Background There is evidence from animal and in vitro models of the protective effects of caffeine in Alzheimer’s disease. The suggested mechanisms through which caffeine may protect neurons against Alzheimer’s disease pathology include the facilitation of beta-amyloid clearance, upregulation of cholinergic transmission, and increased neuronal plasticity and survival. Epidemiological studies support that Alzheimer’s disease patients consume smaller amounts of coffee beverages throughout their lives as compared to age-matched cognitively healthy individuals. Objective The aim of the present study was to determine whether the negative association between Alzheimer’s disease and coffee consumption may be influenced by a common genetic predisposition, given the fact that the pattern of coffee consumption is determined by both environmental and genetic factors. Method We conducted an in silico search addressing the association between genetic polymorphisms related to coffee consumption and the diagnosis of Alzheimer’s disease. We further investigated the interactions between genes located in regions bearing these polymorphisms. Results Our analysis revealed no evidence for a genetic association (nor interaction between related proteins) involving coffee consumption and Alzheimer’s disease. Discussion The negative association between Alzheimer’s disease and coffee consumption suggested by epidemiological studies is most likely due to environmental factors that are not necessarily regulated by genetic background.

Background Ghrelin is a potent hormone with central and peripheral action. This hormone plays an important role in the regulation of appetite, food intake, and energy balance. Studies have suggested that ghrelin is involved with eating disorders (ED), particularly bingeing and purging. Genetic variants have also been studied to explain changes in eating behavior. Methods We conducted a literature review; we searched PubMed, Scientific Electronic Library Online (SciELO), and LILACS databases using the keywords “eating disorder”, “ghrelin”, “polymorphism”, “anorexia nervosa”, “bulimia nervosa”, “binge eating disorder”, and their combinations. We found 319 articles. Thirty-nine articles met the inclusion criteria. Results High levels of ghrelin were found in patients with anorexia nervosa (AN), especially in the purging subtype (AN-P). There was also a positive correlation between fasting ghrelin level and frequency of episodes of bingeing/purging in bulimia nervosa (BN) and the frequency of bingeing in periodic binge eating disorder (BED). Some polymorphisms were associated with AN and BN. Conclusion Changes in ghrelin levels and its polymorphism may be involved in the pathogenesis of EDs; however, further studies should be conducted to clarify the associations.

In this study, we investigated the associations between single-nucleotide polymorphisms in GAB2 (rs2373115), GSK3B (rs6438552) and SORL1 (rs641120) and Alzheimer's disease (AD), both alone and in combination with the APOE*4 allele.