Exposure to maternal smoking during fetal life affects food preferences in adulthood independent of the effects of intrauterine growth restriction.

Prenatal smoking exposure and the balance of nutrients chosen in adulthood

Smoking during pregnancy can affect fetal growth, but reduced growth may not account for every later association. This study asked whether prenatal smoking exposure was related to adult dietary patterns even after differences in fetal growth were taken into account.

Following a birth cohort into young adulthood. Researchers examined adults from the 1978–1979 Ribeirão Preto birth cohort in Brazil. Around age twenty-four, 424 participants who had been exposed to maternal smoking during pregnancy were compared with 1,586 who had not. A food-frequency questionnaire measured their usual diet.

The analysis accounted for birth weight relative to gestational age, as well as factors including current BMI, sex, physical activity, smoking and maternal and participant education. This helped distinguish the observed smoking-exposure association from some other measured influences on diet.

The finding concerned a ratio. Exposed participants had a higher carbohydrate-to-protein intake ratio. The study did not find significant differences in the individual macronutrient intakes themselves. It would therefore be inaccurate to summarize the result simply as eating more carbohydrate: the supported finding concerns the balance between carbohydrate and protein.

The authors proposed that prenatal tobacco exposure could influence developing appetite-regulation systems, drawing on experimental evidence from other studies. This cohort analysis did not measure those systems or establish that nicotine was the causal factor.

Its contribution is to suggest that different prenatal exposures may have dietary associations beyond those captured by birth size alone. Birth weight is one developmental measure, while smoking exposure contains additional information. Establishing the mechanism would require distinguishing prenatal biological effects from the family, social and later-life influences that can accompany the exposure.