Health and Bread Intervention Trials (HABIT): Is Nutrient-Rich Bread an Effective Way of Promoting Cognitive Functioning?

Abstract

Growing evidence demonstrates that regular consumption of dietary nutrients such as unsaturated fatty acids, nitrate, and reduced sodium can maintain the structural integrity of the brain and in doing so promote cognitive functioning. However, consuming sufficient amounts of such nutrients can be an economic and timely challenge. Incorporating nutrients into a dietary staple, such as bread, may be an effective way of introducing these into everyday diets. The present study investigated the effects of a 12-week dietary intervention involving the manipulation of 3 key nutrients in bread (increased unsaturated fatty acids from hazelnuts, increased nitrate from beetroot, and reduced sodium) on cognitive function. Participants (n=106) were randomly allocated to 1 of 4 bread conditions (hazelnut, beetroot, low-sodium, or control). A neuropsychological battery was administered at 4 time points and consisted of 6 tasks measuring different aspects of cognitive functioning: Pro (choice reaction time), Anti (inhibitory control), Pro/Anti (task switching), Simon (selective attention), Forward and Backward Spatial Span (spatial short-term and working memory), and Forward and Backward Digit Span (verbal short-term and working memory). Three hypotheses were explored: (1) that consuming the hazelnut bread would be associated with performance improvements across the cognitive tasks, (2) that consuming the beetroot bread would be associated with improvements in speeded reaction time tasks, and (3) that consuming the low sodium bread would be associated with performance improvements across the cognitive tasks, but especially on Forward and Backward Spatial Span. Overall, no significant improvements in cognitive function were observed following the consumption of any of the 3 intervention breads when compared to the control bread. These findings contrast with previous research that has demonstrated links between the consumption of these nutrients and improved cognitive function. Possible reasons for the null results, as well as limitations and future directions, are discussed.