India has the second largest number of people with type 2 diabetes (T2D) globally. Epidemiological evidence indicates that consumption of white rice is positively associated with T2D risk, while intake of brown rice is inversely associated. Thus, we explored the effect of substituting brown rice for white rice on T2D risk factors among adults in urban South India. A total of 166 overweight (BMI ≥ 23 kg/m2) adults aged 25–65 years were enrolled in a randomised cross-over trial in Chennai, India. Interventions were a parboiled brown rice or white rice regimen providing two ad libitum meals/d, 6 d/week for 3 months with a 2-week washout period. Primary outcomes were blood glucose, insulin, glycosylated Hb (HbA1c), insulin resistance (homeostasis model assessment of insulin resistance) and lipids. High-sensitivity C-reactive protein (hs-CRP) was a secondary outcome. We did not observe significant between-group differences for primary outcomes among all participants. However, a significant reduction in HbA1c was observed in the brown rice group among participants with the metabolic syndrome (−0·18 (se 0·08) %) relative to those without the metabolic syndrome (0·05 (se 0·05) %) (P-for-heterogeneity = 0·02). Improvements in HbA1c, total and LDL-cholesterol were observed in the brown rice group among participants with a BMI ≥ 25 kg/m2 compared with those with a BMI < 25 kg/m2 (P-for-heterogeneity < 0·05). We observed a smaller increase in hs-CRP in the brown (0·03 (sd 2·12) mg/l) compared with white rice group (0·63 (sd 2·35) mg/l) (P = 0·04). In conclusion, substituting brown rice for white rice showed a potential benefit on HbA1c among participants with the metabolic syndrome and an elevated BMI. A small benefit on inflammation was also observed.

Studies on the effects of consuming 100 % fruit juice on measures of glycaemic control are conflicting. The purpose of the present study was to systematically review and quantitatively summarise results from randomised controlled trials (RCT) examining effects of 100 % fruit juice on glucose–insulin homeostasis. Eligible studies were identified from a systematic review of PubMed and EMBASE and hand searches of reference lists from reviews and relevant papers. Using data from eighteen RCT, meta-analyses evaluated the mean difference in fasting blood glucose (sixteen studies), fasting blood insulin (eleven studies), the homeostatic model assessment of insulin resistance (HOMA-IR; seven studies) and glycosylated Hb (HbA1c; three studies) between the 100 % fruit juice intervention and control groups using a random-effects model. Compared with the control group, 100 % fruit juice had no significant effect on fasting blood glucose (−0·13 (95 % CI −0·28, 0·01) mmol/l; P = 0·07), fasting blood insulin (−0·24 (95 % CI −3·54, 3·05) pmol/l; P = 0·89), HOMA-IR (−0·22 (95 % CI −0·50, 0·06); P = 0·13) or HbA1c (−0·001 (95 % CI −0·38, 0·38) %; P = 0·28). Results from stratified analyses and univariate meta-regressions also largely showed no significant associations between 100 % fruit juice and the measures of glucose control. Overall, findings from this meta-analysis of RCT suggest a neutral effect of 100 % fruit juice on glycaemic control. These findings are consistent with findings from some observational studies suggesting that consumption of 100 % fruit juice is not associated with increased risk of diabetes.

The metabolic syndrome (MetS) is known to be associated with elevated serum ferritin levels. The possible association with other Fe markers has been less well studied. We aimed to investigate the cross-sectional association of soluble transferrin receptor (sTfR) and ferritin levels with the MetS components, insulin resistance and glycosylated Hb (HbA1C). The sample consisted of 725 adults, aged 19–93 years (284 men, 151 premenopausal and 290 postmenopausal women), from the Croatian island of Vis. Serum sTfR and ferritin levels were measured by immunoturbidimetry and electrochemiluminescence assays, respectively. The MetS was defined using modified international consensus criteria. Logistic and linear regression analyses were conducted to investigate the associations adjusting for age, fibrinogen, smoking status, alcohol consumption and BMI. Prevalence of the MetS was 48·7 %. Standardised values of ferritin were positively associated with all of the MetS components (except high blood pressure and waist circumference) in men (P<0·05). Ferritin was significantly associated with the MetS in men (adjusted OR 1·78 (95 % CI 1·31, 2·42)) and postmenopausal women (1·71 (95 % CI 1·12, 2·62)). Interestingly, sTfR was independently and positively associated with homoeostatic model assessment for insulin resistance in men (adjusted β=0·44 (95 % CI 0·14, 0·75), P=0·004) and postmenopausal women (adjusted β coefficient=0·34 (95 % CI 0·05, 0·63), P=0·020). However, there was no significant relationship between serum sTfR levels and the MetS or its components. Neither ferritin nor sTfR was significantly associated with HbA1C (P>0·05). sTfR levels could be spuriously elevated in subjects with insulin resistance and without association with the MetS or its components. We conclude that different markers of Fe metabolism are not consistently associated with cardiometabolic risk.

