Protein-rich foods block cholera bacteria from taking hold

Researchers at UC Riverside have found something unexpected: what you eat can dramatically change how severe a cholera infection becomes. In tests with infected mice, diets high in protein—particularly casein from milk and cheese, and wheat gluten—nearly prevented the bacteria from establishing itself in the gut.

This matters because cholera still kills thousands each year, mostly in Asia and Sub-Saharan Africa where clean water is scarce. The infection causes severe diarrhea and can be fatal without treatment. Current medical responses focus on rehydration and antibiotics, but neither stops the toxins the bacteria releases into the body.

How protein changes the game

Ansel Hsiao, the study's senior author at UC Riverside, was surprised by how powerful the effect was. "I wasn't surprised that diet could affect the health of someone infected with the bacteria," he said. "But the magnitude of the effect surprised me."

When the team fed mice different diets—high protein, high carbohydrate, or high fat—only the protein-rich diets made a real difference. High-fat diets had almost no effect. Carbohydrate-heavy diets helped slightly. But casein and wheat gluten were the clear winners, cutting cholera's ability to colonize the gut far more effectively than a balanced diet.

The mechanism is elegant. Cholera bacteria use a tiny needle-like structure on their surface—called the type 6 secretion system—to inject toxins into nearby cells. This helps them kill competing bacteria and establish themselves. Certain proteins interfere with this structure, making it harder for cholera to gain a foothold.

A low-risk public health tool

What makes this finding practically useful is simplicity. Casein and wheat gluten are already recognized as safe by regulators. They don't carry the risk of antibiotic resistance that comes with drugs. For communities with limited access to clean water and medical care, a dietary intervention could be a realistic way to reduce infection severity without expensive or complex infrastructure.

Hsiao expects these results would translate to humans, though human trials haven't happened yet. He's also curious whether high-protein diets might protect against other bacterial infections beyond cholera—a question his team plans to explore.

"The more we can improve peoples' diets, the more we may be able to protect people from succumbing to disease," he said.

The research was published in Cell Host & Microbe in 2025.