Summary: A Brazilian study of 728 infants found that consuming ultra-processed foods in the first year of life can alter gut microbiota diversity and composition, with stronger negative effects in children who were not breastfed. Breastfed infants showed higher levels of beneficial Bifidobacterium, while non-breastfed children who ate processed products had increased abundances of bacterial genera previously associated with obesity and gastrointestinal disease.
The research also indicates that breastfeeding can partially buffer the harmful influence of ultra-processed foods on the developing gut microbiome. These findings are concerning because more than 80% of infants in the study had been exposed to ultra-processed products before age two, contrary to World Health Organization recommendations.
Key facts:
- Increase in potentially harmful bacteria: Non-breastfed infants who consumed ultra-processed foods exhibited higher levels of bacterial genera linked in other studies to obesity and gastrointestinal problems.
- Protection from breastfeeding: Breast milk was associated with a higher relative abundance of Bifidobacterium and an attenuated effect of ultra-processed foods on microbiota composition.
- Widespread early exposure: Over 80% of children in the cohort consumed ultra-processed products during their first year, despite guidelines discouraging such foods before age two.
Source: FAPESP
A Brazilian cohort study of 728 infants up to one year old shows that intake of ultra-processed foods can detrimentally affect the diversity and makeup of the intestinal microbiota, with more pronounced changes in children who are not breastfed.
The results were published in the journal Clinical Nutrition and are part of the MINA Study – Maternal–Infant in Acre, a birth cohort following children born in 2015–2016 in Cruzeiro do Sul, Acre, Brazil. The project received funding from FAPESP.
Children who were still receiving breast milk at one year had higher relative abundance of Bifidobacterium, a genus widely regarded as beneficial for early gut health. In contrast, weaned children who consumed ultra-processed foods—such as packaged snacks, filled cookies, chocolate drinks, soft drinks, artificial juices, ice cream and instant noodles—showed increased levels of genera including Sellimonas and Finegoldia. These genera were uncommon in breastfed children and have been associated in other studies with obesity and gastrointestinal conditions later in life.
“We found that breastfeeding reduced the harmful effects of ultra-processed food consumption on gut microbiota composition,” says Lucas Faggiani, the study’s first author and a doctoral candidate at the School of Public Health, University of São Paulo (FSP-USP). The group of children who were breastfed and did not consume ultra-processed products showed a more stable microbiota and more favorable health markers, largely due to higher levels of Bifidobacterium.
The MINA cohort is notable for its size and for being population-based in a remote Amazonian region with elevated social vulnerability. According to project coordinator Marly Cardoso (FSP-USP), ultra-processed products are readily available in the region and can displace traditional foods and even breastfeeding in early life.
Sample collection and analysis
Researchers collected anal swabs with stool samples when participants turned one year old (2016–2017). Samples were handled under a protocol developed at the Institute of Tropical Medicine (IMT) of the USP School of Medicine and shipped under cold conditions to São Paulo for storage and processing. Sequencing was performed by an external laboratory in South Korea using automated genome sequencing; Brazilian researchers then analyzed the data with bioinformatics tools.
Beyond the lower abundance of Bifidobacterium in weaned children, the study identified higher relative abundances of Firmicutes in non-breastfed infants, a genus often associated with adult-like microbiota and potentially early maturation. The genus Blautia was also more abundant among weaned infants who consumed ultra-processed foods; however, literature remains inconclusive about whether Blautia is beneficial or detrimental to health.
“There is still a lack of robust longitudinal evidence to establish causal links between some bacterial genera and later health outcomes,” Faggiani notes. The research team plans to continue following the cohort to monitor long-term health effects related to early microbiota changes and dietary exposures.
The study also received support from FAPESP via a postdoctoral fellowship awarded to co-author Paula de França.
About this microbiome and diet research news
Author: Heloisa Reinert
Source: FAPESP
Contact: Heloisa Reinert – FAPESP
Image: Credit: Neuroscience News
Original Research: Open access. “Effect of ultra-processed food consumption on the gut microbiota in the first year of life: Findings from the MINA–Brazil birth cohort study” by Lucas Faggiani et al., Clinical Nutrition.
Abstract
Effect of ultra-processed food consumption on the gut microbiota in the first year of life: Findings from the MINA–Brazil birth cohort study
Background and aims
The first years of life are critical for establishing the gut microbiota, and early diet is a major determinant. Breastfeeding is known to shape the infant microbiome favorably, but the impact of ultra-processed food (UPF) consumption in infancy remains understudied in large, longitudinal cohorts. This prospective study examined the effects of UPF intake on gut microbiota during the first year of life.
Methods
The analysis included 728 children from the MINA–Brazil birth cohort with 16S rRNA gut microbiota data available at the one-year follow-up. Breastfeeding data were collected after birth and during follow-up visits. Complementary feeding was assessed with a semi-structured questionnaire referring to the day before the interview at one year. Researchers created a combined variable of breastfeeding practices and UPF consumption and used it as the main exposure in adjusted median regression models for alpha diversity metrics. Beta diversity was evaluated using PERMANOVA with Bray–Curtis dissimilarity and distance-based redundancy analysis (db-RDA). Relative abundances were analyzed using ANCOM-BC (FDR-corrected) and MaAsLin2, both adjusted for covariates.
Results
Weaned children who consumed UPF showed a significant increase in alpha diversity across multiple indices and distinct beta diversity compared with breastfed children who did not consume UPF. Breastfed, non-UPF-consuming infants displayed higher relative abundance of Bifidobacterium and lower relative abundance of Firmicutes, Blautia, Sellimonas, and Finegoldia than weaned UPF consumers.
Conclusion
These findings suggest that early consumption of ultra-processed foods may negatively affect the diversity and composition of the infant gut microbiota, with more pronounced effects in children who have been weaned. Continued follow-up of this cohort will help clarify potential long-term health consequences.