Xinyan Bi

Spices in the management of diabetes mellitus.

Diabetes mellitus (DM) remains a major health care problem worldwide both in developing and developed countries. Many factors, including age, obesity, sex, and diet, are involved in the etiology of DM. Nowadays, drug and dietetic therapies are the two major approaches used for prevention and control of DM. Compared to drug therapy, a resurgence of interest in using diet to manage and treat DM has emerged in recent years. Conventional dietary methods to treat DM include the use of culinary herbs and/or spices. Spices have long been known for their antioxidant, anti-inflammatory, and anti-diabetic properties. This review explores the anti-diabetic properties of commonly used spices, such as cinnamon, ginger, turmeric, and cumin, and the use of these spices for prevention and management of diabetes and associated complications.

Prevalence of Vitamin D Deficiency in Singapore: Its Implications to Cardiovascular Risk Factors

Objective Vitamin D deficiency is a global health challenge and has been linked to type 2 diabetes and other chronic diseases. However, the relationship between vitamin D status, body composition, and cardiovascular risks has not been well characterized in Asian populations. The objectives of this study were to examine the factors associated with the low vitamin D levels in a sunny tropical region and to assess the role of vitamin D status in cardiovascular risk factors. Design and Methods This was a cross-sectional study. One hundred and fourteen healthy participants (59 males and 55 females) residing in Singapore took part in this study. Plasma 25OH-D3 concentration was measured by using LC-MS/MS. Body fat (%) was measured by using three different techniques including bioelectrical impedance analysis (BIA), BOD POD, and dual-energy X-ray absorptiometry (DEXA). Basic anthropometric measurements, fasting blood glucose (FBG), fasting serum insulin (FSI), and lipid profiles were obtained using standard protocols. Results Approximately 42% of the participants were vitamin D deficient (< 20 ng/mL). Vitamin D status was inversely associated with body fat (%), homeostasis model assessment of insulin resistance (HOMA-IR), and total cholesterol/high density lipoprotein (TC/HDL) ratio, while positively associated with lean body mass (LBM) and hand grip strength (HGS). Conclusions The high prevalence of vitamin D deficiency in a sunny tropical region reinforces the need to recognize that sunlight alone is not the precursor for optimal vitamin D status. This raises the need to investigate public health measures that will encourage exposure to sunlight without overexposure that is harmful to skin. More importantly, vitamin D deficiency is associated with increased cardiovascular risks, i.e. HOMA-IR, TC/HDL, and LDL/HDL. Future studies should attempt to elucidate the potential mechanisms.

Correlation of adiposity indices with cardiovascular disease risk factors in healthy adults of Singapore: a cross-sectional study

BackgroundObesity has long been highlighted for its association with increased incidence of cardiovascular disease (CVD). Nonetheless, the best adiposity indices to evaluate the CVD risk factors remain contentious and few studies have been performed in Asian populations. In the present study, we compared the association strength of percent body fat (PBF) to indirect anthropometric measures of general adiposity (body mass index (BMI) and body adiposity index (BAI)) and central adiposity (waist circumference (WC), and waist-to-hip ratio (WHR)) for the prediction of CVD risk factors in healthy men and women living in Singapore.MethodsA total of 125 individuals (63 men and 62 women) took part in this study. PBF was measured by using three different techniques, including bioelectrical impedance analysis (BIA), BOD POD, and dual-energy X-ray absorptiometry (DEXA). Anthropometric measurements (WC, hip circumference (HC), height, and weight), fasting blood glucose (FBG), fasting serum insulin (FSI), and lipid profiles were determined according to standard protocols. Correlations of anthropometric measurements and PBF with CVD risk factors were compared.ResultsIrrespective of the measuring techniques, PBF showed strong positive correlations with FSI, HOMA-IR, TC/HDL, TG/HDL, and LDL/HDL in both genders. While PBF was highly correlated with FBG, SBP, and DBP in females, no significant relationships were observed in males. Amongst the five anthropometric measures of adiposity, BAI was the best predictor for CVD risk factors in female participants (r = 0.593 for HOMA-IR, r = 0.542 for TG/HDL, r = 0.474 for SBP, and r = 0.448 for DBP). For males, the combination of WC (r = 0.629 for HOMA-IR, and r = 0.446 for TG/HDL) and WHR (r = 0.352 for SBP, and r = 0.366 for DBP) had the best correlation with CVD risk factors.ConclusionMeasurement of PBF does not outperform the simple anthropometric measurements of obesity, i.e. BAI, WC, and WHR, in the prediction of CVD risk factors in healthy Asian adults. While measures of central adiposity (WC and WHR) tend to show stronger associations with CVD risk factors in males, measures of general adiposity (BAI) seems to be the best predictor in females. The gender differences in the association between adiposity indices and CVD risk factors may relate to different body fat distribution in males and females living in Singapore. These results may find further clinical utility to identify patients with CVD risk factors in a more efficient way.

