other · for irregular digestion
Psyllium
Forms a gel that evens out stool consistency, whichever direction things have gone.
Say that in clinical terms
Soluble fiber forms gel to normalize stool consistency, provides prebiotic substrate for beneficial bacteria.
How strong is the research?
Solid evidence
5 papers read, 3 supporting.
Who was studied: Adults meeting diagnostic criteria for chronic constipation.
How much to take
daily
5–10 g
Take with at least 8oz water. Separate from medications by 2 hours.
Before you take it
- No Tolerable Upper Intake Level (UL) has been established for psyllium husk by the FDA, NIH IOM, or NIH ODS; studied supplemental doses in clinical trials typically range from 3.4 to 10 g/day
- Must be taken with at least 240 mL (8 oz) water — swallowing without adequate fluid can cause esophageal or intestinal obstruction
- Reduces absorption of multiple oral medications — oral drugs should be taken at least 2 hours before or 4–6 hours after psyllium; documented interactions include digoxin, warfarin, lithium, carbamazepine, and tricyclic antidepressants
- Antibiotic interaction is asymmetric — tetracyclines and quinolones should be taken at least 2 hours before or 4–6 hours after psyllium to avoid reduced antibacterial efficacy
- May potentiate the glucose-lowering effect of insulin and oral hypoglycemic agents; patients on diabetes medications should monitor blood glucose and consult their prescriber before starting psyllium
- Rare anaphylactic hypersensitivity reactions have been reported, most commonly in individuals with occupational psyllium powder exposure (healthcare workers, food manufacturing); individuals with latex sensitivity may be at elevated risk
- Contraindicated in individuals with esophageal narrowing, GI obstruction, difficulty swallowing, or fecal impaction
- Bloating, gas, and flatulence are common side effects, especially during the first 3–10 days of use as the gut microbiome adjusts; initiating at a lower dose and gradually titrating upward can improve tolerance
What we make of it
The strongest independent evidence of any bulk fibre, and guidelines back it.
The detail
Psyllium has better independent evidence than any other bulk-forming fibre for chronic constipation. The American College of Gastroenterology recommends it in its 2022 guideline, and Cochrane-affiliated reviews agree.