- Experts are interested in how diet and nutrients might influence inflammatory bowel disease (IBD).
- A narrative review notes key nutrients of the Mediterranean diet that could have particular benefits for people with IBD.
- The review highlights the need for more research into the specific underlying mechanisms surrounding nutrients, IBD, and the microorganisms in the gut.
Inflammatory bowel disease (IBD) refers to a group of chronic conditions that impact the intestines. The two primary types of IBD are Crohn’s disease and ulcerative colitis.
The Mediterranean diet is one dietary pattern that may help people with IBD.
A recent narrative review published in the journal Nutrients discussed nutrients specific to the Mediterranean diet and how they might affect IBD.
A few of the nutrients highlighted include plant-derived protein, omega-3 polyunsaturated fats, and resveratrol. A deeper understanding in this area could help improve approaches for helping people with IBD.
The review authors note that gut microorganisms affect the development of IBD. Thus, they note that diet could be very helpful in adjusting the gut microbiome in people with IBD.
The Mediterranean diet has several components, including high amounts of fiber, fruits, and vegetables and low consumption of ultra-processed food.
The diet can likely help with both management and prevention of IBD and is already a recommendation in most cases of IBD. But, as the authors also note, the precise reasons why the Mediterranean diet can help the gut microbiome for people with IBD is a little unclear.
The authors used PubMed to identify recent research in this area, primarily looking at data from 2019 to 2024. They used keywords in their search like preclinical, Mediterranean diet, and inflammatory bowel disease.
The authors looked at several nutrients in their research. First, they looked at carbohydrates. For example, they found some data to support the notion that fructo-oligosaccharides may help improve intestinal permeability in people with Crohn’s disease and increase certain levels of desirable gut microorganisms.
Additionally, the data suggest that components like chitosan, pectic polysaccharides, and fruits like cranberries may offer benefits. However, some dietary fibers may lead to negative effects in some people who have active IBD.
Next, researchers looked at proteins. The data supports that plant-derived proteins may have anti-inflammatory properties.
Nuts and seeds may help decrease proinflammatory bacteria and improve bacterial diversity. Certain dairy products found in the Mediterranean diet may also be helpful, like kefir.
Kefir has high levels of Lactobacillus and may help modulate gut microbiota and improve inflammation. The amino acid tryptophan may also help, but more research is required to confirm its effects.
The Mediterranean diet primarily includes unsaturated fats, with olive oil being a big fat source. Olive oil contains polyphenols and other elements that may help with inflammatory disorders.
However, more research on olive oil’s benefits will be helpful, and it appears that the composition of the olive oil may impact its effects.
Researchers also highlight that omega-3 polyunsaturated fatty acids from fish and seeds have anti-inflammatory properties.
Some human studies support that omega-3 fatty acids’ anti-inflammatory properties help with IBD, but the data is mixed. One case-control study found that seafood and nuts may contribute to IBD development. These and other data suggest the need for more research on fat and IBD.
Dietitian Natasha Haskey, PhD, RD, who was not involved in this review, commented to Medical News Today that:
“This is a comprehensive review providing evidence-based rationale as to the benefits of the Mediterranean diet in IBD, written by experts in the field. The diet’s anti-inflammatory, antioxidant, and gut microbiota-modulating properties can help maintain remission and potentially reduce disease flares […] The inclusion of key nutrients like polyphenols, omega-3 fatty acids, and fiber may synergize with existing pharmacological treatments, potentially enhancing therapeutic outcomes and addressing nutritional deficiencies common in IBD.”
The authors further delved into the potential benefits of red wine, which is part of the Mediterranean diet. Some studies suggest that consuming moderate red wine could help protect people from developing IBD or IBD progressing.
Components of red wine that may be beneficial include resveratrol, which may help minimize intestinal inflammation and increase levels of helpful microorganisms, and tannins.
However, the authors note that consuming excessive alcohol could make IBD worse, and it is not entirely clear if the benefits come from drinking red wine alone.
Certain pigments in the Mediterranean diet may also be helpful. For example, quercetin is found in foods like onions, berries, and citrus fruits. It may help promote the growth of helpful gut microorganisms, decrease harmful microorganisms, reduce intestinal permeability, and inhibit chronic inflammation.
The problem arises from its low bioavailability and water solubility, which current research is trying to address. The pigment astaxanthin in some seafood may help minimize inflammation and preserve mucosal integrity.
Lycopene, a carotenoid, also holds promise. It is in some red fruits like tomatoes. It may help with inflammation reduction, affect immune responses, and help preserve the intestinal barrier.
However, the authors say that more research is required because some studies have suggested that specific vitamins, antioxidants, and minerals could contribute to IBD development.
Other nutrients that may be beneficial include curcumin, a component of turmeric, epigallocatechin gallate found in green tea, and vitamin D. Each of these components requires more research.
Finally, the authors note that the Mediterranean diet contains multiple compounds that may have a combined effect, that adherence could be challenging, and that individualizing dietary strategies are important for people with IBD.
This review does have some limitations. First, the authors focused on data from a specific timeframe and only used one database. They also only included studies written in English. Therefore, they could have missed some data in this area.
This review focused on preclinical evidence. Thus, more research is required to confirm what this narrative review reports. The review received funding from the European Crohn’s and Colitis Organization fellowship 2024, awarded to one of the review authors. Additionally, some of the authors noted conflicts of interest.
Berkeley Limketkai, MD, PhD, director of clinical research at the UCLA Center for Inflammatory Bowel Disease, who was not involved in this review, noted that “most of the information presented is drawn from preclinical data due to the dearth of clinical studies.”
“While each of these purportedly beneficial nutrients/food types are components of the Mediterranean diet, they are not unique to the diet,” he pointed out. “This thus raises the question of whether other dietary patterns that combine these individual components would similarly be beneficial for IBD:
Finally, Limketkai added: “As the review summarizes existing data and is not a research study per se, it does not specifically add to what is already known about diet and IBD. The evidence presented nonetheless reinforces the benefits of the Mediterranean diet while diving into detail about the components that confer the Mediterranean diet its anti-inflammatory effects.”
The review authors highlight that more research is needed into the interactions between the microbiome of the small and large intestines and nutrients.
Future research can occur at several levels, including animal and human studies. Future research could also explore how physical activity plays into effects, as physical activity is a key component of the Mediterranean lifestyle.
Rudolph Bedford, MD, a board-certified gastroenterologist at Providence Saint John’s Health Center in Santa Monica, CA, who was not involved in the review, told MNT that:
“The future research [that needs to be undertaken should address] how these components of the Mediterranean diet interact with the gut microbiome. The gut microbiome consists of over 10 trillion bacteria. It is probably amongst the largest immunologic organs in the body. So, preventing things like low-grade inflammation within the gut, how does that happen? How is it that the diversity of these bacteria interacting with the various dietary components actually prevent the disease from occurring or modify the disease process itself?”
