Maternal ultra-processed food intake ups risk of childhood obesity

Mothers who regularly eat ultra-processed foods during the child-rearing period appear to increase the risk of overweight or obesity in their children, irrespective of maternal and offspring lifestyle risk factors, a study has shown.

“Our study highlights the potential benefits of limiting ultra-processed food consumption among mothers and women of reproductive age to reduce the risk of overweight in their children,” the researchers said. “However, we should not overlook social determinants of health that could impede women from reducing ultra-processed food intake.” [BMJ 2022;379:e071767]

The possible determinants included a lack of time to prepare unprocessed food, the additional costs of a healthier diet, the likelihood that mothers are not solely responsible for household foods, and limited access to healthy food options due to geographical location. [J Nutr Metab 2014;2014.pmid:27094573]

This population-based prospective cohort study included 19,958 mother-child pairs (45 percent boys, aged 7‒17 years at enrolment) with a median follow-up of 4 years until age 18 years or the onset of overweight or obesity. A subsample of 2,925 mother-child pairs with data on peripregnancy diet were also included.

The researchers used multivariable-adjusted, log binomial models with generalized estimating equations and an exchangeable correlation structure to account for associations between siblings and to estimate the relative risk (RR) of offspring overweight or obesity defined by the International Obesity Task Force.

Of the children, 2,471 (12.4 percent) developed overweight or obesity. Maternal consumption of ultra-processed foods during the child-rearing period significantly correlated with overweight or obesity in the offspring after adjusting for established maternal risk factors and offspring’s ultra-processed food intake, physical activity, and sedentary time.

Moreover, the group with the highest maternal intake of ultra-processed food (group 5) had a 26-percent higher risk compared with the lowest consumption group (group 1; RR, 1.26, 95 percent confidence interval [CI], 1.08‒1.47; p_trend<0.001).

Subgroup analysis of participants with peripregnancy diet information revealed that, while rates were higher, peripregnancy ultra-processed food intake did not substantially contribute to an increased risk of offspring overweight or obesity (n=845, 28.9 percent; group 5 vs group 1: RR, 1.17, 95 percent CI, 0.89‒1.53; p_trend=0.07).

Such associations were not modified by age, sex, birth weight, and gestational age of offspring or maternal body weight.

Mechanisms

“Although the underlying pathways of our findings have not yet been fully elucidated and remain beyond the scope of this investigation, maternal diet during child rearing is likely to shape offspring’s diet and lifestyle choices, which … exert a profound impact on their risk of overweight or obesity,” the researchers said. [J Am Diet Assoc 2011;111:1301-1305; J Am Diet Assoc 2011;111:1314-1321]

“Our results showed that the association between maternal ultra-processed food intake during the child rearing period and offspring risk of overweight or obesity was independent of offspring’s lifestyle risk factors,” they added.

This finding suggests other mechanisms by which maternal ultra-processed food intake might influence the risk of childhood overweight, such as long-term in utero imprinting and the presence of uncharacterized gene by environmental factors. [Endocrinology 2013;154:4560-4569; Proc Natl Acad Sci U S A 2008;105:17046-17049; Environ Epigenet 2017;3:dvx007]

“Further study is needed to confirm these findings and to understand the underlying biological mechanisms and environmental determinants,” the researchers said. “These data support the importance of refining dietary recommendations and the development of programs to improve nutrition for women of reproductive age to promote offspring health.”