Inter-relationship of serum leptin levels with selected anthropometric parameters among a non-diabetic population: a cross-sectional study.

PURPOSE: Association between serum leptin levels and anthropometric parameter is well established in western countries according to the specific WHO cut-off values assigned for those populations, whereas it is not clearly defined for Asians especially with respect to gender. Thus, the objectives of this study were to determine the relationship of serum leptin levels with body mass index (BMI), waist circumference (WC), waist to hip ratio (WHR) to identify the variations of serum leptin levels with gender and to evaluate the serum leptin levels in risk and non-risk groups based on their anthropometric values. SUBJECTS/METHODS: A cross-sectional study was carried out among 226 apparently healthy subjects (non-diabetics, age 20-70 years). Height, weight, WC, hip circumference (HC) and mid arm circumference (MAC) were measured. BMI, WHR, waist to height ratio (WHtR) were calculated. Fasting blood samples were collected. Serum leptin levels were measured using human leptin ELISA kits. RESULTS: Majority of the participants were females (59.3%). Serum leptin levels were significantly higher in females (24.8 ± 17.1 ng/mL) compared to males (9.3 ± 7.9 ng/mL). Significant positive correlations (P < 0.05) were observed between serum leptin levels and all anthropometric parameters except height in both genders. The risk groups according to BMI, WC and WHR in females were hyperleptinaemic and had significantly (P < 0.05) higher serum leptin levels than the non-risk groups. CONCLUSIONS: Linear trend was observed for serum leptin levels with weight, BMI, WC, HC, WHR, MAC and WHtR in both genders. Though the serum leptin levels were higher among risk groups, according to WHR, WC and BMI, the hyperleptinaemia was observed only among females. LEVEL OF EVIDENCE: A descriptive cross-sectional study, Level V.

Sri Lankan rice mixed meals: effect on glycaemic index and contribution to daily dietary fibre requirement.

INTRODUCTION: The glycaemic index (GI) concept ranks starchy foods according to the blood glucose responses following ingestion. When considering commonly consumed Sri Lankan meals, only a few can be categorised as low GI. However, a significant negative correlation between the GI of Sri Lankan meals and fibre content has been observed indicating the potential to reduce the GI of meals by incorporating naturally occurring sources of fibre. Thus, the objective of this study was to study the effect of increased edible quantities of fibre on the GI of rice meals consumed in Sri Lanka. METHODS: Meal 1 consisted of rice with several meal accompaniments (lentil curry, boiled egg, coconut gravy and Centella asiatica (gotukola) leaves salad). Meal 2 contained similar constituents as meal 1 and a Lasia spinosa (kohila) rhizome salad. The composition of meal 3 was similar to meal 2 but contained Trichosanthes cucumerina (snake gourd) salad instead of Lasia spinosa salad. Meal 3 contained similar fibre contents as meal 1 and similar meal size as meal 2. The glycaemic indices of the three meals were determined with healthy individuals (n=10, age=20-30 yrs, BMI=24 +/- 3 kg/m2) using bread as the standard. RESULTS: Meals 1 and 3 contained total dietary fibre (TDF) contents of 15.2g. Meal 2 contained 16.3g TDF. The GI values of the three meals were 63 +/- 5, 57 +/- 5, 61 +/- 5 respectively and were not significantly different from one another (p>0.05). The GI of the rice mixed meal 2 was reduced by 9% when total edible dietary fibre content of the actual meal was increased by 7.2%. CONCLUSION: The study results show that the GI of rice mixed meals may be reduced by including naturally occurring sources of fibre with starchy staples while fulfilling daily dietary fibre requirement of an adult at low cost.

Nutritional assessment of a jackfruit (Artocarpus heterophyllus) meal.

OBJECTIVES: The mature jackfruit (Artocarpus heterophyllus) is consumed in Sri Lanka either as a main meal or a meal accompaniment. However, there is no scientific data on the nutrient compositions of cooked jackfruit meals. Thus, the objective of the study was to carry out a nutritional assessment of a composite jackfruit breakfast meal comprising seeds and flesh. DESIGN: A jackfruit meal comprising of flesh (80% available carbohydrate) and seeds (20% available carbohydrate) was included in the study. The study was carried out in a random cross over design. Setting University of Sri Jayewardenepura. Study participants Healthy individuals (n=10, age: 20-30 yrs). MEASUREMENTS: The macronutrient contents, rapidly and slowly available glucose (SAG) contents, water solubility index of the jackfruit meal were determined according to standard methods. The GI of the meal was calculated according to FAO/WHO guidelines. RESULTS: The moisture content of the boiled jackfruit flesh was high (82% FW). Jack seeds contained 4.7% protein (FW), 11.1% total dietary fibre (FW) and 8% resistant starch (FW). Jackfruit meal elicited a GI of 75. The Glycaemic Load (GL) of the normal serving size of the meal is medium. The slowly available glucose (SAG) percentage of jackfruit meal (30%) was twice that of the standard. The boiled jackfruit flesh contained disintegrated starch granules while seeds contained intact swollen and disintegrated granules. CONCLUSIONS: The jackfruit seeds are a good source of starch (22%) and dietary fibre. The meal is categorized as a low GI meal. The low GI could be dueto the collective contributions from dietary fibre, slowly available glucose and un-gelatinised (intact) starch granules in the seeds.

Chemical compositions and glycemic responses to banana varieties.

