By Rob Winwood
South Africa is a widely diverse country with varied living conditions and resources, diverse ethnic groups and different traditional eating patterns. This new study assessed the lipid profile of red blood cell (RBC) membrane total phospholipids in relation to the dietary intake (assessed by 24 hour diet recall) of children aged 2–5 years and their mothers from three very different geographical communities, each with their own, distinct dietary patterns (1). The fatty acid content of RBCs is thought to be a good indicator of long-term fatty acid status.
The De Aar community is a land-locked urban community in the Northern Cape (NC) province where mutton is eaten widely. The Ocean View urban community is based on the Western Cape (WC) and has access to fresh fish. Finally, the rural, landlocked community of the Sekhukhune District of Limpopo Province (LP) consumes a traditional diet based on maize porridge and leafy vegetables with a relatively low total fat intake. In each community, approximately 100 members took part in the study.
The main source of calories in the urban communities’ diet was sugar and bread, whereas in Limpopo Province, it was maize porridge. The RBC lipids of the LP children and mothers had the healthiest blood lipid profile, having the highest proportion of polyunsaturated fatty acids (PUFAs), omega-3 and omega-6 fatty acids, but the lowest level of saturated fats.
The overall omega-3 fatty acid intake was disturbingly low in children from all communities studied. The median combined intake of eicosapentaenoic acid (EPA) and docosahexaenoic acid was a mere 50, 55 and 3 mg a day for the NC, WC and LP communities, respectively. The intake values for their mothers were only marginally better. Typically the advised minimum daily intake for small children is between 100 and 200 mg/day. The comparable mean EPA plus DHA levels in the RBCs (expressed as percentage of fatty acids) of the children was 3.78, 4.53 and 4.94 percent for the NC, WC and LP communities, respectively. Such values place the individuals at greatly increased risk of cardiovascular disease later in life. However, it is of interest that despite have virtually no obvious intake of EPA and DHA in their food, the Limpopo community children still had the highest RBC EPA plus DHA status of the three communities. A possible explanation of this is that the LP children are almost exclusively Black African and have a relatively low consumption of omega-6 fatty acids in their diet. The NC and WC communities feature a range of different racial groups and consume a more westernized diet rich in omega-6 fatty acids. The consumption of higher levels of omega-6 fatty acids is known to suppress endogenous production of EPA and DHA from ALA (alpha linolenic acid).
South Africa is anthropologically regarded as the “cradle of mankind.” Interestingly, the local, indigenous people seemed to have retained their ability to activate the necessary dehydrogenase and elongation enzymes to make EPA and DHA from the readily available ALA substrate. The further Homo sapiens have drifted from their African home the less active these enzymes appear to be (2).