The answer to your first question is: probably nothing. Fact is, there is no scientific evidence which shows that regular intake of multivitamins supplements either delays aging, or protects the average healthy adult from disease and infection. The good news though is that multivitamins, as long as they’re not taken in excessive amounts, do not cause any harm. At worst, they just give the kidneys and the liver, the organs which are responsible for excreting waste and excess materials from the body, additional work.
The only people who can benefit from vitamins supplementation are the very old, the very young, pregnant women, sick and convalescing patients, and people with certain chronic diseases. Healthy adults will not profit from them.
Vitamins are organic (i.e., carbon-containing) compounds that are needed by the body in minute amounts for normal health, growth, development and reproduction. Their absence is not compatible with life and their deficiency results in illness. Except for vitamin D, which can be synthesized by the skin (provided it is exposed to sunlight) the vitamins cannot be produced by the body; they have to be provided for in the diet.
There are 14 known essential vitamins, but there are several organic compounds, called vitamin-like substances, that might ultimately be categorized as vitamins as soon as their roles in human nutrition are established.
The essential vitamins are classified based on their solubility properties into either water-soluble or fat-soluble. The fat-soluble vitamins are vitamins A, D, E & K while the water-soluble vitamins are vitamin C (ascorbic acid) and those that comprise the vitamin B complex group: vitamin B1 or thiamine; vitamin B2 or riboflavin, vitamin B3 or niacin, vitamin B5 or pantothenic acid, vitamin B6 or pyridoxine, vitamin B12 or cobalamin, biotin, cholin and folacin or folic acid.
Except for cobalamin, the body cannot store large quantities of the water-soluble vitamins, but it takes a long period of deprivation before deficiency syndromes appear. Besides, they are abundant in food products. Hence, in normal adults, all it takes to provide sufficient amounts of water-soluble vitamins is a well-balanced diet. Supplements are not necessary.
In contrast to water-soluble vitamins, surplus amounts of fat-soluble vitamins can be stored by the body, but unlike the former, the latter can only be absorbed in the intestine if fat absorption is taking place normally. Thus, conditions that interfere with fat absorption can lead to a deficiency in one or in all the fat-soluble vitamins. Nevertheless, in normal people, a well-balanced diet guarantees sufficient amounts of fat-soluble vitamins. Hence, supplements are likewise not necessary.
The basis for the common belief that vitamin supplements can prevent disease and delay aging is the fact that some vitamins, specifically vitamins A, C and E are powerful antioxidants. Antioxidants are substances that protect the cells of the body by devouring free radicals. Free radicals are highly reactive atoms or groups of atoms that are by-products of the normal activities of the cells. They serve a useful purpose because they help kill bacteria and other harmful microorganisms, but if present in excess they damage the cells and contribute to the development of such disorders as cancer, heart disease and many conditions associated with aging.
Conceivably therefore, supplementation with antioxidants such as multivitamins can prevent heart disease, some cancers and other degenerative conditions. Unfortunately, scientific studies have not established the presumed beneficial effects of mega doses of vitamins A, C and E on cancer, heart disease and other degenerative conditions. Worse, results of some studies even suggest that high doses of these antioxidants may have adverse effects. In addition, they sometimes interfere with the action of some drugs such as those used to improve cholesterol levels.
In short, multivitamin pills are not fountains of youth, neither are they an insurance policy against disease. In fact, they cannot even substitute for a balanced diet.
