How Gut Bacteria Adapt to Roasted and Heated Foods

Researchers found that gut bacteria can repurpose existing enzymes to break down compounds formed when foods are heated.

Heating food creates new compounds that contribute to the flavor and browning seen in foods such as crusty bread, fried meat, and roasted coffee. Researchers from Ludwig-Maximilians-Universität München and Technische Universität Dresden found that gut bacteria can use existing enzymes to break down some of these compounds, shedding light on the relationship between diet and the gut microbiome (1^✔ ✔Trusted Source
Deciphering underground decarboxylase activity towards Nε-modified lysine derivatives in enterobacteria

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The team focused on Nε-carboxymethyllysine (CML), a modified form of the amino acid lysine commonly found in heated foods. Because these modified amino acids are not completely absorbed in the small intestine, they reach the large intestine, where they interact with gut microorganisms involved in digestion, immunity, and overall health.

How Do Gut Bacteria Process Heated Food Compounds?

The research team demonstrated in the gut bacterium Escherichia coli that the enzyme SpeC is able to break down CML in addition to its previously known function. “The bacteria do not need to develop entirely new tools for this task. Instead, they repurpose their existing repertoire in a creative way,” says Lassak. It is particularly notable that SpeC does not recognize CML alone, but, like a Swiss pocket knife, the enzyme can also process other chemically modified amino acids.

SpeC Acts Like a ‘Swiss Pocket Knife’ Enzyme

“From an evolutionary perspective, this is significant,” says Erica Aveta, who shares first authorship with Patroklos Vougioukas. “Such side activities can give bacteria an initial route to access new dietary compounds. If such a compound becomes regularly available, adaptation can turn the ‘Swiss pocket knife’ SpeC into a more efficient tool specialized for this task.”

Could Heated Foods Influence the Gut Microbiome?

Computational analyses suggest that such degradative capacities are widespread in the human gut microbiome. The study also identifies links to several diseases associated with diet and lifestyle, including bowel cancer, fatty liver disease, and hepatitis. It is conceivable, for example, that the bacterial breakdown of CML creates advantages for certain bacteria in an inflamed gut environment. In addition, novel biogenic amines are produced during the breakdown of the chemically modified amino acids – a molecular group that is the subject of intense debate as mediators of bacteria-host communication.

What Are the Potential Health Connections?

“These links do not yet prove a cause-and-effect relationship,” cautions Jürgen Lassak. “But they do suggest that processed food, microbial metabolic pathways, and health status may be more closely connected than previously assumed,” adds Michael Hellwig.

Reference:

1. Deciphering underground decarboxylase activity towards Nε-modified lysine derivatives in enterobacteria – (http://dx.doi.org/10.1016/j.foodchem.2026.150234)

Source-Medindia