Borobudur revisited: soy consumption may be associated with better recall in younger, but not in older, rural Indonesian elderly.

Previous reports have suggested that high frequent tofu consumption is associated with worse cognitive function in East Asian elderly. Some studies also found an increased risk of dementia with high tofu consumption in those older than 65years of age. Tofu and other soy products, such as tempeh, contain high levels of plant estrogens or isoflavones. This study revisited a rural Central Javanese population (56-97 years of age) who were covered by the Borobudur District Health Centers. Data on cognitive performance were available for n=142 participants. Results showed positive linear associations of weekly tofu (beta=.22, p<0.05) and tempeh (beta=.23, p<0.01) consumption with immediate recall, which were significant in those with an average age of 67 years. In those with an average age of 80 years, the earlier reported negative association of tofu with immediate recall was no longer significant. Lifestyle changes (reduction of tofu consumption after dissemination of results) or "healthy survivor effects" may have been responsible for this finding. These findings may be reminiscent of the "Window of Opportunity" theory, which suggests that estrogenic compounds can exert positive effects on verbal memory, but not in older men and women, when no or negative effects of these compounds on brain cells and cognition have been found. Long-term, placebo-controlled treatment studies should investigate whether tempeh, a fermented soybean product that also contains folate, can maintain cognitive function in middle-aged and elderly participants. Crown