Wednesday, July 28, 2010

What To Drink Part 2: What's Wrong with Milk?

Here is our second installment in the series: What To Drink
Read the first part here: What's Wrong With Juice?

Milk has been the norm for a child's meal-time beverage for quite some time.  I know in my family we ALL drank milk with dinner.  And since fatphobia was (and still is for the misinformed) still the rage, our milk was the lowest percentage of fat still palatable.  For me, that was 1%.  I always looked upon skim milk with disgust as being cloudy water, but respected those who could sacrifice their sense of taste to drink it.  Skim milk was hardcore.  But do adults really need milk?  Do kids really need milk?

This is a highly debated topic amongst the paleo/primal community.  For many, nutrition is like religion and dairy is one of the saints.  Personal stories take either side of the debate: some being healed by dairy (notice it is raw dairy), others eliminating it from their diets for even better health.  

Let's dive in. 

Can You Be Healthy WITHOUT Milk?

Since milk is a given for most families, let's play devil's advocate.  Does anyone really need milk?  The common argument is over calcium.  If I don't drink milk, can I get enough calcium?  Paleo dieters, the lactose intolerant, and others who withhold dairy from their diets need to get their calcium from other food sources (fish, shellfish, and leafy greens).  It also helps if they and don't muck up their digestive tract's absorption by consuming grains or legumes, which contain phytates that bind to minerals like calcium and which carry an acidic load that leads to calcium loss.  

Can you be healthy without milk?  Yes, even kids can be healthy without milk, following a paleo diet.  Here is Robb Wolf's analysis of the paleo diet for kids.  His conclusion?  It is definitely more healthy than following the USDA guidelines AND you get enough nutrients that it looks like you are taking a nutritional supplement; the recommended dietary allowances (RDA) are blown out of the water!  

However, you might have noticed that calcium is below the RDA.  Before this alarms you, read how Dr. Loren Cordain, author of The Paleo Diet, explains that here.  Basically, your absorption of calcium is improved when you have a healthy gut, so no worries and no need to drink milk.   Leafy greens like brassica plants (ex. kale) have calcium we can absorb better than milk, and a paleo diet keeps the acids and bases in balance so you aren't leaching calcium from your bones.  In fact, the high protein in a paleo diet increases calcium absorption and builds bone rather than breaking it down.  Finally, as a low glycemic diet, the paleo diet controls insulin levels thereby avoiding hyperinsulinemia (elevated insulin), which leads to urinary calcium loss.  

Cordain doesn't include dairy in his diet for numerous reasons, like the proteins most are allergic to, the inflammatory effect, the autoimmune disease risk, etc.  Here are the specifics from his blog's question and answer section:
  • Milk is a source of estrogens and dihydrotestosterone precursors, which can increase the risk of certain cancers and acne.
  • Milk increases IGF-1, and the IGF-1/IGFBP-3 ratio, and this increases the risk of certain cancers and acne--among other diseases--as explained by Dr. Cordain in his 2003 paper “Hyperinsulinemic diseases of civilization: more than just syndrome X” 
  • Milk contains insulin, and bovine insulin differs in only 3 amino acids from human insulin. This feature can increase the risk of Type 1 diabetes in genetically susceptible persons.
  • Betacellulin: is a hormone belonging to the EGF family of hormones. If it is confirmed that Betacellulin is able to enter circulation, then there is a very good possibility that it may increase the susceptibility of certain epithelial cancers.
  • Milk elevates insulin as much as white bread. Constantly elevating plasma insulin levels may lead to insulin resistance, which is at the root of several metabolic diseases such as obesity, type 2 diabetes or hypertension.
  • High calcium intake adversely affects zinc absorption, a key mineral in more than 300 enzymatic reactions.
  • Milk contains several allergenic proteins.
  • Dairy products, especially hard cheeses, yield a very high net acidic load which might lead to calcium and muscle loss and decrease growth hormone.
There's even more explanation here, also on his Paleo Diet Blog.  Here are the main points (see site for citations and much more depth):
1) Milk and fermented milk (yoghurt, for instance), despite having a low Glycemic Index and Load, elicit a very high insulin response and this has been shown repeatedly in intervention studies.   
2) Cow’s milk appears to be involved in certain Autoimmune diseases (AD):
  •  Type 1 Diabetes 
  • Multiple Sclerosis  
  • Rheumatoid Arthritis 
  • Crohn's disease 
  • Sjögren's syndrome 
  • IgA nephropathy 
  • Behçet's disease 
  • Celiac Disease. 
3) Hormones in Milk:  
Here’s a short list of some hormones present in cow’s milk that could be problematic for humans:
  • Insulin
  • IGF-1
  • Betacellulin (BTC)
  • Estrogens (particularly Estrone Sulfate)
  • Precursors of Dihydrotestosterone (DHT)
4) Milk has a very high calcium/magnesium ratio and may contribute to some micronutrient imbalances. 
Unfortunately, there is no comparison of Cordain's list of traits between raw milk and conventional pasteurized milk, so we don't know how much of a difference raw milk can make.  As you will read in our next installment, raw milk makes all the difference in the quality and potential nutrition of the milk. 

