N Guest et al, 2018. Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes, Medicine & Science in Sports & Exercise, published online.

ABSTRACT

PURPOSE: Many studies have examined the effect of caffeine on exercise performance, but findings have not always been consistent. The objective of this study was to determine whether variation in the CYP1A2 gene, which affects caffeine metabolism, modifies the ergogenic effects of caffeine in a 10-km cycling time trial.

METHODS: Competitive male athletes (n=101; age: 25 ± 4 years) completed the time trial under three conditions: 0, 2 or 4 mg of caffeine per kg body mass, using a split-plot randomized, double-blinded, placebo-controlled design. DNA was isolated from saliva and genotyped for the -163A>C polymorphism in the CYP1A2 gene (rs762551).

RESULTS: Overall, 4 mg/kg caffeine decreased cycling time by 3% (mean ± SEM) versus placebo (17.6 ± 0.1 vs. 18.1 ± 0.1 min, p = 0.01). However, a significant (p <0.0001) caffeine-gene interaction was observed. Among those with the AA genotype, cycling time decreased by 4.8% at 2 mg/kg (17.0 ± 0.3 vs. 17.8 ± 0.4 min, p = 0.0005) and by 6.8% at 4 mg/kg (16.6 ± 0.3 vs. 17.8 ± 0.4 min, p < .0001). In those with the CC genotype, 4 mg/kg increased cycling time by 13.7% versus placebo (20.8 ± 0.8 vs. 18.3 ± 0.5 min, p = 0.04). No effects were observed among those with the AC genotype.

CONCLUSION: Our findings show that both 2 and 4 mg/kg caffeine improve 10-km cycling time, but only in those with the AA genotype. Caffeine had no effect in those with the AC genotype and diminished performance at 4 mg/kg in those with the CC genotype. CYP1A2genotype should be considered when deciding whether an athlete should use caffeine for enhancing endurance performance.

The post N Guest et al, 2018. Caffeine, CYP1A2 Genotype, and Endurance Performance in Athletes, Medicine & Science in Sports & Exercise, published online. appeared first on Coffee and Health.

E A Hu et al, 2018. Coffee Consumption and Incident Kidney Disease: Results from the Atherosclerosis Risk in Communities (ARIC) Study, American Journal of Kidney Disease, published online.

ABSTRACT

BACKGROUND:
Moderate coffee consumption has been suggested to be associated with lower risk for chronic conditions such as diabetes, a major precursor to chronic kidney disease (CKD). However, the association between coffee and CKD has not been fully established.

STUDY DESIGN:
Prospective cohort study.

SETTING & PARTICIPANTS:
14,209 participants aged 45 to 64 years from the Atherosclerosis Risk in Communities (ARIC) Study.

PREDICTORS:
Coffee consumption (cups per day) was assessed at visits 1 (1987-1989) and 3 (1993-1995) using food frequency questionnaires.

OUTCOMES:
Incident CKD defined as estimated glomerular filtration rate < 60mL/min/1.73m2 accompanied by ≥25% estimated glomerular filtration rate decline, CKD-related hospitalization or death, or end-stage renal disease.

RESULTS:
There were 3,845 cases of incident CKD over a median of 24 years of follow-up. Men, whites, current smokers, and participants without comorbid conditions were more likely to consume higher amounts of coffee per day. After adjustment for demographic, clinical, and dietary factors, higher categories of coffee consumption were associated with lower risk for incident CKD compared with those who never consumed coffee (HR for <1 cup per day, 0.90 [95% CI, 0.82-0.99]; 1-<2 cups per day, 0.90 [95% CI, 0.82-0.99]; 2-<3 cups per day, 0.87 [95% CI, 0.77-0.97]; and ≥3 cups per day, 0.84 [95% CI, 0.75-0.94]). In continuous analysis, for each additional cup of coffee consumed per day, risk for incident CKD was lower by 3% (HR, 0.97; 95% CI, 0.95-0.99; P<0.001).

LIMITATIONS:
Self-reported coffee consumption and observational design.

CONCLUSIONS:
Participants who drank higher amounts of coffee had lower risk for incident CKD after adjusting for covariates. Coffee consumers may not be at adverse risk for kidney disease.

The post E A Hu et al, 2018. Coffee Consumption and Incident Kidney Disease: Results from the Atherosclerosis Risk in Communities (ARIC) Study, American Journal of Kidney Disease, published online. appeared first on Coffee and Health.

