(Santa Barbara, Calif.) Working with researchers at the University of Pittsburgh and the Cincinnati Children's Hospital, anthropologists at UC Santa Barbara have found high levels of beneficial omega-3 fatty acids in the breast milk of economically impoverished Amerindian woman as compared to women in the United States. Their research appears in the current issue of the journal Maternal and Child Nutrition.
The study compared breast milk fatty acid composition in U.S. and Tsimane women. The Tsimane live in Amazonian Bolivia, and eat a diet consisting primarily of locally grown staple crops, wild game, and freshwater fish. Samples of Tsimane mothers' milk contained significantly higher percentages of the omega-3 fatty acid docosahexaenoic acid (DHA), which is crucial for infant cognitive and visual development.
Additionally, the percentages of DHA in breast milk did not significantly decrease across the first two years postpartum, the period during which infant brains experience peak growth and maximal uptake of DHA. This was also true for the U.S. women, and the study suggests that extended breastfeeding by both U.S. and Tsimane mothers may provide infants with a constant source of DHA during the critical period of brain development.
"The fatty acid composition of breast milk varies with the fatty acid composition of a mother's diet and fat stores. Ancestral humans likely consumed omega-6 and omega-3 fatty acids in equal proportions," said Melanie Martin, a doctoral student in UCSB's Department of Anthropology, and the study's lead researcher. "Tsimane mothers' omega-6 to omega-3 ratios were four to one, much closer to the ancestral estimates than observed in U.S. women."
Unfortunately, the ratio of omega-6 to omega-3 in industrialized diets varies from 10 to 1 to as high as 20 to 1. This is most likely due to the absence of fresh fish, and regular consumption of processed foods and vegetable oils rich in linoleic
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University of California - Santa Barbara