So now you know the argument against dairy.  Personally, I play with dairy in my diet, adding in quality sources and indulgences now and then, and I routinely use raw, grass-fed butter.  But I have tried the N=1 dose and response test after eliminating dairy from my diet, so I know my limitations and that I definitely do have a reaction to dairy, some forms more than others.  We'll talk more about that in our next installment, which answers the question: Can You Be Healthy WITH Milk?

Bottom line: You don't NEED milk to be healthy, even as a kid AS LONG AS you are eating your vegetables and a healthy, balanced diet of meat (and fat) and veggies (and some fruit).  How counter-culture is that?

Thursday, July 15, 2010

What To Drink Part 1: What's Wrong with Juice?

I'm taking a break from the D to discuss all the hubbub about drinks lately.  Have you heard it?  There's a soda tax being debated by politicians.  There's also a stink about flavored (Read: sweetened) milk served in schools and whether or not sports drinks are good for everyone, even after exercise.  Even kombucha has been pulled from the shelves in most supermarkets.  And is fruit juice really healthy like we all thought?  Let's start sipping this topic!

What's Wrong with Juice?

You have probably already read my post Just Say No...To Juice?, but if you haven't now's your chance.  Basically, the problem with juice is that it is too concentrated--you just can NOT eat enough fruit to get the equivalent amount of sugar that is in juice--you'd get sick!  And don't kid yourself, fructose is a sugar, just like high fructose corn syrup, just like table sugar, just like stevia.  They all set things in motion in your body that prepare it for the highly concentrated burst of energy your body knows comes with sweet foods.  It doesn't matter if they are "zero" calorie or low glycemic, sugar and its various forms set the fat storage switch to ON, storing excess carbohydrate as fat.  And unfortunately, fructose isn't like glucose; it doesn't precipitate a surge of insulin that triggers leptin (the hunger hormone) to tell your brain you are full.  From my previous post:
The short story: there is a deadly cycle of fructose leading to fat storage and telling your brain you are still hungry.  For example, fructose has the opposite effect of glucose on the hypothalamus section of the brain controlling feeding behavior.  While blood glucose levels are sensed by the brain and signal a secession to eating, fructose bypasses this metabolic step and actually promotes food intake to continue instead of signaling an end to eating.  
Even the USDA agrees that juice isn't all the "healthy" it's cracked up to be.  In their new guidelines (new and NOT improved, unfortunately) here is their conclusion (page D1-23+) about juice: 
Limited and inconsistent evidence suggests that for most children, intake of 100 percent fruit juice is not associated with increased adiposity, when consumed in amounts that are appropriate for age and energy needs of the child. However, intake of 100 percent juice has been prospectively associated with increased adiposity in children who are overweight or obese. 
Can you say wishy-washy?  But the message stands: juice isn't the best beverage for everyone.  Especially kids.  While their activity levels may be through the roof, it's still not enough to burn those excess calories juice provides.  Keep reading for more on exercise.

But isn't juice made for kids safe?  Isn't it made with their needs in mind?  No.  Check out the worst "kids drink" from The Most Harmful Drinks in America:

Tropicana Tropical Fruit Fury Twister (1 bottle, 20 fl oz)
340 calories
0 g fat
60 g sugars
Sugar Equivalent: Two 7-ounce canisters Reddi-wip
Don’t let Tropicana’s reputation for unadulterated OJ lead you to believe that the company is capable of doing no wrong. As a Pepsi subsidiary, it’s inevitable that they’ll occasionally delve into soda-like territory. The Twister line is just that: a drink with 10 percent juice and 90 percent sugar laced with a glut of artificial flavors and coloring. You could actually save 200 calories by choosing a can of Pepsi instead.
Drink This Instead!
Honest Kids Tropical Tango Punch (1 pouch, 6.75 fl oz)
40 calories
0 g fat
10 g sugars

Um, I think I'll go with water instead.  Thanks!  But scroll through that list of Most Harmful Drinks for some eye-opening beverages you probably once enjoyed too!

