collection, Masterjohn exposes some key limitations of this study including:
  • Timing: The research was conducted over three days in the autumn of 1983, so data on the health and diet of the population as well as foods consumed at different times of year, were not taken into account.
  • Blood samples: The blood samples were pooled by village instead of individually tested.  
  • Disconnected data: Mortality rates were taken years before, from 1973-75.  Upon further investigation, Masterjohn found that these rates conflicted with household questionnaire data in regard to animal-protein consumption and cancer rate.  Higher animal protein consumption did NOT lead to higher cancer mortality, in contrast to the questionnaire results.  Yearly meat intake did NOT yield statistically significant correlations by government statistics or questionnaire.  
  • Standardization: Nutrients from foods were determined from standard tables rather than by testing the food itself.  This limits variability in environment, such as soil quality affecting minerals in the food.  
  • Data Collection: Questionnaires were used that limited the breadth of animal foods in the diet.  For example, "fish and sea food" lumped fish and shellfish--two foods with very different nutrient profiles, and "meat" included poultry, beef, pork, etc.  
Also read Campbell's rebuttal to Masterjohn's review and Masterjohn's subsequent response.  

A review aptly named The China Study by Harriet Hall, MD, a retired family physician and one of the founders of Science-Based Medicine blog, further highlights limitations of the study to include:
  • Age Range: Only adults 35-64 were considered because death certificates for those older than 64 were considered "unreliable."  
Another researcher, a PhD assistant professor at The University of Economics in Romania, named Claudiu Herteliu published a book review of The China Study.  His critique of the methods include:
  • The samples of rural Chinese villages and villagers: were they random?  If not, conclusions about the greater rural Chinese population are at risk.  
  • The pooling of samples, which can lead to problems since assumptions about similarity were NOT proven.  If data is pooled, then conclusions about individual diet and behavior can NOT be substantiated.  Even amongst a rural village, genetic and behavioral inheritance is NOT identical. 
Finally, there are the correlations themselves that lead Campbell to make conclusions and dietary prescriptions.  An article entitled Comparative Anatomy and Physiology Brought Up to Date: Are Humans Natural Frugivores/Vegetarians or Ominvores/Faunivores? by Tom Billings posted at Beyond Vegetarianism also critiques The China Study.  The limitations it proposes include:
  • only 65 observations taken, excluding hundreds of variables, which is not exhaustive and leads to statistical limitations
  • geographical limitations to correlations and to applying these results to other populations and cultures around the world
  • lack of correlations supporting their conclusions:
The China Study report lists only 6 statistically significant correlations between meat-eating and disease mortality. Further, 4 of the correlations are negative, which indicates that the mortality rate for that disease decreased as meat consumption increased. The two diseases that had positive correlations with meat consumption are schistosomiasis, a parasite, and pneumoconiosis and dust disease.
  • that hypotheses generated require clinical testing to validate them--they cannot lead to conclusions or dietary recommendations, especially jumping from group observations to individual dietary prescriptions 
  • the lack of income data, which makes adjustment for the effect of income less reliable--and income would have a close association to degree of Westernization 
  • that NO villages surveyed were actually vegetarian or vegan since the average percentage of energy intake from animal foods ranged from 1-59%
Denise Minger also systematically addresses Campbell's claims with an exhaustive review of his work.  Her critique: The China Study: Fact or Fallacy? lit a fire in the online community and it is well worth the read.  Here is a snippet:
On page 106 of his book, Campbell makes a statement I wholeheartedly agree with:
"Everything in food works together to create health or disease. The more we think that a single chemical characterizes a whole food, the more we stray into idiocy."
It seems ironic that Campbell censures reductionism in nutritional science, yet uses that very reductionism to condemn an entire class of foods (animal products) based on the behavior of one substance in isolation (casein).
In sum, “The China Study” is a compelling collection of carefully chosen data. Unfortunately for both health seekers and the scientific community, Campbell appears to exclude relevant information when it indicts plant foods as causative of disease, or when it shows potential benefits for animal products. This presents readers with a strongly misleading interpretation of the original China Study data, as well as a slanted perspective of nutritional research from other arenas (including some that Campbell himself conducted).
Also read: Cambell's rebuttal to her critique and Minger's response.

