Magnesium Oxide Supplements Help Treat Patients With Chronic Constipation

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Kiwifruit supplementation did not have an impact on stool frequency or consistency, but magnesium oxide supplementation did result in improved stool frequency.

New research shows some over-the-counter supplements, such as magnesium oxide, can help improved symptoms for patients with chronic constipation.1

A team, led by Alice van der Schoot, Department of Nutritional Sciences, King's College London, investigators the effect of food, vitamin, or mineral supplements on stool output, gut transit time, symptoms, and quality of life in adults with chronic constipation.

Over-the-Counter Supplements

Currently, over-the-counter supplements are used to manage chronic constipation. However, the efficacy of these supplements is not currently known.

And there remains a need to research new treatment options.

In the randomized controlled trial, the investigators identified various studies reporting on the administration of food supplements, such as fruit extract supplements, as well as vitamin or mineral supplements in adults with chronic constipation.

The Studies

Eligible studies included this with criteria developed using a patient, intervention, comparators, outcome, and study design approach in comparing food supplements, vitamin, or mineral supplements to placebo in adults with chronic constipation.

The supplements could be administered in tablet, powder, capsule, or solution form.

The team excluded studies focusing on whole foods. They also used a random-effects model to calculate several relevant data points.

The investigators measured stool frequency as bowel movements per week and measured stool consistency using the Bristol Stool Form Scale (BSFS).

Overall, they identified 8 randomized controlled trials involving 787 patients. These trials investigated kiwifruit (n = 3 RCTs), senna (n = 2), magnesium oxide (n = 2), Ziziphus jujuba (n = 1), and Malva Sylvestris (n = 1) supplements.

The Data

The results show kiwifruit supplementation did not have an impact on stool frequency (mean differences [MD], 0.24 bowel movements/week; 95% confidence interval [CI], −0.32 to 0.80; P = 0.40) or consistency (MD, −0.11 Bristol points; 95% CI, −0.31 to 0.09; P = 0.29).

However, the results were better for senna.

While it did not reach statistical significance (relative risk [RR], 2.78; 95% CI, 0.93-8.27; P = 0.07), 61% responded to senna and 28% responded to control.

For the analysis of the other supplements, the investigators found 68% responded to magnesium oxide and 19% responded to control (RR, 3.32; 95% CI, 1.59-6.92; P = 0.001) and magnesium oxide improved both stool frequency (MD, 3.72 bowel movements/week; 95% CI, 1.41-6.03; P = 0.002) and consistency (MD, 1.14 Bristol points; 95% CI, 0.48-1.79]; P = 0.0007).

“Magnesium oxide supplements are effective at improving cardinal symptoms of chronic constipation. Senna and kiwifruit supplements did not impact symptoms; however, findings were based on a small number of studies,” the authors wrote.

The team also said there is a need for more research into the effect of food supplements like kiwifruit supplementation, as well as whole food equivalents in treating patients with chronic constipation.


van der Schoot, A., Creedon, A., Whelan, K., & Dimidi, E. (2023). The effect of food, vitamin, or mineral supplements on chronic constipation in adults: A systematic review and meta‐analysis of Randomized Controlled Trials. Neurogastroenterology & Motility.