Fatty acid composition of mature human milk in Nigeria.

The fatty acid composition of mature human milk from 10 rural Nigerian women was analyzed by high-resolution capillary gas-liquid chromatography and compared to previously determined results on mature human milk from 15 German mothers. Human milk of the Nigerian group contains significantly higher proportions of saturated fatty acids (median 54.07 vs. 42.76% wt/wt). The difference is primarily caused by high values for lauric (C12:0, 8.34%) and myristic acids (C14:0, 9.57%), but not of medium chain fatty acids (C8:0, C10:0), presumably due to increased de novo fatty acid synthesis in the African women consuming a high carbohydrate and low-fat diet. Markedly lower values of oleic and total cis-monounsaturated (22.82 vs. 37.98%) as well as trans-isomeric fatty acids (1.20 vs. 4.40%) in Nigerian milk appear to result from low dietary intakes of animal and partially hydrogenated fats, respectively. Although percentage contribution of linoleic acid (18:2n-6) is similar, arachidonic acid (C20:4n-6) and total n-6 long-chain polyunsaturates with 20 and 22 carbons (n-6 LCP) are higher in the African samples. N-6 LCP secretion with human milk lipids is not correlated to the precursor linoleic acid and seems not to depend on maternal dietary intake of preformed dietary LCP with animal fats. N-3 LCP are very high in milk of the Nigerian women who obtain a large portion of dietary lipids from sea fish, but even then docosaehexanoic (C22:6n-3) and not eicosapentaenoic (C20: 5n-3) is the predominant n-3 LCP in milk.(ABSTRACT TRUNCATED AT 250 WORDS)