Type 2 diabetes (T2D) is a major risk factor of CVD. The effects of purified sardine proteins (SP) were examined on glycaemia, insulin sensitivity and reverse cholesterol transport in T2D rats. Rats fed a high-fat diet (HFD) for 5 weeks, and injected with a low dose of streptozotocin, were used. The diabetic rats were divided into four groups, and they were fed casein (CAS) or SP combined with 30 or 5 % lipids, for 4 weeks. HFD-induced hyperglycaemia, insulin resistance and hyperlipidaemia in rats fed HFD, regardless of the consumed protein. In contrast, these parameters lowered in rats fed SP combined with 5 or 30 % lipids, and serum insulin values reduced in SP v. CAS. HFD significantly increased total cholesterol and TAG concentrations in the liver and serum, whereas these parameters decreased with SP, regardless of lipid intake. Faecal cholesterol excretion was higher with SP v. CAS, combined with 30 or 5 % lipids. Lecithin:cholesterol acyltransferase (LCAT) activity and HDL3-phospholipids (PL) were higher in CAS-HF than in CAS, whereas HDL2-cholesteryl esters (CE) were lower. Otherwise, LCAT activity and HDL2-CE were higher in the SP group than in the CAS group, whereas HDL3-PL and HDL3-unesterified cholesterol were lower. Moreover, LCAT activity lowered in the SP-HF group than in the CAS-HF group, when HDL2-CE was higher. In conclusion, these results indicate the potential effects of SP to improve glycaemia, insulin sensitivity and reverse cholesterol transport, in T2D rats.

Dietary fibre intake has been suggested to reduce blood glucose levels in diabetic patients, particularly when glycosylated Hb (HbA1c) levels are high. In the present study, we used a quantile regression (QR) approach to characterise the possible heterogeneous associations of dietary fibre intake with HbA1c levels in Chinese diabetic patients. A total of 497 diabetic patients participated in the baseline survey in 2006 and in the follow-up survey in 2011, both of which were conducted in Pudong New Area of Shanghai, China. Structured in-person interviews were conducted to collect information on demographic characteristics and lifestyle factors. Dietary intake was assessed using a validated FFQ. Blood samples were collected during the interviews for biochemical assays. QR models were used to examine the heterogeneous associations of dietary factors with HbA1c levels. A significant marginal association of insoluble dietary fibre intake with subsequent HbA1c levels was observed only when the HbA1c level was over 6·8 %. The associations appeared to be greater when the quantile levels of HbA1c were higher. The coefficient estimates were − 0·174 (95 % CI − 0·433, − 0·025) at the quantile of 0·60, − 0·200 (95 % CI − 0·306, − 0·008) at 0·70, − 0·221 (95 % CI − 0·426, − 0·117) at 0·80, and − 0·389 (95 % CI − 0·516, − 0·018) at 0·90. A similar pattern was observed for the associations of dietary glycaemic index (GI) value with HbA1c levels. In conclusion, the present results indicate that the associations of insoluble dietary fibre intake and GI value with subsequent HbA1c levels depend on glycaemic control status in Chinese diabetic patients. More studies are required to confirm our findings.

The present study examines the association of diabetes with BMI (kg/m2) in Asian-Indian and Melanesian Fijian populations sharing a common environment. A population-based survey was used to investigate the risk of diabetes (defined by glycosylated Hb concentration ≥ 6·5 % among participants who denied previous diagnosis of the disease by a medical practitioner) by sex, ethnicity and strata of BMI in a series of age-adjusted logistic regression models. Ethnicity and BMI interactions were compared using WHO and empirically derived BMI cut-off points. Indians had a greater risk (BMI and age adjusted) of undetected diabetes than Melanesians in both males (OR 2·99, 95 % CI 1·73, 5·17; P < 0·001) and females (OR 2·26, 95 % CI 1·56, 3·28; P < 0·001). BMI ≥ 25 to < 30 and ≥ 30 kg/m2 conferred a higher risk of diabetes compared with a BMI ≥ 18·5 to < 25 kg/m2. Risk was higher for males with a BMI ≥ 25 to < 30 kg/m2 (OR 2·35, 95 % CI 1·24, 4·46; P = 0·007) and BMI ≥ 30 kg/m2 (OR 6·08, 95 % CI 3·06, 12·07; P < 0·001) than for females with the same BMI (OR 1·85, 95 % CI 1·11, 3·08; P = 0·027 and OR 2·10, 95 % CI 1·28, 3·44; P = 0·002, respectively). However, the threshold that appeared to differentiate higher risk varied by ethnicity and sex. For Melanesians, BMI thresholds suggested were 25 kg/m2 for males and 32 kg/m2 for females. For Indo-Fijians, these were 24 and 22 kg/m2 for males and females, respectively. Disaggregating by ethnicity and sex, and applying specific evidence-based thresholds, may render BMI a more discriminating tool for assessing the risk of developing diabetes among Fiji adults.