[00:30]
Hello, I’m Dr. Oriana Damas, and welcome to IBDIQ, part of The IBD Project by Takeda, where we’re coming together to help enhance expertise in IBD care—right from the start.
Thank you for joining me today to explore dietary approaches for managing inflammatory bowel disease, or IBD. First we’ll discuss why diet may influence the risk of inflammatory bowel disease. Then, we’ll examine a range of dietary approaches and their potential benefit in Crohn’s disease, or CD, and ulcerative colitis, or UC. We will also review how dietary considerations may be implemented in the care of patients with IBD.
[01:09]
Let’s begin by exploring how diet can contribute to IBD.
Epidemiologic studies reveal that the incidence of IBD has been rising in industrialized countries since the 19th century.1 There has been a similar emergence since the 1950s in the developing world, where IBD was previously unknown.
This growing emergence has been attributed to environmental factors and linked, in part, to the adoption of a Western lifestyle—particularly a Western diet.1-8
A Western diet is high in animal protein and fats, contains processed foods, and is low in fiber.2,3,6,7,9
Researchers used information from the Prospective Urban Rural Epidemiology (or PURE) cohort to examine the association between dietary factors and the risk of developing IBD.10 In the PURE cohort, dietary information was obtained between January 2003 and December 2016 for more than 136,000 adults aged 35 to 70 years using validated questionnaires.
[02:09]
Participants were enrolled from 21 countries, which did not include the US. Although data collection started in 2003, an amendment was added in 2014 to record diagnoses of CD and UC, based on patients’ self-report of the diagnosis.
The dietary study included more than 116,000 qualified participants from the PURE cohorts.10 Patients were followed for a median of 9.7 years. The primary outcome was the development of IBD after completion of the baseline questionnaire.
Among several analyses, researchers examined the link between what they described as “ultra-processed food” consumption and risk of developing IBD.10 They focused specifically on individuals consuming less than 1 serving per day versus higher volumes of up to 5 or more servings per day.
Ultra-processed foods were characterized as packaged items containing additives, artificial flavors, artificial colors, and other chemical ingredients.10
[03:09]
Individuals who consumed 1 to 4 servings of ultra-processed food daily were 1.67 times more likely to develop IBD than those consuming less than 1 serving.10
Those who consumed 5 or more servings were 1.82 times more likely.10
What could account for this effect of diet on the development of IBD?
Dietary patterns might influence the pathogenesis of IBD through specific effects on the intestinal environment.8
A healthy intestinal state is characterized by diversity of the microbial population, with an abundance of beneficial bacteria.11,12 In addition, a thick, intact mucus layer forms a protective barrier separating the bacteria of the intestinal lumen from the epithelial cells of the intestinal walls. This state has been associated with favorable dietary patterns.9,11,12
[04:02]
In contrast, the inflammatory state associated with IBD is characterized by reduced microbial diversity, a higher proportion of potentially harmful bacteria, a thinner mucosal barrier, and a loss of tight junctions between the epithelial cells.8,9,11,12
The impaired barrier function allows potentially harmful bacteria and other molecules to have access to immune cells of the intestinal wall.9,11,12 This can trigger an immune response and the tissue inflammation seen in inflammatory bowel disease. These characteristics have been associated with consumption of a Western diet.9,11
As awareness grows about the potential role of dietary patterns in IBD pathogenesis, there’s increasing interest in how diet can be used as a therapeutic intervention.3-5,13
Before we explore further, it’s important to recognize that there are a number of potential challenges to implementing dietary interventions as therapeutic approaches in IBD.
[05:01]
First, there are limited data from randomized, controlled trials on the therapeutic benefit of diets, although evidence is available for several specific diets, which we’ll review.4,6,13,14
Cultural factors may influence patients’ willingness to follow dietary advice.5,15
Also, social determinants of health—meaning the social, economic, and physical conditions that shape and impact individuals’ healthcare options—may affect dietary approaches.16 For example, key social determinants such as food insecurity may limit the ability to adhere to specific diets.5,15-17
Malnutrition is also a factor to monitor and consider.6,13,18
It’s also important to recognize that there is no consensus for a singular “IBD diet.”5,13,14
Dietary interventions should involve a focused discussion with the patient and relevant members of the care team to personalize recommendations based on individual circumstances and needs.5,8,14
[06:02]
A number of dietary interventions have been studied in Crohn’s, in ulcerative colitis, and in both forms of inflammatory bowel disease. Diets studied in CD include the exclusive enteral nutrition, or EEN, and the Crohn’s Disease Exclusion Diet, or CDED.2,3,18 The Specific Carbohydrate Diet, or SCD, and the Mediterranean diet have been studied in both CD and UC.2,3,18-19
Diets studied in UC include the Ulcerative Colitis Exclusion Diet, or UCED, and the 4 strategies to SUlfide REduction, or 4-SURE diet.2,20-22 The low FODMAP diet (which addresses fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) may have a role in both UC and CD.2,23,24
Let’s begin by looking at exclusive enteral nutrition, or EEN. This dietary approach has been the most extensively studied.8,13,25
[07:02]
EEN is a dietary regimen in which liquid formula, delivered orally or via nasogastric tube, supplies all of an individual’s nutritional needs, usually for a period of 6 to 8 weeks.18
The American Gastroenterological Association (or AGA) Clinical Practice Update on Diet and Nutritional Therapies in Patients With Inflammatory Bowel Disease, which we’ll refer to as the AGA Nutritional Guidelines, addresses EEN as well as other diets.18
According to the AGA Nutritional Guidelines, EEN is an effective therapy for induction of clinical remission and endoscopic response in Crohn’s disease, with stronger evidence in children than in adults.18 They note that EEN is routinely offered as a steroid-sparing therapy in children with Crohn’s disease.
