Physical Activity, Nutrient Supplementation Interventions Fail to Have Significant Effect on Cognitive Function
Physical activity, supplements not necessarily beneficial over long term in preventing cognitive decline.
Two studies in JAMA examine the effect of physical activity and nutrient supplementation on cognitive function. The news is not encouraging. In one study, Kaycee M. Sink, M.D., M.A.S., of the Wake Forest School of Medicine, Winston-Salem, N.C., and colleagues evaluated whether a 24-month physical activity program would result in better cognitive function, lower risk of mild cognitive impairment (MCI) or dementia, or both, compared with a health education program. Epidemiological evidence suggests that physical activity is associated with lower rates of cognitive decline. Exercise is associated with improved cerebral blood flow and neuronal connectivity and maintenance or improvement in brain volume. Participants (1,635, ages 70-89) in the Lifestyle Interventions and Independence for Elders (LIFE) study were randomly assigned to a structured, moderate-intensity physical activity program that included walking, resistance training, and flexibility exercises or a health education program of educational workshops and upper-extremity stretching. Participants were sedentary adults who were at risk for mobility disability but able to walk about a quarter mile. Measures of cognitive function and dementia were determined at 24 months. The researchers found that the moderate-intensity physical activity intervention did not result in better cognition compared with the health education program. There was also no significant difference between groups in the incidence dementia. ÛÏCognitive function remained stable over 2 years for all participants. We cannot rule out that both interventions were successful at maintaining cognitive function,Û the authors write. Participants in the physical activity group who were 80 years or older and those with poorer baseline physical performance had better outcomes. In another study, Emily Y. Chew, M.D., of the National Eye Institute/National Institutes of Health, Bethesda, Md., and colleagues tested the effects of oral supplementation with nutrients on cognitive function. Participants were randomly assigned to two groups.åÊ All participants were also given varying combinations of vitamins C. E. beta carotene, and zinc. In addition to annual eye examinations, several validated cognitive function tests were administered via telephone by trained personnel at baseline and every 2 years during the 5-year study. The average age of the participants was 73 years, and 57.5 percent were women. There were no statistically significant differences in change of measures of cognitive function for participants randomized to receive supplements vs those who were not. Regarding the lack of effect of the supplements, the authors speculate that the supplements were started too late in the aging process and that supplementation duration of 5 years may be insufficient. ÛÏThe process of cognitive decline may occur over decades, thus a short-term supplementation given too late in the disease may not be effective.Û My opinion – I wouldn’t let this stop you from exercising. I have mixed feelings on the supplement side. I personally have to take them to prevent osteoporosis and build calcium and I have used combination of supplements in the past to lose almost 30 pounds.