Quantity and variety of fruit and vegetable intake in midlife and cognitive impairment in late life: a prospective cohort study.

There is limited evidence on fruit and vegetable intake in relation to cognitive function. This study aimed to evaluate the associations of quantity and variety in fruit and vegetable intake in midlife with cognitive impairment in late life. We used data from 16 737 participants of the Singapore Chinese Health Study, a population-based cohort study. The participants provided dietary data at recruitment at median age of 52·5 (range: 45-74) years and also participated in the third follow-up interview 20 years later at median age of 72·2 (range: 61-96) years. Quantity and variety of fruits and vegetables consumed at baseline were measured using a validated FFQ. Cognitive impairment at the third follow-up was defined using a Singapore-modified version of Mini-Mental State Examination. About 14·3 % participants had cognitive impairment. In multivariable logistic regression models, comparing extreme quartiles for intake of fruits and vegetables combined, the OR (95 % CI) associated with cognitive impairment was 0·83 (95 % CI: 0·73, 0·95; P-trend = 0·006) for quantity and 0·76 (95 % CI: 0·67, 0·87; P-trend< 0·001) for variety scores. Independently, those with increased variety of fruit intake or higher quantity of vegetable intake also had significantly 22 % and 15 % reduced odds of cognitive impairment, respectively. Finally, compared with those with low intake for both quantity and variety, those with both high quantity and variety for fruits and vegetables had 23 % reduction in odds of cognitive impairment. In conclusion, increase in quantity and variety of fruits and vegetables in midlife may reduce the risk of cognitive impairment in late life.

The effect of coffee consumption on insulin sensitivity and other biological risk factors for type 2 diabetes: a randomized placebo-controlled trial.

BACKGROUND: In observational studies, coffee consumption has been consistently associated with a lower risk of type 2 diabetes mellitus. Trials examining the effect of coffee consumption on glucose metabolism have been limited by the use of surrogate insulin sensitivity indices, small sample sizes, lack of blinding, and short follow-up duration. OBJECTIVES: We aimed to overcome limitations of previously conducted coffee trials in a randomized placebo-controlled trial of the effect of coffee consumption on insulin sensitivity. METHODS: We conducted a 24-wk randomized placebo-controlled trial in 126 overweight, non-insulin sensitive (HOMA-IR ≥1.30), Chinese, Malay, and Asian-Indian males and females aged 35-69 y. Participants were randomly assigned to receive 4 cups of instant regular coffee (n = 62) or 4 cups of a coffee-like placebo beverage (n = 64) per day. The primary outcome was the amount of glucose metabolized per kilogram of body weight per minute (Mbw) assessed during steady-state conditions with a hyperinsulinemic euglycemic clamp. Secondary outcomes included other clamp-based insulin sensitivity measures, biological mediators of insulin sensitivity, and measures of fasting glucose metabolism. RESULTS: Coffee consumption did not significantly change insulin sensitivity compared with placebo (percentage mean difference in Mbw = 4.0%; 95% CI: -8.3, 18.0%; P = 0.53). Furthermore, no significant differences in fasting plasma glucose (2.9%; 95% CI: -0.4, 6.3%; P = 0.09) or biological mediators of insulin resistance, such as plasma adiponectin (2.3%; 95% CI: -1.4, 6.2%; P = 0.22), were observed between coffee and placebo groups over 24 wk of intervention. Participants in the coffee arm experienced a loss of fat mass (FM) (-3.7%; 95% CI: -6.3, -1.1%; P = 0.006) and reduction in urinary creatinine concentrations (-21.2%; 95% CI: -31.4, -9.5%; P = 0.001) compared with participants in the placebo arm over 24 wk of intervention. CONCLUSIONS: Consuming 4 cups/d of caffeinated coffee for 24 wk had no significant effect on insulin sensitivity or biological mediators of insulin resistance but was associated with a modest loss of FM and reduction in urinary creatinine concentrations.This trial was registered at clinicaltrials.gov as NCT01738399. Registered on November 28, 2012. Trial sponsor: Nestlé Research, Lausanne, Switzerland. Trial site: National University of Singapore.

Influence of temperate, subtropical, and tropical fruit consumption on risk of type 2 diabetes in an Asian population.

