According to new research, if the suckling infant has a certain version of a gene that helps process fatty acids.
The argument over whether intelligence is innate or environmentally influenced has raged for more than a century. One of the most recent issues in the nature versus nurture debate is the effect of breast-feeding on IQ.
Research shows that the fatty acids in human milk may influence brain development. Using that data as a springboard, a group of scientists, led by a team at the King's College London Institute of Psychiatry, set out to determine how the makeup of infants interacts with their mothers' milk to affect intelligence.
The researchers found that breast-fed infants with at least one or more of the common variation had an IQ score that was, on average, six to seven points higher than that of a nonnursed kid with similar genetics.
But breast-feeding did not appear to affect those children (10 percent of the population) with only the less common variant. The scientists ruled out other factors, including birth weight and the mother's social class and IQ, finding that they had no impact.
The exact mechanism by which the enzyme coded by FADS2 might influence IQ is not known, but Moffitt suggests two possible roles: The gene variants may affect the conversion of dietary precursors to long-chain polyunsaturated fatty acids, which aggregate in the brain in the early months after birth. Alternatively, the presence of long-chain polyunsaturated fatty acids may act on the gene itself, causing it to turn on or off, thereby affecting the metabolic pathway the acids use.
The authors note that since the time that study subjects were breast-fed, many baby formula manufacturers have begun adding fatty acid supplements to their products, potentially giving them an IQ boosting effect.
Kemo D. (a.k.a. no.7)