• Text smaller
  • Text bigger

Chuck, a short time ago, I read a health article in The Wall Street Journal that said the Institute of Medicine had concluded that too much vitamin D can be hazardous to one’s health. Care to weigh in? – Shirley C., Atlanta

Probably no nutrient has been studied more over the past decade than vitamin D.

Vitamin D is used by the body both to maintain wellness and to treat disease. It aids in the body’s absorption and in retaining proper levels of phosphorus and calcium, which form and maintain strong bones. Vitamin D also helps regulate muscle wellness (including skeletal and heart), immune response and insulin and blood sugar. Recent research also suggests it does a whole lot more, which I will discuss momentarily.

Sources of vitamin D are foods such as eggs, fortified milk, salmon, shrimp, sardines, cod, etc. Among salmon, wild-caught fish have more vitamin D than non-organically farmed fish. Other good sources are D-fortified cereals. The sun also contributes significantly to the daily production of vitamin D; experts say 10 minutes of exposure a day can prevent deficiencies.

On Nov. 30, the Institute of Medicine, established in 1970 as the health arm of the National Academy of Sciences for the purpose of advising the government on proper nutrient levels, released a report that claimed few people are vitamin D-deficient.

But the fact of the matter is the overwhelming scientific evidence is that one-third of Americans are vitamin D-deficient. Even in Great Britain, according to the BMJ, many adults (more than 50 percent) are deficient (It hasn’t helped that each passing generation has led to a greater cocooning of Western society and lack of exposure to sunshine).


Despite the fact that over-intake of vitamin D is indeed possible, most health practitioners I respect believe that most Americans are deficient of vitamins and minerals, including the basic vitamins – A, B, C, D, E and K – magnesium, calcium, fiber and potassium.

The IOM is correct in its research that demonstrates that vitamin D toxicity, often caused by overconsumption, can lead to many ailments, from nausea, fatigue and back pain to more severe bodily threats, such as kidney and tissue damage and even pancreatic cancer.

Scientific studies, however, also have proved that vitamin D deficiency is linked to a host of problems, too, including depression, hypertension (high blood pressure), mental degeneration, autoimmune illnesses, diabetes, strokes, heart disease, rickets and osteomalacia and breast, prostate and colon cancers.

Scientific research across ethnic and cultural lines has identified reduced vitamin D levels as a prime contributor – especially in the wintertime, when daylight is scarce and the weather grows cold – to the increase in cases of infectious illnesses, such as the common cold, the flu and respiratory infections.

That is why even the IOM recommended tripling the daily amount of vitamin D from 200 international units (set in 1997) to 600 IU (and 800 IU after age 71). The IOM also raised the safe consumption limit for vitamin D to 4,000 IU. But the fact again is that the IOM’s recommended dosage of vitamin D is far less than what most medical groups, physicians and nutritionists prescribe.

Even if you eat well, most vitamin D experts recommend that you take at least a 1,000-IU daily supplement. But because you can overtake most vitamins, I recommend that you educate yourself by consulting a reputable guide to supplements, for example, the University of California, Berkeley’s “Wellness Guide to Dietary Supplements.”

So, how much vitamin D should you take? That depends upon several factors: age, weight, diet, health and wellness, skin coloration, where you live, sun exposure, etc.

The Vitamin D Council recommends that you obtain your body’s accurate need by a blood test: “At this time, we advise even healthy people (those without the diseases of vitamin D deficiency) to seek a knowledgeable physician and have your 25(OH)D level measured. If your levels are below 50 ng/mL you need enough sun, artificial light, oral vitamin D3 supplements, or some combination of the three, to maintain your 25(OH)D levels between 50-80 ng/mL year-round.”

A well-balanced diet and life cannot give you all the vitamin D your body needs. You need supplemental vitamins and minerals, but before you purchase and take them, discuss your body’s requirements with your health practitioner. And if you show signs of vitamin D deficiency or its related diseases, you need to be under the care of a physician.

  • Text smaller
  • Text bigger
Note: Read our discussion guidelines before commenting.