Author T. Colin Campbell makes it clear that the China Study itself isn't the only source of his conclusions.  He also uses his own laboratory research and that of others and various clinical studies on a vegetarian-style diet.  Masterjohn takes those other studies to task in his response to Campbell's rebuttal of his original review.  He believes the picking and choosing of which research to include and which to exclude is meaningful and limits the conclusions that can be drawn.  We'll discuss this more below.

Okay, want a snapshot of that "other research" from which Campbell based his conclusions?  Take Dr. Michael Eades's recent commentary: The China Study vs the China study.  It's a proverbial nail in coffin.  The main idea here is "obfuscation."
In fact, in my studied opinion, The China Study is a masterpiece of obfuscation.
It is obfuscatory in so many ways it could truly qualify as a work of obfuscatory genius. It would be difficult for a mere mortal to pen so much confusion, ambiguity, distortion and misunderstanding in what is basically a book-length argument for a personal opinion masquerading as hard science.
In his dissection of key research on animal protein versus plant protein, Dr. Eades found some serious flaws.  For one, the key research uses rats not humans and that fact is not made plainly clear to the reader.  For another, those rats are bred to be very susceptible to cancer, so slight changes in diet can definitely precipitate the desired effect.  For another and another, rats are not humans and they have evolved to withstand plant protein better than animal protein since it is their natural diet.  And the worst part?  The flaws, obfuscation, and misrepresentation are not isolated in The China Study, in fact they are the trend.

Lacking Evidence for the Prescribed Diet 

Setting aside the fact that The China Study authors jumped from correlation to dietary prescription, what is unsettling is that the prescribed diet was NOT followed by any of the groups studied.  While rural Chinese that had a low animal protein diet were concluded to be healthier (keep reading for more on this below), NONE had zero animal protein or followed the vegetarian or vegan approach prescribed by the authors.  Chris Masterjohn in his response to Campbell's rebuttal to his original review addresses the problem of quality in a diet devoid of animal products.  He makes the claim that even just 2% of the diet consisting of animal protein can have health benefits from the nutrient-, vitamin-, and mineral-dense animal foods.  Populations utilizing a small percentage of animal protein in their diets seek out the most beneficial sources, such as shellfish--which in the China Study were obscured by their categorization with fish.

If you look beyond the China Study itself, the clinical trials the authors cite as evidence of the efficacy of the vegan diet do not wholeheartedly endorse this dietary prescription.  Masterjohn shows that only two of the clinical trials actually tested a vegan diet; however, he only describes one in which no control groups were used and results are confounded by weight loss and scope of research (only looking at arthritis, which did improve).  The vegetarian diet clinical trial was confounded by dropout rate, lack of participation at the end, and simultaneous use of cholesterol-lowering drugs.

Another study cited in The China Study as evidence against a high protein diet was Dr. Lester Morrison's heart disease trial.  However, as Anthony Colpo author of The Great Cholesterol Conwho reviewed the study too found: according to Morrison, himself, the study was "high-protein, low-fat" and included protein greater than the RDA that included meat and dairy.  What was the result of the study?  A reduction in heart attack reoccurrence as compared with the control group.

