Vitamins - Dietary Health Benefits

Dietary Health Benefits

The benefits of any dietary factors are very difficult to prove, and to date, there is little evidence that most dietary supplements protect against major diseases in otherwise healthy people with normal eating habits. A diet naturally high in vitamins and minerals can be the best defense against many diseases. Fresh fruits and vegetables and whole grains are the primary sources of vitamins, carotenoids, and vitamins, as well as of fiber and important minerals.

Antioxidants: Pros and Cons

Description of Free Radicals (Oxidants). Currently, the most important benefit claimed for vitamins A, C, E, and many of the carotenoids and phytochemicals is their role as antioxidants, which are scavengers of particles known as free radicals (also sometimes called oxidants). These chemically active particles are byproducts of many of the body's normal chemical processes.

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Description of Antioxidants and Warnings on High-Dose Supplements. Antioxidant vitamins (A, C, and E), carotenoids, and many phytochemicals can neutralize free radicals. Unfortunately, although it is clear that small amounts of these vitamins are required to prevent deficiency diseases, high-dose vitamin C, vitamin E, and beta-carotene supplements may also have pro-oxidant effects, which can be harmful in patients with cancer. In these people, high doses of antioxidant vitamins may actually protect cancer cells just as they do healthy cells.

Protection against Heart Disease

A low dietary intake of vitamins A, C, E, and beta-carotene has been linked to heart disease. Deficiencies in the B vitamins folate (known also as folic acid) and B12 have been associated with elevated blood levels of homocysteine, an amino acid that has been associated with a higher risk for heart disease, stroke, and heart failure. However, supplements of these vitamins, singly or in combination, do not protect against heart disease.

Carotenoids and Heart Protection. Studies have reported that a diet high in fruits and vegetables containing beta-carotene, lycopene, and other carotenoids may reduce the risk of heart attack. Diets low in lycopene (particularly from tomatoes) have been associated with a significantly higher risk of heart disease and stroke.