A mother’s intake of ultra-processed foods may be linked to the risk of obesity in her children

A mother’s consumption of ultra-processed foods appears to be associated with an increased risk of overweight or obesity in her offspring, independent of other lifestyle risk factors, suggests a US study published by The BMJ today.

The researchers say more studies are needed to confirm these findings and understand the factors that might be responsible.

However, they suggest that mothers might benefit from limiting their intake of ultra-processed foods, that dietary guidelines should be refined, and financial and social barriers removed to improve the nutrition of women of childbearing age and reduce childhood obesity.

According to the World Health Organization, in 2020 39 million children were overweight or obese, putting them at increased risk of heart disease, diabetes, cancer and early death.

Ultra-processed foods like packaged baked goods and snacks, fizzy drinks, and sugary cereals are common in the modern Western diet and have been linked to weight gain in adults. However, it is unclear whether there is a link between a mother’s consumption of ultra-processed foods and her offspring’s body weight.

To investigate this further, the researchers drew on data from 19,958 children of 14,553 mothers (45% boys aged 7 to 17 at enrollment) from the Nurses’ Health Study II (NHS II) and the Growing Up Today Study ( GUTS I and II) in the USA.

The NHS II is an ongoing study that in 1989 tracked the health and lifestyles of 116,429 female nurses in the United States aged 25 to 42. Beginning in 1991, participants reported what they ate and drank using validated food frequency questionnaires every four years.

The GUTS I study began in 1996 when 16,882 children (aged 8 to 15 years) of NHS II participants completed an initial health and lifestyle questionnaire and were monitored every year between 1997 and 2001 and every two years thereafter.

In 2004, 10,918 children (aged 7 to 17) of NHS II participants participated in the expanded GUTS II study and were followed up in 2006, 2008 and 2011 and every two years thereafter.

A number of other potentially influential factors known to be highly correlated with childhood obesity were also considered. These included maternal weight (BMI), physical activity, smoking, living status (with or without a partner), and partner’s education, as well as children’s consumption of ultra-processed foods, physical activity, and sedentary time.

A total of 2,471 (12%) children developed overweight or obesity during a median follow-up of 4 years.

The results show that a mother’s consumption of ultra-processed foods was associated with an increased risk of overweight or obesity in her offspring. For example, a 26% higher risk was observed in the group with the highest maternal consumption of ultraprocessed foods (12.1 servings/day) compared to the group with the lowest consumption (3.4 servings/day).

In a separate analysis of 2,790 mothers and 2,925 children with diet information from 3 months before conception to delivery (peri-pregnancy), the researchers found that ultra-processed food intake during pregnancy was not significantly associated with an increased risk for offspring was overweight or obese.

This is an observational study, so no cause can be determined; and the researchers acknowledge that some of the observed risk may be due to other unmeasured factors and that self-reported diet and weight measurements may be misreported.

Other important limitations are the fact that some offspring participants were lost to follow-up, resulting in some of the analyzes being underpowered, particularly those related to ingestion during pregnancy, and that the mothers were predominantly white and unified had similar social and economic backgrounds, so results may not apply to other groups.

Still, the study used data from several large ongoing studies with detailed nutritional reviews over a relatively long period of time, and further analysis found consistent associations, suggesting the results are robust.

The researchers do not propose a clear mechanism underlying these associations, saying the area warrants further investigation.

Nonetheless, “these data support the importance of refining dietary recommendations and developing programs to improve the nutrition of women of childbearing age to promote healthy offspring,” they conclude.