Protein is a vital nutrient, and it plays an important role in muscle growth and tissue repair when you exercise. Over the years, protein shakes have become popular for post-workout refueling and weight loss.
Protein shakes and powders include a wide range of products, including some that are terrible for your gut and others that are fine, says Elena Ivanina, DO, an integrative gastroenterologist in New York City. But most protein shakes and powders should be avoided by people with irritable bowel syndrome (IBS), Dr. Ivanina says.
IBS is a condition involving a group of symptoms, including abdominal pain and changes in bowel movements, such as diarrhea or constipation. Protein powders and shakes with whey, a protein derived from milk, can trigger IBS symptoms. Some may also contain artificial sweeteners and added sugar, which may also cause symptoms.
Why Protein Shakes With Whey Can Trigger IBS
Whey protein powder is a powdered collection of proteins derived from whey, which is the liquid that remains after cheese is made from cow’s milk. It should not be consumed by people with IBS, according to Ivanina.
Various foods affect people with IBS differently, but milk and other dairy products often cause gas and bloating. “Looking at one whey protein complex powder, the ingredients include multiple milk-based items and lecithin, which is an emulsifier,” she says. These ingredients can trigger IBS symptoms and gut inflammation.
Certain sweeteners that may be added to protein shakes, such as sugar alcohols like sorbitol, have also been found to cause gastrointestinal distress in people with IBS.
If you find that protein shakes, especially those with whey protein, trigger your IBS symptoms, get your daily dose of protein from whole-food sources instead. Fish, poultry, eggs, nuts, and seeds can be good options for those eating an IBS diet.
Protein Shakes: What’s in Them and What’s Not
“Protein powders,” Ivanina says, “may include added sugars, unnecessary calories, artificial colors and flavoring, emulsifiers and thickeners, and excessive vitamins and minerals that may impact gut health and symptoms.”
Protein shakes also don’t have the same amount of dietary fiber, antioxidants, and other important substances as you’ll find in protein-rich whole foods. Most people get enough protein (often too much) from the foods they eat, so protein supplements like shakes are often unnecessary in the first place.Ivanina also points out that a nonprofit group called the Clean Label Project studies toxins in protein powders. Its latest report found that many protein powders contain heavy metals like lead, arsenic, cadmium, and mercury.
“While there may be some wholesome and natural protein shake options,” Ivanina says, “the general caution is beware of powders and blends that contain many ingredients and instead stick to wholesome natural foods if you have irritable bowel syndrome.”
What About Meal Replacement Shakes?
Meal replacement shakes have been promoted for people with IBS because they’re easy to digest, but Ivanina says they should also be avoided.
“At this time there is no convincing data supporting [the idea] that meal replacement shakes are good for people with IBS,” she says. “The best management of IBS includes an integrative approach with a gastroenterologist, nutritionist, and therapist to cover the food triggers as well as the gut-brain axis that is so vital to address in IBS.”