Here's more on Tropicana Twister:
Product Details:
Flavored Juice Beverage from Concentrate. With Fruit Force energy releasing B Vitamins! Contains 10% juice.
Filtered Water, High Fructose Corn Syrup, Apple Juice Concentrate, Grape Juice Concentrate, Citric Acid, Pineapple Juice Concentrate, Natural Flavors, Ascorbic Acid (Vitamin C), Pectin, Cherry Juice Concentrate, Sodium Citrate, Red 40, Niacin and Pantothenic Acid.
Not only do you have concentrated natural fructose but added high fructose corn syrup.  Can you say diabetes in a bottle?  Still think juice is healthy?  Okay, you're probably thinking 100% juice is a world away from fruit punches and juice drinks.  Is it really?  Let's look into it. 

Are Fruit and Juice Interchangeable?

No.  But the USDA thinks so.  In their Food Pyramid, one serving of fruit is one cup of fruit OR one cup of fruit juice.  Here is just a few reasons why this is bad:
  • The Sugar
We already discussed the sugar content of juice far exceeds that of whole fruit.  Would it surprise you that it also EXCEEDS that of SODA?  According to this chart from Hooked on Juice comparing 100% fruit juice to Coca-cola, apple juice, grape juice, and cherry juice all EXCEED the total teaspoons of sugar, total carbohydrate, and total calories of Coca-cola in the same 12oz serving (and OJ wasn't lagging far behind).  OMG, I have to say it again, it is so shocking: juice has more sugar than soda!
  • The Fat
But juice is zero fat, you say?  Once absorbed by your digestive tract, fructose goes to the liver, where it replenishes energy stores.  Any excess energy is converted into fat (don't kid yourself, you are NOT using all that energy).  Conversion of excess fructose into triglycerides elevates the fatty acids circulating in your blood, necessitating fat storage.   And fructose is more readily metabolized into fat than glucose, so it's the bad-est of the bad.  We also know that elevated triglycerides are associated with cardiovascular disease.  And you don't have to be obese to have a heart attack--those pesky triglycerides can accumulate in anyone, thick or thin.  
  •  The Metabolic Derangement
Metabolic syndrome leading to diabetes, heart disease, and stroke is associated with insulin resistance and these signs: abdominal obesity, elevated triglycerides, impaired fasting glucose, high blood pressure, low HDL, fatty liver, elevated uric acid, and systemic inflammation (amongst others).  Fructose intake is related to each of those and insulin resistance itself.  While the amount of fructose you ingest needs to be substantial for these problems to surface, do most of us really know how much we are consuming?  Most people on a processed diet are getting fructose from multiple sources since it is the sweetener of choice among manufacturers.  All those sources can DEFINITELY add up.  If you are on a whole foods diet, you are definitely much safer.  But why drink juice then if you can have the whole fruit and get so many more benefits (i.e. fiber, vitamins, minerals) from going to the source?
  • The Risk of Cancer  
Inflammation may be a precursor to some cancers, and since we have already established that fructose can lead to inflammation, it follows that high fructose consumption can set the stage for cancer.  For example, this study illustrates the fructose-cancer link and even found that juice intake had a significant association with pancreatic cancer.    

Not only does fructose set up the right conditions, but it also provides the fuel for the fire.  Ever hear the saying "cancer loves sugar"?  According to research like this, cancer cells have a sweet tooth too.  Cancer cells require amino acids and glucose for cell growth.  And fructose is converted into glucose in the liver.  If you starve your body of sugar, cancer cells will still force your body to produce its own sugar, BUT you aren't feeding the cancer, either.  That is why some cancer therapy diets focus on the elimination of all sources of sugar.  In combination with medical treatment, it can be very successful.  So fight cancer with your diet, don't feed it.  Pretty revolutionary!  
  • The Hunger
Fructose by-passes the normal metabolic step turning off your hunger; instead, it just makes you hungrier.  It may even break your appetite control mechanism by inducing leptin (the hormone that tells your brain you're full) resistance.   
  • The Ease of OD
It is quicker and easier to drink calories than to eat them, so you can easily go overboard on juice. 
  • The Processing
Processed juice loses its nutritional value, especially its quantity of vitamin C, with exposure to high temperature, exposure to light (through clear containers), and long shelf life.  
  • The Damage to your Teeth
Juice can lead to cavities, just like any other sugar.  For example, "bottle caries" are cavities that result from letting children suck on bottles (of juice or milk) while sleeping. 
  • The Waste
It's wasteful.  Think of all the packaging required for an apple or orange or even a container of berries.  Now compare that with a box/can/carton/bottle of juice.  Think of all the oil required to process fruit into juice, create the packaging, package the juice, and transport it.  Which has more environmental impact?
    Is a cup of juice still a cup of fruit?

