Previous studies have shown in animal studies that a special protein called brain-derived neurotrophic factor (BDNF) is vital for brain cell survival and function, improved brain plasticity (or ability to change from experience), and long-term memory. JAMA Neurology reported that researchers from the Framingham Heart Study have suggested that higher serum BDNF levels may protect against future occurrences of dementia and Alzheimer’s disease, especially in the select subgroups of women, individuals 80 and older, and higher in participants with college degrees.
Circulating BDNF levels increase with physical activity and caloric restriction, which suggest the associations between lifestyles and mental health.
2131 dementia-free Framingham Study original and offspring participants were followed up from 1992 and 1998, respectively, for up to 10 years. During the follow-up of the study, 140 participants developed dementia, 117 of whom had Alzheimer’s disease. After statistical analysis, the researchers found that each standard deviation increment in BDNF resulted in a 33% decreased the risk for dementia and Alzheimer’s disease. The upper-three quintiles had approximately 21.5 times more serum BDNF than the bottom quintiles. Genetic variations in brain-derived neurotrophic factor were not associated with the risk of developing Alzheimer’s disease.
"We suggest that serum BDNF may play a role in the development of Alzheimer's disease, especially in older women, the group at highest risk for Alzheimer's disease," the researchers wrote. "This is of particular interest because serum BDNF levels can be elevated through simple lifestyle measures such as increased physical activity."
Dr. Sudha Seshadri and colleagues looked at subgroups of age, gender, educational attainment and realized that BDNF-dementia associations varied widely. They were nearly absent in men, participants younger than 80, and those without at least a college degree. Each standard deviation increase in BDNF decreased the risk of dementia in men by 12%. The trend was stronger for those with college degrees with a decreased risk of 17%.
Seshadri and colleagues suggested that these hypotheses “needs further exploration and additional studies”.