Adjusting diet–outcome associations for random error: comparison of associations based on observed and estimated usual intakes

How does caffeine influence memory? Drug, experimental, and demographic factors

Caffeine is a widely used nootropic drug, but its effects on memory in healthy participants have not been sufficiently evaluated. Here we review evidence of the effects of caffeine on different types of memory, and the associated drug, experimental, and demographical factors. There is limited evidence that caffeine affects performance in memory tasks beyond improved reaction times. For drug factors, a dose-response relationship may exist but findings are inconsistent. Moreover, there is evidence that the source of caffeine can modulate its effects on memory. For experimental factors, past studies often lacked a baseline control for diet and sleep and none discussed the possible reversal of withdrawal effect due to pre-experimental fasting. For demographic factors, caffeine may interact with sex and age, and the direction of the effect may depend on the dose, individual tolerance, and metabolism at baseline. Future studies should incorporate these considerations, as well as providing continued evidence on the effect of caffeine in visuospatial, prospective, and implicit memory measures.

Breakfast patterns and their association with body mass index in Brazilian adults

The objective was to investigate the relationships between body mass index (BMI), skipping breakfast, and breakfast patterns in Brazilian adults. We analyzed data of 21,003 individuals aged between 20 to 59 from the Brazilian National Dietary Survey 2008-2009. Breakfast was defined as the eating occasion between 5 and 10a.m. with the highest usual food consumption (exceeding 50Kcal/209.2kJ). Dietary patterns were derived by the factor analysis of 18 food groups (usual intake). Controlling for confounders linear regressions of BMI were used to verify the associations considering the survey design. Skipping breakfast was not associated with BMI. Three breakfast patterns were observed (48% variability): Brazilian Northern (positive loading for meats, preparations with corn, eggs, tubers/roots/potatoes, dairy products, savory snacks/crackers, fruit juices/fruit drinks/soy-based drinks); Western (positive for fruit juices/fruit drinks/soy-based drinks, sandwiches/pizza, baked/deep-fried snacks, chocolate/desserts, cakes/cookies) and Brazilian Southeastern (cold cut meat, milk, cheese, coffee/tea, bread). The Brazilian Southeastern pattern was inversely associated with BMI, while the Brazilian Northern pattern was directly associated with it. Therefore, the results suggest a role for breakfast quality in the association with BMI. Thus, a Brazilian Southeastern breakfast usual intake may be inversely associated with BMI.