    What about Juice for Energy-Refueling after Exercise? 

    Short answer: it's not ideal.  There are much better means.  Juice and fructose in general isn't a great post-workout (PWO) energy refuel because, according to Robb Wolf:
    Fructose has a nasty habit of up-regulating hepatic GLUCOSE uptake. So not only does the fructose preferentially fill liver glycogen, spuring fat gain, but it partitions glucose into the same fate. Hence my PWO meal of chicken breasts and yams.
    and in his Post WO Nutrition post:
    Fruit should be used sparingly in this meal if one is focused on optimized glycogen repletion as fructose refills liver glycogen first, and once liver glycogen is full we up-regulate the lipogenic activity of the liver and start down the road towards fat gain and insulin resistance. 
    And don't think you could actually burn off that Jamba Juice smoothie or that you are just replenishing your energy after a workout.  Unfortunately, exercise alone is NOT enough to burn the calories you consume.  Science Daily just reported on the EarlyBird Diabetes Study on children in the UK that shows "physical activity had no impact on weight change."  The article suggests that physical activity plays LITTLE IF ANY role in childhood obesity.  If active little kids can't burn off their poor diets with exercise, think us adults have a chance?

    TIME magazine ran a piece a year ago called Why Exercise Won't Make You Thin.  Basically, we tend to reward ourselves after working out or feel like we have a free pass to eat poorly the rest of the day.  And exercise may create an energy deficit that makes us hungry, which is counter-productive to weight loss goals.  Their conclusion:
    In short, it's what you eat, not how hard you try to work it off, that matters more in losing weight. 
    Of course, I totally disagree with the article's attack on exercise, but the message still stands.  Exercise must go hand in hand with NUTRITION to get the results you seek.  Exercise is NECESSARY and leads to a fitter, healthier you, but don't think it alone can determine your health.  And we certainly can't use exercise as an excuse to eat poorly.  Maybe it works for Top Chef host Padma, who can spend her life in the gym and doesn't mind looking skeletal, but it's NOT for most of us.  We need exercise AND a healthy diet.  The base of OUR pyramid is nutrition: 

    So Why Is Juice Still Being Served in Schools?

    Almost NO one sees juice as a problem!  It still has the healthiness glaze about it.  Juice is still thought of as a health food drink.  And with Jamba Juice stepping up to offer its smoothies in school just as sodas are being banned left and right, it's no wonder juice is still the "healthy" alternative.  Unfortunately, as we discussed above, that is NOT the case.  Kids (and adults) are much better off eating the whole fruit, NOT drinking the juice.  Juice should be the last ditch effort to suck down some vitamins when you are in a serious bind--NOT the daily accompaniment to our meals.  

    The good news?  Legislation is moving that will limit juice consumption at daycare facilities in California and North Carolina.  At least some people are connecting the dots between childhood obesity and too much sugar, even from a supposedly "benign" source like juice.   And more and more schools are banning sugared drinks, which gets rid of the sugared juices too.  But not the 100% juices.  Why don't we make whole fruits more available and exchange those servings of fruit juice for the real thing?

    And for all of our concerns over proper hydration, what is wrong with water?  Why can't kids use the water fountains?  For all the toxicity and contamination fears with tap water, there are just as many with the cultivation and processing of juice.  I'd rather drink the water. 

    Why does it really matter in the whole scheme of things?

    We are getting fatter as a species.  Childhood obesity is at an all-time high.  If there was nothing to lose from downing a little sugar, then there wouldn't be an issue.  But there is.  There is our future to lose.  If we set our kids up with solid nutrition and nutritional knowledge NOW, we are giving them the best legacy we can provide.  Give them a love and appreciation for real food, whole food, and slow food that doesn't come out of a box, can, carton, or bottle.  

    Bottom line: Use water to hydrate and use whole fruit to get your juice!  To start on this process, try weaning yourself off juice by watering it down.  The less you rely on sugar, the better your system and health will be and the more you will appreciate sweetness in moderation.

    Keep reading the on-going series for more about the best beverages!

    Next up: What's Wrong With Milk?

