Infant growth and development begins in the womb and continues at a rapid pace during the first months and years of life. Breastfeeding provides optimal nutrition for this development, especially when the mother’s nutrition itself is optimal. The fat content of breast milk is of great importance to infant development—especially when it comes to the omega-3 fatty acid DHA, and the omega-6 fatty acid metabolite arachadonic acid (AA) which are both concentrated in the infant brain during the last trimester and first few months of life.1

The main polyunsaturated fatty acids (PUFAs) found in breast milk are AA and its precursor, linolenic acid (LA), the parent essential omega-6 fatty acid. DHA is found in lower concentrations, but is considered to be a particularly important component of breast milk. The fat content of breast milk varies greatly, however, depending on the diet of the mother. There is considerable debate as to what fatty acid compositions are considered optimal.

In women consuming a Westernized, Standard American Diet (SAD), dietary intake of DHA, and levels of DHA in breast milk, are lower than in mothers eating traditional, hunter-gatherer diets. The omega-6 to omega-3 ratio of the SAD diet is between 10:1 to 25:12,3 (that’s 10 to 25 times more omega-6 than omega-3), whereas the ratio of a hunter-gatherer diet it more like 1:1 to 2:1.4 It can be difficult to achieve hunter-gatherer omega-6/omega-3 status, however, so many experts agree that anywhere from 1:1 to 4:1 is optimal.

In a recent study published in the journal Maternal & Child Nutrition, researchers stated, “Currently, infant formulas are modeled on breast milk compositions of US women, despite high inter-population variability in milk PUFA composition, and the high [omega-6]/low omega-3 PUFA in US milks. It has been suggested, therefore, that standards for formula and milk fatty acid composition should derive from populations consuming non-industrialized diets.”

The researchers evaluated the fatty acid content of breast milk in mothers from Ohio consuming a typical SAD diet, and compared it to that of indigenous Tsimane mothers from the Amazon rainforest in Bolivia consuming a diet that more closely resembles human ancestors—that is, they live off the land.5

“The Tsimane mothers’ average milk DHA percentage was 400 percent higher than that of the Cincinnati mothers, while their average percentages of linoleic and trans fatty acids were 84 percent and 260 percent lower, respectively,” stated Melanie Martin, the lead researcher. “Despite living in economically impoverished conditions, Tsimane mothers produce breast milk that has more balanced and potentially beneficial fatty acid composition as compared to milk from U.S. mothers.”

High amounts of DHA in breast milk mean that the mother herself has high amounts of DHA in her body, which is stored there after eating DHA-containing omega-3s. As it turns out, DHA is beneficial for both mother and babe. Lower DHA content in breast milk and lower seafood consumption have been linked to higher rates of postpartum depression.6 In addition, maternal supplementation with DHA and EPA (the other main omega-3 fatty acid found in fish oil) during pregnancy and breastfeeding has been associated with higher IQ in the children at four years of age.1 And high amounts of DHA in breast milk have also been associated with improved vision in infants.7 These benefits make perfect sense because DHA is found in highest concentration in the brain and retina of the eye.

Since the SAD diet is so far off the ideal omega-6 to omega-3 ratio, most, if not all, people would do well to supplement with omega-3 fish oil—especially DHA during pregnancy and lactation. Optimizing the omega-6 to omega-3 ratio is possibly the single most important thing people can do to support overall health.


  1. I.B. Helland, et al., “Maternal supplementation      with very-long-chain n-3 fatty acids during pregnancy and lactation      augments children’s IQ at 4 years of age.” Pediatrics. 2003 Jan;111(1):e39-44.
  2. P.M. Kris-Etherton, et al., “Polyunsaturated      fatty acids in the food chain in the United States.” Am J Clin Nutr. 2000      Jan;71(1 Suppl):179S–88S.
  3. A.P. Simopoulos, “Omega-3 fatty acids in health      and disease and in growth and development.” Am J Clin Nutr. 1991      Sep;54(3):438–63.
  4. A.P. Simopoulos, “The importance of the ratio of      omega-6/omega-3 essential fatty acids.” Biomed Pharmacother. 2002      Oct;56(8):365–79.
  5. M.A. Martin, et al., “Fatty acid composition in      the mature milk of Bolivian forager-horticulturalists: controlled      comparisons with a US sample.” Matern      Child Nutr. 2012 Jul;8(3):404-418.
  6. J.R. Hibeln, et al., “Seafood consumption, the      DHA content of mothers’ milk and prevalence rates of postpartum      depression: a cross-national, ecological analysis.” J Affect Disord. 2002 May;69(1-3):15-29.
  7. M.H. Jorgensen, et al., “Is there a relation      between docosahexaenoic acid concentration in mothers’ milk and visual      development in term infants?” J      Pediatr Gastroenterol Nutr. 2001 Mar;32(3):293-6.