Missing or Flawed Mechanisms

Dr. T. Colin Campbell writes that a mechanism is necessary to link correlations to causation.  For example, he says that even though telephone poles correlate with heart disease (in countries where there are more telephone poles, there is more incidence of heart disease) there is no mechanism to explain the correlation (they are two entirely different things), whereas the correlation between smoking and lung cancer is meaningful since there is a biological mechanism visible: smoke damages lung tissue, and damaged cells are more likely to become cancerous.  (see page 41 of The China Study)

Despite the need for a mechanism, Campbell links animal-based diet to diabetes without explanation, according to Dianne Cowan at The Migraineur in her review of The China Study.  She expresses frustration at this slip:
So, there might be a correlation between animal product consumption and diabetes, but without that mechanism, it’s gonna be hard to show causation.
Meanwhile, there is also a correlation between carbohydrate consumption and diabetes, and there is a mechanism that explains it:  carbohydrate consumption leads to an insulin response; excessive carbs mean excessive insulin; after a while the insulin receptors in the cell wear out, leading to higher blood sugar; pancreatic beta cells try to compensate by producing more insulin, while at the same time, chronic high blood sugar causes more beta cells to die.  Where does excessive consumption of protein and fat fit into all this?
Chris Masterjohn (discussed above) has difficulty finding the biological connection between diet and cancer in his response to Campbell's rebuttal of his original review.  In The China Study, the authors state,
We measured six blood biomarkers that are associated with animal protein intake. Do they confirm the finding that animal protein intake is associated with cancer in families? Absolutely. Every single animal protein-related blood biomarker is significantly associated with the amount of cancer in a family.
However, Masterjohn looked into this claim and found some problems.  Of the six biomarkers associated with animal protein intake only plasma copper is actually associated with cancer and with animal protein intake, but not at the exclusion of plant consumption, since vegetarians have MORE copper in their diets than meat-eaters.  Thus, a critical connection of animal protein to cancer is lost.

According to wikipedia, The China Study authors do cite mechanisms to support their conclusions against animal protein.  For example, they base their argument of animal protein leading to Western diseases upon the association of dietary animal protein with high cholesterol and high cholesterol and disease, or the Lipid Hypothesis.  Unfortunately, the Lipid Hypotheses has been discredited because there is not enough evidence (see Weston Price Foundation: The Skinny on Fats) to link a diet rich in saturated fat and/or animal protein with heart disease or high cholesterol with heart disease, since it is the particle size of LDL and the triglycerides that have the strongest association with disease (see this research review).  A ketogenic diet with low carb and high fat and high animal protein actually lowers small, dense LDL that do lead to heart disease (see these studies: Journal of Nutrition, International Journal of Cardiology, etc.).

Other mechanisms The China Study draws upon to support their conclusions include:
  • the antioxidants in plants as counteracting harmful free radicals to protect from disease.  While true, the fact that many plants also introduce harmful elements to the body like lectins, gluten, and antinutrients do NOT make plants a health boon.  See The Paleo Diet's discussion of grains and legumes for more information on how plants can harm rather than nourish.  
  • animal protein pushes growth, which can promote the growth of disease.  This is good and bad.  Growth is obviously beneficial to the growth and maintenance of living beings, but can get out of control with growth and spread of disease.  Valid point, but plants are also at the root of inflammation (see Cooling Inflammation and Mark's Daily Apple for a current series on gut health) and their carbohydrates pave a path to heart disease, obesity, and diabetes (see The Heart Scan Blog).  Heck, sugar feeds cancer!  So excuse me if I am NOT convinced of the animal protein-cancer link (which I also discussed in my Starter Series: Eat meat.)  To me, it looks like plants are doing much more damage than animal-based foods.   
  • the acid-base balance is given as a mechanism to reduce animal protein since it is acidic and tips our scale toward the acid side, which results in leaching calcium from our bones (osteoporosis), which then sets up more problems due to the roaming calcium in our blood.  My counter: grains are acidic too and don't come with the benefit of omega-3 fatty acids, vitamins, minerals, or nutrients in such density as in grass-fed, wild-caught,  or pastured meat.  For more, see Dr. Cordain's Cereal Grains: Humanity's Double Edged Sword and Acid-Base Balance from the Paleo Diet website.      

Correlation with Disease: Is it the animal-based protein or other accoutrements of a Western diet? 

While there is NO argument with a Western diet leading to greater incidence of disease, the cause of that increased risk is debatable.

