Mom’s heartfelt advice, “Remember to take your vitamins”, although given with the best of intentions, should now be given with several new caveats. There are two types of vitamins: water soluble, such as C and the B family, and fat soluble such as A, D, E and K.
- Water soluble vitamins pass quickly through the body. Whatever is not utilized is eliminated via urine excretion.
- Fat soluble vitamins remain in the body’s tissues for prolonged periods of time. This buildup can cause toxicity if these vitamins are taken in large quantities.
The old wisdom is that as long as one took the recommended daily allowances, and did not take too many fat soluble vitamins, one did not have much to worry about. It is therefore very rare to find serious cases of water-soluble vitamins causing medical problems. Some exceptions are that in recent studies high doses of vitamin B6 and folic acid (a vitamin B9 derivative) have been linked in some studies to nerve damage and an increased risk of developing colon polyps respectively.
Recent studies have caused alarm by stating that some very commonly taken vitamins are actually raising the risk of death. One prime example is that of the so-called antioxidant vitamins A and E. An antioxidant is a substance that slows the bodily process of oxidation or formation of “free radicals”, molecules which can cause disease and aging.
A recent article in JAMA, the Journal of the American Medical Association, stated that beta carotene (a vitamin A derivative), and vitamins A and E, previously regarded as effective antioxidants, might actually increase the risk of death. There was a 7%, 16% and 4% increased risk of mortality respectively. The study further speculated that the reason for this unsettling finding might be that the antioxidants may interfere with the body’s natural defense mechanisms that fight off disease and aging.
The public’s obsession with antioxidants has caused many to forget the warnings regarding mega-doses of fat soluble vitamins. Toxicity studies on such synthetic supplements have not been as thorough as those done on true pharmaceuticals.
Perhaps further studies will reveal whether it is merely a question of toxicity or one of actual interference with the body’s natural mechanisms or both. Until then, it is still wise to limit the use of synthetic fat soluble vitamins to recommended doses or simply to rely on their natural food sources such as eggs, milk, spinach and fruits for vitamin A and whole grains, and leafy green vegetables for vitamin E.
It is equally wise to limit one’s use of B6 and folic acid as well until further studies are done. Relying on food sources for nutrients is still the safest way to get one’s daily intake of required vitamins and minerals without concern for consequences of “overdosing”.