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Researchers said the fast-mimicking diet worked better than a water-only diet. Getty Images

A fasting-mimicking diet may one day be helpful for those with Crohn’s disease or ulcerative colitis.

A recent study from the University of Southern California (USC) found an eating plan in which a low-calorie diet reduced inflammation in the intestine and reversed the pathology of inflammatory bowel disease (IBD) in mice.

Researchers say the results could be significant in the treatment of IBD.

“We had shown that the fast-mimicking diet was effective against a multiple sclerosis (MS) mouse model and also provided initial evidence for its effect against MS in humans. We suspected it could be effective against many autoimmune diseases, particularly those involving the gut,” Valter Longo, PhD, study author and the director of the USC Longevity Institute at the USC Leonard Davis School of Gerontology, told Healthline. “This is important because it addresses potential strategies to truly reverse, and not just keep under control, widespread illnesses such as Crohn’s disease and ulcerative colitis.”

In Dr. Longo’s study, one group of mice underwent a four-day, fast-mimicking diet in which they consumed roughly 50 percent of their normal calorie intake on day 1, and 10 percent of their normal intake on days 2, 3, and 4.

A second group of mice fasted only with water for 48 hours.

The researchers found that the mice who underwent a fasting-mimicking diet followed by their normal diet showed a reversal of some IBD pathologies and associated symptoms.

The mice in the water-fasting group didn’t experience the same benefit, suggesting that particular nutrients in the fasting-mimicking diet assist in anti-inflammatory changes in the gut as well as the promotion of a healthy microbiome.

The researchers say the fasting-mimicking diet encouraged an increase in intestinal stem cells by supporting a growth in healthy gut microbiota.

“Water-only fasting was effective mostly in promoting intestinal regeneration. The fast-mimicking diet instead was effective in reversing disease pathology by regulating microbiota, regeneration, and inflammation,” Longo said.

IBD is an umbrella term to describe these two conditions that are characterized by chronic inflammation of the gastrointestinal tract. Common symptoms include abdominal pain, rectal bleeding, weight loss, fatigue, and persistent diarrhea.

In 2015, about 3 million American adults reported having Crohn’s disease or ulcerative colitis.

The precise cause of IBD remains unknown. However, it’s believed the condition is due to a faulty immune system.

In the body of a healthy person, the immune system attacks foreign invaders, such as viruses, to protect the body. In IBD, the immune system incorrectly responds to gut bacteria and causes the gastrointestinal tract to become inflamed.

Various types of medication are available to treat IBD. In severe cases, surgery may be an option.

But according to Brigid Boland, MD, assistant professor of medicine at the University of California San Diego and a spokesperson for the American Gastroenterological Association, finding the right treatment can be difficult.

“The treatment of IBD is challenging. It’s a complicated disease that requires an underlying genetic predisposition, environmental and microbial triggers, leading to an overactive immune response,” Dr. Boland told Healthline. “Treating IBD or reversing pathology is challenging. Even the most effective drugs for IBD don’t induce long-term remission in the majority of people with the disease. As a result, finding better therapies for IBD remains a priority and an ongoing research focus.”

Currently no diet has consistently treated inflammation caused by IBD, or put the disease into remission.

Some diets, such as the fermentable oligo-, di-, monosaccharides, and polyols (FODMAP) diet, can assist with symptoms, but they must be combined with other treatments to adequately manage the disease and prevent complications.

“Finding a way to control this disease with diet would be an incredible achievement and could prevent lifelong medical therapy,” Jesse Stondell, MD, an assistant professor of gastroenterology and an IBD specialist at UC Davis Health, told Healthline. “There’s a strong desire within medical and patient communities to find this type of solution.”

“We know for sure that people with IBD have very different bacteria living in their bowels compared to people without the disease,” Dr. Stondell said. “It’s not known if this is a cause or effect of the IBD, but many scientists have theorized that correcting the bacterial imbalance could lead to improvement in the disease. Unfortunately, this has proven to be very difficult to achieve.”

Many of the experts who spoke with Healthline advise against people with IBD trying a fasting-mimicking diet as the effectiveness of this in humans has yet to be determined.

The researchers say further study in the form of a randomized clinical trial is essential to determine the safety and efficacy of such a diet in humans.

Kian Keyashian, MD, a clinical assistant professor of medicine at the Stanford School of Medicine in California, said the results of the study are promising, but will require examination of more elements to determine success in humans.

“Studies for fast-mimicking diets in the general population have shown some health benefits,” Dr. Keyashian told Healthline. “However, the translation of such animal studies to humans requires consideration of additional factors. In addition, safety of these diets for people with IBD have not been studied.”

“People with IBD are at increased risk of malnutrition, and any restriction in diet can further exacerbate this,” he said. “There needs to be good demonstration of efficacy and safety of any restricting diet in human trials before these diets can be recommended for people with IBD.”