Is Daily Use of Psyllium Husk as a Laxative Harmful?

Psyllium husk — or psyllium powder, which is simply the ground-up husks — comes from the seeds of the herb Plantago ovata, and is usually sold as a fiber supplement, but it also acts as a bulk-forming laxative. If you're going to take a laxative, psyllium is one of the simplest and shows promise for providing a few other health benefits too. But if you find yourself taking psyllium daily over the long term, you should probably have a chat with your doctor.

Psyllium husk comes in several forms, including powder, capsules and chewable wafers; you'll find it in the pharmacy or over-the-counter medicine sections of most supermarkets and almost every health food or supplement store. With that said, it isn't always labeled as psyllium. For example, the popular fiber/laxative supplement Metamucil is actually psyllium husk. You may also see psyllium sold under such brand names as Cilium, Alramucil, Genfiber, Maalox Daily Fiber Therapy and Hydrocil.

Read more: The 10 Best Supplements

When you take psyllium, you must drink at least 8 ounces of liquid along with the supplement. All that liquid does two things: First, it allows the psyllium husk to absorb water and "plump" in your intestines, forming a bulky stool that's easy to pass. That's what differentiates a bulk-forming laxative like psyllium from a stimulant laxative such as cascara sagrada, which triggers muscular contractions to move stool through your intestines.

Second, the liquid helps prevent the psyllium husk from forming a blockage in your intestines or simply increasing constipation instead of helping it — two of the biggest potential side effects of a bulk-forming laxative such as psyllium.

Although fiber supplements like psyllium are some of the gentlest laxatives you can take, Medline Plus still recommends that you don't take psyllium for more than a week unless your doctor tells you to.

Why the limited duration? There are two reasons. First, if you need to take a laxative for extended periods of time, it may signal a less-obvious problem that would benefit from a doctor's attention. Second, as gentle as psyllium husk fiber is, all laxatives bring with them some risk of side effects, such as interacting with medications or complicating medical conditions such as appendicitis or bowel obstructions.

Your doctor can help you anticipate or deal with such side effects — but only if you talk to him about what you're taking.

Read more: The 12 Most Overrated Supplements

Aside from the risk of intestinal blockage, psyllium husk can also interact with some medications. Medline Plus warns that you shouldn't take digoxin, salicylates or nitrofurantoin within three hours of taking psyllium, while the Linus Pauling Institute also warns that psyllium can reduce absorption of several medications, including lithium, warfarin and carbamazepine, if you take the medications and psyllium at the same time.

Both of these warnings are excellent examples of why you should always check in with your doctor before adding any new supplements to your regimen, even something as innocuous as psyllium.

Fiber supplements, such as psyllium husk, can also affect blood sugar levels, so make sure you speak with your doctor if you have diabetes. Although psyllium has been shown to have some benefit in lowering cholesterol, if you have a history of heart disease, high blood pressure or kidney disease, you should speak to your doctor before taking psyllium.

Before you start taking a fiber powder like psyllium every day, take a moment and consider what's prompting you to do so. If you routinely struggle with constipation, the Mayo Clinic notes that sometimes simple lifestyle changes, such as adjusting your diet to include fiber-rich foods, drinking plenty of water and exercising regularly, may be all it takes to eliminate constipation.

Constipation isn't the only reason you might be looking into taking a supplement like psyllium daily. There's a growing body of evidence to show that taking psyllium husk regularly can improve your cholesterol profile too.

In a 2018 meta-analysis published in the American Journal of Clinical Nutrition, researchers performed a systematic review of 28 clinical trials and found that taking psyllium fiber significantly reduced LDL cholesterol levels.

In light of such results, it may be tempting to take psyllium husk long term for its cholesterol benefits. But remember that if you have a cholesterol condition that requires this sort of treatment, you should consult your physician. That goes doubly if you're on any medication, which, as innocuous as it is, psyllium can still interact with.

In a 2019 trial published in the journal Clinical Nutrition ESPEN, researchers found that psyllium not only decreased constipation symptoms, it also helped with weight loss and improved the patients' cholesterol levels. However, the same study also found that flaxseed appeared to be even more effective in every measure.

Increased fiber intake — whether through diet or through viscous fiber supplements like psyllium — is also widely recognized to improve blood sugar control in individuals with Type 1 or Type 2 diabetes. Along somewhat similar lines, a 2016 study published in the journal Appetite noted that psyllium fiber was effective at reducing feelings of hunger and the desire to eat between meals, which in turn may help with weight control.

Also interesting is the revelation, published in a 2019 issue of the International Journal of Molecular Sciences, that using psyllium husk creates significant changes in intestinal microbes, more so if you're constipated when you take the psyllium — although it's not entirely clear what the ultimate effects of those changes may be.

And finally, a 2017 randomized, double-blind trial published in the journal Clinical Gastroenterology and Hepatology showed that taking psyllium fiber produced a notable decrease in pain for children with irritable bowel syndrome.