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Background: Breast milk iodine concentration (BMIC) may be an indicator of iodine status during lactation, but there are few data comparing different analytical methods or timing of sampling. The aims of this study were: (i) to optimize a new inductively coupled plasma mass spectrometry (ICP-MS) method; and (ii) to evaluate the effect of analytical method and timing of within-feed sample collection on BMIC. Methods: The colorimetric Sandell-Kolthoff method was evaluated with (a) or without (b) alkaline ashing, and ICP-MS was evaluated using a new 129 I isotope ratio approach including Tellurium (Te) for mass bias correction (c) or external standard curve (d). From iodine-sufficient lactating women (n = 97), three samples were collected within one breast-feeding session (fore-, mid-, and hind-feed samples) and BMIC was analyzed using (c) and (d). Results: Iodine recovery from NIST SRM1549a whole milk powder for methods (a)-(d) was 67%, 24%, 105%, and 102%, respectively. Intra-and inter-assay coefficients of variation for ICP-MS comparing (c) and (d) were 1.3% versus 5.6% ( p = 0.04) and 1.1% versus 2.4% ( p = 0.33). The limit of detection (LOD) was lower for (c) (0.26 lg/kg) than it was for (d) (2.54 lg/kg; p = 0.02). Using (c), the median [95% confidence interval (CI) obtained by bootstrap] BMIC (lg/kg) in foremilk (179 ) and in mid-feed milk (184 [CI 160-220]) were not significantly different ( p = 0.017), but were higher than in hindmilk (175 ; p < 0.001). In foremilk using (d), ; p < 0.001 vs. (c)). The variation in BMIC comparing (c) and (d) (13%) was greater than variation within feeding (5%; p < 0.001). Conclusions: Because of poor recoveries, (a) and (b) should not be used to measure BMIC. Compared with (d), (c) has the advantages of higher precision and a lower LOD. In iodine-sufficient women, BMIC shows low variation within a breast-feeding session, so timing of sampling is not a major determinant of BMIC.

BackgroundThe dietary shift from indigenous and traditional plants (ITPs) to cash crops and exotic plant food sources increases the risk of malnutrition and other nutrition-related non-communicable diseases, especially in poor rural communities. Farm communities in South Africa have been associated with poor nutritional status and extreme poverty. ITPs have been found to be affordable sources of several micronutrients. However, knowledge of and the use of these plants are declining, and little is known about the child’s acceptance of dishes prepared with ITPs. This knowledge can be used to improve the general acceptance of ITPs. This study aimed to gain insight into parents’ knowledge and perceptions and their use of ITPs in a farming community in the North West Province and to assess children’s acceptance of and preference for dishes made with African leafy vegetables (ALVs) and Swiss chard.MethodsParents (n = 29) responsible for food preparation for children in grade 2 to 4 in two schools were purposively selected for four focus group discussions. A sensory evaluation assessed the children’s (n = 98) acceptance of, preference for and intended consumption of dishes made with leafy vegetables. The dishes were made of Amaranthus spp., Cleome gynandra, Cucurbita maxima, Vigna unguiculata and Beta vulgaris.ResultsParents mentioned 30 edible ITPs during the focus group discussions. Parents had knowledge of available ITPs and their use as food. Location, seasonal variation and rainfall affected the availability of and access to ITPs. Sun-dried ITPs were stored in sacks for later use. ITPs were perceived as healthy, affordable and delicious, hence acceptable to the parents. The children also evaluated the dishes made with ALVs as acceptable in terms of colour, smell and taste. Swiss chard was preferred, most likely because of the children’s exposure to this vegetable. Children indicated that they would like to eat these leafy vegetables twice a week.ConclusionThese results look promising for the promotion of ITPs as a strategy to reduce malnutrition in rural farm communities and for potential inclusion of these micronutrient-rich ALVs in school feeding programmes to improve the nutritional status of children.

Objective: A randomized controlled trial was conducted to assess the effect of African leafy vegetable (ALV) consumption on Fe, Zn and vitamin A status in children. Design: Children were randomly allocated to receive either a 300 g cooked ALV dish and school meal starch (n 86) or the normal school meal (n 81) five times per week for three months. ALV in the dish consisted mainly of Amaranthus cruentus (at least 80 %) and the remainder of Cleome gynandra, Cucurbita maxima or Vigna unguiculata. Nutrient content and consumer acceptance of the ALV dish were also determined. Setting: North West Province, South Africa. Subjects: Grade R to grade 4 children (6-12 years old) of two farm schools. Results: The ALV dish contributed 11·6-15·8 mg Fe and 1·4-3·7 mg Zn. At baseline, prevalence of deficiencies in the intervention group was 16·0 %, 16·3 %, 7·0 % and 75·6 %, respectively, for anaemia (Hb < 11·5 g/dl), Fe (serum ferritin < 15 µg/l), vitamin A (serum retinol < 20 μg/dl) and Zn (serum Zn < 65 μg/dl); and in the control group 10·5 %, 18·5 %, 2·5 % and 75·3 %, respectively. No significant estimated intervention effect was found. Conclusions: This randomized controlled trial showed that ALV were unable to improve serum retinol, serum ferritin or Hb if there are only mild deficiencies present. Furthermore, despite the low Zn status in the study population, ALV consumption did not improve serum Zn concentrations either.

Objective:Lactating women and their infants are susceptible to iodine deficiency and iodine excess. In South Africa, no data exist on the iodine status and thyroid function of these vulnerable groups.Methods:In a cross-sectional study, urinary iodine concentrations (UIC), thyroid function, and breast-milk iodine concentrations (BMIC) were assessed in 100 lactating women from a South African township and their 2-4-month-old breastfed infants. Potential predictors of UIC, thyroid function, and BMIC, including household salt iodine concentrations (SIC) and maternal sodium excretion, were also investigated.Results:The median (25th-75th percentile) UIC was 373 (202-627) μg/L in infants and 118 (67-179) μg/L in mothers. Median household SIC was 44 (27-63) ppm. Household SIC and maternal urinary sodium excretion predicted UIC of lactating mothers. Median BMIC was 179 (126-269) μg/L. Age of infants, SIC, and maternal UIC predicted BMIC. In turn, infant age and BMIC predicted UIC of infants. Forty-two percent of SIC values were within the South African recommended salt iodine fortification level at production of 35-65 ppm, whilst 21% of SIC were >65 ppm. Thyroid-stimulating hormone, total thyroxine, and thyroglobulin concentrations in the dried whole blood spot specimens from the infants were 1.3 (0.8-1.9) mU/L, 128±33 mmol/L, and 77.1 (56.3-105.7) μg/L, respectively, and did not correlate with infant UIC or BMIC.Conclusion:Our results suggest that the salt fortification program in South Africa provides adequate iodine to lactating women and indirectly to their infants via breast milk. However, monitoring of salt iodine content of the mandatory salt iodization program in South Africa is important to avoid over-iodization of salt.