    Fructose, Insulin Resistance, and Metabolic Dyslipidemia

    Thursday, July 8, 2010

    Sunshine of Your Love Part 7: Supplementation Source

    We already know that we can get our vitamin D from the sun, food (especially fish), and supplementation.  We also know that a combination of sources is most likely to meet your vitamin D needs, which (according to the Vitamin D Council and a growing consensus) are much higher than prescribed by the government's Adequate Intake levels.  Since vitamin D is a hormone, it plays mega-important roles in our bodies, like maintaining calcium levels so you don't go leaching it out of your bones.  In our previous discussions, we've established the source for sunlight vitamin D (UVB rays) and food (fortified ones are out since they are processed, but fish and seafood are definitely in), so let's take a closer look at where supplemental vitamin D comes from.

    Why You Should NOT Take Vitamin D2

    In previous installments, we discussed that there are two different types of vitamin D (D2 and D3) and they are NOT equivalent.  Here's why:

    Vitamin D supplementation was first used back in the 1930s with rickets, a softening of the bones that leads to bowing (at this point most sources would show you some really gross pictures of deformed legs, but I think your imagination and mad Google skillz will suffice).  While both D3 (animal-derived, called cholecaliciferol) and D2 (plant-derived, called ergocalciferol) are effective at treating rickets, the same cannot be said for raising serum 25(OH)D concentrations, the vitamin D you need in your body to perform its tasks.

    Vitamin D3 is derived from animal sources (we'll discuss those in the next sections) while vitamin D2 is obtained from plants.  Vitamin D2 is made when sterols (fat-like substances) in yeast are irradiated with UVB rays.  While similar to our own process of making vitamin D from our own fatty substances (i.e. cholesterol) in our skin, plant "cholesterol" is not the same as ours, so it produces a different type of vitamin D that behaves differently in our bodies.

    According to the Vitamin D Council vitamin D2 is NOT naturally found at high levels in our bodies.  Even though we eat plants, we do NOT take in appreciable amounts of vitamin D2 (it is only a small quantity in a plant), so when we use D2 as a supplement, such high quantity of a novel substance can be toxic.  In fact, there is evidence that D2 is more toxic in overdose than D3, despite D2 being only half as potent in the body and metabolized more quickly.  D2 also goes through a different metabolic process than D3, creating different end products that aren't natural to our bodies either.  Suffice it to say, if you can get D3, why use D2 and take these risks?  Not convinced yet?  There's more!

    In "The case against ergocalciferol (vitamin D2) as a supplement" published in 2006 in the American Journal of Clinical Nutrition, the authors make their argument against using vitamin D2 to fortify foods or to take as a supplement.  They bring up some important points:
    • The differences between the two are present at a metabolic level; they go through different metabolic processes in the body that use vitamin D3 more efficiently than D2.  
    • Studies have found that vitamin D3 is two to three times (perhaps even more) as effective as D2 at raising 25(OH)D levels.  
    • Whereas vitamin D3 is used to prevent bone fractures, vitamin D2 has not been effective.  
    • Vitamin D2 isn't as stable as vitamin D3, so shelf life and storage are a concern.  
    Need it even plainer?  Here is straight from the horse's mouth: the Vitamin D Council's 2006 newsletter:
    If you take ergocalciferol, or "vegetarian vitamin D", be warned. Ergocalciferol is not vitamin D, but a vitamin D-like patent drug whose patent has expired. It does not normally occur in the human body and is probably a weak agonist at the receptor site, meaning it may actually partially block vitamin D actions. Ergocalciferol is the villain in most of the reported cases of toxicity in the world's literature. All bets are off in terms of measuring blood levels if you take ergocalciferol. Some of the labs can pick it up and some cannot. Do not take ergocalciferol—it is not vitamin D.
    Bottom line: You can NOT meet your supplemental vitamin D needs through vitamin D2, so only use vitamin D3!

    Now we know why we need vitamin D3.  So what is the best source of D3 for supplementation?  Let's look at our options:

    The Fish Source

    Fish, especially oily fish like mackerel, salmon, anchovies, and sardines, naturally have high levels of vitamin D and omega-3 fatty acids.  The same applies to their "oil" or refined, distilled form used for supplementation.  Fish are a good source of vitamin D compared to terrestrial creatures because they consume so much plankton (or the fish that eat the plankton), which are producing loads of vitamin D from the sun.  They also make some in their skin when they get near the water's surface, but much more is produced from eating plankton.  Fish oil can be a good source of vitamin D, if it still has its D.  However, most fish oil is stripped of its vitamin D during purification and it has to be added back in to be a source for both.

