Cost of diet in relation to nutrient intake of infants residing in an HIV-exposed environment

Abstract

About 1.4 million women living with HIV infection become pregnant every year in Africa. South Africa is not an exception with the HIV prevalence of 26.3% among women of reproductive age. The number of HIV-exposed-uninfected (HEU) infants is expanding due to the success of the prevention of mother to child transmission (PMTCT) of HIV programmes. HEU infants are at risk of low nutritional status. The cost of diet in terms of complementary foods may be high; such as fortified commercial foods, and low for staple foods with poor nutrient density. There is little known or documented about the cost of a diet of six-months infants. The present study investigated and compared the cost of diet in relation to nutrient intake and feeding practices of HEU versus HIV-unexposed-uninfected (HUU) infants aged six-months. This cross-sectional descriptive study was a sub-study of the Siyakhula study, which recruits low-risk pregnant HIV-infected and HIV-uninfected women in the South-West Tshwane, Gauteng Province. The study longitudinally follows up their HEU and HUU children for two years. For this study, a self-designed cost of food questionnaire with a single 24-hour recall questionnaire was used. The SAMRC FoodFinder™ program was used for meal analysis to quantify nutrient intake. The estimation of diet cost utilised supermarket food prices and diet diaries method. The prices of food items were collected from three local supermarkets. The cost of diet and nutrient intake were derived by relating the food items and nutrients to food prices per 100g of raw food. At the time of data collection, 236 of recruited participants had six-months-old infants. Mother-infant-pairs (n=101) with complete feeding practices and infant dietary data were investigated (HEU (n=46); HUU (n=55)). A sub-study for the cost of diet was conducted on infants who had consumed complementary foods and breast milk substitutes (HEU (n=39); HUU (n=51)). Maternal HIV infection was associated with lower household income (p<0.01) and educational attainment (p=0.04). The median age of infants was 6m.3d (6.1;6.6) for HEU and 6m.4d (6.1;6.9) for HUU infants; p=0.53. Most feeding practices did not differ between HEU and HUU infants: early initiation of breastfeeding (75% vs 76%; p=0.96); any current breastfeeding (62% vs 71%; p=0.37); exclusive breastfeeding (46% vs 33%; p=0.15) and mixed feeding: 7% (HEU) vs 31% (HUU); p=0.01). Common complementary foods consumed by HEU and HUU infants included commercial infant cereals (49% vs 71%; p=0.035); fruits and vegetables (33% vs 16%; p=0.05) and maize meal porridge (26% vs 16%; p=0.24). The mean daily cost of diet among HEU vs HUU infants was ZAR40.60±41.70 vs ZAR29.50±31.10 (p=0.43). Only cost and intakes of iron and vitamin C differed between HEU and HUU infants: iron cost ZAR 0.00 (0.00;0.00) per group; p=0.02, and intakes were 5.00mg (2.10;10.30) vs 7.10mg (4.95;13.70); p=0.03. Vitamin C cost ZAR 0.01 (0.00;0.01) per group; p=0.02, and intakes were 43.00mg (14.00;98.50) vs 70.00mg (35.00; 124.50); p=0.01, for HEU and HUU, respectively. The percentages of nutrient intake adequacy for HEU and HUU infants were high for iron, zinc and calcium, while vitamin B12 was high in HUU group (86% vs 64%; p=0.03). Suboptimal breastfeeding practices show that more effort is required to strengthen support and promote breastfeeding. There is inequality in the cost of diet between HEU and HUU infants. Caregivers of HEU infants spend more on less iron and vitamin C intakes. It is more cost-effective to buy commercial infant cereals with a higher nutrient density to ensure optimal infant nutrition.