Moms’ Caffeine Consumption May Affect Babies’ Brains

Findings Could Explain Why Caffeine Exposure In-Utero Increases Kids’ Risk for Obesity

By Brandon Levy

Tuesday, February 21, 2023

Between books, the media, and well-meaning friends and relatives, new parents are inundated with advice about how to set their kids up for a happy and healthy future. However, what parents do before their children are even born can also have a huge impact on how they turn out. For instance, new IRP research suggests that a pregnant woman’s caffeine consumption can rewire her baby’s brain in ways that put the child at increased risk for obesity later in life.¹

As the long morning lines at coffee shops make clear, caffeine is a mainstay of most people’s lives. Nevertheless, doctors have long cautioned pregnant women to significantly curtail their caffeine intake. For instance, the American College of Obstetricians and Gynecologists currently recommends that expecting mothers consume less than 200 milligrams per day, which is roughly the amount found in two, six-ounce cups of coffee.

Such recommendations stem from the ways a stimulant like caffeine might affect the delicate process of a fetus’ development. Infants are extra susceptible to potential unintended consequences from caffeine because of specific changes to how a woman’s body functions during pregnancy, particularly during the first three months.

“The liver metabolizes nutrients and converts them into a simpler form so they can be used properly, but what happens during the first trimester is that metabolism slows down, and especially so for caffeine,” explains Khushbu Agarwal, Ph.D., the new study’s first author and a postdoctoral fellow in the lab of IRP Lasker Scholar Paule Joseph, Ph.D. “Caffeine can cross through the placental membrane in its raw, unmetabolized form and easily crosses the blood-brain barrier and starts accumulating in the infant’s brain.”

Dr. Agarwal and Dr. Joseph, the study’s senior author, wondered whether caffeine’s influence on the developing brain might help explain why the children of pregnant women who consume more than the recommended daily dose are more likely to be overweight or obese. To investigate their theory, they took advantage of data from the Adolescent Brain Cognitive Development (ABCD) Study, which since 2013 has been collecting information on nearly 12,000 children at multiple points throughout their lives.

As expected, children ages 9 to 11 whose mothers consumed more caffeine while pregnant tended to have a higher body mass index (BMI), a measure of the ratio between a person’s height and weight. In addition, those kids tended to consume more sugar in their daily diets, particularly from soft drinks like soda.

The new study’s most intriguing findings, however, came from analyzing brain scans taken as part of the ABCD study. These included readouts of activity in the children’s brains while they were doing a task that required them to respond quickly to specific pictures based on associations they had previously learned that linked the images to monetary rewards. The scans showed that children whose mothers consumed more caffeine while pregnant tended to have less activity in the medial frontal cortex (MFC) during the ‘anticipation’ phase of the task, during which the participants awaited the opportunity to respond to an image linked to a monetary gain or loss. The MFC, located in the brain’s frontal lobe, is involved in planning, making decisions, and evaluating rewards like cash or tasty foods. Interestingly, the children whose MFC regions were less active during that part of the task also tended to have higher BMIs.

Finally, compared to children whose mothers did not consume caffeine while pregnant, those whose mothers consumed caffeine weekly or daily during pregnancy tended to have a thicker insula, which is the primary brain region involved in detecting sweet and other tastes. This suggests that the insula may be more responsive to sweet foods in children who were exposed to more caffeine in the womb.

“Sweet taste development for kids happens early in life, and babies are born with a highly developed sense of taste,” says Dr. Joseph. “If there are some changes in the brain structures that are important for sweet taste perception, then there’s a lot of things that could be happening downstream. Therefore, we need to investigate how these changes in the insula impact how children experience tastes and, in turn, their dietary habits later in life.”

“It may be that exposure to caffeine prenatally is affecting the development of the frontal lobe because it accumulates in the brain,” adds Dr. Agarwal. “It takes a long time for the frontal lobe to develop compared to other regions of the brain, and with excessive accumulation of caffeine, there’s a possibility that the development of the frontal lobe is slowed down compared to other babies.”

As a next step, Dr. Joseph and Dr. Agarwal plan to use additional neuroimaging data from the ABCD study to figure out whether exposure to caffeine in the womb affects neuronal communication between the MFC and the insula. They also hope to follow up with the ABCD study’s participants in the future to see how caffeine exposure in the womb influences weight and health as the kids get older. Nevertheless, even without that information, their new study adds to mounting evidence that doctors should encourage expecting mothers to reduce caffeine consumption even below the currently recommended levels, as well as provide practical advice about how to do so.

“Out of unawareness, many women consume a lot of caffeine because they’re not aware of the recommended dose or the sources of caffeine,” says Dr. Agarwal. “It’s not just coffee and tea. It could be food products, it could be chocolates, it could be medicines. There are many products that have caffeine in some form, and women need to be made aware of that.”

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References:

 [1] Agarwal K, Manza P, Tejeda HA, Courville AB, Volkow ND, Joseph PV. Prenatal Caffeine Exposure Is Linked to Elevated Sugar Intake and BMI, Altered Reward Sensitivity, and Aberrant Insular Thickness in Adolescents: An ABCD Investigation. Nutrients. 2022 Nov 3;14(21):4643. doi: 10.3390/nu14214643.

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