What is Psyllium?
Psyllium is a robust herb that grows around the world but is most commonly found in India, which remains the largest producer of psyllium husk today. It is also referred to as Isabghol (Ispaghol in Pakistan), derived from the Sanskrit words “asp” and “ghol,” together meaning “horse flower.” The whole seed has been used in traditional Iranian medicine for hundreds of years.
The inner seed contains many starches and fatty acids, making it an excellent natural additive for animal feed. The outer coat (the husk) is ground down into mucilage, a term describing clear, colorless, gelatinous dietary fiber that confers the majority of health benefits in both humans and animals.
Not only does it have health benefits, but its gel-like character makes it a popular addition to foods to produce desired thickening and texture.
Health Benefits of Psyllium Husk
Psyllium Husk Treats Constipation
Adding psyllium husk to your diet is proven to reduce constipation by drawing in and absorbing water as it passes through the gut. This causes the stool to soften and expand, making it simultaneously easier to move while stimulating normal gut flow.
In multiple small human studies (following up to 15 patients in one study), psyllium husk significantly decreased stool transit time and increased both bulk weight and relative stool softness.
This was achieved without disrupting nutrient absorption.
Furthermore, in a multi-site DB-RCT involving 170 patients, psyllium was more superior in softening stool and treating chronic constipation than docusate sodium (a stool softener commonly used in healthcare settings).
A study in rats found that psyllium was more effective than cellulose (insoluble fiber found in most plants) in creating stool moisture, likely due to its soluble fiber content that resists fermentation.
Psyllium Husk May Relieve Diarrhea
Psyllium husk may also relieve diarrhea, which may seem strange considering its long-proven role in reducing constipation.
In 2 human studies (with as many as 39 subjects), psyllium husk increased stool transit time and improved the consistency of the stool in patients with diarrhea. In the same studies, patients with constipation had decreased transit time.
While the mechanism for controlling diarrhea is less understood, this study in living mice (in addition to rabbit/pig guts) may shed some light:
- Psyllium husk treated constipation in mice. But, it also stimulated muscarinic and 5-HT4 receptors of the gut, which would complement the physical stimulation it produces.
- When psyllium husk was given to mice with diarrhea, transit time was slowed and stool consistency improved. Receptor pathways were changed in these mice as well, specifically blocking calcium ion channels and activation of the NO-cGMP pathways, which would combine to inhibit gut flow.
With that information in mind, it may help to think of psyllium husk as a “regulatory” fiber rather than strictly anti-diarrheal or anti-constipation. This makes it an excellent option for patients with irritable bowel syndrome, who often have diarrhea and constipation.
A randomized controlled pilot study evaluated psyllium husk in 60 cancer patients with radiation-induced diarrhea, showing a decrease in both the incidence of diarrhea and the severity of symptoms].
Sometimes diarrhea is an unavoidable side-effect of another medication. Patients with liver failure may have a liver-caused brain injury, where ammonia builds up in the blood and causes altered mental status. This is treated with lactulose, which can cause significant amounts of diarrhea.
A randomized crossover study of 8 patients showed that psyllium husk delayed stomach emptying and reduced the speed of gut transit, possibly due to the poor fermentation of psyllium husk compared to other fibers.
Psyllium Husk May Lower Blood Sugar Levels
Multiple types of fiber have the ability to curb your blood sugar.
In multiple double- and single-blind RCTs (with as many as 125 subjects), psyllium husk significantly reduced both fasting and after-meal blood sugar levels, reduced insulinsspikes, and decreased the absorption of glucose, with a reduction in HbA1c.
Similar results were seen in a meta-analysis of 7 studies of 378 patients, including 3 that were randomized and blinded.
In a small DB-RCT of 49 patients, psyllium husk not only improved fasting blood sugar and HbA1c levels but enhanced patient tolerance to metformin (a very common oral medication for treating type 2 diabetes).
It is important to note that these results were achieved when psyllium husk was consumed with meals.
Psyllium Husk May Aid in Weight Loss
Psyllium husk may be able to help with weight loss by increasing fullness.
In a 200-subject DB-RCT, consuming psyllium husk with meals increased fullness and reduced subjective appetite sensation, resulting in weight loss (approximately 10 lbs.).
The mechanism behind this may be explained by a small RCT of 12 patients that found that psyllium delayed stomach emptying, which likely contributes to the increased fullness and reduced appetite.
Another triple-blind study of 17 females revealed the same changes in fullness and appetite and found that subjects inherently reduced their daily fat intake.
Not only is psyllium husk associated with weight loss, but another double-blind RCT study of 72 patients showed that it reduced BMI and total body fat percentage. The study does note that while this was achieved with psyllium husk alone, combining it with a healthy diet produced superior results .