| A report published online on September 1, 2010 in the British Journal of Nutrition revealed a protective effect for a number of antioxidant nutrients against all-cause and disease-specific mortality in older individuals over a 13 year average period. "The purpose of the present paper is to explore the predictive significance of a selection of biochemical indices for nutrients that are believed to mediate redox-modulatory (antioxidant or pro-oxidant) functions in living tissues," the authors write. "Evidence that subsequent all-cause mortality may be predicted by vitamin C intakes and/or status has been obtained in several previous studies, and similarly for carotene and selenium." Researchers at MRC Human Nutrition Research in Cambridge and University College in London evaluated data from 1,054 participants in the British National Diet and Nutrition Survey, which enrolled men and women aged 65 and older from 1994 to 1995. Blood samples obtained upon enrollment were analyzed for plasma vitamin C, retinol, alpha-tocopherol, gamma-tocopherol, carotenoids, zinc, copper, iron, selenium and a1-antichymotrypsin, a serine protease inhibitor that is increased during inflammation. Four day dietary records were analyzed for the intake of these nutrients and energy intake. The participants were followed through September, 2008 and the causes of any deaths were documented. Seventy-four percent of the men and 62 percent of the women enrolled in the Survey died over the course of follow-up. Increased plasma vitamin C, alpha-carotene, selenium, zinc and iron were significantly associated with a reduction in all-cause mortality, as was the dietary intake of vitamin C, carotenoids, zinc, copper and total energy. These patterns remained fundamentally similar when deaths from vascular, cancer and respiratory diseases were separately considered, however, increased dietary vitamins C and E were found to confer a significant protective effect against cancer, and dietary vitamin E protected against respiratory disease in males (while carotenoid intake was protective in women). An association of elevated plasma copper and a1-antichymotrypsin levels with increased mortality was explained by the fact that a1-antichymotrypsin and a major copper-containing plasma protein increase during inflammatory states. "A number of baseline nutrient status indices with ‘redox-modulatory’ connotations appear to predict all cause, primary vascular disease, cancer or respiratory disease mortality in older British adults," the authors conclude. "Future studies should attempt to determine, first, which nutrients are the most frequent predictors of all-cause and specific-cause mortality in different populations, and second, whether these predictions can imply causal relationships, such that dietary or other interventions might promote disease-free longevity." |
