Research supports a healthy diet and moderate exercise for protection against cognitive decline and dementia. Results presented at last year’s Alzheimer’s Association Conference in Vienna, Austria, suggest that a “heart healthy” diet and maintaining or increasing physical activity may help preserve memory and thinking abilities.
The research looked at the effects of the so-called Dietary Approaches to Stop Hypertension (DASH) diet, which consists of fruit, vegetables, nuts or legumes, whole grains, low-fat dairy and fish. The diet is often recommended for high blood pressure or pre-hypertension. A consequence of reducing blood pressure is a reduction in the risk of Alzheimer’s disease and dementia.
Researcher Dr. Heidi Wengreen of Utah State University and colleagues followed 3,831 people 65 years of age or older. Greater adherence to the diet was linked with better cognitive functioning. In four assessments over 11 years, those in the top fifth for adherence to the diet scored significantly higher than did those in the bottom fifth.
Four of the nine food groups were also independently associated with cognitive function scores. These were vegetables, whole grains, low-fat dairy, and nuts or legumes. “Our results suggest that including whole grains, vegetables, low-fat dairy foods, and nuts in one’s diet may offer benefits for cognition in late life,” Wengreen said. “However, we need more research before we can confidently say how much of these foods to include in your diet to experience some benefit.”
Dr. William Thies of the Alzheimer’s Association commented, “We can’t do anything about aging or family history, but research continues to show us that there are lifestyle decisions we all can make to keep our brains healthier, and that also may lower our risk of memory decline as we age.”
Also at the conference, Dr. Deborah Barnes of the University of California, San Francisco, and colleagues presented evidence based on 3,075 older adults that cognitive decline was slower in those whose exercise levels remained constant or increased.
In the study, physical activity was calculated by number of minutes walked per week at the beginning of the study, and after two, four, and seven years. At each time point, participants were classified as sedentary (0 minutes per week), low (less than 150 minutes per week) or high (150 minutes per week or more).
Just over a fifth (21 percent) of study participants were consistently sedentary, 12 percent maintained their activity levels, 26 percent had declining levels, and 41 percent had increasing or fluctuating levels.
Cognitive decline occurred faster in those who were consistently sedentary, followed by those with declining activity levels and those with increasing or fluctuating activity levels. It was slowest in those who maintained their activity levels. Sedentary individuals who started a new exercise program showed improvements in their cognitive function, particularly the ability to process complex information quickly.
Barnes said, “We found that older adults who were sedentary throughout the study had the lowest levels of cognitive function at the beginning and experienced the fastest rate of cognitive decline. Cognitive decline also was faster in those whose physical activity levels consistently declined during the study period.
“Sedentary individuals should be encouraged to engage in physical activity at least occasionally,” she recommends. “People who are currently active should be encouraged to maintain or increase their activity levels.”
Dr. Mary C. Tierney of the University of Toronto, Canada, has examined the links between activity levels and cognition, this time in postmenopausal women. She explains that long-term strenuous physical activity decreases lifetime exposure to ovarian hormones, which may play a protective role against breast cancer. But it has also been associated with increased risk of cognitive impairment. Conversely, long-term physical activity is linked to improved cognition.
Tierney carried out a study of 90 women aged 50 to 63 years, within ten years of passing through menopause. Analysis showed that long-term strenuous activity was consistently associated with poorer performance on memory and brain function tests, such as semantic memory, working memory, delayed verbal recall, and sustained attention. On the other hand, moderate physical activity was consistently associated with better performance on all of the tests.
Presenting the results at the Alzheimer’s Association Conference, Tierney’s research team stated, “Strenuous physical activity, while protective for breast cancer, may have deleterious effects on later life cognition, whereas moderate long-term physical activity may improve later life cognition.
“The consistency of the direction of the relationships of these preliminary findings has important implications for lifestyle recommendations and supports the need for large-scale longitudinal studies including both women and men.”
Wengreen, H. J. et al. DASH diet adherence scores and cognitive decline and dementia among aging men and women: Cache County study of Memory Health and Aging. Presented at the 2009 Alzheimer’s Association International Conference on Alzheimer’s Disease (ICAD 2009) held in Vienna, Austria, from July 11-16, 2009.
Barnes, D. E. et al. The impact of changes in physical activity levels on rate of cognitive decline in a biracial cohort of non-demented elders. Presented at the 2009 Alzheimer’s Association International Conference on Alzheimer’s Disease (ICAD 2009) held in Vienna, Austria, from July 11-16, 2009.
Tierney, M. et al. Intensity of long-term physical activity and later life cognition in postmenopausal women. Presented at the 2009 Alzheimer’s Association International Conference on Alzheimer’s Disease (ICAD 2009) held in Vienna, Austria, from July 11-16, 2009.