Table of Contents
- Highlights
- Introduction
- Carotenoids
- Phytochemicals
- Healthy Foods
- Dietary Health Benefits
- Resources
- References
Studies have indicated that, while B vitamin supplements help lower homocysteine levels, they have no effect on heart disease outcomes. Research is under way to evaluate the benefit of vitamins on reducing stroke risk.
Protection against Cancer
Many fresh fruits and vegetables contain chemicals that may fight many cancers, including lung, breast, colon, and prostate cancers. Examples of important cancer fighting foods include cruciferous vegetables (such as cabbage, Brussels sprouts, and broccoli), tomatoes (which contain lycopene), and carrots (which contain alpha-carotene).
Any protective effects of vitamins or specific phytochemical against cancer, however, appear to depend on the cooperative effort among them. Supplements of any vitamins or food chemicals have not shown any benefits.
Additionally, certain supplements may actually encourage tumor growth.
Vitamins and Cancer Protection. Because many cancers are thought to be initiated by the effects of oxygen-free radicals on DNA, the antioxidants A, C, and E and beta-carotene have been intensively studied. Beta-carotene supplementation increases lung cancer risk in smokers and persons exposed to asbestos.
In 2006, a study for the National Institutes of Health reviewed randomized trials evaluating the effectiveness and safety of multivitamin and mineral supplements in preventing cancer and chronic disease. The reviewers concluded that current evidence is not sufficient to determine that multivitamin and mineral supplements prevent cancer or chronic disease.
Carotenoids and Cancer Protection. A number of studies have reported that fruits and vegetables rich in carotenoids may protect against many cancers. Lycopene, found in tomatoes, may protect against prostate, colon, lung, and bladder cancers. Supplements, however, do not offer any advantage.
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Review Date: 10/08/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine,
Harvard Medical School; Physician, Massachusetts General Hospital.
Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M.,
Inc.
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)