Impact of protein-rich meals on glycaemic response of rice.

Asians typically consume carbohydrate-rich and high-glycaemic-index diets that have been associated with an increased risk of developing type 2 diabetes. Rice is rarely eaten alone such that it is of interest to investigate the effects of co-ingesting different protein-rich meals with rice on insulin and glycaemic response. This study had a randomised, controlled, non-blind, cross-over design in which fifteen healthy Chinese male participants were required to come on non-consecutive days. Five rice-based test meals were served: rice alone (control), rice with fish (RWF), rice with egg white (RWE), rice with soya beancurd (taukwa) (RWT) and rice with chicken (RWC). The control meal consisted of 50 g of available carbohydrate, whereas all other test meals contained additional 25 g of protein. RWT was the only meal that showed significantly lower glucose response when compared with the control (P<0·05). RWF and RWE had significantly higher insulin response, but no significant increase was observed in RWT and RWC when compared with the control (P<0·05). RWT and RWF showed significantly higher glucagon secretion as compared with the control (P<0·05). The four test meals studied showed varying effects, with RWT showing the greatest reduction in glycaemic response. Therefore, the ingestion of soya beancurd with rice may have a direct impact on reducing the risk in Asians transiting from being pre-diabetics to diabetics.

Evaluation of antioxidant capacity of Chinese five-spice ingredients

Abstract Phenolic compounds in spices were reportedly found to possess high antioxidant capacities (AOCs), which may prevent or reduce risk of human diseases such as cardiovascular disease, cancer and diabetes. The potential AOC of Chinese five-spice powder (consist of Szechuan pepper, fennel seed, cinnamon, star anise and clove) with varying proportion of individual spice ingredients was investigated through four standard methods. Our results suggest that clove is the major contributor to the AOC of the five-spice powder whereas the other four ingredients contribute to the flavour. For example, the total phenolic content as well as ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) values increased linearly with the clove percentage in five-spice powder. This observation opens the door to use clove in other spice mixtures to increase their AOC and flavour. Moreover, linear relationships were also observed between AOC and the total phenolic content of the 32 tested spice samples.

Body Fat Measurements in Singaporean Adults Using Four Methods

Few studies have been conducted to measure body composition in Asian populations. In this study, we determined the percent body fat (PBF) by using dual-energy X-ray absorptiometry (DEXA), air-displacement plethysmography (ADP or BOD POD), bioelectrical impedance analysis (BIA) and skinfold (SKF) in 445 healthy Singaporean adults. We observed that the BOD POD, BIA and SKF estimates of PBF were highly correlated with that from DEXA (as a reference method) among Singaporean adults. However, they all underestimated PBF (differences of 3.9% for BOD POD, 5.6% for BIA and 12.5% for SKF). Our results filled a gap in the literature by testing the relationships between DEXA and BOD POD, BIA and SKF in a large sample with a wide range of body mass index (BMI) from 16.1 to 37.5 kg/m2 and age from 21 to 69.2 years. The differences of PBF measured by different methods were dependent on age, gender and ethnicity. No significant difference was observed between DEXA and BOD POD in men aged > 40 or in BMI tertile 3. However, the mean difference between DEXA and BOD POD was significant in women. Different measuring methods of estimating PBF therefore must be cautiously interpreted.

Android fat as a determinant of metabolic syndrome: Sex differences

OBJECTIVES Regional fat accumulation may play an important role in the pathogenesis of metabolic syndrome (MetS) and cardiovascular diseases, yet the results are controversial. The aim of this study was to determine the relationship between regional fat accumulation and MetS as well as the underlying mechanism in Chinese adults. METHODS We conducted a cross-sectional study of 428 Chinese adults (166 men and 262 women). Android and gynoid fat percentage (AFP and GFP) were measured by dual energy x-ray absorptiometry. Fasting lipid parameters were analyzed by chemistry analyzer COBAS. RESULTS Forty-six (28%) men and 34 (13%) women had MetS according to the modified National Cholesterol Education Panel Adult Treatment Panel III definition for South Asia. AFP was strongly correlated with more metabolic risk factors than GFP in men. In women, AFP and GFP showed significant opposite effects on triacylglycerol, high-density lipoprotein cholesterol, and waist circumference. On multivariate regression, AFP was an independent determinant of MetS in men after adjustment for confounding factors. For women, both AFP and the homeostatic model assessment for insulin resistance were predictors for MetS. CONCLUSIONS Increased android fat may play a direct role in the development of MetS in Chinese adults. However, the associations between android fat, insulin resistance, and MetS are sex-dependent. This is probably due to different effects of sex hormones on adipose tissue or by genetic factors between sexes. Knowing the sex differences in developing MetS may help design sex-specific preventive strategies that will benefit the overall population health.

