The impact of carotenoids on cognitive function in the elderly
"Cognitive decline in the elderly is a significant public health issue. Oxidative stress and inflammation are believed to be involved in the pathogenesis of cognitive decline.
Genetics might influence the magnitude of an individual immune response to vitamin E supplementation in respiratory tract infections, says a new US study.
In the study, data from a previous randomized controlled trial were used: 617 elderly nursing home residents (mean: 84.6 years) were allocated to receive either vitamin E (200 IU alpha-tocopherol) or a placebo daily for one year (1). Based on blood samples, physical examinations and interviews, the incidence and duration of respiratory infections were assessed. While vitamin E supplementation had no significant effect on incidence or number of days with total (upper and lower) infections, the researchers observed a protective effect on upper respiratory tract infections, particularly the common cold, in some subgroups of the elderly population. To examine whether the effect of vitamin E on respiratory infections was dependent on genetic backgrounds, the researchers analyzed the DNA of 500 participants in the new study (2). The results showed that the effect of vitamin E was influenced by the sex of the participant and genetic factors: genetic variations (so called polymorphisms) at immunoregulatory genes seem to contribute to individual risk of respiratory infections.
References:The scientists commented that the recommendations for vitamin E supplementation as a preventive measure against respiratory infections should consider genetics and sex. They hypothesized that differences in individual genetics could help explain some of the large-scale intervention trials which have not demonstrated a health benefit to vitamin E supplementation. However, further studies would be needed to verify the results and understand the mechanisms driving them, they concluded.