A Brazilian study of 728 children up to one year of age shows that the consumption of ultra-processed foods can negatively affect the diversity and abundance of the intestinal microbiota, with a more pronounced effect in children who are not breastfed.
The results were published in the journal Clinical Nutrition, as part of the "MINA Study – Maternal-Infant in Acre: birth cohort of the Brazilian Western Amazon" , which is following a group of children born between 2015 and 2016 in Cruzeiro do Sul, in the state of Acre, Brazil, with funding from FAPESP (read more at agencia.fapesp.br/40651 and agencia.fapesp.br/37047 ).
Children who were still receiving breast milk had higher levels of Bifidobacterium, a genus of bacteria known to be associated with good gut health.
On the other hand, those who were not breastfed and consumed ultra-processed products, such as packaged snacks, filled cookies, chocolate drinks, soft drinks, artificial juices, ice cream, instant noodles, among others, had a higher abundance of genera such as Selimonas and Finegoldia, which are not very abundant in the group of breastfed children and are typically present in individuals with obesity or gastrointestinal diseases in adolescence and adulthood.
"We also found that breastfeeding attenuated the harmful effects of consuming ultra-processed foods on the composition of the gut microbiota. The group of children who received breast milk and did not consume ultra-processed products had a more stable microbiota and better health markers, mainly due to the greater abundance of Bifidobacterium," says the first author of the study, Lucas Faggiani , who is doing his doctoral studies at the School of Public Health of the University of São Paulo (FSP-USP) and received FAPESP grants during his undergraduate studies ( 17/25232-2 and 19/00248-9 ).
"To date, there hasn't been a study with so many participants that has analyzed the composition of the intestinal microbiota during the first year of life in relation to the consumption of ultra-processed products, just when the immune system is forming. Although the region is difficult to access, these products can be easily obtained and end up replacing traditional foods and even breastfeeding," explains Marly Cardoso , professor at FSP-USP and coordinator of the project.
In addition to the sample size, Faggiani adds, the study stands out for being a population-based cohort in an Amazon region with a high level of social vulnerability, which contributes to the study of variables that are little explored in the literature on this subject.
Long term
The researchers collected samples between 2016 and 2017, when the children taking part in the cohort turned one year old. The samples were collected and stored according to a protocol developed at the Institute of Tropical Medicine (IMT) of the USP School of Medicine, coordinated by Ester Sabino , a professor at the institution. The anal swabs with the stool samples were stored at low temperatures and sent to São Paulo.
While collecting these samples and data such as the children's weight and height, the mothers answered a questionnaire that included whether or not they were breastfeeding and the eating habits of the family and the child.
The microbiota samples were sent to a specialized company in South Korea for automated genome sequencing, which is much faster than traditional sequencing. In Brazil, with the data in hand, the researchers performed the analysis using bioinformatics tools.
In addition to the levels associated with Bifidobacterium (abundant in breastfed children and low in weaned children), Selimonas and Finegoldia (high in non-breastfed children and those consuming ultra-processed foods), the researchers also detected a higher occurrence of the Firmicutes genus in the group of children who were no longer breastfed, even in those who did not consume ultra-processed foods. The genus is a potential marker of an adult microbiota, suggesting early maturity.
Another genus found in abundance in the weaned and ultra-processed consumer group was Blautia. Although some studies have found the same association, there is still no consensus on whether it is beneficial or harmful. "There's a lack of robust studies to establish a cause-and-effect relationship between this genus and health outcomes," comments Faggiani.
"We'd noticed that consumption of ultra-processed products occurred in more than 80% of the children taking part in the study in the first year of life, when the World Health Organization's (WHO) recommendation is not to offer these products before the age of two. Given these results, we're continuing to follow these children to monitor possible adverse health outcomes in the long term," concludes Cardoso.
The work was also supported by FAPESP through a postdoctoral fellowship awarded to Paula de França , co-author of the article.
About FAPESP
The São Paulo Research Foundation (FAPESP) is a public institution with the mission of supporting scientific research in all fields of knowledge by awarding scholarships, fellowships and grants to investigators linked with higher education and research institutions in the state of São Paulo, Brazil. FAPESP is aware that the very best research can only be done by working with the best researchers internationally. Therefore, it has established partnerships with funding agencies, higher education, private companies, and research organizations in other countries known for the quality of their research and has been encouraging scientists funded by its grants to further develop their international collaboration.
