How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Wheat bran
Wheat bran makes stools heavier and accelerates slow transit: this is its best-established effect. Against irritable bowel syndrome, constipation in hospital or colon polyps, trials are disappointing.
Benefits
- Heavier stools and faster transit: a meta-analysis finds this effect in healthy people as well as in those suffering from irritable bowel syndrome or constipation.
- Chronic constipation: in 24 patients, 20 g of wheat bran per day performed better than a placebo on stool frequency and transit time; transit only returned to normal in those whose colon was slow.
- Regulated transit in both directions: about 20 g per day accelerated slow transits and slowed down fast transits, in 18 students and 10 adults; oat flakes had no effect.
- No need to drink more: in 11 volunteers, 30 g per day increased stool weight and frequency just as much with or without 600 mL of extra fluid.
- Fewer laxatives after surgery: in 16 hospitalized orthopedic surgery patients, those who ate more wheat bran had bowel movements more often and requested fewer laxatives.
- Lower total cholesterol and triglycerides: in healthy young men, 0.5 g per kilo per day for 4 weeks reduced total cholesterol by 10% and triglycerides by 24%.
- Gestational diabetes: added to a low glycemic load diet, wheat bran reduced the proportion of women requiring insulin (38.9% against 76.9% without fiber), in 31 women.
- Fewer bile acids in stools: in patients operated on for colon adenomas, 13.5 g per day of wheat bran fiber for 9 months reduced them, compared to 2 g.
Precautions
HDL: in healthy young men, HDL-cholesterol (the "good" one) dropped even more than total cholesterol. Tolerance: in 188 patients with irritable bowel syndrome, wheat bran was less well tolerated than partially hydrolyzed guar gum; in another trial, oat fiber tablets produced fewer side effects. Limitations: irritable bowel syndrome: in 59 patients, 30 g per day did not do better than the control group (52% improvement against 65%); compared to partially hydrolyzed guar gum, 40% success against 60%. Constipation: the meta-analysis considers it only partially effective in restoring normal transit in constipated individuals. Colon polyps: in a randomized trial on wheat bran fiber, the supplement did not reduce their recurrence. Neither stress, mood, nor other measured health markers changed in two recent trials (55 g per day of extruded bran, 20 g of finely ground bran). Trials are often old and small (5 to 69 participants for the most part).
Recommended dosage
In trials: 20 to 30 g of wheat bran per day, up to 40 g.
How to take it
- Dose: 20 g per day in trials on constipation and transit, 30 g in others.
- Coarse rather than fine: a review reports that coarse bran increases stool water, whereas finely milled bran hardens them.
- Fluid: drinking 600 mL more changed nothing regarding its effect in healthy volunteers.
- Duration: 4 weeks in the cholesterol trial, up to 9 months in the one on bile acids.
- Compared to psyllium: to increase stool volume in case of chronic constipation, a review finds psyllium 3.4 times more effective.
- What does not work: 40 g per day did not prevent constipation in 200 hospitalized patients.
Did you know?
Wheat bran regulates transit in both directions: in 18 students and 10 adults, about 20 g per day accelerated slow transits, but slowed down those that were fast to begin with.
What the studies say
This randomized, triple-blind, placebo-controlled trial evaluated the effects of 55 g of extruded wheat bran per day on the psychobiological functions of 69 healthy men. The consumption of extruded wheat bran increased serum acetate and butyrate. However, the intervention did not modulate psychobiological functions, such as stress response or mood, nor secondary gut health measures.
Dalile B, La Torre D, Kalc P, Zoppas F, Roye C, Loret C, Lamothe L, Bergonzelli G, Courtin CM, Vervliet B, Oudenhove LV, Verbeke K. — Frontiers in nutrition (2022) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more