3. Magnesium
It’s not uncommon to be deficient in magnesium when you have Crohn’s.
But like vitamin C, magnesium can upset your GI tract and may add to all-too-familiar symptoms like diarrhea and nausea.
The effect is more common with certain types of magnesium, like magnesium citrate and oxide. Magnesium glycinate, on the other hand, may be less likely to cause GI symptoms.
But if you’re thinking of supplementing with any form of magnesium, you should talk it over with your gastroenterologist first. “The right dose depends on blood tests, diet, disease location, prior bowel surgery, symptoms, and current treatment,” Dr. Stanton says.
4. Oral Iron Supplements
Iron is another mineral that can be hard for many people with Crohn’s to get enough of.
If you’ve had blood tests that show you’re deficient, hold off on buying iron pills. Your gastroenterologist may recommend iron infusions instead.
First and foremost, pills aren’t as effective as infusions at bringing your iron level back up.
“Especially when inflammation is active with Crohn’s disease, oral iron absorption can be compromised and replenishes deficient iron stores less effectively than intravenous iron,” says Limketkai.
Oral iron can also cause uncomfortable side effects like nausea, diarrhea, constipation, and abdominal pain.
“Moreover, oral iron darkens stool, which can mask the presence of GI bleeding, which can also appear as dark or black stool,” Limketkai says.
5. Fiber Supplements
It’s great to get fiber in your diet whenever you’re able to tolerate it, since it can support gut health and actually help keep your Crohn’s symptoms under control.
But the preferred way to get your fill is from whole foods like fruits and vegetables, whole grains, and beans or other legumes, such as lentils.
“Taking a supplement might make you bloated or cause gas or cramping,” says Supriya Rao, MD, a gastroenterologist with Tufts Medicine in Lowell, Massachusetts.
And depending on your Crohn’s severity, symptoms, and any complications you have (such as strictures), you may need to reach for certain types of fiber or to modify the texture of fiber-rich foods.
Supplementing might make sense if you need help getting the recommended 25 to 34 grams of fiber per day.
In that case, talk with your gastroenterologist to figure out the right product for you. Dr. Rao usually suggests psyllium husk to her patients, since it’s well studied and less likely to cause GI symptoms than other fiber supplements.
6. Probiotics
There are lots of good reasons to enjoy probiotic-rich foods like yogurt, tempeh, miso, and sauerkraut.
But there’s no solid evidence that probiotic supplements can help control your Crohn’s, and they could cause side effects like abdominal pain, gas, and bloating.
“For Crohn’s disease, probiotic supplements have not been shown to reliably induce or maintain remission, or to prevent relapse,” Stanton says.
In rare instances, taking a probiotic could lead to serious infection.
The chances are higher if you’re flaring or if you’re taking a Crohn’s medication that suppresses your immune system, says Stanton.
7. Immune-Boosting Herbs
Avoid taking herbs that may claim to give your immune system extra oomph — like echinacea, astragalus, Asian ginseng, ashwagandha, and mushroom blends, to name a few — without talking to your gastroenterologist.
While there’s not much research on how immune-stimulating herbs impact people with Crohn’s, it’s possible that they could work against your prescribed treatment. “An underlying issue with the Crohn’s disease process is an overactive or hyperactive immune system, for which medical treatments are designed to calm the immune system. Taking an immune-stimulating compound does the exact opposite of what one hopes to achieve,” says Limketkai.
8. Supplements With Sugar Alcohols
Sugar alcohols like xylitol, erythritol, sorbitol, and mannitol aren’t believed to be harmful in moderation. But the sweeteners, which are often found in gummies, powders, and chewable pills, are known for triggering gas, bloating, and diarrhea. And people with Crohn’s are even more prone to experiencing discomfort after ingesting them.
Fortunately, sugar alcohols are easy to spot on a product’s ingredient list, so always check before buying something new.