The immune system and Antioxidants
The immune system is an important defense against invading foreign pathogenic microorganisms such as cancer-causing viruses and is essential for the healing of injured tissues. Foreign antigens and cell injury evoke an immune response that through a complex process, including acute inflammation, removes the pathogenic microbes and cellular debris. Newly formed cancer cells may acts as foreign agents that evoke an immune response, producing natural killer (NK) cells that can remove cancer cells from the body. If there are not enough NK cells, newly formed cancer cells can establish themselves in the body and grow.
Antioxidants in our body defend against damage produced by free radicals. Some antioxidants are made in the body, whereas others are consumed through a diet containing fruits and vegetables. Both dietary and endogenous antioxidants are essential for optimal health and cancer prevention. The biological half-lives of most micronutrients are highly variable; therefore, they should be taken twice a day to maintain steady levels of these micronutrients in the body. Most micronutrients are very sensitive to light and should be stored in the dark. In a solid form such as a tablet, most (except vitamin A) are stable at room temperature.
Most antioxidants at certain doses are considered safe; however, some, such as vitamin A, beta-carotene, and vitamin E, at high doses can be harmful after long-term daily consumption. The window of safety for selenium and vitamin A is very narrow. Selenium at high doses, for example, can cause cataracts. We believe that daily supplementation with a multiple-micronutrient preparation containing dietary and endogenous antioxidants, B vitamins, vitamin D, and selenium (but not iron, copper, or manganese) should be useful for maintaining optimal health and for cancer prevention.
Although most adverse health events occur primarily from the consumption of certain herbs, the term dietary supplements includes both these herbs and antioxidants, which has created misunderstanding among the general public about the safety of antioxidants. However, vitamins A, C, and E and carotenoids, glutathione, R-alpha-lipoic acid, coenzyme Q10, and L-carnitine have had few reported adverse health events for decades, and these adverse health events only occur when these supplements are taken at very high doses.