Feeling gassy, bloated or a little queasy after your whey shake? You're not alone, and it's usually not in your head. Most of the time the cause is one of three things: lactose, a milk allergy, or the sweeteners mixed into the powder. Here's how to tell them apart and what to try instead.
Is lactose intolerance the reason whey upsets my stomach?
Often, yes. Lactose is the main sugar in milk, and digesting it takes an enzyme called lactase. Approximately 65% of the human population has a reduced ability to digest lactose after infancy, and in the US about 36% of people have lactose malabsorption, according to the National Institute of Diabetes and Digestive and Kidney Diseases. Undigested lactose is fermented by gut bacteria, which can cause bloating, gas and diarrhea.
Whey concentrate keeps more lactose than whey isolate, so a concentrate is more likely to cause symptoms. Many people tolerate small amounts of lactose, so symptoms can depend on how much you have at once. For more, read our guide to lactose intolerance and gut health.
Could I be allergic to whey?
Possibly. Milk is one of the nine major food allergens in the US, and whey is one of the milk proteins that can trigger an allergic reaction. The FDA notes that food allergy reactions range from mild symptoms such as hives and lip swelling to severe, life-threatening anaphylaxis. A milk allergy is an immune reaction, which makes it different from lactose intolerance.
If you notice hives, swelling, wheezing or vomiting after whey, stop taking it and see a doctor or allergist for testing rather than troubleshooting on your own. Get emergency help for any trouble breathing.
Can sweeteners in protein powder cause stomach problems?
They can. Many flavored protein powders use high-intensity sweeteners such as sucralose, which the FDA has approved and which is about 600 times sweeter than sugar, or sugar alcohols such as sorbitol, erythritol and xylitol. Sugar alcohols are the more common cause of digestive upset: foods likely to supply 50 grams of sorbitol a day must carry the label statement "Excess consumption may have a laxative effect." If a powder bothers you, check the ingredient list for these before blaming the protein.
What's a gentler alternative to whey?
If dairy doesn't agree with you, a plant protein avoids both lactose and milk proteins. So Lean & So Clean is a chef-crafted organic protein with 23g of complete plant protein from pea and rice, two servings of organic greens, no added sugar and no artificial sweeteners, fillers or gums. To compare labels, see how to choose a clean plant-based protein powder, and for more on whey itself, what whey protein is.
You shouldn't have to put up with bloating to hit your protein goals. Notice how you feel, read the label and pick the protein that suits your body.