    Last time we discussed how multitasking our vitamin D and omega-3 needs can spell trouble.  Since we need such high dosage of omega-3 (see the brilliant Whole 9 fish oil calculator), even if our diet is pretty damn sound, we tend to OD on the vitamin D and on vitamin A if we use cod liver oil.  It's just so high in vitamins A and D and so low in the precious EPA and DHA for omega-3s that we either OD and get the omega-3s we need, or we short change our omega-3 needs to meet our vitamin D requirements.  And whether or not we even need any supplemental vitamin A is another can of worms...

    Another problem with fish oil as our source for vitamin D is contamination with heavy metals (like mercury), PCBs, and dioxins.  Predatory fish like mackerel and salmon accumulate toxins because they straddle a higher rung on the ladder of who eats whom.  Another concern is for liver oils, like cod liver oil.  While regular fish oil is usually derived from all/other parts of the fish, cod liver oil is derived from the liver and the liver's function is to detoxify the blood, so it's where toxins accumulate.  It follows that your cod liver oil if not purified extremely well could be a source of toxic contaminants to your system.  The Weston A Price Foundation counters that vitamin A (also in cod liver oil) protects against dioxins (at least in animal studies) and that mercury is not present in the liver, but in the protein.      

    Even if you jump through all the hoops to find the best, most purified source, you could still be in danger.  The contaminants that are supposedly purified from fish oil might still be present, according to this lawsuit that surfaced in March.  It is disconcerting when you trust those guarantees of purity on the labels only to find out they're lies.  However, with this big lawsuit taking the major companies to task, you can bet on ALL the companies stepping up their game and improving their products.  So I am not going to agonize over the brand I choose. 

    Another concern that is gnawing at me: the depletion of fisheries through our fish oil consumption (read this short article from Time Magazine and this one from the New York Times).  Over-reliance breeds over-fishing.  It is a troubling issue.  I know I have to eat to survive, but when does the cost of meeting my needs overbalance the ecological scales to the point of no return?  Although I am and will NEVER be a vegetarian, I still consider the cost of meeting my needs and try to minimize my impact as much as possible in my ever-evolving journey.  While I still take my fish oil, I hope that alternative and more sustainable sources become viable.  :)

    To counterpoint, many of the fish used as sources of fish oil (like anchovies and mackerel) are fast-reproducers, so their numbers can bounce back as long as they are not over-fished beyond the limits of their natural replenishment.  Here is more about cod liver oil processing from the Weston Price Foundation.  For more than you would ever want to know about fish oil production, browse this page from the United Nations.

    The Wooly Source

    Most vitamin D3 (cholecalciferol) in supplements comes from sheep's wool, from which the oil or fat (called lanolin) in extracted.  Animals that don't have their skin exposed to the sun make their vitamin D in their hair, fur, or wool.  Glands in their skin secrete cholesterol that reacts with UVB rays to create vitamin D (a process very similar to our own production of vitamin D by cholesterol in our skin).  Animals ingest that vitamin D in their hair, fur, or wool by grooming themselves.  Isn't that cute?  Doesn't that make you want to go and lick your dog, cat, or bunny to meet your vitamin D needs?  No?

    The lanolin used for supplements is obtained from shearing sheep of their wool.  To extract the lanolin, wool is washed in hot water and cleaned with scouring detergents that separate out the dirt, salts, and lanolin by centrifuge.  The lanolin is concentrated and then exposed to UVB radiation to create cholecalciferol, or vitamin D3.  Since its source is wool, lanolin is a naturally renewable resource since sheep can be shorn once a year during their lifespan of 10-12 years (on average).  As far as an animal product goes, this is pretty humane :)

    Bottom line: If you want to find the best, most renewable source of vitamin D3 by supplement, choose a brand that uses lanolin or sheep's wool.

    Stay tuned for more explorations into the wide world of vitamin D!  I hope you are learning more than you thought you'd ever want to know about vitamin D right along with me.  If you have more to add or different avenues you'd like me to explore, please let me know!

    Coming Soon: Testing for Vitamin D (as soon as I get back my own results!)

    Additional References Used
    Wikipedia entries on vitamin Dlanolin, sheep shearing, and domestic sheep.
    The World's Healthiest Foods: Vitamin D 

    This is NOT medical advice to take vitamin D or any other supplements.  Consult your doctor (and try to educate him/her with this information), do some research, and formulate your OWN plan.