Beef or chicken: Spanish researchers study which is better for the gut microbiota.

A recent study has analyzed the effects of beef and chicken consumption on the intestinal microbiota with researchers from the IIS Aragón.

The intake of Red meat, whether processed or unprocessed, has been considered a risk factor for type 2 diabetes and cardiovascular disease. In this context, it is noteworthy that its consumption has been criticized from environmental, health, and ethical perspectives.

In addition, consumers are increasingly interested in their possible health effects, as well as on sustainable production methods and their origin. However, There is limited evidence on the impact of meat consumption on the human gut microbiota..

Beef or chicken?

Given this situation, a team of Spanish researchers evaluated the effects of beef and chicken consumption on the gut microbiota. The study's authors are: Isabel Rueda-De Torre (GENUD – Growth, Exercise, Nutrition and Development), Julio Plaza-Diaz (Biomedical Research Network Center for the Pathophysiology of Obesity and Nutrition – CIBERObn), María L. Miguel-Berges (GENUD – Growth, Exercise, Nutrition and Development), Angel Gil (Biomedical Research Network Center for the Pathophysiology of Obesity and Nutrition – CIBERObn), Laura Grasa (Aragon Health Research Institute), Luis Mariano Esteban (Polytechnic School of La Almunia, University of Zaragoza), Sergio Sabroso-Lasa (Genetic and Molecular Epidemiology Group – GMEG), María M. Campo (Agri-Food Institute of Aragon), Pilar Santolaria (Department of Animal Production and Food Science, University of Zaragoza), Luis A. Moreno (GENUD – Growth, Exercise, Nutrition and Development) and Alba M. Santaliestra-Pasías (GENUD – Growth, Exercise, Nutrition and Development).

The team conducted a randomized, crossover, controlled clinical trial, which included two phases of interventionThe participants were Healthy young adults without endocrine, metabolic, chronic, or nutritional diseasesSpecifically, most of the participants were between 18 and 22 years old. On the other hand, only 16 individuals who completed stool sample collection at all four time points were included in the final analysis, resulting in exploratory findings. 

These participants were assigned randomly assigned a chicken-based diet (lean white meat) or a diet based on Pyrenean beef (lean red meat from cattle raised in local extensive livestock systems).

They were then instructed to consume their assigned diets. three times a week and follow their usual diet. Thus, they began with a chicken- or beef-based diet for eight weeks and then switched to the alternative diet for another eight weeks, with a five-week washout period between the two periods. The nutritional value of both diets was similar.

The calculation was also made diet quality index (ICD) to evaluate the general eating habits, beyond the assigned products. Stool samples were also collected at the beginning and end of each intervention, in addition to a food frequency questionnaire at the beginning.

Bacterial DNA was then extracted from the stool samples and its concentration and purity were measured. The intestinal microbiota was analyzed by amplification and sequencing of the V3-V4 regions of 16S rRNA..

At this point, relative abundances and alpha diversity were calculated. A signed-rank test was used. Wilcoxon paired to assess differences in alpha diversity indices and relative abundance between the start and end of each experimental period. Intervention effects were examined using a linear mixed-effects model for repeated measures.

Results in the intestinal microbiota

As mentioned previously, the study included 16 people, with an average age of 20 years. It should be noted that no significant differences in sociodemographic characteristics were observed between participants who started on a chicken-based diet and those who started on a beef-based diet. Although the initial Diet Quality Index (DQI) was comparable between groups, a significant decrease of this after the chicken-based diet, which could have influenced subsequent changes in the microbiota.

After eight weeks, the group that consumed lean beef showed some decreases in certain types of gut bacteria, but only the reduction in Chloroflexota was considered statistically significant, meaning that this change is unlikely to be due to chance. No notable changes in overall gut microbial diversity were observed in this group.

In the group that consumed chicken, it was observed significant reductions in bacteria Synergistota y Chloroflexota, as well as clear decreases in wealth indicators and microbial diversity intestinal. Statistical significance means that these changes are unlikely to be due to chance.

When looking at the specific bacteria in more detail, the beef-based diet caused a significant increase in Blautia and group decreases Eubacterium halli, Roseburia y CoprococcusThe chicken-based diet caused decreases in several bacteria, including the group Eubacterium eligens, Saccharofermentans, Bacteroides, Adlercreutzia y Lachnospira, and increases in Blautia, Sphingomonas and the AD3011 group of Family XIII.

The linear mixed model revealed that both dietary interventions had a significant influence on bacterial phyla. Both diets were significantly associated with reductions in Synergistota y Chloroflexota and an increase of Bacillota. In addition, both diets significantly reduced species richness, the index of Shannon and the index of Fisher. However, the index of Simpson reverse showed a significant reduction only after the introduction of the chicken-based diet.

A significant period-related effect was observed: the relative abundance of Synergistota y Chloroflexota increased, while that of Bacillota decreased during the second period. In addition, alpha diversity showed substantial increases in species richness and indices of Shannon y Fisher during the second experimental period, compared to the first.

The chicken-based diet was associated with a broader decline in microbial functional capacity, including reductions in pathways related to the initiation of fatty acid biosynthesis, gluconeogenesis, and aromatic amino acid biosynthesis. Microbial functional activity remained relatively stable following the intervention with the beef-based diet.

Moderate changes in microbial composition

In summary, the findings indicate Moderate changes in microbial composition at the phylum level following chicken- or beef-based diets, with no significant differences between the two interventions. While both diets decreased microbial richness and diversity, significant reductions were only observed after the chicken-based diet, suggesting that the beef-based diet may have a relatively minor impact on microbial diversity.

Now, The authors warn that the results should be interpreted with caution Due to the small sample size and exploratory nature of the study, studyFurthermore, the local and extensive production system specific to Pyrenean beef may limit its generalization to other red meats.

Source: diarionutricion.com