When it comes to nursing moms and their babies, an elegant web of cause and effect connects climate, breast milk, gut microbes and infant health.

That web was clearly illustrated by a recently published study involving 33 women and their babies in the West African nation of The Gambia. The research team, including scientists from UC Davis and UC Agriculture and Natural Resources, found that complex breast milk sugars called oligosaccharides helped protect nursing babies from illness and also influenced the mixture of microbes in the infants' guts.

The researchers also showed that changes in food availability from season to season could affect the...