Gut bacteria reveal why foods affect people differently, study finds

A new study published in Scientific Reports has uncovered why people respond differently to the same foods. Researchers found that gut bacteria play a key role in how the body processes dietary compounds. The findings suggest that metabolic reactions depend more on microbial functions than simply which bacteria are present.

The work focused on red raspberries as a model food. However, the same principles apply to other plant-based foods rich in bioactive molecules like polyphenols.

The team used longitudinal intervention trials to track how participants metabolised raspberry compounds. Advanced machine learning algorithms helped identify biomarkers linking microbial activity to metabolic changes. Those with gut microbiomes rich in genes for polyphenol breakdown, short-chain fatty acid production, and anti-inflammatory processes showed the greatest improvements after eating raspberries.

Functional signatures in the microbiome correlated with how efficiently the body processed key nutrients. This means the way gut bacteria *work*—not just their presence—determines how well someone benefits from certain foods. The study did not specify participant demographics, such as country of origin or regional distribution. While broader trends in Germany and Switzerland highlight diverse populations, the research itself lacks detailed cohort breakdowns. Researchers emphasised that these microbial patterns could inform personalised nutrition plans. Tailoring diets based on an individual's microbiome might optimise health and reduce the risk of metabolic diseases like diabetes or obesity.

The findings open the door for microbiome-based tests that predict how a person will respond to specific foods. Future studies will need to include larger, more varied groups to confirm the results. Scientists also plan to explore whether these microbial signatures remain stable over time and across different diets.