Tuesday, November 30, 2010

Vitamin D - Do The New Recommendations Fall Short? What Vegans Need To Know About Vitamin D.

IOM Triples Recommended Vitamin D Intake
In 1997, the Institute of Medicine (IOM) set the adequate intake level of vitamin D at 200 IUs for people less than 50, 400 IUs for those 50 to 70 and 600 IUs for people over 70. The new recommendations call for 600 IUs daily for everyone, including children, up to adults age 70 and 800 IUs for those over 71.
Although this triples the amount recommended for younger people, many health professionals feel that this new level still missed the mark.

What is Vitamin D and Where does it come from? Is it Vegan?
Vitamin D is a fat soluble vitamin. There are two forms.
* Vitamin D2 (ergocalciferol) is made by converting a sterol found in plants and yeast. Since it is plant based, it is considered vegan. Mushrooms, when exposed to sunlight, are another source of this important vitamin.
* Vitamin D3 (cholecalciferol) is produced by the skin when exposed to the sun. It is also found in animal products and some fatty fish. Vitamin D3 supplements are made from lanolin from the wool of sheep and are not considered vegan.
* 25-hydroxyvitamin D is the hormonally active form of vitamin D that the body makes from Vitamin D2 and D3. When you test your blood levels for vitamin D, they are testing for 25-hydroxyvitamin D.

Is D3 Better then D2?
Several early studies showed that vitamin D3 was more effective in raising the serum levels of 25-hydroxyvitamin D when taken in very high doses. In a more recent study by Holick, it was found that both forms are equally effective, when taken in more typical doses of 1,000 IU per day, in increasing and maintaining serum levels of 25-hydroxyvitamin D. This is good news for vegans who prefer the plant based vitamin D2.

But I'm a Sun Loving Vegan, Isn't that Enough?
I too love getting as many nutrients from nature as possible. But trying to determine the amount of sunlight one can safely take to provide adequate vitamin D levels is difficult. Reading some of these descriptions is almost comical so I'll defer to other sources to tell you how much, what longitude and latitude, time of day, time of the year, color of your skin, how much suntan lotion you're wearing, etc.. I'm getting exhausted just listing these! This vitamin is critical to so many things, why not just supplement?

Why is Vitamin D Important?
Vitamin D has long been associated with bone health since it regulates how body absorbs calcium and phosphorus. Recent studies have linked low vitamin D levels to:
* Increased risk of cardiovascular disease
* Higher incidence and severity of depression
* Higher risk of rheumatoid arthritis in women
* Increased risk of prostate, breast and colon cancers
* Severe asthma in children
* Cognitive impairment in older adults.
Research also has shown that vitamin D shows promise in preventing and treating:
* Type 1 and type 2 diabetes
* Multiple Sclerosis
* High blood pressure
* Significant reduction in the incidence of seasonal influenza.
* Parkinson disease

Did the IOM Fall Short?
OK, I must give credit that the IOM actually raised the bar but many experts do not feel that they raised it enough and I agree. Much of the controversy centers around the optimal blood level of vitamin D. Vitamin D advocates, such as the International Osteoporosis Foundation, feel that 30 ng/ml is the optimal level. Some experts feel that this level should even be higher than that. Life Extensions recommends levels as high as 50 ng/ml. But the IOM panel dismissed these recommendations and concluded that for 97% of the population, 20 ng/ml of vitamin D is sufficient.

Who is at Risk for Vitamin D Deficiency
Some people have a much higher risk of vitamin D deficiency. These include:
* Those with osteoporosis
* People over age 50
* People with dark skin who have reduced capability of converting the sun's rays to vitamin D
* Obese people
* People on certain medications like prednisone and anti-seizure drugs like Dilantin
* People with fat malabsorption as is associated with those with Crohn's, celiac and other diseases
* People who work indoors and avoid the sun

Can you get Too Much?
Since vitamin D is fat soluble, the body stores it. Taking excessive amounts can potentially result in hypercalcemia, or too much calcium in the blood. Hypercalcemia symptoms include:
* Loss of appetite
* Constipation
* Confusion
* Weakness
The IOM panel increased the acceptable upper limit of daily intake of vitamin D from 2,000 IU to 4,000 IU from supplements and food sources.

What Should I Do?
If you are a RAW FOOD VEGAN who doesn't supplement, you have a high chance of being vitamin D deficient since there are NO ADEQUATE plant sources of vitamin D. Of course it you work shirtless in a field all day and you are light skinned and close enough to the equator, this may not be a problem. (But your chances of skin cancer exceed you likelihood of vitamin D deficiency!)
Vegans in general may also be vitamin D deficient since they don't eat fatty fish and may avoid foods fortified with vitamin D3.
Here's what my husband and I do:
* We asked our doctor to test our blood levels of 25-hydroxyvitamin D.
* Doug and I want our levels to be over 40 ng/ml based on what we've read but ask your doctor what he or she recommends. Hopefully the answer will be at least 30 ng/ml. If it's 20 ng/ml, find another doctor.
* Our intake is at least 2,000 IU per day. Nature's Life makes a 2,000 IU vitamin D2 supplement in a vegetarian capsule.
* Be sure to include amounts found in fortified foods like soy milk. Hats off to Silk for supplementing their soy milk with vegan D2 !

Mushrooms, an Interesting Development
It turns out that mushrooms can convert the sun's rays into vitamin D too! In fact, the USDA has been working with the Monterey Mushroom company to grow a mushroom with increased levels of vitamin D. By exposing the mushrooms to UV light, the mushrooms create a stable amount of the nutrient which is maintained even after cooking or freezing! I actually bought some this weekend so they are now on the shelves!

Don't Forget the Kids
A study in Japan found that giving 1,200 IU per day to school age children from December through March cut down the incidence of seasonal flu by 42% so don't forget the kids this winter!

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Sandy said...

Actually, the New York Times just came out with an article yesterday on this saying that it's a myth that you need to supplement vitamin D and calcium. Doctors studied it thoroughly and this is what they found.

Dr. Joanne L. Mumola Williams said...

I read the New York Times article and although I agree that far too much calcium is being pushed on people, I feel there is real merit in vitamin D supplementation based on what I have read and studied. Much more research is required and always beneficial. For optimal health, my readers should have their blood levels tested and have this discussion with their doctors based on their lifestyle, diet and family history. This is especially important for raw food vegans.
Thanks for your input!