Background: Findings on the relation between fruit consumption and the risk of type 2 diabetes mellitus (T2DM) have been inconsistent.Objectives: We examined whether the consumption of total, temperate, subtropical, and tropical fruit is associated with T2DM risk and whether differences in the carbohydrate quality of fruit influence T2DM risk in Asians.Design: We included 45,411 participants in the Singapore Chinese Health Study who were 45-74 y old and had no diabetes, cancer, or cardiovascular disease at recruitment (1993-1998). Fruit intake was assessed with the use of a validated food-frequency questionnaire. Physician-diagnosed incident T2DM cases were reported at follow-up 1 (1999-2004) and follow-up 2 (2006-2010) interviews. Cox proportional hazards regression was used to estimate HRs and 95% CIs of diabetes risk.Results: In 494,741 person-years of follow-up, 5207 participants developed T2DM. After adjustment for lifestyle and dietary risk factors, high total fruit consumption was not consistently associated with lower T2DM risk [men: HR of 1.33 (95% CI: 1.04, 1.71) for ≥3 servings/d compared with <1 serving/wk (P-trend = 0.17); women: HR of 0.88 (95% CI: 0.71, 1.11) (P-trend = 0.008); P-interaction = 0.003]. The direct association in men was observed for higher-glycemic index (GI) fruit [HR: 1.51 (95% CI: 1.22, 1.86) for ≥1 serving/d compared with rarely consumed; P-trend = 0.001] but not for lower or moderate GI fruit. In women, the consumption of temperate fruit, but not of subtropical or tropical fruit, was associated with lower T2DM risk [HR: 0.79 (95% CI: 0.67, 0.92) for ≥1 serving/d compared with rarely; P-trend = 0.006].Conclusions: The consumption of temperate fruit, such as apples, was associated with a lower risk of T2DM in women, whereas the consumption of higher-GI fruit, such as bananas, was associated with higher risk in men. The impact of fruit consumption on the risk of diabetes may differ by the type of fruit, which may reflect differences in the glycemic impact or phytochemical content.

Optimal anthropometric measures and thresholds to identify undiagnosed type 2 diabetes in three major Asian ethnic groups.

OBJECTIVE: To identify optimal anthropometric measures and cutoffs to identify undiagnosed diabetes mellitus (UDM) in three major Asian ethnic groups (Chinese, Malays, and Asian-Indians). METHODS: Cross-sectional data were analyzed from 14,815 ethnic Chinese, Malay, and Asian-Indian participants of the Singapore National Health Surveys, which included anthropometric measures and an oral glucose tolerance test. Receiver operating characteristic curve analyses were used with calculation of the area under the curve (AUC) to evaluate the performance of body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHTR) for the identification of UDM. RESULTS: BMI performed significantly worse (AUCMEN = 0.70; AUCWOMEN = 0.75) than abdominal measures, whereas WHTR (AUCMEN = 0.76; AUCWOMEN = 0.79) was among the best performing measures in both sexes and all ethnic groups. Anthropometric measures performed better in Chinese than in Asian-Indian participants for the identification of UDM. A WHTR cutoff of 0.52 appeared optimal with a sensitivity of 76% in men and 73% in women and a specificity of 63% in men and 70% in women. CONCLUSIONS: Although ethnic differences were observed in the performance of anthropometric measures for the identification of UDM, abdominal adiposity measures generally performed better than BMI, and WHTR performed best in all Asian ethnic groups.

A randomized placebo-controlled trial of the effect of coffee consumption on insulin sensitivity: Design and baseline characteristics of the Coffee for METabolic Health (COMETH) study.

BACKGROUND: Coffee consumption has been consistently associated with a lower risk of type 2 diabetes mellitus in cohort studies. In addition, coffee components increased insulin sensitivity in animal models. However, data from intervention studies on the effect of coffee consumption on glucose metabolism have been limited by small sample sizes, lack of blinding, short follow-up duration and the use of surrogate indices of insulin sensitivity. We designed the Coffee for Metabolic Health (COMETH) study to evaluate the effect of coffee consumption on insulin sensitivity. METHODOLOGY: The COMETH study is a double-blind randomized placebo-controlled 24-week trial. Participants were overweight, male and female habitual coffee consumers who were of Chinese, Malay and Asian-Indian ethnicity. We excluded smokers, persons with diabetes, and persons with low insulin resistance (HOMA-IR < 1.30). Participants were randomly assigned to receive daily 4 cups of instant regular coffee or 4 cups of a coffee-like placebo beverage. The hyperinsulinemic euglycemic clamp was performed at baseline and at the end of 24 weeks to determine changes in the bodyweight standardized M-value. Secondary outcomes included changes in fasting glucose and insulin sensitivity mediators such as adiponectin, markers of inflammation, liver function, and oxidative stress.We enrolled 128 participants, 126 (57.1% males; aged 35-67 years) of whom completed baseline assessments. DISCUSSION: If improvement in insulin sensitivity in the coffee group is significantly greater than that of the placebo group, this would support the hypothesis that coffee consumption reduced risk of type 2 diabetes through biological pathways involving insulin sensitivity. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01738399. Registered on 28 November 2012. Trial Sponsor: Nestlé Research Center, Lausanne, Switzerland. Trial Site: National University of Singapore.