Is the Low-Residue Diet Still Relevant?

What constitutes a low-residue diet? The phrases “low residue”, “low fibre” and “low roughage” are often used interchangeably in clinical practice, but they are not synonyms.

• A low-residue diet is low in foods that contain high amounts of indigestible components that promote increased faecal volume (e.g. celery, fruit and vegetable skins, stalks and seeds), but also limits foods that promote colonic residue, such as dairy milk [2].
• A low-fibre diet includes all foods that are free of fibre (e.g. dairy products) and limits food that are higher in fibre (e.g. fresh fruit and vegetables, whole grains, legumes, nuts and seeds). Low-fibre foods tend to be more refined and processed.
• A low-roughage diet commonly only limits foods that are high in indigestible components and likely to cause a physical bowel blockage. This may include limiting tough meat as well as pips and skins of fruit and vegetables.

What is the evidence for using a low-residue or low-fibre diet in active IBD? There is limited evidence to support the theory that a low-residue diet during active IBD is associated with reduced symptoms [3]. Patients often restrict dietary intake during a flare due to inflammation-associated anorexia [4] and, anecdotally, patients associate eating with abdominal pain and bowel motions. A randomised controlled trial of a low-fibre diet compared to an unrestricted diet in 71 patients with mostly (n=58) active Crohn’s Disease found no difference in disease activity or functional symptoms between the groups [5]. This suggests that a strict low-fibre diet is not usually necessary to manage symptoms of active disease.

The currently recommended dietary and nutrition treatments for active Crohn’s Disease are fibre free (e.g. exclusive enteral nutrition) or low in insoluble fibre (e.g. partial enteral nutrition with an exclusion diet) but are not low residue as they often contain dairy proteins. Exclusive or partial enteral nutrition with a dairy protein formula is the most commonly used treatment [6]. All diet and nutrition treatments alter the gut microbiome composition and function in some capacity, and it is hypothesised that it is this mechanism, rather than reduction in faecal bulk, which reduces IBD symptoms and gut inflammation.

Evidence against long-term low-residue diets Patients with IBD consistently eat less fibre than the general population [7] and less than recommended dietary guidelines for the prevention of diseases such as cardiovascular disease and bowel cancer [7]. Recent evidence suggests that consuming adequate fibre, or types of fibre, may be important in promoting maintenance of remission. A large dietary survey of 1130 patients with Crohn’s Disease found that patients in the highest quartile of fibre intake were less likely to have a flare within the six-month follow-up period (adjusted odds ratio 0.58; 95% CI 0.37–0.90) [8]. In patients with a normal ileal pouch-anal anastomosis (n=39), low consumption of fruit (<1.45 servings per day) was associated with development of pouchitis within 12 months (log rank test, p=0.02) while higher consumption of fruit was associated with greater pouch microbial diversity [9]. A high-fibre, low-fat diet was recently compared with an improved standard American diet (higher fibre than a usual American diet) in a randomised, cross-over intervention study in 17 patients with mild or inactive Ulcerative Colitis [10]. The high-fibre diet was well tolerated by patients, reduced markers of inflammation (C-reactive protein) and promoted a favourable gut microbiome composition, including increased abundance of the butyrate-producing bacterium Faecalibacterium prausnitzii. Conversely, supplemental fibre has not consistently been found to improve disease inflammation [11]. A limitation of many of the fibre supplement studies is that background dietary intake is not controlled or assessed. Fibre in a whole food form also comes with many other nutrients (e.g. vitamins, minerals and phytochemicals) that likely confer anti-inflammatory and metabolic benefits.

Broadly, the current evidence suggests that a diet containing adequate fibre (25–30 g per day) may positively alter the gut microbiome, reduce markers of inflammation and promote maintenance of remission, so it should be recommended to most IBD patients.

Practical tips for clinicians:

• A thorough nutritional assessment (by a trained health professional, such as a dietitian) and access to recent imaging or intervention studies are essential to be able to individualise dietary recommendations.
• If recommending a low-fibre or low-residue diet during active disease, give patients a time frame (usually weeks) for using a low-residue diet and then encourage them to consume fibre after that time.
• Recommend that patients eat slowly and chew foods well.
• Provide education, or links to reputable websites, on how to resume eating a healthy diet that contains fruit, vegetables and whole grains.
• Provide education on healthy eating to maintain health during remission.
• Monitor annually for nutritional deficiencies and consider using vitamin and mineral supplementation in patients on a long-term low fibre diet.

References

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2. Sorathia AZ, Sorathia SJ. Low residue diet. StatPearls. Treasure Island (FL)2021.
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4. Gerasimidis K, McGrogan P, Edwards CA. The aetiology and impact of malnutrition in paediatric inflammatory bowel disease. J Hum Nutr Diet. 2011;24:313–26.
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6. Logan M, Gkikas K, Svolos V, et al. Analysis of 61 exclusive enteral nutrition formulas used in the management of active Crohn's disease – new insights into dietary disease triggers. Aliment Pharmacol Ther. 2020;51:935–47.
7. Day AS, Davis R, Costello SP, Yao CK, Andrews JM, Bryant RV. The adequacy of habitual dietary fiber intake in individuals with inflammatory bowel disease: a systematic review. J Acad Nutr Diet. 2021;121:688–708 e3.
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9. Godny L, Maharshak N, Reshef L, et al. Fruit consumption is associated with alterations in microbial composition and lower rates of pouchitis. J Crohns Colitis. 2019;13:1265–72.
10. Fritsch J, Garces L, Quintero MA, et al. Low-fat, high-fiber diet reduces markers of inflammation and dysbiosis and improves quality of life in patients with ulcerative colitis. Clin Gastroenterol Hepatol. 2021;19:1189–99 e30.
11. Peters V, Dijkstra G, Campmans-Kuijpers MJE. Are all dietary fibers equal for patients with inflammatory bowel disease? A systematic review of randomized controlled trials. Nutr Rev. 2021. doi: 10.1093/nutrit/nuab062. Online ahead of print.