Vitamins E & C: Why The RDA May Be Wrong!

Is it possible that the Recommended Daily Allowance (RDA) for certain vitamins such as E and C could be too low? Well to be frank, yes! But the question that needs to be asked is whether higher doses confer additional benefits?
Is it possible that the Recommended Daily Allowance (RDA) for certain vitamins such as E and C could be too low? Well to be frank, yes! Vitamins are classified as "organic, essential nutrients required in minute amounts to perform specific functions that promote growth, reproduction, or maintenance of health and life". Minute amounts, in this statement refer to the RDA for vitamins such as E and C, which are 9 mg and 60 mg respectively. But the question that needs to be asked is whether higher doses confer additional benefits?

Functions In The Body

Vitamins E and C are major contributors to optimum functioning of the body.

Vitamin C, for example, is a water-soluble vitamin that is involved in hundreds of vital biological processes in the body. A few of these biological processes include collagen and connective tissue production, antibody production, and significant antioxidant properties. Vitamin E also serves as a valuable antioxidant. Antioxidants by definition, are compounds that protect other compounds from oxidation by being oxidized themselves.

Vitamin E is a fat-soluble antioxidant that is one of the body's primary defenders against oxidation. Its importance lies in the fact that it protects the lipids and other vulnerable components of the cells and their membranes from destruction. Antioxidant nutrients, such as vitamins E and C, act as scavengers of oxygen-derived free radicals, thereby helping to prevent cell and tissue damage that would cause degenerative diseases. As mentioned previously, the RDA values of vitamins C and E for adults are 60 mg and 9 mg respectively. However, these RDA values, like all the RDA are intended to maintain health in healthy people - not restore health in sick people or prevent life-threatening diseases.

In addition, as vitamin C is water-soluble, it is not only readily absorbed and circulated throughout the body, but readily excreted as well. Because of this, frequent doses of vitamin C are highly recommended just to meet the RDA. Vitamin E is a fat-soluble vitamin, which makes it less readily excreted. However, as vitamin E is one of the body's primary defenders against oxidation, it is quickly used up and therefore also needs to be replenished rather frequently.

Studies And Their Conclusions

A great deal of research is being conducted on larger doses of vitamins E and C in the prevention of life-threatening diseases. One such disease happens to be America's number one cause of death - Coronary Heart Disease (CHD). Other diseases studied include several types of cancer such as colon, prostate, pancreatic, lung and esophageal.

One set of studies, the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study with Low-dose Vitamin E Supplementation (50 mg daily) and the Cambridge Heart Antioxidant Study (400-800 mg daily) resulted in evidence that large supplemental doses of vitamin E significantly reduces the risk of prostate cancer.

Within this study, a group of 29, 133 male smokers in Finland (50-69 years of age), took a pill containing either 50 mg alpha-tocopherol (a form of vitamin E), 20 mg beta-carotene, both or a placebo daily for 8 years.

"Results from this study showed that daily supplementation with vitamin E pills reduced the chance of having a heart attack by 77 percent."

Results have shown that those individuals taking the vitamin E had 32 percent fewer cases of prostate cancer and 41 percent fewer deaths from prostate cancer. Another study from Cambridge, England looked at the effect of 400-800 IU (~120 mg) of vitamin E per day on 2000 people who were currently suffering from CHD.

Results from this study showed that daily supplementation with vitamin E pills reduced the chance of having a heart attack by 77 percent. The benefits of vitamin C supplementation were also demonstrated in a study conducted by researchers at Cambridge University in the UK. They examined the relationship between blood levels of vitamin C status and angina in women aged 45-74. They found that those women with higher vitamin C levels had a 66 percent reduced risk of angina. In addition, other studies regarding vitamin C have shown a protective effect with regards to several forms of cancer (e.g., prostate, lung, colon and breast cancers).

Application

It is clear that the antioxidant vitamins E and C do have a significant positive effect on the body. Sound evidence has shown that by increasing daily intake of these two vitamins to more than twice that of the RDA, the probability of obtaining two of the most deadly diseases are greatly reduced. This is not to say that such vitamins are to be now labeled "wonder drugs", as there are still many studies in progress in determining their full effects in prevention and treatment of certain diseases.

It is still essential that a healthy diet and active lifestyle be maintained. Yet still, when comparing the overall benefit of supplementation of vitamins E and C, it is evident that the health benefits far outweigh the alternative. Therefore, supplementing vitamin C and E in addition to daily exercise and a healthy diet may be one of the healthiest resolutions of the millennium yet!

References

Adams AK et al. Antioxidant vitamins and the prevention of coronary heart disease. Am Fam Physician 1999;Sep 1;60(3):895-904.
Kristal AR et al. Vitamin and mineral supplement use is associated with reduced risk of prostate cancer. Cancer Epidemiol Biomarkers Prev 1999;8(10):887-92.
Marchioli R. Antioxidant vitamins and prevention of cardiovascular disease: laboratory, epidemiological and clinical trial data. Pharmacol Res 1999 Sep; 40(3):227-38.
Whitney H, Cataldo C, Rolfes S. Understanding Normal and Clinical Nutrition. Wadsworth Publishing Company; 1998.
Author: Kelli Trampe is currently finishing her studies in nutrition and dietetics at the University of Nebraska-Kearney. She can be reached at Kellitrm@aol.com.