Journalist Gary Taubes, author of Good Calories, Bad Calories, has tackled The China Study, courtesy of a question-answer session at Dr. Eades's blog.  His take?  It's the sugar.  High-carb or low-carb, high-fat or low-fat, the variable we should be looking at is sugar: refined carbohydrate.  He says that sugar was the lowest quantity food item ("sugar consumption wasn't even measured in the study since it was so low") in the The China Study; thus, lack of sugar is the key to their health and that of many rural/traditional peoples. 

Anthony Colpo author of The Great Cholesterol Con reviewed the study, too.  He found fault with Campbell's attack of all animal-based protein.  Campbell saw that children in the Philippines on a Western diet had higher rate of liver cancer.  He also saw that rats fed casein, a protein in dairy products, got cancer.  Putting two and two together, he concluded animal-based protein leads to cancer.  Unfortunately, Colpo explains, dairy products have two proteins: casein and whey.  While casein did cause cancer, whey had the opposite effect, improving the health of rats fed whey protein.  Colpo continues his review by detailing potential deficiencies for a vegan diet and goes back to the original China Study to review the data and find correlations.  Notably, he found that wheat and wheat flour were associated with a significantly higher risk of coronary heart disease, although these were never mentioned by Campbell.  Here are some other correlations based on the original research:
Animal protein, fish protein, meat intake, saturated fat, and fat calories were all negatively associated with all-cause mortality in infants, children, teenagers and adults, although none of the associations reached statistical significance (for those unfamiliar with research-speak, a negative correlation means that as intake of these foods increased, mortality risk decreased; failure to reach statistical significance means that researchers can't be sure these findings were not due to chance).
No statistically significant relationships, protective or otherwise, were found for milk intake, fiber, cereal grains, legumes, and vegetables among those aged 0-64.
The only other dietary factor that was significantly associated with overall mortality among those aged 0-64 was soy sauce (not soy products), which showed a 43% decrease in mortality risk (p=0.001).
With regards to specific types of cancer, no statistically significant associations were observed for total protein, animal protein, fish protein, meat intake, milk intake, saturated fat, total fat, fiber, cereal grains, legumes, vegetables and mortality from colorectal or breast cancers.
Heart disease?
No statistically significant associations were observed for total protein, animal protein, fish protein, meat intake, milk intake, saturated fat, total fat, fiber, legumes, and mortality from coronary heart disease.
Here is what another researcher, Chris Masterjohn whom we introduced above, looking into that study DID find:
It is interesting to see, however, the general picture that emerges. Sugar, soluble carbohydrates, and fiber all have correlations with cancer mortality about seven times the magnitude of that with animal protein, and total fat and fat as a percentage of calories were both negatively correlated with cancer mortality.
The only statistically significant association between intake of a macronutrient and cancer mortality was a large protective effect of total oil and fat intake as measured on the questionnaire. As an interesting aside, there was a highly significant negative correlation between cancer mortality and home-made cigarettes! 
Dr. Hall, cited above from Science-Based Medicine, found contradictions with Campbell's research as well.  In her review, she cites a few PubMed articles attributing the health of vegetarians to their consumption of fruit and vegetables, not the exclusion of animal protein.  Dr. Lawrence Wilson in his review comes to the same conclusions.  He also highlights factual errors in the book, most already discussed.  For example, the authors assert that vitamin D deficiency arises from too much protein and dairy in the diet (Wilson says he was unable to find any study supporting this statement) and that all vitamin D needs can be met by the sun (the deficiency of those even living in sunlight-drenched areas like Florida runs contrary).  Similarly, Tom Billings, author of an article cited above that detailed The China Study limitations also presents evidence of no significant difference in most cancer rates amongst vegetarians and non-vegetarians, referencing a study by Key et al. 1998.  One thing is for certain: there are no clear cut associations here.

