Breastmilk with a high omega-6 to omega-3 fatty acid ratio induced cellular events similar to insulin resistance and obesity in 3T3-L1 adipocytes.

BACKGROUND: An imbalance of omega (n)-3 and n-6 polyunsaturated fatty acids (PUFA) during critical periods of development may have adverse effects on the health of the newborn in later life.
OBJECTIVES: We hypothesized that breastmilk with higher n-6 to n-3 PUFA ratio will have higher inflammatory cytokines and initiate cellular events similar to insulin resistance and obesity.
METHODS: Breastmilk was collected from healthy women who gave natural birth at full term. Breastmilk fatty acids were measured using gas chromatography; samples were pooled based on the n-6 to n-3 PUFA ratio (high, medium and low), and soluble cytokines were measured. Pooled samples were used to treat 3T3-L1 cells; mRNA expression of diacylglycerol acyltransferase2, stearoyl-CoA desaturase-1, leptin and RPLPO was measured.
RESULTS: Breastmilk with a higher ratio of n-6 to n-3 PUFA showed higher pro-inflammatory cytokines; there was a direct correlation between n-6 PUFA and pro-inflammatory cytokines. Breastmilk with a higher ratio of n-6 to n-3 PUFA increased the expression of genes involved in lipogenesis.
CONCLUSIONS: Pro-inflammatory cytokines in breastmilk are associated with higher levels of n-6 PUFA in breastmilk and has the capacity to alter adipose tissue metabolism to likely predispose the newborn to a higher risk of obesity in later life.