Nutrition and Cognitive Function in Amazonian Horticulturalists

Lifestyle factors including nutrition, may play a role in the development of cognitive impairment. Previous studies based in the United States have shown that nutrient deficiencies in vitamin B-12 and folate can increase the risk of developing mild cognitive impairment in adults, while high levels of potassium increase the risk of cognitive impairment. Among the Tsimane and Moseten subsistence communities in Bolivia, there is a low prevalence of Alzheimer’s dementia and related diseases, but any impacts of micronutrients on cognitive impairment have not been assessed. Using a mixed longitudinal design to estimate nutrient intake via 855 dietary recall questionnaires (24-hour) from 370 Tsimane and Moseten aged 43-85 years (mean age 62 years, 47% male), a culturally specific dementia assessment (3MSE, KIKA, neurological exam) was conducted, and individuals were diagnosed as having normal cognition, mild cognitive impairment, or dementia. Logistic regressions with clustered standard errors (to account for multiple dietary questionnaires per individual) examined the association between dietary intake and cognitive impairment. Controlling for age, sex, body mass index, and education, those with higher daily caloric intake had a lower odds ratio of cognitive impairment, with every 100 additional calories associated with decreased risk (OR = 0.95, p=0.032). Higher B-12 intake was associated with lower cognitive impairment, while higher potassium intake was associated with greater cognitive impairment. The presented data indicate a correlation between diet and nutrition and cognitive impairment within a subsistence population. This observation underscores the potential tradeoffs individuals face in allocating resources towards survival versus the upkeep of cognitive faculties, reflecting broader considerations in life history strategies.