Sagarika Ekanayake

Carbohydrate-rich foods: glycaemic indices and the effect of constituent macronutrients.

The glycaemic index (GI) ranks foods according to their acute glycaemic impact and is used in planning meals for patients invoking glycaemic control through diet. Kurakkan (Eleusine coracana) flour roti, rice flour roti, atta flour roti, boiled breadfruit (Artocarpus altilis/Artocarpus communis) and boiled legumes (mungbean, cowpea and chickpea) were categorized as low-GI foods (relative to white bread; Prima Crust Top™), and the corresponding GI (± standard error of the mean) values were 70±8, 69±7, 67±9, 64±7, 57±6, 49±8 and 29±5, respectively. Kurakkan flour pittu and wheat flour roti were classified as medium-GI foods with GI values of 85±6 and 72±6. Hoppers, rice flour pittu, wheat flour pittu and Olu-milk rice (seeds of Nymphaea lotus) were categorized as high-GI foods, and the corresponding GI (± standard error of the mean) values were 120±8, 103±7, 101±8 and 91±8, respectively. The GI values significantly (P<0.01) and negatively correlated with the insoluble dietary fibre (ρ = − 0.780), soluble dietary fibre (ρ = − 0.712) and protein (ρ = − 0.738) contents in grams per 100 g digestible starch containing foods.

Nutritional evaluation of protein and starch of mature Canavalia gladiata seeds.

Evaluation of true digestibility (TD), biological value (BV) and net protein utilisation (NPU) of diets made with raw and processed seed flour from mature Canavalia gladiata seeds were carried out with male Sprague-Dawley rats. The weight gain of the rats fed with diets containing raw whole seed and raw cotyledon alone were significantly lower (P = 0.05) than that of the group fed with the reference diet. Processing the cotyledons (dry-autoclaved or roasted) significantly (P < or = 0.05) increased the weight gain of the rats when compared to the weight gain of rats fed diets prepared with raw seed flour. NPU of raw (whole seed 13.8; cotyledon 27.6) was significantly lower (P < or = 0.05) than the reference diet (79.5). The NPU of processed samples was also significantly lower (P < or = 0.05) when (dry-autoclaved 25.1; roasted 25.1) compared to the reference diet fed group (79.5). The BV of the processed samples (dry-autoclaved 31.1; roasted 37.7) was significantly lower (P < or = 0.05) than that of raw (53.6) cotyledon. In contrast TD increased (P < or = 0.05) with processing (dry-autoclaved 80.9; roasted 65.9) when compared to raw cotyledon (51.4). In vitro protein digestibility for the raw whole seed and cotyledon was 71.7 and 70.1% respectively. In vitro starch digestibility of raw and processed cotyledon flour samples indicated dry-autoclaved sample to have the highest digestibility.

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.

Green leafy porridges: how good are they in controlling glycaemic response?

Green leafy porridges made with leaf water extracts, rice and coconut milk are common Sri Lankan dietary remedies for diabetes. Though water and ethanolic extracts of most leaves elicit hypoglycaemic effects, data are not available on the efficacy when leaf extracts are incorporated into porridges. Thus, an effort was made to evaluate the proximate compositions and glycaemic index (GI) of some commonly consumed green leafy porridges. The GI of rice porridge and coconut milk porridge were measured to evaluate the effect of other ingredients other than the leaf extracts. Rice was the main contributor to carbohydrate (56–68% on dry weight) and water was the main component in porridges (89–93%). Fat and total dietary fibre contents ranged between 2.5–27% and 5–10%, respectively. The GI of all porridges was low (GI ≤ 55), except Cassia auriculata which had a high GI of 77 ± 12. The GIs of coconut milk, Aerva lanata, Hemidesmus indicus, Scoparia dulcis, Asparagus racemosus, Cephalandra indica, Cardiospermum halicacabum, Murraya koenigii and Aegle marmelos were 31 ± 5, 32 ± 5, 40 ± 8, 39 ± 8, 37 ± 4, 49 ± 8, 46 ± 8, 44 ± 8 and 50 ± 8, respectively. All porridges had a low or medium glycaemic loads ( ≤ 19). However, peak blood glucose reductions of ≥ 25% were observed in all leafy and coconut milk porridges, except in C. auriculata and Atlantia zeylanica, when compared with the glucose control. Therefore, green leafy porridges, except Cassia, can be recommended as breakfast meals for diabetics due to their low GI, peak blood glucose reduction and presence of other nutrients in green leaves.

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.

Anti-diabetic properties of rice-based herbal porridges in diabetic Wistar rats.

The present study aims to investigate anti‐hyperglycaemic, anti‐hyperlipidaemic and toxic effects of long‐term consumption of selected green leafy porridges in a streptozotocin‐induced diabetic Wistar rat model. Porridges made with Asparagus racemosus Willd. (AR), Hemidesmus indicus (L) R. Br. W. T. Aiton (HI), Scoparia dulcis L. (SD) and coconut milk porridge (CM) were incorporated into diets of diabetic Wistar rats. Diabetic control (DM) and normal control groups (NC) were provided with standard rat diet. Fasting blood glucose (FBG), HbA1c, C reactive protein (CRP), total cholesterol (TC), high‐density lipoprotein cholesterol (HDL‐C), liver enzymes and creatinine were measured. Feed and water intake among diabetic groups were significantly high when compared with those of NC (p < 0.05). All rats in SD (mean = 39 ± 19 g) and NC (mean = 114 ± 7 g) groups gained weight, whereas most rats in other diabetic groups lost weight. Among the diabetic groups, SD group had the lowest mean FBG, FBG increment percentage (45%) and HbA1c (5.8 ± 2.1). FBG increment percentage and HbA1c of SD group were not significantly different to those of NC (38%; 4.7 ± 0.7) (p > 0.05). Among the diabetic groups, lowest TC (119 ± 20.6 mg/dL) and highest HDL‐C (33 ± 6.3 mg/dL) were also detected in SD group. Alanine transaminase and creatinine were not significantly different (p > 0.05) among diabetic groups but significant when compared with those of NC. When compared with those of NC, aspartate transaminase levels were significantly (p < 0.05) high in SD, CM and DM groups. Body weight : liver weight and body weight : pancreas weight ratios and CRP were not significantly different among all groups. The study proved that SD porridge reduced weight loss, elicited hypoglycaemic and hypolipidaemic properties, and caused no toxicity in diabetes‐induced Wistar rats. Copyright

