John Glendinning
Professor John Glendinning

A new study authored by John Glendinning, the Ann Whitney Olin Professor of Biology, along with Ana Paula Morales Allende ’15 and Joyce Tang ’17 suggests that fetal alcohol exposure (FAE) reduces the taste system’s responsiveness to the bitter flavor and burning sensation of many varieties of alcoholic beverages. These factors make alcohol unappealing to some people, but, for reasons that are unclear, are less of a deterrent in young people exposed to alcohol before birth. The study was published in the Journal of Neurophysiology.

Previous studies have found that FAE reduces the sense of smell of alcohol and that teens exposed to alcohol in utero have an increased risk of alcohol abuse. “It is possible that FAE makes the flavor of alcohol less aversive. This could increase the risk of adolescents experimenting with alcohol and developing a pattern of abuse,” Glendinning’s team wrote.

Glendinning’s team compared oral sensory responses to alcohol and its flavor components, namely bitter (quinine), sweet (sugar) and burning and irritation (capsaicin and mustard oil) in adolescent rats with FAE and control rats (or rats without FAE). They recorded responses from two nerves that convey input about taste to the brain and one nerve that conveys input about oral burning and irritation to the brain.

Compared with control rats, the taste nerves of FAE rats showed weaker responses to alcohol and quinine taste during adolescence. The reduced responses of these taste nerves to the bitter taste function persisted into adulthood, implying lifelong impacts. The FAE rats also experienced reduced burning and irritation to alcohol during adolescence.

The results demonstrate that FAE reprograms the rat’s nerves’ response to bitter taste and burning sensation, suggesting that exposure to alcohol before birth may make drinking more appealing to teens. More study is needed to determine exactly how alcohol exposure before birth reprograms different parts of the nervous system, Glendinning’s team noted.

Glendinning studies feeding and taste, with a focus on the role of taste and the modern diet. His research areas include how the taste system processes complex mixtures in food; the impact of pre- and post-natal experiences on taste; and the relationship between sugar intake and weight gain. Glendinning joined the Barnard faculty in 1996. He discussed recent research on the link between taste buds and insulin release here.