The Importance of Vitamins in Our Diet

In general, most people know the importance of vitamins in our diet. But many people do not know which vitamins are really important in maintaining good health.

I would like to revisit an article I had discussed about ten years ago on this topic. Not much has changed since. The topic was also discussed in a Clinical Practice article in the New England Journal of Medicine (NEJM) titled, “What vitamins should I be taking, doctor?”

Medical teaching says that a healthy individual, who eats a good diet, does not require vitamin supplements. He should be able to meet his vitamin needs from his healthy diet. But the public interest in vitamin supplements is enormous – sometimes due to misguided reasons. Almost 30 percent of our population takes vitamin supplements. And there is no control over it.

Because the food we eat contains too many nutrients, it would be almost impossible to conduct double blind trials to see if vitamins do have improved clinical outcomes. Also the users of vitamin supplements may have healthier lifestyles or behaviours than nonusers. This would distort any clinical trial results.

The good thing about vitamin supplements is that there is greater likelihood of good than harm and cost of supplements is not that high so the authors of the article in the NEJM recommend the following vitamin supplements for healthy individuals. There is substantial evidence that higher intake of:
1. folic acid (400 ug/day),
2. vitamin B6 (2 mg/day),
3. vitamin B12 (6 ug/day), and
4. vitamin D (400 IU/day) will benefit many people, and a
5. a multivitamin will ensure an adequate intake of other vitamins for which the evidence of benefit is indirect.

The authors say a multivitamin is especially important:
-for women who might become pregnant
-for persons who regularly consume one or two alcoholic drinks per day
-for the elderly, who tend to absorb vitamin B12 poorly and are often deficient in vitamin D
-for vegetarians, who require supplemental vitamin B12 and
-for poor urban residents, who may be unable to afford adequate intakes of fruits and vegetables.

It should be noted that recent recommendation for vitamin D suggests all adults should take 1,000 to 2,000 IU daily. The upper level for safe vitamin D intake has not been well defined but is probably as high as 250 μg (10,000 IU) daily but in clinical practice, supplementation with this dose of vitamin D is rarely required.

Physicians who encourage their patients to take vitamin supplements should also educate their patients regarding healthy lifestyle and about healthy nutritious diet. Foods contain many additional important components, such as fiber and essential fatty acids and vitamin pills cannot be a substitute. Vitamin pills do not compensate for the massive risks associated with smoking, obesity, or inactivity, say the authors of the NEJM.

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