Vitamin C supplements were associated with a lower prevalence of more severe cognitive impairment in a study involving 117 people . This study suggests vitamin C may protect against cognitive impairment. Studies like this suggested that antioxidant vitamins may protect the brain against damage caused by free radicals and other reactive oxygen species. These can be formed from external insults or internally as molecular byproducts of basic cellular metabolism. Neurons are especially vulnerable to damage caused by free radicals, which is believed to be one pathway for the development of Alzheimer’s disease.
Researchers examined data from the Cache County Study, a large, population-based investigation of the prevalence and incidence of Alzheimer’s disease. This involved approximately 4,700 residents who were sixty five or older and were assessed during two separate time periods (from 1996-1997 and again from 1998-2000) . Researchers found the combined use of vitamin E and C supplements resulted in a reduced incidence of Alzheimer’s disease controlling for age, sex, education and general health by about 64%.
Interestingly, the researchers saw no appreciable decrease if people took vitamin E or vitamin C alone, or if they took a multivitamin. The authors explained that the use of vitamins E and C may offer protection against Alzheimer’s disease when taken together in higher doses. Incidentally, a British government funded expert group on vitamins and minerals (EVM) recently recommended a safe upper limit of 800 IU vitamin E for daily supplementation and 1000mg for vitamin C.
- Michael Paleologos, Robert G. Cumming and Ross Lazarus Cohort Study of Vitamin C Intake and Cognitive Impairment Am J Epidemiol 1998; 148: 45–50.