Chemical compositions and glycemic indices of four varieties of banana (Musa spp.) (kolikuttu-Silk AAB, embul-Mysore AAB, anamalu-Gros Michel AAA, seeni kesel-Pisang Awak ABB) were determined. Silk, Gros Michel, Pisang Awak and Mysore contained the highest percentages of starch (14%), sucrose (38%), free glucose (29%) and fructose (58%) as a percentage of the total available carbohydrate content respectively. Total dietary fiber contents of four varieties ranged from 2.7 to 5.3%. Glycemic indices of Silk, Mysore, Gros Michel and Pisang Awak were 61 ± 5, 61 ± 6, 67 ± 7, 69 ± 9 and can be categorized as low against white bread as the standard. A single banana of the four varieties elicited a low glycemic load. Thus, consumption of a banana from any of these varieties can be recommended as a snack for healthy or diabetic patients who are under dietary management or pharmacological drugs to regulate blood glucose responses in between meals.

Do Sri Lankan meals help decrease blood glucose response?

OBJECTIVE: The prevalence of diabetes mellitus (DM) has rapidly increased in Asian countries including Sri Lanka during the past decade. Scientific data on postprandial glycaemic influence of common meals is essential when formulating diets. Objectives of this study were to analyse glycaemic indices (GI) of five common meals and effects of macronutrients, sources of carbohydrates, and physicochemical properties of starch on observed GI values. DESIGN: The meals analysed were; 1 - red rice (AT 353) meal, 2 - red rice mixed meal, 3 - stringhopper (wheat flour) meal, 4 - stringhopper (rice flour) meal, 5 - manioc (Manihot esculenta) meal. SETTING: University of Sri Jayewardenepura. SUBJECTS: Healthy individuals (n=10; age: 20-30 years). MEASUREMENTS: GI of each meal was calculated according to FAO/WHO guidelines by taking the ratio of incremental area under blood glucose curve (IAUC) of test and the standard. RESULTS: GI of meals 1-5 were 99 +/- 10, 60 +/- 5, 104 +/- 7, 102 +/- 11 and 120 +/- 9 respectively. The glycaemic response to rice mixed meal was significantly lower (p<0.05) than the others. The total dietary fibre content showed a significant negative correlation (p=0.044) with the GI value while the protein showed a non-significant negative relationship (p>0.05). Red rice had a combination of intact, swollen and disintegrated starch granules while string hoppers and manioc showed only the latter two types. CONCLUSION: The rice mixed meal has the lowest glycaemic index. Presence of dietary fibre and a legume reduces the glycaemic response. Cooking may change the glycaemic response of certain food.

Glycaemic indices of three Sri Lankan wheat bread varieties and a bread-lentil meal.

The glycaemic index (GI) concept ranks individual foods and mixed meals according to the blood glucose response. Low-GI foods with a slow and prolonged glycaemic response are beneficial for diabetic people, and several advantages have been suggested also for non-diabetic individuals. The recent investigations imply an increasing prevalence of diabetes mellitus in Sri Lanka. Thus, the present study was designed primarily to determine the glycaemic indices of some bread varieties in Sri Lanka as bread has become a staple diet among most of the urban people. A second objective was to observe the effects of macronutrients and physicochemical properties of starch on GI. Glycaemic responses were estimated according to FAO/WHO guidelines and both glucose and white bread were used as standards. Non-diabetic individuals aged 22-30 years (n=10) participated in the study. The test meals included white sliced bread, wholemeal bread, ordinary white bread and a mixed meal of wholemeal bread with lentil curry. The GI values (+/-standard error of the mean) of the meals were 77+/-6, 77+/-6, 80+/-4, 61+/-6, respectively (with glucose as the standard). The GI values of the bread varieties or the meal did not differ significantly (P >0.05). However, the meal can be categorized as a medium-GI food while the other bread varieties belong to the high-GI food group. A significant negative correlation was obtained with protein (P=0.042) and fat (P=0.039) contents of the food items and GI. Although the GI values of the foods are not significantly different, the inclusion of lentils caused the GI to decrease from a high-GI category to a medium-GI category. According to the present study, a ratio of 1.36 can be used to interconvert the GI values obtained with the two standards.

A polymerase chain reaction based method for the detection of Culex quinquefasciatus (Diptera: culicidae).

Culex quinquefasciatus Say is the major vector of the filarial parasite Wuchereria bancrofti (Cobbold) which causes lymphatic filariasis in humans. A repetitive DNA sequence from the genome of C. quinquefasciatus has been cloned and completely sequenced. The 693 bp cloned fragment had an A+T content of 72%. Dot matrix analysis of the fragment did not reveal any direct or inverted repeats within it. Southern blot analysis using a variety of restriction enzymes appeared to indicate that the cloned fragment was interspersed within the genome with a copy number of approximately 30,000. A search of the GenBank database did not reveal significant homologies to any previously cloned sequences. Although the probe was sensitive enough to detect picogram quantities of DNA, it was not specific for C. quinquefasciatus, as it hybridized with DNA from other mosquito species, Culex pseudovishnui Colless, Culex gelidus Theobald, Culex tritaeniorhynchus Giles, Anopheles vagus Dönitz and Mansonia uniformis (Theobald). However PCR primers derived from the cloned sequence, IpC, were found to be specific and amplified only C. quinquefasciatus DNA. The optimized PCR assay was found to be very sensitive and was capable of detecting DNA from all stages of C. quinquefasciatus thus making it an ideal diagnostic tool.