Fermented food intake during pregnancy could reduce the risk of neurodevelopment disorders in children – Japanese study

Researchers analysed data from the Japan Environment and Children’s Study (JECS) and found that that fermented food intake during pregnancy may have beneficial associations with several areas of neurodevelopment in children.

“Fermented foods improve intestinal bacterial flora, and their effect is produced mainly by probiotics, including Bifidobacterium, Lactobacillus, and Streptococcus species. Furthermore, functional components produced by the fermentation process affect intestinal flora. The colonisation of the intestinal bacterial flora begins immediately at birth, and the original bacterial community is established within the first week after birth. Furthermore, the formation of the intestinal bacterial flora during the neonatal period will dictate immune system development in childhood and affect the composition of the intestinal bacterial flora for the child’s entire life. In addition, one of the most important determinants of intestinal bifidobacteria in infants is the colonisation of Bifidobacterium breve in the mother’s gut and vagina,”​ wrote the researchers in Asia Pacific Journal of Clinical Nutrition​.

Additionally, accumulating evidence suggests that changes in the composition of intestinal bacterial flora play an important role in the gut-brain axis.

“Therefore, we speculated that the composition of intestinal bacterial flora may be associated with not only neurological diseases but also with neurodevelopment in children,” ​said the researchers.

Fermented foods play an important role in establishing intestinal bacterial flora, and previous research showed that the composition of the intestinal bacterial flora might be associated with neurodevelopment. Therefore, the researchers conducted a study of JECS data to investigate associations between maternal intake of fermented foods consumed during pregnancy and early neurodevelopment in offspring.

The study​

The JECS is a nationwide government-funded birth cohort study investigating the links between environmental factors and children’s health and development. The pregnant women participating in the JECS were recruited from 15 areas across Japan between January 2011 and March 2014.

Data for 73,522 pregnant women were studied. Their intake of four common fermented foods during pregnancy was assessed using a food frequency questionnaire (FFQ), a list of foods and beverages with response categories to indicate usual frequency of consumption over the study period.

Participants’ intake of four fermented foods – miso soup, fermented soybeans, yogurt, and cheese – in the average diet from the beginning of pregnancy was assessed using an FFQ during the second or third trimester. The questionnaire comprised a list of foods with standard portion sizes commonly consumed in Japan.

The intake amount of each food was then divided into four groups or quartiles. The first quartile included the smallest amounts eaten, the second and third quartiles had moderate amounts, and the fourth quartile had the largest amounts eaten.

Neurodevelopment for participants’ infants between 10–13 months old was estimated using the Japanese version of the Ages and Stages Questionnaires third edition (ASQ3). The scale comprises 21 age-specific structured questionnaires across five domains: communication, gross motor skills, fine motor skills, problem-solving skills, and personal social skills.

The questionnaire comprises 30 questions that can be answered with “yes,” “sometimes,” or “not yet.” “Yes,” which corresponds to 10 points, indicates that the respondent’s child demonstrates the ability to do the specific activity described by the item; “sometimes,” which corresponds to 5 points, indicates that the skill of the respondent’s child is emerging; and “not yet,” which corresponds to 0 points, indicates that the respondent’s child has not yet shown evidence of the ability to do that specific activity. Scores range from 0 to 60 for each domain.

The results showed that miso soup was associated with a significantly reduced risk of delay in communication skills in the second and fourth quartiles, and fermented soybeans was associated with a reduced risk in the third quartile. Fermented soybeans were also associated with a significantly reduced risk of delay in fine motor development in the third and fourth quartiles, and cheese showed preventive effects in the third and fourth quartiles. Eating moderate amounts of fermented soybeans during pregnancy was linked to better problem-solving skills in the second and third quartiles, as was eating higher amounts of cheese in the third and fourth quartiles. Yoghurt was associated with a significantly reduced risk of delay in personal-social skills in the third and fourth quartiles and that of cheese was associated with a reduced risk in the third quartile. No reductions in risk were observed for gross motor skills.

“In this study, we found that maternal intake of fermented foods during pregnancy may protect against neurodevelopmental delay in early childhood, supporting our initial hypothesis. Among the five neurodevelopmental domains assessed, the effects were clearly observed in communication, fine motor, problem-solving, and personal-social skills,”​ said the researchers.

Further exploring the potential of fermented foods on early neurodevelopment​

The researchers noted that in the context of the gut-brain axis, associations have been found between bacterial intestinal flora and developmental disorders in children. For example, previous research by Nikolov et al​ reported that 22.7% of children with pervasive developmental disorders were positive for gastrointestinal problems, primarily constipation and diarrhoea. Furthermore, compared with children without gastrointestinal problems, those with them showed greater symptom severity in measures of irritability, anxiety, and social withdrawal. In another study, De Angelis et al​ evaluated the faecal microbiota in patients with autism spectrum disorder (ASD) and pervasive developmental disorder not otherwise specified and in healthy children and found that levels of Clostridium and Bacteroides genera were higher in children with ASD and that levels of Bifidobacterium species were lower in children with ASD compared with healthy children.

However, long-term follow-up is needed for those children suspected of having neurodevelopmental delay in this study. Moreover, the maternal intake of fermented foods did not affect children’s gross motor skills in this study. This finding may indicate that the maternal intake of fermented foods affects only neurodevelopment, not motor development, although the mechanisms are unclear. 

“In conclusion, we found an association between the maternal intake of fermented foods during pregnancy and early neurodevelopment in offspring, suggesting that if pregnant women were to consume more fermented foods, their children might avoid neurodevelopmental delay in early childhood. We plan to conduct a follow-up study when these children are three years old to further clarify the association further,” ​said the researchers.

Source: Asia Pacific Journal of Clinical Nutrition​

DOI:​ 10.6133/apjcn.202401_33(1).0008​

Maternal fermented food intake and infant neurodevelopment: The Japan Environment and  Children’s Study​

Authors: Tomomi Tanaka, Kenta Matsumura et al.​

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