Does basal metabolic rate drive eating rate

There have been recent advances in our understanding of the drivers of energy intake (EI). However, the biological drivers of differences in eating rate (ER) remain less clear. Studies have reported that the fat-free mass (FFM) and basal metabolic rate (BMR) are both major components that contribute to daily energy expenditure (EE) and drive EI. More recently, a number of observations report that higher ER can lead to greater EI. The current study proposed that adults with a higher BMR and higher energy requirements would also exhibit higher ERs. Data on BMR, FFM, and ER were collected from 272 Chinese adults (91 males and 181 females) in a cross-sectional study. Analysis showed significant positive associations between BMR and ER (rs = 0.405, p < 0.001), and between FFM and ER (rs = 0.459, p < 0.001). BMR explained about 15% of the variation in ER which was taken to be metabolically significant. This association provides metabolic explanation that the differences in an individuals BMR (hence energy requirements) may be correlated with ERs. This merits further research.

Does Circulating Leptin Play a Role in Energy Expenditure

OBJECTIVES It has been demonstrated that leptin influences the energy balance by regulating appetite and increasing energy expenditure (EE). However, the relationship between circulating leptin and EE is confounded owing to variations in body composition. The aim of this study was to determine the role of circulating leptin in energy regulation and to examine whether the leptin-mediated changes in EE are associated with adiposity among healthy adults living in Singapore. METHODS We conducted a cross-sectional study of 300 participants (112 men). Resting metabolic rate (RMR) was measured by indirect calorimetry. Body composition (i.e., fat mass [FM] and fat-free mass [FFM]) was measured by dual-energy x-ray absorptiometry. Serum leptin levels were determined by radioimmunoassay. RESULTS There were strong correlations between circulating leptin levels, FM, and RMR in healthy men and women. After normalization of RMR by a power function model (kcal·kg FFM0.86·d-1), the influence of FFM can be effectively removed. The normalized RMR was significantly associated with both FM (r = 0.28, P < 0.001) and log leptin (r = 0.35, P < 0.001). In the stepwise multiple regression analysis, leptin level is the major predictor for normalized RMR, accounting for 12% of the variation. In contrast, FM did not explain any variation in normalized RMR. CONCLUSION Leptin may be a more significant predictor of normalized RMR than FM per se. The contribution of FM to RMR could be via a mechanism that is related to leptin-dependent responses involved in energy homeostasis.

Ultrasound measurement of intraabdominal fat thickness as a predictor of insulin resistance and low HDL cholesterol in Asians

OBJECTIVES Insulin resistance (IR) is important in the pathogenesis of diabetes, the prevalence of which has become a major public health threat in Asia. The aim of this study was to use ultrasound measurements of abdominal fat thickness to predict IR and low high-density lipoprotein cholesterol (HDL-C) levels among Singaporean adults. METHODS A total of 399 healthy Singaporeans (mean age 36.7 ± 14.3 y; 43.4% men) took part in this study. Preperitoneal fat thickness (PFT) and subcutaneous fat thickness (SFT) were determined by ultrasound. RESULT We found that both PFT and SFT had significant positive correlations (P < 0.05) with fasting insulin concentration, homeostasis model assessment of insulin resistance, triacylglycerol (TG), and blood pressure, and negatively correlated to serum HDL-C in all participants. Separating men and women, PFT was an independent determinant of IR and low HDL-C only in men. On receiver-operating characteristic curve analysis, PFT ≥1.2 cm was the optimal cutoff value to identify IR and low HDL-C in men. On the other hand, SFT was the determinant of IR, elevated TG, and low HDL-C only in women. An SFT of 1.1 cm was the optimal cutoff value to define IR, elevated TG, and low HDL-C in women. CONCLUSIONS Results of this study suggested that ultrasound measurements of PFT and SFT could provide simple and useful indices of IR and lipid disorders for healthy Singaporean men and women. They might have the diagnostic values for predicting cardiovascular risks in this population.