Q: I keep hearing about so many different supplements on social media. Which one do you most often recommend to your patients?

A: In most cases, the supposed benefits of supplements popularized on social media aren’t backed by strong data.

But there is one supplement that robust studies have consistently shown may lower our cholesterol, dampen glucose spikes, help us stay full longer, and even aid in treating constipation and diarrhea — all while serving our microbiome a sweet, sweet feast: psyllium husk.

Psyllium husk — or psyllium, for short — comes from the mainly soluble fiber outer shell of the Plantago ovata plant. It’s the primary ingredient in many over-the-counter fiber supplements, but what sets psyllium apart from other fibers are two unique properties:

• It’s rich in arabinoxylan, a molecule that forms a gel when it contacts water, allowing psyllium to promote special reactions, including the conversion of cholesterol into bile acids, as it makes its way through the digestive tract.

• When psyllium reaches the colon, it becomes a prebiotic for your microbiome, spurring the production of beneficial metabolites like short-chain fatty acids.

These properties result in numerous health benefits that are backed by decades of research. Compared with other supplemental fibers, psyllium also rises above the rest in its ability to reduce the risk of cardiovascular, metabolic and gastrointestinal disease.

The vast majority of us are not meeting the daily dietary fiber recommendations. My first advice would be to fill your plate with a diversity of fiber-rich plants, such as through the Mediterranean diet, for the greatest overall health benefits.

But if that’s unrealistic, I suggest psyllium. You can buy a simple drugstore version fairly cheaply, crushed as a powder or in capsules. You may need to take several capsules at once to reach the recommended dose, and many people might find that inconvenient.

The powders often come in flavors such as berry or orange, meant to be mixed into a glass of water, but if you want my advice: Get the tasteless kind (ensure there are no additives or sweeteners) that you could stir into the cup of coffee that you’re drinking each morning anyway. That java may taste a bit grittier — or even take on a jellylike consistency if you let it linger too long — but considering that’s where your personal sacrifice ends, it’s a (nearly) effortless intervention with potentially outsize payoffs.

Psyllium’s benefits go beyond the gut

Wonderful as psyllium is for gut health, its benefits go well beyond that (and even within gut health, psyllium is far more than a simple laxative). Here are a few of the ways studies have repeatedly shown psyllium can impact your health:

Cardiovascular health: Psyllium can reduce cholesterol levels by impacting multiple pathways, one of which possibly involves alterations in the microbiome. Another mechanism involves trapping bile acids in psyllium’s gel, forcing the liver to use up cholesterol to produce more bile acids and thereby effectively lower the amount of cholesterol remaining in your blood. A 2018 meta-analysis of 28 randomized controlled trials including about 1,900 participants found that supplementation with 10.2 grams of psyllium daily over a minimum of three weeks led to significant reductions in LDL cholesterol, non-HDL cholesterol, and apoB — a marker that can help determine your heart disease risk. The average reduction in LDL cholesterol with psyllium was about 13 mg/dL.

Hunger and glucose tolerance: Another benefit of psyllium is that it helps prolong the amount of time it takes to absorb glucose from the rest of your meal. This is because when psyllium transforms into a gel, it delays nutrient absorption by the small bowel, which helps tame glucose spikes while allowing you to feel full longer. A randomized double-blinded controlled trial found that taking 7.4 grams of psyllium in the morning led to feeling significantly less hunger during the day, decreased caloric consumption at subsequent meals and lowered blood glucose levels. Other studies have found that a dose of at least 10 grams per day can improve levels of hemoglobin A1C — which measures your average blood sugar over the past three months — by about 1.37 mmol/L.

Bowel health: Psyllium is a perfect place to start if you have diarrhea or if you have constipation. The gel attracts water and swells to produce more bulk when you’re constipated, helping your gut contract and pass a hard stool. But that same gel will also soak up water if you’re having a bit of diarrhea. Because of these neutralizing properties, psyllium is among the first-line recommendations in the treatment of irritable bowel syndrome and fecal incontinence. Even more than that, psyllium protects against gut inflammation and has been shown to boost beneficial bacteria in the microbiome that produce butyrate, a short-chain fatty acid that supports gut and immune health.

How much psyllium should I take? Are there any risks?

A typical serving is 10 to 15 grams — around two teaspoons of powder — but several studies have found benefits at doses of 20 to 30 grams daily. Start with a lower dose, such as a half-teaspoon, and see how you do, slowly working your way up to a standard serving over one or two weeks. It’s important to remember that psyllium needs to be taken with an adequate amount of liquid to form a gel — so consume each serving in at least an eight-ounce cup.

Psyllium is widely considered safe, but it’s always a good idea to ask your doctor before starting a new supplement. The main downsides are gastrointestinal: Some people will experience bloating, gas or loose stools with higher amounts. But these symptoms typically ease as your body adapts to the increased fiber. There have been extremely rare cases of psyllium allergy reported.

What I want my patients to know

It’s very possible that if you start taking psyllium daily, you’ll see a change in your bowel habits. They may become looser. You may start pooping two or three times per day instead of once every day. This change is healthy. Pooping a couple times a day is par for the course when you’re meeting your fiber goals and feeding your microbiome — and it’s considered normal in much of the world where high-fiber diets are standard. Unless it’s completely disruptive to your day, don’t let a change in your pooping pattern hold you back. Embrace this new you.