C S Venter

Obesity in African women in the North West Province, South Africa is associated with an increased risk of non-communicable diseases: the THUSA study

The objective of the present study was to assess the relationship between anthropometric measurements and risk factors for non-communicable diseases (NCD) in South African black women. A cross-sectional sample of 1040 apparently healthy black female volunteers, 15-70 years old, was recruited from thirty-seven randomly selected sites in the North West Province, stratified according to level of urbanisation. We analysed the association between BMI, waist:hip (WHR), waist circumference (WC) and skinfold measurements and the following risk factors for NCD: blood pressure, serum lipids, fasting serum glucose and insulin and plasma fibrinogen, by using age-adjusted correlation analyses and stepwise regression analysis. Of the subjects, 28.6 % were obese (BMI>30). After adjustment for age and smoking status, BMI correlated significantly with diastolic blood pressure (r 0.21, P=0.037), serum triacylglycerols (TG) (r 0.30, P=0.003), fasting glucose (r 0.29, P=0.005) and log fasting insulin (r 0.24, P=0.02). There was a significant negative correlation between BMI and HDL-cholesterol (r -0.38, P<0.001). Similar but stronger correlations were found between both WC and WHR and these risk factors. Together with age, WC was a significant predictor of TG, HDL-cholesterol and fasting glucose in regression analysis, while subscapular skinfold was a significant predictor of diastolic blood pressure and fasting glucose concentration. Triceps skinfold was a significant predictor of total serum cholesterol, LDL-cholesterol, plasma fibrinogen and the insulin sensitivity index. Measures of obesity, particularly WC, are associated with the risk for NCD in black South African women, in which a high rate of obesity has been found.

Integrated nutrition science: from theory to practice in South Africa.

OBJECTIVE To describe an integrated, holistic conceptual framework and research paradigm for a better understanding of the nutrition transition in middle- and low-income countries. MOTIVATION Current inability effectively to prevent the increasing burden related to changes in food consumption patterns and other health behaviours of populations in transition motivates a new approach for nutrition research and practice. In this proposed approach, broader and integrated dimensions of science and practice may be applied for a better understanding of this complex phenomenon. RESULT Examples from our own studies are given and quoted to illustrate how results from transdisciplinary studies were used to design an integrated, holistic programme to improve quality of life of people infected with HIV. CONCLUSION Based on these experiences it is argued that the more holistic and integrated approach should and could lead to more effective and sustainable interventions to prevent the adverse health consequences of the nutrition transition. At the same time such an approach will contribute to efforts to conserve the environment and also human, living and natural resources.

Measuring micronutrient intakes at different levels of sugar consumption in a population in transition: the Transition and Health during Urbanisation in South Africa (THUSA) study

Abstract Objective: The objective was to investigate the absolute micronutrient intake and the possibility of micronutrient dilution of added sugar in the diets of an African population in nutritional transition. Design: A cross-sectional, comparative, population-based design was used. Respondents who consumed sugar were divided into four quartiles of percentage of added sugar intake. Setting: The setting was 37 randomly selected rural and urban areas of the North West province. Subjects: The subjects were 1 742 adult volunteers (739 men and 1 003 women), aged between 15–65 years. After exclusion of low-energy reporters, the sample comprised 1 045 subjects (472 men and 573 women). Outcome measures: The outcomes measures were the macronutrient and micronutrient intakes of subjects in different quartiles of added sugar intake and body mass index (BMI). Results: The average intake of added sugar was 10.01% of total energy (67.12 g) in men and 11.2% total energy (67.10 g) in women. Respondents who consumed the most added sugar had significantly lower mean intakes of alcohol, but higher intakes of energy, macronutrients and most micronutrients. The diets of those in the highest sugar intake group contained significantly less thiamine, riboflavin, niacin, vitamin B12, pantothenic acid, biotin, magnesium, phosphorus and zinc per 4.18 MJ. At every level of added sugar consumption, the mean intakes of fibre (men only), folate, ascorbic acid and calcium (men and women) did not meet the dietary reference intakes [estimated average requirements (EAR)] and pantothenic acid and biotin (women only) did not meet the adequate intake. There were no significant differences in mean BMI across the quartiles of added sugar intakes in men, but the mean BMI of women who consumed the most added sugar was significantly higher than that of those who consumed less sugar. Respondents who consumed the most added sugar had significantly higher intakes of fruit (men only), bread and soft drinks, and lower intakes of maize meal and alcohol (men and women). Conclusion: Absolute intakes of most micronutrients were significantly higher in consumers with a high sugar intake [Quartile (Q) 4] compared with the lowest consumers of sugar (Q1). The lowest percentages of participants whose micronutrient intakes fell below the EAR were in Q4 and Q3. However, expression of micronutrient intake per 4.18 kJ (micronutrient dilution) revealed significantly less of most micronutrients per 4.18 MJ for men and women who consumed the most added sugar, compared with those who consumed the least.