On the other hand, EEN is not as widely prescribed for adult patients, due in part to challenges with compliance. When tolerated in adults, according to the AGA, it may be effective for inducing remission.18
[08:03]
Since there can be potential challenges with adherence to EEN, alternative approaches that incorporate or are composed entirely of whole-food components have been studied in IBD.18,26 One of these is the Crohn’s Disease Exclusion Diet, or CDED.
CDED integrates whole foods with partial enteral nutrition, or PEN.18 This alternative may be easier to adhere to than the 100% liquid regimen with EEN.
It was designed to exclude or limit foods thought to adversely affect the intestinal microbiome or alter the function of the intestinal barrier.18
The CDED follows a 3-phase protocol. During the first 6 weeks, patients receive half of their nutrients from PEN, while avoiding insoluble fiber, red or processed meat, artificial additives, seeds, dairy, and certain oils.2,26
Then, during weeks 7-12, patients consume 25% of their nutrients from PEN, while foods such as legumes are reintroduced, along with additional fruits, certain starches such as corn, and one yogurt per day.2,26
[09:15]
Starting from week 13 and lasting at least 9 months, patients can continue the regimen with a more flexible, personalized approach, allowing for wider food choices.2,18,26
The AGA Nutritional Guidelines note that CDED may be an effective therapy for induction of clinical remission and endoscopic response in mild to moderate Crohn’s disease of relatively short duration.18 CDED may be easier to follow than EEN, which may help with compliance.
Let’s look next at the Specific Carbohydrate Diet, or SCD.
The SCD is a regimen designed entirely as a whole foods diet and has been studied in patients with Crohn’s disease and patients with UC.2,27
[10:00]
The SCD permits the intake of monosaccharides, such as certain fresh fruits, nonstarchy vegetables, as well as meat, eggs, most oils, nuts, and honey.27,28
The SCD limits disaccharides and polysaccharides, such as sugar, grains, canned fruits and vegetables, and potatoes. Canned and processed meats, milk, and candy are also excluded. 27,28
The AGA Nutritional Guidelines describe but do not make a specific recommendation for the SCD, noting that there have been limited large-scale studies showing evidence of benefit.18 In addition, the guidelines note that the regimen can be challenging to follow.
The Mediterranean diet has been extensively studied in a variety of medical conditions, including Crohn’s and ulcerative colitis.18,29 It has been studied for its anti-inflammatory and cardiovascular benefits.4,5,18,19,29,30
The Mediterranean diet is rich in fruits, vegetables, complex carbohydrates, and olive oil and is low in red meats, saturated fats, ultra-processed foods, and added sugar.18
[11:09]
The Mediterranean diet was studied in a randomized, controlled trial of patients with Crohn’s disease and an uncontrolled, prospective study that included patients with Crohn’s and UC.2,18,28,31
According to the AGA Nutritional Guidelines, unless there is a contraindication, all patients with IBD should be advised to follow a Mediterranean diet for their overall health and general well-being.18
They note that the Mediterranean diet may improve diversity of the gut microbiome and that it has been associated with other long-term health benefits, including a reduction in cardiovascular risk.18
Let’s now turn to the Ulcerative Colitis Exclusion Diet, or UCED.21
The UCED is a 2-phase diet that limits the consumption of animal fats, sulfated amino acids, total protein, iron from meat sources, and food additives.20 The UCED was studied in pediatric and adult patients with mild to moderate UC.2,20,21,32
[12:10]
The first phase of the UCED involves primarily fruits and vegetables over 6 weeks.20 Rice and potatoes are allowed without limitations, but chicken, eggs, yogurt, and pasta must be consumed in limited, prescribed amounts. The UCED does not allow red meat or processed foods. Intake of sugars from sources other than fruits is reduced.
