Long-term effects of coffee and caffeine intake on the risk of pre-diabetes and type 2 diabetes: Findings from a population with low coffee consumption

BACKGROUND AND AIM

Here, we examined the potential effect of coffee consumption and total caffeine intake on the occurrence of pre-diabetes and T2D, in a population with low coffee consumption.

METHODS AND RESULTS

Adults men and women, aged 20-70 years, were followed for a median of 5.8 y. Dietary intakes of coffee and caffeine were estimated using a 168-food items validate semi-quantitative food frequency questionnaire, at baseline. Cox proportional hazards regression models, adjusted for potential cofounders, were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between coffee and caffeine intakes and incidence of pre-diabetes and T2D. The total population was 1878 adults (844 men, 1034 women) and 2139 adults (971 men, 1168 women) for analysis of pre-diabetes and T2D, respectively. During the follow-up period the incidence of pre-diabetes and T2D was 30.8% and 6.6%, respectively. Forty-three percent of our subjects were no coffee drinker whereas 51.4% consumed 1 cup of coffee/week and 6.0% consumed more than 1 cup of coffee/week. A lower risk of pre-diabetes (HR = 0.73, 95% CI = 0.62-0.86) and T2D (HR = 0.66, 95% CI = 0.44-1.00) was observed in coffee drinkers compared to non-drinkers, in the fully adjusted models. Higher dietary intake of caffeine (≥152 vs. <65 mg/d) was accompanied with a borderline (P = 0.053) reduced risk of pre-diabetes (HR = 0.45, 95% CI = 0.19-1.00).

CONCLUSION

Our findings indicated that coffee drinking may have favorable effect in prevention of pre-diabetes and T2D.

Contribution of dietary amino acids composition to incidence of cardiovascular outcomes: A prospective population-based study

BACKGROUND AND AIM

Considering the limited data on the cardiovascular effects of dietary amino acid intakes, we assessed possible association of dietary amino acids with the risk of cardiovascular (CVD) events in a prospective population-based study.

METHODS

Participants without CVD (n = 2369) were recruited from the Tehran Lipid and Glucose Study and were followed for a mean of 6.7 years. Dietary protein and amino acid intakes were assessed at baseline (2006-2008); demographic, lifestyle and biochemical variables were evaluated at baseline and follow-up examination (2012-2014). Multivariate Cox proportional hazard regression models, adjusted for potential confounders, were used to estimate risk of CVD across tertiles of dietary amino acids.

RESULTS

Mean total protein intake was 76.9 ± 27.5 g/d, and dietary protein had no significant association with the risk of CVD (HR = 1.23, 95% CI = 0.65-2.31, and HR = 0.52, 95% CI = 0.19-1.41, in the second and third tertiles, respectively). After adjustment of potential confounders, the amino acid pattern with higher load of glycine, cysteine, arginine and tryptophan, was negatively associated with CVD (HR = 0.28, 95% CI = 0.09-0.88, P for trend = 0.08). Higher intake of sulfur-containing amino acids (cysteine and methionine), and potentially cardioprotective amino acids (arginine, cysteine, glutamic acid, glycine, histidine, leucine and tyrosine) corresponded to 73% (HR = 0.27, 95% CI = 0.09-0.86) and 74% (HR = 0.26, 95% CI = 0.09-0.78) decreased risk of CVD events. Higher intake of glutamic acid and proline (% of dietary total protein) increased the risk of CVD (HR = 1.30, 95% CI = 1.03-1.64, and HR = 1.33, 95% CI = 1.10-1.60, respectively).

CONCLUSION

These novel data provide evidence to suggest that amino acid composition of diet may modify the risk of CVD events.

Colors of fruits and vegetables and 3-year changes of cardiometabolic risk factors in adults: Tehran lipid and glucose study

BACKGROUND/OBJECTIVES

We aimed to investigate the associations of colors of fruit and vegetable (FV) subgroups, with 3-year changes of cardiometabolic risk factors.

SUBJECTS/METHODS

This longitudinal study was conducted in the framework of Tehran Lipid and Glucose Study, between 2006-2008 and 2009-2011, on 1272 adults. Total intake of FV and their subgroups have been assessed by a validated semi-quantitative food frequency questionnaire at baseline (2006-2008) and again at the second examination (2009-2011). Demographics, anthropometrics and biochemical measures were evaluated at baseline and 3 years later. The associations of anthropometric and lipid profile changes with FV subgroups were estimated.

RESULTS

The mean age of men and women at baseline was 39.8±12.7 and 37.3±12.1 years, respectively. Mean total intake of FV, red/purple, yellow, green, orange and white FV was 706±337, 185±95, 141±91, 152±77, 141±87 and 22±18 g/day, respectively. In men, 3-year changes of weight (β=-0.13, P=0.01) and waist circumference (β=-0.14, P=0.01) were related to intake of red/purple FV; the yellow group was inversely associated with 3-year changes of total cholesterol (β=-0.09, P=0.03) and High-density lipoprotein cholesterol (β=-0.11, P=0.03). Consumption of green and white FV was inversely related to abdominal fat gain, and atherogenic lipid parameters in men (P<0.05). In women, higher intake of red/purple FV was associated to lower weight and abdominal fat gain, fasting serum glucose and total cholesterol (P<0.05); yellow FV was also related to 3-year weight gain (β=-0.11, P=0.01).

CONCLUSIONS

Various colors of FV subgroups had different effects on cardiometabolic risk factors; higher intake of red/purple FV may be related to lower weight and abdominal fat gain, and yellow, green and white FV may be related to lipid parameters.