Noakes on children's nutrition, organ meats and the Karoo
Dr Lize van Stuijvenberg and Dr Ali Dhansay, Scientists at the South African Medical Research Council (MRC), Cape Town
Letter submitted to the Cape Times (21 July 2014)
The articles (Cape Times 16 and 17 July 2014) by Tanya Farber on sport scientist Professor Tim Noakes' proposed research regarding the promotion of organ meat consumption in the Karoo, refer.
As scientists who have published research conducted on the subject, we are disturbed by certain aspects of the reports. Prof Noakes speaks about a long term project among farm workers and their families in the Karoo. We trust that the results of this ten year project will be valid, since there is no mention of a control group of farm workers on a different diet. It would be unethical to conduct a research study where the design may be seen to be flawed at the outset. We understand, though, that such details were not included in the article. The questions posed, however, do remain.
Of concern is his assumption that these communities do not eat offal. Research conducted by the MRC's Nutritional Intervention Research Unit in the Hantam Karoo showed that between 80 and 90% of the children under five years of age do eat liver. Further, contrary to what Prof Noakes claims, it is the low-income families that eat liver more often. This work was published in an international peer-reviewed journal (Van Stuijvenberg et al., 2012; Nelet al., 2013).
We urge restraint regarding the promotion of unlimited consumption of organ meat. Liver is an exceptionally rich source of vitamin A; too much liver may put young children at risk of vitamin A toxicity. One to two portions of liver per month are enough to meet vitamin A requirements, while eating more than two portions per week will exceed the Upper Intake limit defined by the Institute of Medicine (IOM).
A further concern is the risk of teratogenicity in pregnant women, especially those who consume liver more than once a week. The World Health Organisation warns against excessive intake of vitamin A during pregnancy, and health authorities in countries such as England, Finland and the Netherlands advise pregnant women to limit their intake of liver. Promoting liver intake in the socio-economically vulnerable and uninformed, without warning about the dangers of excess, would be unethical.We urge sport scientist Professor Noakes to exercise (no pun intended) caution when dealing with the complex matter of nutrition, especially childhood nutrition.
Van Stuijvenberg ME, Schoeman SE, Lombard CJ, Dhansay MA. Serum retinol in 1-6-year-old children from a low socio-economic South African community with a high intake of liver: implications for blanket vitamin A supplementation. Public Health Nutr. 2012 Apr;15(4):716-24. doi: 10.1017/S1368980011002126.
Nel J, van Stuijvenberg ME, Schoeman SE, Dhansay MA, Lombard CJ, du Plessis LM. Liver intake in 24-59-month-old children from an impoverished South African community provides enough vitamin A to meet requirements. Public Health Nutr. 2013 Nov 28:1-8.