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.