The second phase of the UCED, which occurs in weeks 7-12, offers greater flexibility, allowing for a wider variety of fruits and vegetables and the introduction of certain amounts of grains.20
Another diet that has been studied in adults with mild to moderate UC is the 4 strategies to SUlfide REduction, or the 4-SURE, diet.21,22
[13:00]
The 4-SURE diet consists of 4 principles.22
The first is to consume 10-15 grams a day of resistant starch and 5 grams a day of slowly fermentable non-starch polysaccharides, such as those found in whole grains, fruits, vegetables, nuts, and legumes.22
Second, limit protein to 75-90 grams per day.22
Third, restrict sulfur-containing amino acids, found in beef, poultry, fish, eggs, and hard cheese.22,33
And fourth, avoid certain food additives, such as sulfates, nitrates, and carrageenan.22
The final diet we’ll explore today is the low FODMAP diet. This diet may have a role in both Crohn’s disease and ulcerative colitis as a remedy for specific symptoms in some patients.2,18,24
FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which are fibers and sugars that are poorly absorbed by the small intestine.2,18
[14:04]
There are 3 phases in this diet.34 In the first, or restriction phase, the diet dramatically reduces FODMAP intake for about 4 to 8 weeks.
The second is the reintroduction phase, during which foods from each FODMAP category are reintroduced over approximately 6 to 10 weeks to assess individual tolerance and identify specific triggers.34
That is followed by a personalization phase, which develops a long-term regimen customized to the individual patient.34 This long-term diet includes tolerated foods and omits those associated with symptoms, with the goal of increasing dietary variety.
The low FODMAP diet may be useful for reducing symptoms similar to those seen in irritable bowel syndrome, or IBS, such as bloating, nausea, and abdominal pain.2,3,24
The AGA Nutritional Guidelines note that this approach may be worth trying on a short-term basis in patients with an IBD flare who are experiencing concomitant IBS-like symptoms.18 The guidelines recommend that patients return to a healthy Mediterranean-style diet after symptom resolution.
[15:17]
In summary, diets studied primarily in Crohn’s include EEN, which uses liquid nutrition only, and CDED, which includes whole foods and may be easier to implement.18 Both the SCD and the Mediterranean diet have been studied in Crohn’s and UC.2,18,19 The UCED and the 4-SURE diet were developed specifically for ulcerative colitis. 2,20-22 A low FODMAP diet may offer short-term help in Crohn’s or UC when patients have superimposed symptoms similar to IBS.2,23,24
Now that we’ve discussed specific diets that have been studied for patients with IBD, let’s discuss some considerations that may help in incorporating diet into patients’ IBD treatment plan.
[16:05]
Sensitivity to patients’ dietary cultural traditions should be considered and may help increase the likelihood of adherence.5,15 Dietary recommendations can be adapted to specific cultural contexts.15
Within many cultural diets, for example, there are likely to be foods with anti-inflammatory properties that align with the health benefits of the Mediterranean diet.15
Identifying these culturally significant foods and incorporating them into a Mediterranean-style eating plan may make the diet more appealing and easier for patients to follow while respecting their culinary traditions and preferences.15
Food insecurity may be an issue for patients with inflammatory bowel disease.5,15,16 The lack of consistent access to enough affordable, nutritious food may result in skipped meals, smaller portions, or reliance on processed foods.16,17
[17:00]
Evidence from a cohort of 128 adult patients with IBD has shown that those at higher risk of food insecurity were significantly more likely to consume highly processed food and less likely to consume unprocessed food, compared with those not at risk of food insecurity.17
Providers can be mindful of such obstacles for patients facing financial challenges and be prepared to offer dietary alternatives that are consistent with patients’ economic circumstances.15,17
Suggestions are available, for example, on how to follow a Mediterranean diet while on a tight budget.17 These include the use of canned fruits and vegetables, packed in water rather than sugar or salt; frozen fruit or vegetables without flavoring; canned fish such as tuna or salmon for protein; purchasing food in bulk, such as rice, potatoes, and cereal; and seeking fresh produce that is local and in season.
[18:00]
Looking ahead, future research may also provide opportunities for greater personalization in dietary therapy of IBD.2,7
It may one day be feasible to tailor dietary recommendations to an individual’s unique metabolism, intestinal microbiome, and food preferences, thus addressing each patient's specific nutritional needs in a way more likely to support disease management.2,7
Now, let’s summarize the key points from our discussion. First, we talked about how a Westernized diet appears to play a role in IBD risk and may have specific adverse effects on intestinal health at the level of the microbiome.2,8,9,11 Then, we reviewed specific dietary regimens that have been studied in Crohn’s, UC, or both.2,3,18-24 With these, we noted AGA guidelines, where applicable.18
We noted that challenges to dietary implementation include limited data and malnutrition considerations, as well as cultural factors and food insecurity.5,6,13-16,18
[19:05]
Patients therefore may benefit most when providers consider each patient’s unique circumstances in suggesting a dietary component for the management of their IBD.2,5,7
Thank you for your interest and for spending some time with IBDIQ today to help adapt to the evolving care needs of all patients with IBD.
