Antioxidants: Nutrients That Can Slow Alzheimer's

People need oxygen to live, but oxygen also has a downside. In the body, some oxygen molecules become so highly chemically reactive that they disrupt other body processes. These troublemaker molecules are called free radicals, and many scientists believe that the damage they inflict (oxidative damage) is at the root of both cancer and heart disease. (Smoking and a high-fat diet greatly increase the number of free radicals in the blood.)



Free radicals also contribute to the development of Alzheimer's disease. The destructive action of free radicals fits neatly with two other risk factors for Alzheimer's: one form of the gene for apolipoprotein E (APOE) and beta-amyloid. The APOE gene controls synthesis of apolipoprotein, which transports cholesterol in the blood. People with two copies of the APOE4 variety of this gene have higher concentrations of low-density lipoprotein (LDL, so-called "bad cholesterol" because it increases risk of heart attack). High LDL levels have also been linked to Alzheimer's risk.



In addition, high LDL levels also seem to favor deposition of beta-amyloid, the major component of the senile plaques characteristic of Alzheimer's. Beta-amyloid appears to react with the cells that line blood vessels in the brain to produce excessive quantities of free radicals, which damage brain tissue even more. Brain tissue is highly susceptible to free radical damage because, unlike many other tissues, it does not contain significant amounts of protective antioxidant compounds.



Fortunately, certain nutrients -- antioxidants -- can prevent the oxidative damage free radicals cause. Antioxidant nutrients include:


  • Vitamin A

  • Vitamin C

  • Vitamin E

  • The mineral selenium

  • The carotenoids, among them beta-carotene


These nutrients are abundant in plant foods, and many studies show that as fruit and vegetable consumption increases, risk of cancer decreases. A few studies have investigated the effects of antioxidants on Alzheimer's disease. Results to date have been intriguing.