Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2006
Publication Date: 3/1/2007
Publication URL: jn.nutrition.org/cgi/reprint/137/3/676
Citation: Mclean, E.D., Allen, L.H., Neumann, C.G., Peerson, J.M., Siekmann, J.H., Murphy, S.P., Bwibo, N.O., Demment, M.W. 2007. Low plasma vitamin B-12 in Kenyan school children is highly prevalent and improved by supplemental animal source foods. Journal of Nutrition. 137:676-682, 2007. Interpretive Summary: It is now recognized that there is a high prevalence of vitamin B12 deficiency in many regions of the world, but it is not known whether this is caused by a low intake of the vitamin or by inability of some populations with infections to absorb the vitamin from food. This study took place in rural Kenya where the authors have previously identified a high prevalence of vitamin B12 deficiency. Subjects were 503 school children who were studied before, during and after they received food supplements (maize and beans, milk or meat equal in energy content) at school. At baseline 40% of the children were B12 deficient and nearly 70% were deficient or depleted in the vitamin. Serum B12 concentration was correlated with their usual intake of animal source foods. Animal source food intake was very low for all children, but those in the lowest tertile of animal source food intake were 6.28 times more likely to be deficient than those in the upper tertile. Supplementation with meat or milk over a one or two year period greatly reduced the prevalence of low serum vitamin B12. We conclude that low intake of animal source foods is the primary cause of deficiency in these children, and that providing them with more milk or meat improves their vitamin B12 status.
Technical Abstract: The high prevalence of vitamin B-12 deficiency in many regions of the world is becoming recognized as a widespread public health problem, but it is not known to what extent this deficiency results from a low intake of the vitamin or from its malabsorption from food. In rural Kenya, where a previous study identified a high prevalence of inadequate vitamin B-12 intakes, this study examined whether plasma vitamin B-12 concentrations were associated with dietary sources of the vitamin at baseline and could be increased by supplementation with animal source foods (ASF). The 4 experimental groups in 503 school children were: 1) control (no food provided); 2) githeri (a maize and bean staple with added oil); 3) githeri + meat (githeri + minced beef); 4) githeri + milk (githeri + milk). Feedings were isocaloric. Dietary data were collected at baseline, and biochemical data at baseline and after 1 and 2 y of feeding. Baseline plasma vitamin B-12 concentration was 193.6± 105.3 pmol/L and correlated with % energy from ASF (r=0.308, P<0.001). The odds ratio for low plasma vitamin B-12 (<148 pmol/L), which occurred in 40% of children, was 6.28 [95% CI: 3.07-12.82] for the lowest vs.highest ASF intake tertile (P , 0.001). Feeding ASF (meat or milk) greatly reduced the prevalence of low plasma vitamin B-12 (P<0.001). The high prevalence of low plasma vitamin B-12 concentrations in these children is predicted by a low intake of ASF, and supplemental ASF improves vitamin B-12 status.