Brains of formula-fed babies differ.

Is the way to a baby's mind through its stomach? A new report suggests that formula-fed infants may end up with a smaller supply of chemicals important for brain development than they would have if fed on breast milk.

Researchers at the Royal Hospital for Sick Children in Glasgow, Scotland, analyzed brain tissue from 22 babies who had died in the first 43 weeks of life. The researchers looked for biochemical differences between formula- and breast-fed infants.

The brains of breast-fed infants contained a higher percentage of docosahexaenoic acid (DHA), a polyunsaturated fatty acid, than did the brains of babies nourished with over-the-counter formula, they report in the Oct. 3 LANCET.

The apparent shortage of DHA in formula-fed infants may prove important, the researchers suggest. As a baby's brain grows, its cerebral cortex hungrily takes in DHA and other polyunsaturated fatty acids. These building blocks become part of the tissue that makes up one-quarter of the brain's solid mass.

Do higher concentrations of DHA lead to better, smarter baby brains? For now, the researchers decline to draw any firm conclusions about DHA's effects on learning, memory, or other brain functions. However, they add, should future research establish that low levels of DHA impair the proper development and functioning of babies' brains, "failure to maintain an intake of fatty acids similar to that provided by mature human milk may cause permanent adverse side effects."