Chicken vs. beef: new Spanish study questions white meat’s ‘gut health’ benefits

By: Trademagazin Date: 2025. 08. 21. 11:17

For decades, chicken was considered “healthier” than red meat. A recent Spanish study, however, suggests that from a gut-microbiome perspective the picture is less clear: a chicken-based diet reduced microbial diversity, whereas incorporating a lean beef from the Pirenaica breed did not show such unfavorable changes—indeed, it increased the proportion of certain beneficial bacteria (such as Blautia).

What did the study examine?

Published in July, the study enrolled 16 healthy participants aged 18–22. For eight weeks, three times per week at lunch they ate either chicken or Pirenaica beef prepared in several ways (steamed, baked, grilled, breaded). This was followed by a five-week “washout” period, after which participants switched to the other meat. Stool samples were collected at the start and end of each eight-week period to analyze the gut microbiota.

Key findings

Both diets produced only minor changes in the gut microbiota.
During the chicken phase, diversity decreased and the proportions of some beneficial bacterial groups fell.
During the beef phase, the more notable shift was mainly in the phylum Chloroflexota; levels of Blautia increased, a genus that may help protect the gut mucosal barrier and exert anti-inflammatory effects.
Pirenaica beef’s naturally higher potassium, zinc, and B-vitamin content may have contributed to the observed effects.

A reduction in microbial diversity is a risk pattern seen in several chronic conditions (IBD, type 2 diabetes, obesity, cardiometabolic diseases) — hence the attention to the decline observed during the chicken phase.

Important limitations — why not to overinterpret?

Small sample size: only 16 participants — statistically fragile.
Young, healthy cohort: findings are not generalizable to older adults or those with chronic illnesses.
Self-reported diet and no strict control of overall intake: other foods consumed during the study could have influenced the microbiome.
Meat quality and preparation matter: results cannot be generalized to all beef or all chicken; different breeds, husbandry, and cooking methods can yield different effects.

Expert reactions

Independent experts deem the study promising but not a basis for extreme dietary takeaways. According to the nutrition research director of the U.S. National Cattlemen’s Beef Association, the findings align with prior work showing that lean beef can be part of a balanced, healthy diet. The main lesson is that meat type, quality, and moderation are key.

What should we do in the kitchen?

Don’t demonize any single type of meat — aim for variety.
Keep the microbiome-friendly basics: vegetables, fruits, whole grains, legumes, and fermented foods (yogurt, kefir, fermented vegetables).
If you eat meat, choose lean cuts and favor gentle cooking methods (steaming, baking, moderate grilling).
Focus on the overall pattern: the state of the gut microbiota is shaped not by a single food but by long-term dietary habits.

Bottom line: this small, carefully executed study is a useful signal — chicken is not necessarily superior for gut health to a lean, quality beef. Until larger, controlled trials confirm these observations, a balanced, fiber-rich diet and moderate meat consumption remain the soundest advice.