Soluble-fibre concentrate lowers plasminogen activator inhibitor-1 in baboons (Papio ursinus)

The effects of a soluble NSP (fibre) concentrate (SFC) on plasma fibrinogen and plasminogen activator inhibitor-1 (PAI-1), serum and liver lipids and lipoproteins and glucose tolerance were compared with those of bezafibrate (BF), a lipid-lowering drug, in obese baboons (Papio ursinus). The basal diet was a high-fat (37% of total energy), low-NSP (12.4 g/d) Westernized diet, supplemented for 8 weeks with either 20 SFCg/baboon per d or 6.7 mg BF/kg body weight per baboon per d. SFC supplementation significantly lowered PAI-1, total serum cholesterol, HDL-cholesterol and circulating free fatty acid levels. BF significantly lowered total serum cholesterol, but unexpectedly raised serum triacylglycerol levels. Although not statistically significant, the mean liver triacylglycerol concentration of baboons fed on BP was lower than that of baboons fed on SFC supplements. These results suggest that: (1) the mechanism of action of the two cholesterol-lowering treatments differ, with BF having a liver triacylglycerol-lowering effect and (2) the SFC ahd additional beneficial effect on fibrinolysis by lowering PAI-1 levels.

Alcohol intake and micronutrient density in a population in transition: the transition and health during urbanisation in South Africa (THUSA) study

Abstract Objective: To investigate the possibility of micronutrient dilution by alcohol in the diets of an adult population in nutrition transition. Design: A cross-sectional, comparative, population-based study. Setting: The African population of the North West Province, South Africa. Subjects: One thousand seven hundred and fifty-seven participants (742 men, 1 015 women) aged 15 years and older from 37 randomly selected sites from rural and urban areas. Outcome measures: Outcome measures included alcohol consumption at different levels of urbanisation. Nutrient intakes in different alcohol intake categories (abstainers, light-to-moderate, and heavy drinkers) and body mass indices of men and women, separately. Results: Sixty-one per cent of men and twenty-five per cent of women reported alcohol consumption. Mean daily alcohol consumption of light-to-moderate drinking men (< 30 g per day) and women (< 15 g per day) were 8.3 g and 3.7 g respectively and 80.4 g and 36.6 g for “heavy drinkers”, defined as men consuming more than 30 g alcohol/day (18% of the study population) and women who drank more than 15 g alcohol/day (6% of the study population). Sorghum and commercial beer were the most popular alcoholic beverages. Alcohol intake increased from rural to urban middle class, with a shift from sorghum to commercial beer with urbanisation. Men consuming the most alcohol had significantly higher mean intakes of most macro- and micronutrients. For both men and women only the percentage of energy from fat decreased significantly as the alcohol intake increased. The intake of some micronutrients did not meet the Dietary Reference Intake (DRI, Estimated Average Requirement, EAR) at all levels of alcohol consumption. However, the DRIs for pantothenic acid, biotin, magnesium and zinc were met only in men consuming the most alcohol. There was no significant difference in BMI across the different alcohol consumption categories although the total energy intake increased with an increase in alcohol consumption. Conclusion: In this population in transition, urbanisation increased the consumption of alcoholic beverages. Mean energy intake from alcohol of heavy-drinking men (18.1% of total energy, TE) and women (11.7% of TE) was significantly higher than in the other groups but this did not cause an overall micronutrient dilution effect. It seems that respondents who have the money to buy alcoholic drinks can possibly also afford more healthy and nutritious food.

More evidence for capillary sampling in the determination of glycaemic index

Introduction and objective. The glycaemic index (GI) can be determined using capillary blood or venous plasma sampling. The aim of this study was to compare the GIs of three South African oat products determined using both capillary blood and venous plasma.

Some health benefits of low glycaemic index diets - a systematic review

Background: Controversy exists regarding practical use of the glycaemic index (GI), often with reference to the responsibility of health professionals to advise consumers only when scientific evidence supports their recommendations. There are indications that low-GI diets may improve health, but the strength of the evidence is not known.

The effect of extrusion processing on the glycaemic index of dry bean products

Background: Both wheat pasta and dry beans have low glycaemic indices (GIs). However, it has been shown that several factors, including method of processing, may influence the GI of a food. Extrusion of dry beans is a relatively new dry cooking process and provides a convenient alternative to the ingestion of dry beans.