Single Antioxidants Don't Prevent Heart Disease

Photo Credit: Marcelo Alves

A new research article published in the prestigious Archives of Internal Medicine provides further evidence that supplementing with mega-doses of antioxidant vitamins does not prevent heart disease.

In this new research study, more than 8,000 women took vitamin C, vitamin E, beta-carotene, a combination of the above, or placebo. All of the women in the study had either existing cardiovascular disease or multiple risk factors for this condition. They took the vitamins on average for nearly 10 years.

At the conclusion of the study, little difference was seen in the incidence of heart attacks and strokes, or death from any cause in women who were taking the vitamin supplements compared to placebo. A modest reduction in stroke incidence was noted in women taking both vitamin C and E, but the researchers concluded that this was likely to be random chance due to the lack of protective effect seen with similar combinations.

Now that we have dozens of studies with hundreds of thousands of participants, I think doctors can pretty safely conclude that prescribing high doses of single antioxidant vitamins does not provide significant protection against heart disease. This is a finding that may disappoint some consumers, but I think one that in retrospect should not be terribly surprising.

Researchers have been interested in the use of antioxidants in the prevention of heart disease since the observation that free radical damage is an event that helps to trigger the process of artery blockage. Since antioxidants help prevent free radical damage, their supplementation is a logical approach to protection of the arteries and prevention of this blockage. A major complication with antioxidant supplementation, however, involves the interactive nature of antioxidants. Antioxidants work as a team in the body to quench these free radicals. Studies have generally found that single antioxidant interventions do not provide full protection against free radicals, and in some instances, have suggested that mega-doses of single nutrients can actually increase free radical production.

Another significant issue is that the forms of antioxidants used in the studies are not those found in the typical healthy diet. For example, the alpha tocopherol form of vitamin E (even assuming they are using the natural rather than synthetic form) is gamma tocopherol, the form found in the human diet and highest concentration in the blood. In fact, high dosages of alpha tocopherol actually decrease gamma tocopherol. This is important since the gamma form is far more protective of the heart than alpha. In addition, beta carotene is only one of several hundred carotenoids found in the diet. High dosages of beta carotene actually decrease the abortion of other carotenoids from the diet.

There are ongoing clinical research trials using more comprehensive antioxidant formulas that have the potential to provide a better vitamin approach in cardiovascular disease. Unfortunately, they still do not seem to be addressing the issue of appropriate form.

Photo Credit: Ali Karimian

Until the results from more comprehensive antioxidant studies with appropriate dosage forms are in, cardiovascular disease prevention should primarily focus on good diet and lifestyle habits. If you want to take antioxidant supplements, use modest dosages and forms which are closest to those found in nature. For example, use mixed tocopherols which have more gamma than alpha tocopherol and mixed carotenoids rather than just beta carotene.

Here are a few of the things I tend to stress with my patients:

• Aerobic exercise 5+ days per week
• Smoking cessation
• Diets rich in fresh fruits and vegetables daily
• Cold water fish twice weekly
• Weight control
• Stress reduction
• Low saturated and trans fats (often by eliminating fried foods and processed foods containing hydrogenated oils)

~Matt Brignall, ND

References:

• Cook NR, Albert CM, Gaziano JM, et al. A randomized factorial trial of vitamins C and E and beta carotene in the secondary prevention of cardiovascular events in women: results from the Women's Antioxidant Cardiovascular Study. Arch Intern Med. 2007;167:1610-8.
• Lonn E, Bosch J, Yusuf S, et al. Effects of long-term vitamin E supplementation on cardiovascular events and cancer: a randomized controlled trial. JAMA. 2005 Mar 16;293(11):1338-47.
• Omenn GS, Goodman GE, Thornquist MD, et al. Effects of a combination of beta carotene and vitamin A on lung cancer and cardiovascular disease. N Engl J Med. 1996;334:1150-5.
• Waters DD, Alderman EL, Hsia J, et al. Effects of hormone replacement therapy and antioxidant vitamin supplements on coronary atherosclerosis in postmenopausal women: a randomized controlled trial. JAMA. 2002;288:2432-40.

Related Topics:

• Vitamins: Separating Fact From Fiction
• Antioxidants, Vitamin E, Beta-Carotene and Cardiovascular Disease

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