Probiotics are a hot topic in the field of nutrition, in part because there’s research that indicates the bacteria in your intestinal tract helps you in many ways, from dodging Type 2 diabetes to soothing volatile emotions. But do you know if the probiotic you’ve chosen has been rigorously tested? Or if it’s been found to do you more good than harm? (Yes, harm is possible; after all, they’re live microorganisms.)

To find out, you can start by checking out www.labdoor.com. It found 16 of 37 tested probiotics contained viable bacteria amounts that were less than half of what their labels claimed, and just 23 of 37 received an ingredient safety score of 90 or higher out of 100.

Don’t overlook a powerful way to promote a healthy intestinal biome: fermented food. So let’s get into the guts of the matter.

What are probiotics? They’re bacteria and yeasts that help digest food, regulate glucose levels, digest (ferment) fiber, produce vitamins (biotin, vitamin B12 and K, folic acid and thiamine), regulate salt levels, promote immune system strength, produce mood-­altering hormones and more.

Does that mean it’s full speed ahead with any old probiotic supplement? Nope. You want to choose a probiotic that delivers benefits. A recent study in Cell found that many (but not all) folks’ digestive tracts actually block some probiotics from successfully colonizing. If you stop taking those specific probiotic supplements — which we suspect may not deliver many living microbes to your gut after they pass through your stomach acid — and the surviving good bacteria don’t stick around. You also want to make sure they are safe for you. The National Center for Complementary and Integrative Health says that there are reports linking some probiotics to severe side effects, such as dangerous infections. This is especially important for folks with serious medical problems or weakened immune systems.

Does that mean you shouldn’t take probiotic supplements? No. But you need to make sure that your gut isn’t so inflamed or unhealthy that taking a probiotic is potentially risky. As one of the researchers who published a new study on gut inflammation in Proceedings of the National Academy of Sciences says: “When the gut barrier is healthy, probiotics are beneficial. When it is compromised, however, they can cause more harm than good.

Turns out if you have gastrointestinal problems, autoimmune diseases such as lupus or multiple sclerosis, chronic fatigue syndrome, fibromyalgia, arthritis, allergies, asthma, acne, obesity or even mental illness, you may have leaky gut (an intestinal lining that’s inflamed and allows bacteria and other material to pass into the bloodstream), and there’s a chance that some probiotics can permeate the gut/blood barrier and cause you problems.

So how can you nurture good gut bacteria and heal a leaky gut?

>> Talk with your doc about diagnosing the symptoms you have that make you think it would be smart to take a probiotic. Bloating, gas and diarrhea, for example, aren’t normal. Discuss getting a reliable analysis of your gut biome. A stool sample won’t tell you what’s actively colonized your intestines.

>> Tamp down gut inflammation by avoiding highly processed foods, added sugars and excess alcohol. Find out if you have food sensitivities, intolerances or allergies.

>> Eat “The Big Two.”

No. 1: Foods that contain prebiotics. They keep good bacteria healthy and increase nutrient absorption and bowel regularity. That’s dried beans/legumes, garlic, asparagus, onions, leeks, certain artichokes, green bananas and wheat.

No. 2: Foods that contain probiotics. Lactobacillus and bifidobacterium are the most common groups of probiotics. That’s miso, tempeh, kefir, kim chee, sauerkraut, many pickles and yogurt.

Consult your doc about taking a probiotic supplement to help ease your gut inflammation and to keep your gut healthy.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.