Studies on hypercarotenemia due to excessive ingestion of carrot, pumpkin and papaw

Hypercarotenemia is diagnosed by yellowing of skin. The present study was carried out to study the carotenoids, their metabolites and the vitamin A levels in hypercarotenemics on reporting, changes in serum carotenoids following cessation of feeding carotenoid-bearing foods, and to determine the carotenoids in stools of hypercarotenemics and non-hypercarotenemics. Hypercarotenemic subjects (n = 35) were tested on reporting for a 2-month to 3-month period. Feces from hypercarotenemics (n = 5) and non-hypercarotenemics (n = 8) were extracted and subjected to reverse phase-high-performance liquid chromatography. A questionnaire was administered to parents (n = 35) of these hypercarotenemic children. The serum α- and β carotenoids varied from 119 g/dl to trace and from 149 g/dl to trace respectively, with the monohydroxy metabolites varying from 214 g/dl to nondetectable and polyhydroxy metabolites from 823 g/dl to 7.0 g/dl. Longitudinal studies indicated that serum carotenoid levels declined while vitamin A levels were maintained. α-Carotenes and β-carotenes were not detected in the feces of hypercarotenemics but were present in non-hypercarotenemics.

Effect of three edible oils on the intestinal absorption of caffeic acid: An in vivo and in vitro study

Polyphenolic antioxidants are mainly absorbed through passive paracellular permeation regulated by tight junctions. Some fatty acids are known to modulate tight junctions. Fatty acids resulting from the digestion of edible oils may improve the absorption of polyphenolic antioxidants. Therefore, we explored the effect of three edible oils on the intestinal absorption of caffeic acid. Rats were fed with soybean oil and caffeic acid dissolved in distilled water. Caffeic acid contents in the plasma collected up to 1 hr were quantified. The experiment was repeated with coconut oil and olive oil. Component fatty acids of the oils were individually tested in vitro for their effect on permeability of caffeic acid using Caco-2 cell monolayers. Highest absorption of caffeic acid was observed in animals fed with coconut oil. In vitro transport percentages of caffeic acid in 2.5 mmol/L solutions of fatty acids were 22.01±0.12 (lauric), 15.30 ± 0.25 (myristic acid), 13.59 ± 0.35 (linoleic acid), 3.70 ± 0.09 (oleic acid) and 0.10–2.0 (all other fatty acids). Lauric acid and myristic acid are the two major fatty acids present in coconut oil. Therefore, these fatty acids may contribute to the higher absorption of caffeic acid in the presence of coconut oil.

Ethnic Fermented Foods and Beverages of Sri Lanka

In Sri Lanka, fermented foods, though not many, have been used as meals or part of a meal from ancient times, and they are fitted into the meal pattern in a variety of ways. Sri Lanka being a land of multiethnic groups, the cuisine is influenced by the Portuguese, Dutch, Malays, Arabs, and the South Indians who have left their culinary characteristics. This chapter summarizes various aspects of fermented food products, some traditional products specific to the country which are not many, and also some fermented foods that are produced in Sri Lanka and consumed by all Sri Lankans. The products described are categorized into milk-based products, cereal- and legume-based products, vegetable products, fish- and meat-based products, and alcoholic beverages. The enhancement of nutritive value and health benefits obtained by consuming such products is not well documented and known by many people. Therefore, it is important to carry out further investigations regarding the nutritive value and health effects of various fermented foods available in Sri Lanka.

Dietary Habits of Type 2 Diabetes Patients: Variety and Frequency of Food Intake

The objective of the present study was to observe the dietary patterns and food frequencies of type 2 diabetes patients attending the clinics of the Family Practice Center of the University of Sri Jayewardenepura, located in a highly urbanized area in Sri Lanka. An interviewer administered questionnaire based cross-sectional study was conducted among randomly selected 100 type 2 diabetes patients [age 35–70 years; mean age 55 ± 9 (males = 44; females = 56)]. The data were analyzed by SPSS version 18.0 software. Vegetables, fatty foods, and poultry consumption were in accordance with the national guidelines. A significant percentage (45.5%) consumed rice mixed meals for all three meals and only 67% consumed fruits at least once a day. Majority (71%) consumed full-cream milk and sugar intake (77%) was in accordance with the guidelines. Noncaloric sweetener usage was nonexistent. Daily green leafy vegetable intake and the quantity consumed were inadequate to obtain beneficial effects. From the study population, 44% [females 50%; males 36%] of the patients were either overweight or obese. However, only 60% of those patients accepted that they were either overweight or obese. Only 14% exercised daily while 69% never exercised. Study revealed the importance of educating patients with type 2 diabetes on dietary changes and more importantly the involvement in regular physical exercises.