Vitamin D levels in adults are also low and vitamin D deficiency is being linked to an increasing number of serious, chronic conditions and auto-immune diseases. (See also my post “Vitamin D. Now I’m a believer”).

Everyone seems to agree on what’s causing the problem. We spend less time outdoors, we’ve been drilled by dermatologists (and cosmetic companies) on the use of sunscreen to protect our skin against skin cancer and premature aging. We (and our kids) get a lot less vitamin D from our diet, chiefly because we drink less milk and more soda than we used to.

(Milk does not contain vitamin D naturally, of course. It’s fortified with vitamin D. Fish are the best natural sources of vitamin D.)
It’s harder to agree on the solution.  Some argue that high dose vitamin D supplements are the answer. It’s a logical leap, but it’s still a leap. While we have evidence linking low vitamin D levels to many diseases, there’s less evidence to prove that taking vitamin D supplements reduces those risks.  (Correlation does not equal causation.)

It also takes a heck of a lot of vitamin D supplementation to correct a vitamin D deficiency. While the current RDA for vitamin D is 400IU, it can take 10,000 to 50,000IU a day to replenish depleted vitamin D stores in the body. High doses of vitamin D have been found to be safe and well-tolerated.

Nonetheless, many experts are wary of this kind of super-high-dose supplementation without medical oversight.
Exposing the unprotected skin to sunlight is a much more efficient way to raise vitamin D levels in the body, but it proves very difficult to make recommendations about how much sunlight a given person needs. It depends on how much skin is exposed, your latitude, your altitude, the time of day, the time of year, atmospheric conditions, and your skin color. (Yikes!).  Plus, you have to weigh the benefits of vitamin D production against the risk of skin cancer and/or sun damage.

Please read the complete

For many people – myself included when I first started researching all the options that were proposed as potential cures for cancer – this kind of study – and the treatment of it in the newspapers – seems to carry an awful lot of weight. Answer that! a voice in your head says. There’s a study that’s scientific and it disproves the value of vitamin D. Simple!

Unfortunately life – and truth – are rarely simple. But there is one pattern that seems to be fairly consistent and this is a very good example of it. Almost every study that ‘disproves’ the value of taking vitamin and mineral supplements does so by testing small quantities of the item. In this case, the women seeking a protective effect from vitamin D were only taking 400iu. if you look up the Recommended Daily Allowance (RDA) – or ‘Reference Intakes’ as they are now known as – you will find that the figure is 400iu. So the study has shown that the standard recommended allowance of vitamin D is useless.

Actually, this is in agreement with what the vitamin/mineral advocates have been saying for decades. They have said that the official RDA figures for all the vitamins and minerals have been set very low – indeed unhealthily low. Everyone making claims for the value of vitamin D – in fact – says that an average daily intake should be in the region of 2,000 iu minimum and 4-6,000iu may be preferable.

Now, it is very difficult to get 2,000iu of vitamin D from food sources such as cod liver oil.  The best source of vitamin D is sunlight. Exposure to sunlight of course varies according to lattitude and season. You won’t get much vitamin D in New York in winter – certainly not as much as you will get in Florida in the summer. Half an hour on the beach in Florida will allow you to absorb 10,000 iu of vitamin D. And do you feel sick from over-dosing? Of course not. You feel great.

As I said earlier the vitamin crowd don’t pay a great deal of respect to RDA figures. And, belatedly, it seems that doctors are catching up as I found at this link where the medical author argued for a minimum of 1,000iu vitamin D – http://www.medscape.com/viewarticle/541149

So the next time you see a study debunking this or that mineral or vitamin look a little closer and ask: How much of the vitamin were they testing? and How does that compare with what vitamin advocates are saying?

The panel on vitamin D and cancer was part of the 2008 Annual Research Conference on Food, Nutrition, Physical Activity and Cancer, presented by the American Institute for Cancer Research (AICR) in Washington, DC.

Vitamin D is an essential nutrient, and vitamin D deficiency has been linked to chronic diseases, including some cancers. Humans acquire vitamin D in two ways – from exposure to sunlight, and from the diet. (Most of the vitamin D in American diets comes from foods that have been fortified with it, such as milk and cereal.)

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