Specific probiotic types and strains can help manage chronic constipation in adults

Chronic constipation is one of the most common disorders of the gut-brain interaction, affecting approximately one in ten adults worldwide. It has a substantial impact on quality of life and is associated with economic burdens, including direct costs and lost productivity¹.

Emerging evidence suggests that intestinal transit time is a key factor in shaping gut microbiota composition and metabolic activity, which is likely to impact constipation and long-term gut health. While people often first try dietary changes to control constipation symptoms, existing guidelines for constipation management generally include limited dietary advice, with a main focus on increasing fiber intake and ensuring adequate fluid intake.¹.

The new guidelines from the British Dietetic Association (BDA) provide the first comprehensive, evidence-based recommendations for the use of supplements, foods and drinks, and whole diets for chronic constipation^2.3.

The guidelines were developed through four systematic reviews and meta-analyses of 75 randomized controlled trials and assessed using the GRADE approach with a Delphi consensus process.

The guidelines include a total of 59 recommendations evidence supporting the use of kiwifruit, plums, rye bread and water with high mineral content. Six randomized controlled trials (RCTs) have shown that 2-3 kiwifruit per day can increase bowel frequency and reduce overall bowel symptoms. Kiwis in particular were associated with fewer side effects than prunes or psyllium supplements. In addition, two RCTs showed that six to eight slices of rye bread per day can increase bowel frequency and shorten intestinal transit time, but may worsen intestinal complaints compared to white bread. High mineral water was another intervention that, compared to tap water or low mineral water, improved treatment response in 4 RCTs.

It is likely that a synergy of multiple components in foods is responsible for their effects on specific constipation outcomes. In human studies, plums and kiwifruit have been shown to alter the gut microbiota, with plums increasing fecal weight and kiwifruit increasing small intestinal and fecal water content.⁴. The extent to which water with a high mineral content improves constipation by shaping the intestinal microbiome is unknown.

In addition to foods and drinks, several supplements can help relieve constipation. Psyllium supplements, kiwi supplements, magnesium oxide supplements, and certain probiotic strains may improve specific constipation outcomes. Multiple RCTs (n = 16) have consistently shown that psyllium (ispaghula fiber) could improve stool production and strain, with optimal effects at doses higher than 10 g/day and longer treatment duration (³4 weeks). Based on 30 RCTs examining probiotics, their effects were species, strain and outcome specific. Remarkably, Bifidobacterium lactis, Bacillus coagulans lilac-01, Lactobacillus reuteri DSM-17938, en Escherichia coli Nissle 1917 could improve bowel frequency. Kiwi supplements can improve incomplete evacuation and abdominal pain. Magnesium oxide supplements (0.5-1.5 g/day) have been shown to consistently improve constipation outcomes, including response to treatment, stool frequency, stool consistency, and overall symptoms of constipation; Please note that the dose should be increased gradually to a controlled tolerance level.

Mechanisms by which probiotics may exert an effect on intestinal motility and constipation include influencing intestinal regulatory T cells, shaping the gut microbiota and fermentation byproducts, which in turn appear to influence intestinal motility via the enteric nervous system, rather than the brain-gut axis.⁵.

However, there was insufficient evidence to support a complete dietary approach to constipation, including the traditional advice of eating a high-fiber diet. Furthermore, there was little evidence for other interventions, including specific probiotics (e.g. Lactobacillus casei Shirota), prebiotics (inulin-type fructans softened stool consistency but did not result in a clinically meaningful effect), synbiotics and senna supplements. Furthermore, no suitable RCTs have been found for oats and flaxseed, making it not possible to make any recommendation about their benefits for constipation.

A physician-friendly tool has also been developed to support the implementation of these guidelines in daily practice:

The BDA Guidelines for Chronic Constipation emphasize the importance of high-quality evidence in guiding nutritional interventions for the management of disorders of the gut-brain interaction. They also remind us that clinical trials in nutrition face more challenges than trials of pharmacological interventions, especially given the methodological issues, complex composition of foods, monitoring of adherence, and the impact of background diet and diet-microbiome interactions on the outcomes studied.⁶.

Although current evidence does not support some nutritional interventions that target the gut microbiome in healthy adults with chronic idiopathic constipation, they may be worth trying in specific clinical contexts. For example, in patients with Parkinson’s disease, a fermented milk containing probiotics and prebiotics was found to improve constipation without major side effects. Now that evidence is emerging that the benefits of nutritional interventions are catching up on constipation outcomes, healthcare professionals have effective options to offer their adult patients with chronic constipation rather than the vague advice to eat more fiber, drink more water, and increase exercise.

References:

1. The Lancet Gastroenterology Hepatology. Bridging the evidence gap in the nutritional approach to intestinal disorders. Lancet Gastroenterol Hepatol. 2025; 10(12):1053. two: 10.1016/S2468-1253(25)00326-7.
2. Rejects E, goes to school, Barrett K and all. British Dietetic Association Guidelines for the Dietary Management of Chronic Constipation in Adults. J Hum Nutr Diet. 2025; 38(5):e70133. doi:10.1111/jhn.70133.
3. Rejects E, goes to school, Barrett K and all. British Dietetic Association Guidelines for the Dietary Management of Chronic Constipation in Adults. Neurogastroenterol Motil. 2025; 37(12):e70173. doi: 10.1111/nmo.70173.
4. Katsirma Z, Ontslag E, Mats A and al. Fruits and their impact on the intestinal microbiota, intestinal motility and constipation. Food Function. 2021; 12(19):8850-8866. two: 10.1039/d1fo01125a.
5. Dimidi E, Scott SM, Whelan K. Probiotics and constipation: mechanisms of action, evidence for effectiveness and use by patients and healthcare professionals. According to Nutr Soc. 2020; 79(1):147-157. doi: 10.1017/S0029665119000934.
6. HM Student HM, Yoo CK, WD, et al. Optimal design of clinical trials of nutritional interventions in disorders of the gut-brain interaction. Ben J Gastroenterol. 2022; 117(6):973-984. two: 10.14309/ajg.0000000000001732.