Objective: To examine associations of midlife tofu consumption with brain function and structural changes in late life.Geez, those with high tofu consumption were up to twice as likely to have low cognitive performance. That tofu stuff really messes you up!
Methods: The design utilized surviving participants of a longitudinal study established in 1965 for research on heart disease, stroke, and cancer. Information on consumption of selected foods was available from standardized interviews conducted 1965–1967 and 1971–1974. A 4-level composite intake index defined “low-low” consumption as fewer than two servings of tofu per week in 1965 and no tofu in the prior week in 1971. Men who reported two or more servings per week at both interviews were defined as “high-high” consumers. Intermediate or less consistent “low” and “high” consumption levels were also defined. Cognitive functioning was tested at the 1991–1993 examination, when participants were aged 71 to 93 years (n=3734). Brain atrophy was assessed using neuroimage (n=574) and autopsy (n=290) information. Cognitive function data were also analyzed for wives of a sample of study participants (n=502) who had been living with the participants at the time of their dietary interviews.
Results: Poor cognitive test performance, enlargement of ventricles and low brain weight were each significantly and independently associated with higher midlife tofu consumption. A similar association of midlife tofu intake with poor late life cognitive test scores was also observed among wives of cohort members, using the husband’s answers to food frequency questions as proxy for the wife’s consumption. Statistically significant associations were consistently demonstrated in linear and logistic multivariate regression models. Odds ratios comparing endpoints among “high-high” with “low-low” consumers were mostly in the range of 1.6 to 2.0.
Conclusions: In this population, higher midlife tofu consumption was independently associated with indicators of cognitive impairment and brain atrophy in late life.
The elevated prevalence of cognitive impairment we observed in the highest compared with the lowest midlife consumers of tofu was roughly of the magnitude as would be caused by a four year difference in age or a three year difference in education. In this study population, 20% to 25% of the burden of cognitive impairment appears attributable to midlife tofu consumption—an effect size of enormous public health importance, yet not readily discernable in comparisons across populations of diverse education, occupation, age distribution and genetic composition, especially when studied using different methods.