Biochemical assessment of the nutritional status of infants, children and adolescents in South Africa (1997-2022): a systematic review.

Objective: To conduct a systematic review of the published peer-reviewed articles on the biochemical assessment of nutritional status of South African infants, children and adolescents in 1997-2022.

Design: Online databases (Pubmed, CINAHL, EbscoHost and SAePublications) were used to identify thirty-nine papers.

Setting: South Africa, 1997-2022.

Participants: Infants, children and adolescents.

Results: Vitamin A deficiency prevalence was 35-67 % before 2001 and mostly below 16 % after 2008. Anaemia ranged from 5·4 to 75·0 %, with 36-54 % of infants below 1 year being anaemic. Among 0- to 6-year-olds, iron deficiency (ID) was 7·2-39·4 % in rural and 16-41·9 % in urban areas. Zn deficiency remained high, especially among 0- to 6-year-olds, at 39-48 %. Iodine insufficiency (UIC < 100 µg/l) was between 0 and 28·8 %, with excessive levels in two areas. Vitamin D deficiency was 5 % for 11- to 17-year-olds in one urban study but 33-87 % in under 10-week-old infants. The 2005 national survey reported sufficient folate status among 0- to 6-year-olds, and vitamin B₁₂ deficiency was 0-21 %. Low-grade inflammation was between 5 % and 42 % depending on the biomarker and cut-offs.

Conclusions: Vitamin A status may have improved meaningfully during the last 25 years in South Africa to below 16 %, and iodine and folate deficiency appears to be low particularly among 0- to 6-year-olds. However, confirmation is needed by a national survey. Anaemia, Fe and Zn deficiencies still pose severe problems, especially among 0- to 6-year-olds. Sufficient data on vitamin D and B₁₂ status are lacking.