Robb Wolf, nutrition guru and strong proponent of the Paleo Diet, tackled The China Study with this post: Heard of T. Colin Campbell?  He discusses a debate he spearheaded between Campbell and Loren Cordain, The Paleo Diet author.  We'll discuss that in Further Resources below.  An important point that Robb Wolf brings up is the existence of paradoxes.  The premise of vegetarian or vegan diet as the healthiest diet has to hold up when compared to different societies and it deflates when given the Inuit Paradox.  The Inuit Paradox sees a disconnect with current nutritional advice to go low-fat and high-carbohydrate in order to lose weight and be healthy.  In fact, the Inuit did best on a high animal fat diet and did poorly when forced to subsist on lean protein as their energy source in an extreme environment that makes carbohydrate very scarce.  The Inuit did not have the trappings of modern dietary diseases like cancer, diabetes, or heart disease.  As with most (if not all?) aboriginal peoples, switching over to a Western Diet has brought disease and death, NOT prosperity, at least in health.  If the animal protein and fat if anything fell, how can they cause these diseases?  And the Inuit are not alone; there are many more paradoxes out there to discredit a vegetarian diet (ex. French, Masai, Spanish, etc.).

Bottom line: high fat, including animal fat, is actually beneficial!  Surprise, surprise!  We addressed this in the past with the posts Saturated with Fat, Fatphobia, and Starter Series Part 3: Eat Fat.  The healthy fats are monounsaturated, saturated, and omega-3 fatty acids (you also need omega-6, but we want to minimize it and maximize omega-3, read the cited posts for more information).  Now, you can get monounsaturated and even saturated fat from plants like avocados, olive oil, and coconut oil.  The plant world can cover those, but what about the essential omega-3 fatty acids?  We need  to consume animals, especially fish and their oils.  Sorry, but nuts and seeds just don't cut it since they come with the price of high omega-6 fatty acids or in flaxseed's case: disquieting phytoestrogens, rancidity, and possible links to prostate cancer (see Mark's Daily Apple).  You just aren't going to find the omega-3's outside of animal products in the forms our body needs most: EPA and DHA.  Even flaxseed requires conversion from ALA to DHA and EPA, which is inefficient.  So to get this metabolically healthy and heart-healthy high-fat diet, you need animal foods.  And if aboriginal people are getting sick when they Westernize their diet away from their high-fat and high-protein diets--that points the finger to something else nefarious, NOT the animal foods.

Saving the Best for Next Time
There are virtually no nutrients in animal-based foods that are not better provided by plants.
Yes, that was stated in The China Study, and yes, that is completely wrong.  Virtually does nothing to soften the blow of that unsubstantiated stupidity.  The fact is that vegetarians and vegans KNOW that their diet is deficient and seek out supplements to try to fix that.  It's not a secret.  I can understand that there are many reasons for one to follow a vegetarian/vegan diet, but "healthier than eating meat" is NOT a well-supported argument.  For now, let's just counter that statement with B-complex vitamins, zinc, and omega-3 essential fatty acids and we'll discuss this whopper another day.  It deserves our full attention and can easily stand alone, just like the cheese, Hi-Ho, the derry-o, the cheese stands alone.

To Summarize

1.  There are serious limitations to the original China Study on which the book is based.

2.  The prescribed vegan diet was NOT observed in the China Study itself, tested through the author's research, or convincingly elucidated through referenced clinical trials.

3.  There are missing or flawed mechanisms providing the integral connections to link animal protein to disease.  As such, it is NOT clear if animal protein actually does lead to disease or if vegetarian or vegan diets are, in fact, healthier.

4.  Westernized diets do lead to increased prevalence of disease, but blaming that on the consumption of animal foods is NOT supported by the research.

5.  A vegetarian diet, and especially vegan diet, is NOT the best source for nutrition.

Whew!  Done!  At least for now.  I leave you with some further resources to further feed your mind.

Further Resources

Here is a list of other resources that branch off from those already cited.  Each is worth a read for their contributions to the argument.

