Ulcerative colitis can benefit from better eating

Stan Cohen

The title of the journal report says it well. "Low-fat, high-fiber diet reduces markers of inflammation and dysbiosis and improves the quality of life in patients with ulcerative colitis," especially when you understand that dysbiosis means that there is an imbalance in the intestinal bacteria, and that imbalance is felt to contribute to intestinal diseases, especially inflammatory bowel disease. 

But that's not the whole story. As the authors explain, studies have shown that an increased risk of ulcerative colitis (UC) is seen in those on high-fat diets and animal meats. They also note that Hispanic immigrants who adopt a standard American diet, with lots of sugar and little in the way of fruits and vegetables, are also at more risk for developing UC. (J Fritsch and others, Gastroenterology 2021, pages 1189-1199)

So they decided to compare 2 diets to see if they could lessen the risk of UC with either or both of them. They enrolled 38 participants with UC in clinical remission at the University of Miami and gave them a diet of either a low fat, high fiber diet with 10% of the calories from fat or what they called an improved American diet, with more fruit, vegetables, and fiber (and less sugar) than a typical American diet—but with the typical 35-40% of calories from fat. And halfway through, the participants switched to the other diet. Both diets were better than what the participants were eating before the study, and the food was prepared for them to make sure the participants were getting the intended quantities.   

Unfortunately, only 17 participants (less than half) completed the study and could be analyzed and the whole study was only 8 weeks (4 on each diet)—so it's hard to draw firm conclusions. But they found

The diets were well tolerated (though they may not have been by those who stopped the diet).

All 17 remained in remission. No one worsened. 

Both diets resulted in a better quality of life, measured by 2 different questionnaires. 

Blood and stool markers of inflammation improved, more so with the low-fat diet. 

The intestinal bacteria was healthier on the low-fat diet, and dysbiosis was decreased. 

The reasons for these improvements aren't clear. Lowering the fat content was certainly important, but they also decreased the animal fat, and there may have been some other factors in the diet that was also important. And both diets had more fiber and less sugar than the participants' previous diets.

The diets are relatively expensive, especially catering them or having them prepared, but the authors note that the cost is far less than most of the biologic medicines that many of these patients are on. 

So it seems that the diets did help UC patients in remission. The next question is whether they can also help those with more active disease. We have seen that diets are helpful in Crohn's disease and that was again shown in a recent study with a simple Mediterranean Diet, which is somewhat similar to the low-fat diet in this trial.