Working together, vitamins C, D, B1 (thiamine) and B3 (niacin) prevent cavities and anorexia. If you’re just looking for good doses to try, click here.

These four vitamins are special because they are the only four vitamins associated with named pandemic deficiency diseases. The four diseases are scurvy, rickets, beriberi, and pellegra.

Of these four vitamins, vitamin D is the most unlike other vitamins and is highly toxic in overdose. Vitamin D is nunlike other vitamins because it is not naturally obtained from food. Your body produces the most vitamin D in your skin when it is bare (no sunblock) and untanned and exposed to direct mid-day sunlight (not morning or afternoon sunlight).

Exposing the skin to direct mid day sunlight is easily accomplished. For many people, exposing the skin to the sun feels great. I would argue it feels so good because it is necessary for good health and is risky. That’s the conundrum. Just a little bit too much time – just minutes in intense sunlight for the sun sensitive – results in a painful burn. Way too much sun causes lethal sunburn, and is reported to have been used as a torturous form of execution. Regular sun exposure accelerates aging of the skin and increases the odds of getting skin cancer. Although the skin cancers associated with sun exposure are rarely lethal, they are ugly and leave permanent scars when removed.

Faced with the obvious negatives of sun exposure accompanied by the obvious attractiveness of the sun, the medical establishment has naturally taken on the role of warning the public about the dangers of the sun. Since children (and many adults) naturally tend to get plenty of sunshine because it feels so good, there has not been too much concern about the possibility that great harm could be getting done by insufficient exposure to the sun. Vitamin D was an exception. All healthcare providers recognized the importance of this vitamin. The solution hit upon was to spike the food supply with vitamin D so that everyone would get enough from the diet and would not need to be concerned with getting vitamin D from the sun.

Here the vitamin D conundrum becomes painful. Nature can be very unkind. Vitamin D supplements are far more dangerous than vitamin D produced in the skin by the sun. There are no reports of serious vitamin D side effects from sun exposure. Side effects from regular doses of vitamin D above 2000 IU per day are an ordinary event. Very recent science has proven that regular sun exposure synthesizes 10,000 to 20,000 IU/day of vitamin D in the skin and results in high levels of vitamin D circulating in the bloodstream. At least 4000 to 5000 IU/day of vitamin D by mouth is required to achieve the higher levels of vitamin D achieved from sunshine alone, and daily doses of 10,000 to 20,000 IU/day by mouth normally cause acutely toxic blood levels well above what can be achieved by the sun. Again, it is impossible to cause highly toxic levels of vitamin D in the blood from sun exposure.

There is surprising controversy in the medical community concerning the toxicity of vitamin D supplements. I say surprising because the hard truth is that vitamin D is the active ingredient in a common rat and mouse poison. The poison or “bait” is made up of 1 part vitamin D added to 999 parts of a dry food that the target rats or mice find irresistable. For example, here’s a link to Quintox Seed rat and mouse poison. Vitamin D supplements are toxic to humans too, and have caused nutrition boards headaches ever since the decision was made to supplement the food supply with vitamin D. To learn about the details of vitamin D side effects, read more here.

So – the hard truth is that vitamin D taken by mouth has different effects on the body than vitamin D produced naturally in the skin from sunshine. The harder truth is that excellent health and longevity is associated with regular sun exposure. It is highly likely that most people have to get regular sun exposure and age their skin in order to get the maximum benefits from vitamin D. It is also highly likely that sunlight catalyzes other important reactions in the skin, and that vitamin D is not the only healthy metabolic pathway reliant on the sun.

There’s no one right answer for optimizing the use of vitamin D – hence the conundrum. It’s especially beyond me to figure out how to devise policy to encourage parents and schoolboards to optimize the sun exposure of children. We need to start, however, by reaching a consensus about vitamin D. Are we, or aren’t we, living amidst an epidemic of vitamin D deficiency of our own making. Does vitamin D from the sun prevent cavities and anorexia or not? If it does, are cavities an anorexia an epidemic or are they just an ordinary cost imposed by “necessary” evolutionary pressures from the environment (surely it is eutopian to imagine a society without strong evolutionary pressures imposed by the environment?).

Whatever one might think about policy, I think everyone agrees that access to unbiased, factual information about the importance of vitamin D is a human right. Dark-skinned immigrants to low-sunlight countries and cultures (submarine crews are an extreme) should be explicitly warned of the risks.