Uniformity of human milk.

Compositon of human milk was studied during the feed in six women, through-out the day in one woman on 3 consecutive days and in three women on 39 occasions during established lactation. The total lipid content varied in the course of suckling as well as diurnally in a regular and predictable manner, but the fatty acid composition of the lipid remained constant and was similar in the subjects examined. Fatty acid pattern of milk lipid of one woman supplementing her diet with unsaturated fats was studied. The changes in the milk lipid compostion, induced by the altered diet, are discussed in relation to the mechanism of milk fat synthesis. The described changes in milk composition are specific and may be physiologically significant. The composition of lipid in milk of mothers on adequate and balanced diet shows only limited fluctuations forming a species-specific pattern. The variations that occur in extreme dietary conditions (malnutrition, undernutrition, supplementation) are not random and can be predicted.