There has been a vast amount of medical research indicating that eating a healthy diet produces a more disease-free life. Because of this science, we have established recommended dietary guidelines so people will know exactly what they should be eating. These guidelines recommend a diet that restricts saturated fats and emphasizes whole grains, fresh fruits and vegetables, fresh fish, and lean animal and dairy proteins. A diet containing five to eight servings of fresh fruits and vegetables per day, complex carbohydrates from whole grains, lean proteins, including two servings of blue water fish per week, continues to be an effective strategy to reduce the risk of many diseases.
What researchers found in people who did not have diets that met the established nutritional guidelines was also valuable. These individuals generally ate foods with high levels of saturated fats (from animal proteins and dairy products) and significant amounts of carbohydrates. However, their diets did not contain enough fish and fresh fruits and vegetables. The results were higher levels of heart disease, strokes, diabetes, cataracts, and cancer. What was causing these higher rates of disease? Did the increased health risks come simply from the excess of saturated fats and carbohydrates, or was something missing in their diets from the lack of fresh fruits and vegetables? The answer was yes on both counts.
Diet provides our bodies essential nutrients it needs to function properly. Fresh fruits and vegetables contain many of these nutrients (vitamins and minerals) that are not abundant in the other foods we eat. What we have learned is that the same nutrients found in those fresh fruits and vegetables essential to normal function are needed for protection. These nutrients are called antioxidants. They are an important component of the body's antioxidant defense system.
There has been a great deal of hype and some confusion about what exactly antioxidants can and can't do for us. Here are the facts.
Within the cells, the continuous breakdown of oxygen during normal cellular metabolism results in byproducts called free radicals. These free radicals are compounds missing an electron in their outer shell making them very unstable. Generally, free radicals attack the nearest stable molecule. The most preferred site is the lipid membrane of a nearby cell. The free radical attack on the cell membrane is called lipid peroxidation. The cell that lost an electron from its lipid membrane then becomes a free radical itself, beginning a chain reaction. A lipid peroxidation damaged cell no longer functions normally and usually must be removed by the immune system. Once the process is started, it can cascade, resulting in tissue damage believed to play a role in over sixty disease states.
The body has the ability to prevent free radical chain reactions with compounds called antioxidants. Antioxidants neutralize free radicals by donating one of their own electrons. The antioxidants themselves don't become free radicals because they remain stable even after losing an electron. Normally, the body's antioxidant supply is adequate to handle neutralizing the free radicals it produces, but if antioxidants are unavailable, or if the free radical production becomes excessive, damage can occur. Of particular importance is that free radical damage accumulates with age. Another area of increasing concern is the growing number of free radicals formed inside our bodies from exposure to smoke, sunlight, chemicals and pollution. The term oxidative stress is now used to identify the amount of potential risk an individual faces from free radicals.
The body has two sources of antioxidants. The body can produce two powerful antioxidants on its own. They are glutathione peroxidase and superoxide dismutase. The rest of the body's antioxidants are provided directly from the food we eat. The majority of antioxidant nutrients are found in fresh fruits and vegetables. For the body's antioxidant defense system to be effective, the food we eat must contain adequate amounts of antioxidant vitamins and minerals. It is essential to have an adequate supply available to act as scavengers neutralizing free radicals before cellular damage or tissue damage can begin. There is universal agreement among medical researchers that those individuals who eat five to eight servings of fresh fruits and vegetables each day get adequate antioxidant supplies and have less disease than those individuals who don't.
Recently, there have been some studies that have questioned the role of antioxidants in reducing disease rates. The truth is that these studies were done on individuals who already had significant disease. The fact remains that medical research continues to believe that free radicals cause disease and that the role of antioxidants to neutralize free radicals is essential to minimizing their harmful effects. A diet rich in antioxidants is a preventive strategy more than a treatment strategy in most cases. Medical researchers have also discovered new antioxidants, like lycopene found in tomatoes and polyphenols found in green tea and grapes, while continuing to study the best way to maximize the benefits of vitamin C, vitamin E, beta-carotene, selenium, coenzyme Q10 and many others.
The other truth about antioxidants is that there is no substitute to a healthy diet. The good news about the benefits of adequate antioxidant levels in the body has lead some individuals to believe that simply taking antioxidant supplements is the right approach. This is not the case, especially, if you take large amounts of only one or two antioxidant vitamins or minerals. A much better approach is to follow the recommended nutritional guidelines the best you can and then take a multivitamin. A blend of antioxidant vitamins and minerals, at the levels found in a multivitamin, has proven to be the most accepted scientifically valid approach. Many antioxidant vitamins and minerals actually function better together at lower doses. There is also evidence that too much of a single antioxidant is contraindicated in some individuals. The cautiousness of medical professionals to enthusiastically endorse antioxidant supplements comes more from fears about their overuse than about anything else.
There are individuals who have medical or family histories where additional antioxidant supplements maybe indicated. Those individuals with Age Related Macular Degeneration are an excellent example of people who require special levels of antioxidants that rarely can be met through diet and a multivitamin alone. However, the best counsel to the public is to get expert advice from a healthcare professional about what special antioxidant needs you may have and how much you should take. This way the hype and confusion about antioxidants will be eliminated and the benefits they provide can be individualized to meet your specific needs.
References:
1. J Gerontol 1980 Jan; 35(1): 45-56: Leibowitz BE; Siegel BN
Aspects of free radical reactions in biological systems: aging.
2. Biochim Biophys Act 1981 May 22; 664(2); 266-72 Leung HW; Vang MJ
The cooperative interaction between vitamin E and vitamin C in suppression of peroxidation of membrane phospholipids.
3. Arch Biochem Biophys 1990 Jun; 279(2): 402-5: Sato K; Niki E; Shimasaki H
Free radical-mediated chain oxidation of low-density lipoprotein and its synergistic inhibition by vitamin E and vitamin C.
4. Am J Clin Nutr 1991 Jan; 53 (1 suppl): 3525-3553 Jacques PF; Chylack LTJr
Epidemiological evidence of a role for the antioxidant vitamins and carotenoids in cataract prevention.
5. Ann NY Acad Sci 1992 Sep 30; 669(1) 7-20: Sies H; Stahl W; Sundquist AR
Antioxidant functions of vitamins. Vitamin E and C, beta-carotene and other carotenoids.
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