Introduction
The topic of vitamins along with herbs and dietary supplements of various types has caught the public's attention for the last several decades. Science has only recently begun studies examining the potential positive effects of vitamin supplementation. This article will review some of the most promising research and hopefully dispel much of the exaggerated claims surrounding the topic of vitamins.
Biochemistry of Vitamins
The human body is an incredibly complex machine that performs the tasks of energy production, repair, and reproduction through thousands of biochemical reactions. Nearly all of these reactions require an entity known as an enzyme to occur. Vitamins are usually required components of these enzymes to function properly, in their absence, these reactions will not occur. A well balanced diet supplies all of the required vitamins, therefore, vitamins supplementation should be theoretically unnecessary. A logical question to ask is if a normal amount of vitamins allows these necessary biochemical reactions to occur, can a larger amount increase its effectiveness?
Vitamin C Arguably, vitamin C or ascorbic acid was the first vitamin to come into the public's awareness when Nobel Prize winner Linus Pauling publicly endorsed ingesting large amounts for its positive health benefits. Normally, vitamin C plays a vital role in several biochemical reactions involved in repair and energy production. Initial studies examined the use of 1000mg to 3000mg of vitamin C to decrease the severity of the common cold. Linus Pauling himself published an initial study in 1970. The results of multiple studies has been conflicting. Initial studies did show that vitamin C reduced the duration of the common cold by one to two days, but many studies did not show any significant difference between the placebo (sugar pill) group versus the vitamin C group in the treatment of the common cold. It is probably safe to conclude that if there is a positive effect on the common cold, that it is modest at best. Short term use of high doses of vitamin C is reasonably safe but prolonged use can lead to kidney stone formation. Vitamin E Public attention on vitamin E begin with an exaggerated notion that it could reverse the aging process and enhance fertility. Vitamin E encompasses a group of substances known as the tocopherols which are responsible for preventing damage to cells from the products of energy production. They belong to a class of vitamins better known as the antioxidants. The notion of protection of the body's cells from damage was tested in several studies examining the effect of high doses of vitamin E (200-400 I.U.) and its effect on the damage that occurs to blood vessels of the heart which eventually leads to their hardening and closure causing a heart attack. Several studies now have shown modest benefits by taking vitamin E regularly to reduce heart attack risk. Most recently, several studies are monitoring the protective effects that vitamin E could have on the body to reduce cancer risk. A few tentative results suggest that vitamin E may reduce the risk of prostate and stomach cancer. Multiple ongoing studies are currently examining the effects of vitamin E on other cancers such as lung and colon cancer. Taken at doses ranging from 200-800 I.U., there is almost no risk of a significant side effect from vitamin E. It is reasonable then at this time to take vitamin E due to its potential protective effect and the very low likelihood of adverse effects. Beta Carotene Beta carotene is a natural plant pigment that gives carrots their orange color and is converted into vitamin A when it is ingested. Most of us recall from our school days the role vitamin A plays in the proper functioning of vision, particularly night vision. Vitamin A plays other roles in the body but recently, scientists have examined the possibility that beta carotene may reduce the risk of cancer. Studies involving beta carotene have not been as impressive as they are for vitamin E. One study has shown a modest decrease in esophageal and stomach cancer in Chinese taking beta carotene, vitamin E, and selenium supplements. In a well publicized study reported recently, it was found that male smokers who used beta carotene actually had a slightly higher incidence of lung cancer as compared to the placebo group. The results of studies examining the effects of beta carotene have clearly been inconclusive so far and at high doses, beta carotene can be toxic. The usual doses found on the shelves of health food stores should be generally safe but may impart an annoying yellowish pigment to the soles of the feet and the palms of the hands.Multivitamin Supplementation
With an avalanche of positive studies now being published on numerous vitamins benefiting several special patient groups such as folic acid for children and pregnant women, or vitamin D to aid calcium absorption, it is becoming quite apparent that a multiple vitamin along with a multiple mineral supplement would be much more convenient to take. Few would have the expertise to formulate a custom mixture of vitamins for their specific needs, so a high quality multivitamin, multi-mineral combination would be suitable for the vast majority of average patients.
Recommendations
It appears that vitamin E is showing significant benefits in several early studies. As mentioned above, I believe that the evidence suggests starting vitamin E supplementation now. For convenience, a high quality multivitamin, multi-mineral combination is suggested. Ongoing studies are suggest that vitamins themselves may not provide the desired protective benefits, and that the truly beneficial substances may be in the fruits and vegetables themselves. This fact has been recognized by the National Cancer Institute which recommends a well balanced diet that includes generous portions of vegetable and fruits. Taking vitamins alone does not substitute for a good diet.
Lloyd Ito, MD
11/30/03