According to new research, a good diet and regular exercise don't just help you lose weight. Two studies presented at the annual Alzheimer's Association International Conference on July 14th suggest that if you're an older adult, healthy lifestyle factors may also lower your risk of developing dementia.
In the first study, Dr. Klodian Dhana and his team at Rush University Medical Center in Chicago followed about 2,500 older adults for almost a decade while monitoring several lifestyle factors: their diet, whether they smoked cigarettes, their alcohol drinking frequency, the amount of physical activity they engaged in each week, and their amount of cognitive activity. Researchers found that people who lived a healthier lifestyle - those who maintained a low-fat diet, did not smoke, exercised at least 150 minutes each week, drank in moderation, and were cognitively active - had lower levels of Alzheimer's dementia.
Compared to those who followed zero or only healthy lifestyle behavior, people who abided by two or three healthy behaviors lowered their risk by 39%. Dementia risk was lowered by an astounding 59% for those who followed four or five of the healthy lifestyle factors. This result means that behavioral factors are additive - the more healthy habits people adopt, the lower their risk.
So, what about genetics? When Dr. Dhana limited the dataset to only people with genetic risk factors such as the ApoE4 gene, which is known to increase the risk and lower the age of onset of Alzheimer's, they found that even those with this genetic risk lowered their chances of dementia by living a healthy lifestyle.
In a second study published in JAMA, scientists analyzed data from nearly 200,000 people age 60 or older enrolled in the UK Biobank study, a long-term study of older people that tracks factors contributing to various diseases. They compiled a list of genetic variants that may contribute to dementia and created a risk score for each participant. Researchers also assigned each person a lifestyle score based on four behaviors: diet, exercise, smoking cigarettes, and alcohol use. The goal was to figure out how genetic risk factors and lifestyle factors affect dementia risk, and if they interact to contribute to the disease.
Researchers found that although people with more genetic risk factors had a high risk of dementia compared to those with lower genetic risk scores, those who adopted healthier behaviors were half as likely to develop dementia compared to those who practiced fewer healthy lifestyle habits.
"It's really reassuring in a way, since people say, 'my parents had dementia so I probably inherited bad genes,' " says Dr. David Llewellyn from the University of Exeter and senior author of the study. "It's important that people don't fall into the trap of thinking that depending on your genes, dementia is inevitable. We found that it's not an all or nothing thing. The overall pattern of healthy behaviors and a healthy lifestyle can make a difference."