by S. Todd Stolp MD
©March 2009
Most physicians learn about nutrition in biochemistry and organic chemistry classes. This prepares them well for when patients present with concern about the number of glucose molecules required for the synthesis of one molecule of palmitic acid. Unfortunately, patients are more inclined to ask their physicians whether taking a daily multivitamin is a good idea. A clear answer to the latter question remains obscured by the conflicting conclusions of well-intended research and by the wide variety of patients who inhabit the earth. For the most part, advice on the subject of vitamin supplementation therefore tends to be left to the well-informed discretion of the practitioner under the banner of the “art of medicine.” Nevertheless, there are some facts worth sharing about the ins and outs of vitamin supplements.
Certain things are required for normal health. While humans require water, oxygen and sunlight (for the manufacture of Vitamin D), this initial list provides little to distinguish us from our house plants.
Essential nutrients are defined as substances that are required for normal body functioning, but which cannot be produced by our own bodies. The vitamins are classic examples of essential nutrients. As each vitamin was identified over the past 200 years, or a food product identified that was suspected of containing an essential nutrient compound, the vitamin was given a letter. Thus, we have Vitamin A, B, C etc… “Vitamin G” ended up being the same as Vitamin B2, also known as “riboflavin,” and “Vitamin H” turned out to be another B vitamin called “biotin.” “Vitamin F” turned out to be certain fatty acids, and were therefore reclassified as “essential fatty acids.” Other nutrients that were initially thought to be vitamins were found to be produced by the body, and therefore were dropped from the list.
There are sixteen minerals that are also essential nutrients, including such common friends as calcium and iron, but also some oddballs like Zinc and Molybdenum. Nine out of the 20 traditional amino acids, the building blocks of proteins, are also recognized as essential nutrients.
It is interesting that primitive cultures learned to adjust their diets without the benefit of biochemistry classes to include the essential nutrients. While beans are rich in many essential nutrients, they are deficient in lysine, one of the essential amino acids. Corn, on the other hand is rich in lysine. It was no accident that Aztec societies learned that the marriage of beans and corn provided for a healthy population. The burrito was born.
We now know that some vitamins can protect us from certain illnesses. In 1992 the Centers for Disease Control recommended that all women capable of becoming pregnant should take 400 micrograms of folic acid each day throughout their childbearing years to prevent a birth defect of the brain and spinal column known as a “neural tube defect.” Since that recommendation and the fortification of cereals with folic acid, neural tube defects have declined by nearly 40%. Vitamin D and calcium supplementation is of benefit to post-menopausal women to help prevent the loss of minerals from the bone, thereby helping to prevent osteoporosis.
On the other hand, much research into the benefits of “antioxidant” vitamins – Vitamin C, Vitamin E, and beta carotene – in preventing cancer and heart disease have come to disappointing conclusions. No clear protective benefit was demonstrated. A recent large study of older women taking multivitamins showed no diminished risk of cancer or cardiovascular disease.
It is possible that a subset of the general population may benefit from supplemental vitamins, while others stand to gain nothing. For instance, while a vegetarian diet can provide a perfectly satisfactory supply of all essential nutrients, some vegetarians or vegans (who consume no products of animal origin, including milk) may do better with supplements of Vitamin D and B12. Breast feeding mothers should take vitamin supplements. More dark skinned populations have been found to be deficient in Vitamin D, and this may be partly due to the diminished ability of sunlight to boost Vitamin D, or due to socioeconomic factors influencing diet and nutrition. Vitamin C may help some people who are at risk of gout.
Forty percent of the American population spends over 20 billion dollars per year on dietary supplements. In order to know whether you might benefit from taking supplemental vitamins, it is best to discuss this with your health care provider in light of your dietary habits, medical condition, and other medications consumed. In a world where we are constantly bombarded by marketing messages, it is worth being reminded that nutrition comes from food. It makes little sense to take expensive capsules three times each day that are filled with processed vitamins extracted from vegetables as a supplement to a diet of coffee and doughnuts.
Now eat your broccoli.