Story at a glance
- Our gut health is important for digestive and immune function.
- What we eat can affect the immune cells in the gut.
- Researchers observe in mice how a diet high in fat and sugar may disrupt immune cell function.
Our diets affect our health, we’ve understood that for some time. But how does it affect us in specific ways? That’s trickier. One group of researchers examined the effects of a high fat, high sugar diet, which is common in Western countries, on the gut.
The digestive system, besides having the job of processing all the food you eat, also has important links with the immune system. Diet can also affect how the immune cells in the gut function, although how it does that has not been very well understood.
Experts are interested in the diet’s connections to gut health because of what can happen when the gut isn’t functioning as well as it could. In a new paper published in Cell Host & Microbe, a group of researchers study what happens in mice to try to learn more about this connection. “Inflammatory bowel disease has historically been a problem primarily in Western countries such as the U.S., but it's becoming more common globally as more and more people adopt Western lifestyles,” says lead author Ta-Chiang Liu, who is an associate professor of pathology and immunology at Washington University.
In the experiments, the researchers focused specifically on Paneth cells. These are immune cells in the gut that help to keep inflammation under control. They studied laboratory mice that were bred to overeat and observed what happened with the Paneth cells. Some mice were given a normal diet and others a diet in which 40 percent of the calories came from fat or sugar.
The mice that overate on a regular mouse diet had normal Paneth cells, but the mice who were fed a more Western diet had abnormal Paneth cells. What’s interesting is that the abnormal Paneth cells returned to normal after shifting to a normal diet. “Our research showed that long-term consumption of a Western-style diet high in fat and sugar impairs the function of immune cells in the gut in ways that could promote inflammatory bowel disease or increase the risk of intestinal infections,” says Liu.
This experiment was short, just eight weeks. For mice, that is a good proportion of their lifespan, but for humans that is very little time. In reality, it takes a long time for the health effects of their diet to affect their bodies. The researchers are interested in what those long-term impacts might be. “It's possible that if you have a Western diet for so long, you cross a point of no return and your Paneth cells don't recover even if you change your diet,” says Liu. “We'd need to do more research before we can say whether this process is reversible in people.”
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