The brain has a high oxygen demand and at the same time a high content of polyunsaturated fats (lipids), which are particularly susceptible to lipid peroxidation (oxidative stress). Lipid peroxidation produces free radicals, which in turn damage lipids in the cell membrane. A kind of chain reaction can occur.
In addition, the aging process causes morphological and physiological changes in the brain that lead to a higher production of reactive oxygen species (free radicals) and a decrease in antioxidative capacity. To combat the cytotoxic activities of free radicals, cells are equipped with a variety of antioxidant defense mechanisms, including antioxidant enzymes such as catalase and glutathione peroxidase, and radical scavengers such as vitamin C and vitamin E.
Antioxidants can work by minimizing oxidants, such as free radicals and metal ions, or by interfering with underlying chain reactions. The antioxidants then optimize the cell’s own defense mechanisms.
Vitamin C and Vitamin E
Vitamin E (tocopherols and tocotrienols) is the most important membrane-bound fat-soluble antioxidant, and vitamin C (ascorbic acid) is an important water-soluble antioxidant that protects low-density lipoproteins from oxidation. In vitro studies (tests with substances in the test tube) indicate that antioxidants, including vitamins C and E, may prevent the unphysiological changes in tau protein associated with AD. In addition, vitamin E has been associated with a reduced mortality rate of nerve sites in the hippocampus.
However, there seems to be a synergistic connection between the effects of vitamin C and E, so that it can be assumed that the supplementation of both vitamins together is indeed effective for brain health and the positive effect in AD. However, further studies are needed to be certain.
The vitamin E contained in dietary supplements is usually synthetic and consists of only one of eight natural isoforms (alpha-tocopherol), so vitamin E from food sources should have priority: These also contain important components and phytochemicals that interact with each other, enhance their positive effects against each other, and provide various combinations of tocopherol and tocotrienol forms that can play an important role in the prevention of AD.