M D Machado-Fragua et al, 2018. Coffee Consumption and Risk of Physical Function Impairment, Frailty and Disability in Older Adults, European Journal of Nutrition, published online.

ABSTRACT

PURPOSE:
Habitual coffee consumption has been associated with lower risk of type 2 diabetes and cardiovascular disease. Since these diseases are main determinants of functional limitations, we have tested the hypothesis that coffee intake is associated with lower risk of physical function impairment, frailty and disability in older adults. We focused on women and those with obesity, hypertension or type 2 diabetes because they are at higher risk of functional limitations.

METHODS:
Prospective study with 3289 individuals ≥ 60 years from the Seniors-ENRICA cohort. In 2008-2010 coffee consumption was measured through a validated dietary history. Participants were followed up until 2015 to ascertain incident impaired physical function, frailty and disability, assessed by both self-report and objective measures.

RESULTS:
Compared with non-drinking coffee, consumption of ≥ 2 cups of coffee/day was associated with lower risk of impaired agility in women (hazard ratio [HR] 0.71, 95% confidence interval [CI] 0.51-0.97, P trend 0.04) and in those with obesity (HR 0.60; 95% CI 0.40-0.90, P trend 0.04). Intake of ≥ 2 cups of coffee/day was also linked to reduced risk of impaired mobility in women (HR 0.66; 95% CI 0.46-0.95, P trend 0.02) and among individuals with hypertension (HR 0.70, 95% CI 0.48-1.00, P trend 0.05). Moreover, among subjects with diabetes, those who consumed ≥ 2 cups/day had lower risk of disability in activities of daily living (HR 0.30, 95% CI 0.11-0.76, P trend 0.01).

CONCLUSIONS:
In older people, habitual coffee consumption was not associated with increased risk of functional impairment, and it might even be beneficial in women and those with hypertension, obesity or diabetes.

The post M D Machado-Fragua et al, 2018. Coffee Consumption and Risk of Physical Function Impairment, Frailty and Disability in Older Adults, European Journal of Nutrition, published online. appeared first on Coffee and Health.

Y Miyake et al, 2018. Maternal caffeine intake in pregnancy is inversely related to childhood peer problems in Japan: The Kyushu Okinawa Maternal and Child Health Study, Nutritional Neuroscience, published online.

ABSTRACT

Objectives:
The present prebirth cohort study examined the association between maternal caffeine consumption during pregnancy and behavioral problems in Japanese children aged 5 years.

Methods:
Subjects were 1199 mother–child pairs. Dietary intake was assessed using a diet history questionnaire. Emotional problems, conduct problems, hyperactivity problems, and peer problems were assessed using the Japanese parent-report version of the Strengths and Difficulties Questionnaire. Adjustment was made for maternal age, gestation at baseline, region of residence at baseline, number of children at baseline, maternal and paternal education, household income, maternal depressive symptoms during pregnancy, maternal alcohol intake during pregnancy, maternal smoking during pregnancy, child’s birth weight, child’s sex, breastfeeding duration, and smoking in the household during the first year of life.

Results:
The contributors of caffeine in the diet during pregnancy were Japanese and Chinese tea (74.8%), coffee (13.0%), black tea (4.4%), confectionaries (4.0%), and soft drinks (3.7%). Higher maternal caffeine consumption during pregnancy was independently associated with a reduced risk of peer problems in the children: the adjusted odds ratios (95% confidence intervals) in the first, second, third, and fourth quartiles of maternal caffeine consumption during pregnancy were 1 (reference), 0.61 (0.35–1.06), 0.52 (0.29–0.91), and 0.51 (0.28–0.91), respectively (P for trend = 0.01). Maternal caffeine intake during pregnancy was not evidently related to the risk of emotional problems, conduct problems, or hyperactivity problems in the children.

Conclusions:
Maternal caffeine consumption, mainly from Japanese and Chinese tea, during pregnancy may be preventive against peer problems in Japanese children.

 

The post Y Miyake et al, 2018. Maternal caffeine intake in pregnancy is inversely related to childhood peer problems in Japan: The Kyushu Okinawa Maternal and Child Health Study, Nutritional Neuroscience, published online. appeared first on Coffee and Health.