The Protein Debate
This is a spectacular debate between Loren Cordain, author of The Paleo Diet, and T. Colin Campbell, author of The China Study (just in case you totally missed that connection a hundred times earlier :)).  Although not specifically about The China Study, the two duke it out over its basic premise about dietary protein.  Cordain starts with his article: "The Evolutionary Basis for the Therapeutic Effects of High Protein Diets" in which he concludes:
The evolutionary evidence indicates that so called “high protein diets” (20 – 30 % total energy) and “very high protein diets” (30- 40 % total energy) actually represent the norm which conditioned the present day human genome over more than 2 million years of evolutionary experience. The evolutionary template would predict that human health and well being will suffer when dietary intakes fall outside this range. Hence the current U.S. consumption of protein (15 % total energy) may not optimally promote health and well being. There is now a large body of experimental evidence increasingly demonstrating that a higher intake of lean animal protein reduces the risk for cardiovascular disease, hypertension, dyslipidemia, obesity, insulin resistance, and osteoporosis while not impairing kidney function.
T. Colin Campbell turns the question of "how much protein" around to be how much excess is safe in his article: "How Much Protein Is Needed." Although he states that processed foods may confound or exacerbate the problems associated with animal protein, his conclusion:
My conclusion from these many observations is that animal protein, when added to diets already containing 10% protein, has the potential to promote the development of a wide variety of serious and oftentimes fatal diseases—not only because of the direct effects of protein but also because of the many parallel effects of companion nutrient imbalances created by animal-based foods simply to get access to the extra protein. I find that 10% total dietary protein, which has been long recommended by multiple policy committees and acknowledged in scientific reviews, is not only adequate but also is relatively devoid of risk of serious diseases and other ailments. It just so happens that 10% dietary protein is the same level that is typically found in a diet of varied whole plant-based foods. Increasing dietary protein above this 10% level generally means adding or substituting animal-based foods for plant-based foods but doing so invites a plethora of adverse health effects. To be very clear, I believe that total dietary protein should be 10% of calories, with virtually all of it being in the form of plant-based protein.
In his rebuttal to Campbell's article, Cordain makes a key point:
As I have laboriously and meticulously lain out in my initial essay, there is no credible fossil, archeological, anthropological, anatomical, ethnographic or biochemical evidence to show that members of our genus (Homo) routinely consumed low protein diets. In fact, without the inclusion of energetically dense animal food into the hominin diet, starting at least 2.5 million years ago, our large energetically active brains would not have evolved (16, 34, 35). Accordingly, the fundamental logic underlying Colin’s hypothesis (that low protein diets improve human health) is untenable and inconsistent with the evolution of our own species.
For more gory details on debate, check out this review by a reader of Dr. Eades's website.  A key point:  In their respective articles, Cordain cites 134 references, while Campbell none.  Yes, you heard me: none.  If the wealth of research supports his viewpoint, why not make that abundantly clear by referencing at least some of it?

Other fun resources are:
  • Dr. Eades author of Protein Power critically digests another China Study where researchers decided to blame vegetable oil, not increased fruit and veggies, in making the Chinese obese.  The kicker: there is no statistical difference in the amount of vegetable oil used between those who ate the most carbs and those who ate the least.  What did obesity relate to?  The amount of carbs they were eating.  
Dr. Eades suggests that their higher carbohydrate intake (+10%) and higher calorie intake (+120 kcal/day) are responsible for the weight gain, but I wasn't satisfied with that explanation so I took a closer look.
One of the most striking elements of the 'vegetable-rich' food pattern is its replacement of rice with wheat flour. The 25% of the study population that adhered the least to the vegetable-rich food pattern ate 7.3 times more rice than wheat, whereas the 25% sticking most closely to the vegetable-rich pattern ate 1.2 times more wheat than rice! In other words, wheat flour had replaced rice as their single largest source of calories. This association was much stronger than the increase in vegetable consumption itself! 
  • A cool website called Opposing Views gives you plenty of brain food by providing both sides of the debate for/against vegetarianism with supporting articles.
Did I forget any important reviews opposing The China Study?  Please let me know!  Hopefully this post provides a helpful resource for you next time you encounter The Question!