The effect of food, vitamin, or mineral supplements on chronic constipation in adults: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND

Over-the-counter supplements are commonly used to manage chronic constipation; however, their efficacy remains unclear. We aimed to investigate the effect of food, vitamin or mineral supplements on stool output, gut transit time, symptoms, and quality of life in adults with chronic constipation via a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

Studies were identified using electronic databases, backward citation, and hand-searching abstracts. RCTs reporting administration of food supplements (e.g., fruit extract supplements), vitamin or mineral supplements in adults with chronic constipation were included. Studies administering whole foods (e.g., fruits) were excluded. Risk of bias (RoB) was assessed with Cochrane RoB 2.0. Relative risks (RR), mean differences (MD), or standardized mean differences (95% confidence intervals [CI]) were calculated using a random-effects model.

KEY RESULTS

Eight RCTs (787 participants) were included, investigating kiwifruit (n = 3 RCTs), senna (n = 2), magnesium oxide (n = 2), Ziziphus jujuba (n = 1), and Malva Sylvestris (n = 1) supplements. Kiwifruit supplements did not impact stool frequency (MD 0.24 bowel movements/week [-0.32, 0.80]; p = 0.40) or consistency (MD -0.11 Bristol points [-0.31, 0.09], p = 0.29). Overall, 61% responded to senna and 28% to control; however, this did not reach statistical significance (RR 2.78, [0.93, 8.27]; p = 0.07). Overall, 68% responded to magnesium oxide and 19% to control (RR 3.32 [1.59, 6.92]; p = 0.001). Magnesium oxide improved stool frequency (MD 3.72 bowel movements/week [1.41, 6.03]; p = 0.002) and consistency (MD 1.14 Bristol points [0.48, 1.79]; p = 0.0007).

CONCLUSIONS AND INFERENCES

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. Further research is required to investigate the effect of food supplements (e.g., kiwifruit supplements), as well as their whole food equivalents (e.g., whole kiwifruits) in chronic constipation.

© 2023 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.