ISA statement in response to Zhu et al., NIH study
Low calorie sweeteners can be consumed by pregnant women, with or without gestational diabetes, to help them reduce overall calorie and sugar intake without increasing the risk of obesity later in childhood, contrary to what an NIH study and Press Release suggest.
In the cohort study by Zhu et al.1, published in the International Journal of Epidemiology, the findings supporting that maternal diet drink consumption is associated increased risk of overweight/ obesity at 7 years are actually based on a small group of 85 women with gestational diabetes who consumed low calorie sweetened drinks daily. Surprisingly, no association was found with the consumption of sugar-sweetened beverages.
It is widely known that associations between two factors found in observational studies, like this cohort study by Zhu et al., does not mean that these factors are causally related. The possibility of residual confounding due to other pre- or postnatal obesogenic factors cannot be ruled out, especially since recent evidence shows that developmental pathways to adiposity begin even before birth and are influenced by environmental, genetic and epigenetic factors2.
Mechanistically, this prospective cohort study does not explore, and provides no evidence about, how consumption of low calorie sweetened beverages during pregnancy by women with gestational diabetes, but not sugar-sweetened drinks, would influence risk of overweight/obesity later in childhood. Any microbiome-related mechanism is speculative and the sweet-but-no-calories theory is unlikely to apply because the offspring/ child is not consuming the low calorie sweetened drink.3
Overall, a healthy diet and lifestyle, normal body weight before, and healthy weight gain during pregnancy are all key to the wellbeing of both the mother and child. Low calorie sweeteners can be part of a balanced diet during pregnancy and can help women with gestational diabetes manage their carbohydrate and sugar intake.