Animal studies have shown that a low-fibre diet during pregnancy impairs brain nerve function in offspring. Now, in the first human cohort study on the relation of maternal nutritional imbalance and infants’ brain development, researchers in Japan have investigated if the same effects can be found in humans.
“Most pregnant women in Japan consume far less dietary fibre than what is the recommended intake,” said Dr Kunio Miyake, a researcher at the University of Yamanashi and first author of the study published in Frontiers in Nutrition. “Our results provided reinforcing evidence that undernutrition during pregnancy is associated with an increased risk of neurodevelopmental delay in children.”
Miyake et al. compared the development of children whose mothers had the highest intake of dietary fibre to groups of mothers who consumed successively less fibre during pregnancy.
In comparison to the highest-intake group, the children of mothers in the low-intake groups were more likely to show neurodevelopmental delays. The effect of maternal fibre undersupply was noticeable in several domains related to brain function. Affected were communication skills, problem solving skills, and personal-social skills. The researchers also found delays in the development of large body part movement and coordination, as well as in the coordination of smaller muscles.
The researchers’ results are based on the analysis of more than 76,000 mother-infant pairs from the Japan Environment and Children’s Study. It is an ongoing project aiming to elucidate how the environment affects children’s health.
To collect dietary information about the participants, the scientists used a food frequency questionnaire, which asked respondents about their dietary status during the second and third trimester of pregnancy. Developmental delays were assessed in another questionnaire that was sent to parents once their children were three years old. Based on parents’ answers, the researchers showed the correlation of maternal fibre intake and child brain development.
The researchers also found that the median dietary fibre intake in Japan is just over 10 grams a day. Only 8.4% of Japanese pregnant women consumed enough fibre. They also pointed out that the recommended fibre intake for pregnant women varies: While in Japan the recommended daily dietary fibre intake is 18 grams each day, it is 28 grams in the US and Canada. “Our results show that nutritional guidance for pregnant mothers is crucial to reduce the risk of future health problems for their children,” said Miyake.
The researchers also pointed to certain limitations of their study. “Human studies cannot assess the effects of dietary fibre alone. Although this study considered the impact of folic acid intake during pregnancy, the possibility of other nutrients having an impact cannot be completely ruled out,” Miyake pointed out. “In addition, dietary fibre intake from supplements could not be investigated.”
Research: Mitake K, et al. (2023). Maternal dietary fiber intake during pregnancy and child development: the Japan Environment and Children’s Study. Front Nutr.; doi: 10.3389/fnut.2023.1203669.