Low Residue Diet
For at least the last half century the low-residue diet has been a short-term dietary treatment to help reduce the symptoms of active Crohn’s disease and ulcerative colitis . A longer term low-residue diet may be appropriate for some, but not all, people with intestinal strictures or narrowing of the bowel, although the scientific evidence to support this recommendation is limited. This blogs defines a low residue diet, the scientific evidence for its use during active IBD and when in remission and provides some low residue diet tips.
What is a low-residue diet?
The phrases “low residue”, “low fibre” and “low roughage” are often used interchangeably in clinical practice, but they are not synonymous.
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.
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 more 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 during active IBD?
There is limited scientific evidence to support the theory that a low-residue diet during active IBD is associated with reduced symptoms. People with IBD often restrict dietary intake during a flare due to inflammation-associated poor appetite and, anecdotally, find that eating is associated 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 [1]. 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. 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
It is common for people with IBD to eat less fibre than the general population and less fibre than recommended in dietary guidelines for the prevention of diseases such as cardiovascular disease and bowel cancer. Recent evidence suggests that consuming adequate fibre, or types of fibre, may be important in promoting maintenance of IBD remission. A large dietary survey of 1130 patients with Crohn’s disease found that people 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) [2]. In those with a normal ileal pouch-anal anastomosis (n=39), low consumption of fruit (<1.45 servings per day) was associated with development of pouchitis (pouch inflammation) within 12 months (log rank test, p=0.02) while higher consumption of fruit was associated with greater pouch microbial diversity [3]. 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 [4]. The high-fibre diet was well tolerated, 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 (e.g. psyllium husk) has not consistently been found to improve disease inflammation [5]. 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 people with IBD.
low residue diet tips
If recommended a low-fibre or low-residue diet during active disease, ask your doctor/nurse/dietitian how long (usually weeks) to continue using a low-residue diet. Eating fibre rich foods after this time should be encouraged.
The type of diet recommended, that is a low residue, low fibre or low roughage diet, depends on the length, diameter and number of strictures/narrowed parts of bowel. A thorough nutritional assessment (by a trained health professional, such as a Registered Dietitian) and review of recent imaging (MRI or CT scans) or colonoscopy results helps to individualise dietary recommendations.
Try to eat slowly and chew foods well as this improve tolerance and aids digestion of food in the gut.
Once recovered from an IBD flare, aim to eat a healthy diet that contains a variety of fruit, vegetables and whole grains. Modifying the texture of some foods may improve tolerance e.g. cooked, mashed, blended.
Speak with your doctor about having an annual blood test to screen for nutritional deficiencies.
If a long-term low residue or low fibre diet is needed ask your doctor for an annual blood test to screen for micronutrient deficiency and discuss with your doctor/dietitian about whether a vitamin and mineral supplementation is needed. An IBD dietitian can provide an individualised long term dietary plan.
Carrot hummus
A tasty, high fibre and low FODMAP dip.
2 carrots peeled, diced into 1cm cubes and tossed in olive oil
2 garlic cloves, whole with skin on
2 - 4 Tbsp canned cannellini or butter beans
1 Tbsp olive oil
1 Tbsp tahini
2 Tbsp water
1/2 Tbsp wine or apple cider vinegar
Method:
Roast carrot with whole garlic cloves in the oven at 180 degrees until carrot is tender. The whole, skin on garlic cloves flavour the carrot and oil without adding FODMAPs to the dip.
Add roasted carrot (but not the garlic) and the remaining ingredients to a blender and blend until smooth.
If the mixture is too thick add an extra tablespoon of water.
Season with garlic and garnish with black pepper and olive oil.
Tip: leftover beans can be frozen and used in the next batch of hummus or added frozen into other dishes during cooking e.g. soup or nachos.
References
[1] Levenstein S, Prantera C, Luzi C, D'Ubaldi A. Low residue or normal diet in Crohn's disease: a prospective controlled study in Italian patients. Gut. 1985;26(10):989–93.
[2] Brotherton CS, Martin CA, Long MD, Kappelman MD, Sandler RS. Avoidance of fiber is associated with greater risk of Crohn's disease flare in a 6-month period. Clin Gastroenterol Hepatol. 2016;14:1130–6.
[3] 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.
[4] 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.
[5] 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.