ABSTRACT
BACKGROUND: Observational studies have suggested associations between amount of coffee consumption and decreased risk of neurodegenerative diseases. However, these studies do not consider differences among coffee types, including sweetened, unsweetened, caffeinated, and decaffeinated varieties. OBJECTIVE: This study aims to identify associations between the consumption of various coffee types (sugar-sweetened, artificially sweetened, unsweetened, caffeinated, and decaffeinated) and the risks of Alzheimer's disease and related dementias (ADRD) and Parkinson's disease (PD), along with related mortality. METHODS: This prospective study included 204,847 participants (44.7% males) from the UK Biobank. Cox proportional hazards models were used to assess the associations of coffee type with neurodegenerative outcome. Based on coffee consumption, participants were divided into five groups: non-coffee consumers, >0-1 cup/d, ≥1-2 cups/d, ≥2-3 cups/d, and ≥3 cups/d. RESULTS: Over a median follow-up of 9 years, the study documented 1,696 cases of ADRD, 1,093 cases of PD, and 419 neurodegenerative-related deaths. In the multivariate analysis, compared with non-coffee consumers, those with the highest intake of unsweetened and caffeinated coffee (≥ 3 cups/day) showed hazard ratios (95% confidence intervals) of 0.75 (0.62, 0.91) for ADRD, 0.71 (0.56, 0.91) for PD, and 0.67 (0.44, 1.01) for neurodegenerative-related death. However, no significant associations were noted in either decaffeinated or sugar/artificially sweetened coffee groups (P > 0.05). CONCLUSION: Higher intake of caffeinated coffee, particularly the unsweetened variety, was associated with reduced risks of ADRD and PD. No such associations were observed for sugar-sweetened or artificially sweetened coffee.
ABSTRACT
BACKGROUND: Many studies have investigated the intake of dietary isoflavones in relation to obesity risk, whereas the association using objective biomarkers of isoflavones, particularly equol (a gut-derived metabolite of daidzein with greater bioavailability than other isoflavones) has been less studied. In addition, the associations between equol and gut microbiota profile at the population level remain to be fully characterized. OBJECTIVES: We aimed to identify equol-predicting microbial species and to investigate the associations of equol-predicting microbial species and urinary excretion of isoflavones including glycitein, genistein, daidzein, and equol with diverse obesity markers in free living-individuals. METHODS: In this 1-y longitudinal study of 754 community-dwelling adults, urinary isoflavones, fecal microbiota, height, weight, and circumferences of waist and hip were measured at baseline and again after 1 y. Liver fat [indicated by the controlled attenuation parameter (CAP)] and other body composition were also measured after 1 y. Linear models and linear mixed-effects models were used to analyze the associations for single measure and repeated measures, respectively. RESULTS: Among 305 participants (median age: 50 y, IQR, 37-59 y) including 138 males and 167 females, higher urinary excretion of equol was associated with lower CAP (ß = -0.013, P < 0.001) and body fat mass (ß= -0.014, P = 0.046). No association was found between any other urinary isoflavones and obesity markers (all P > 0.05). We identified 21 bacterial genera whose relative abundance were positively associated with urinary equol concentrations (all Pfalsediscovery rate < 0.05), and constructed an equol-predicting microbial score to reflect the overall equol-producing potential of host gut microbiota. This score was inversely associated with CAP (ß = -0.040, P = 0.011). CONCLUSIONS: High urinary equol concentrations and equol-predicting microbial species could be favorably associated with liver fat and other obesity markers.