Chemo Belly: What It Is and How To Find Relief
Chemotherapy can take a toll on your digestive system, often causing a range of gastrointestinal (GI) issues that some people call chemo belly. Studies show that about 40% of people who have standard-dose chemo will develop chemo belly, as will 60% to 100% of those who receive high-dose chemo. And for some, chemo belly doesn’t stop when treatment does. It can last for years after.
Symptoms of chemo belly
Chemo belly isn’t a medical term. It’s a term people use to refer to GI side effects of chemotherapy.
The symptoms of chemo belly include:
bloating and gas
acid reflux
weight changes
What causes chemo belly?
Chemotherapy works by targeting and killing fast-dividing cells. Cancer cells divide quickly, but so do cells that line the GI system (the esophagus, stomach, and intestines). Chemotherapy can also damage or kill these cells, which can cause digestive issues.
In addition, chemotherapy can trigger inflammation and a type of cell damage called oxidative stress that harms the GI tract. Although these cells repair and regrow quickly, chemo can damage the systems that typically repair GI damage, allowing the symptoms to stick around after you finish treatment.
Chemotherapy can also disrupt the gut microbiome, or the bacteria, viruses, and other microbes that live in the GI tract and help regulate digestion. “It can really damage the amount of healthy bacteria we have in our gut, which can lead to bowel changes and upset stomach,” says Amy Bragagnini, RD, a clinical oncology dietitian at Trinity Health Lacks Cancer Center in Michigan and a spokesperson for the Academy of Nutrition and Dietetics.
Research suggests that chemo may also cause long-term GI symptoms by damaging nerves and muscles that help control the digestive system.
Some people are more likely to develop chemo belly, like those who had digestive issues like irritable bowel syndrome (IBS) before starting cancer treatment, Bragagnini says.
Breast cancer treatments and chemo belly
Although the phrase chemo belly is used to describe the GI side effects of chemotherapy, other breast cancer treatments can cause similar symptoms.
Hormonal therapies can lead to GI discomfort, Bragagnini says, because hormone fluctuations can slow down the digestive process.
Immunotherapy can also cause GI upset because “the revved up immune cells might affect healthy tissues in our gut, which could create inflammation,” Braganini says.
Rarely, radiation for breast cancer can cause short-term nausea and vomiting. Radiation kills most cells that it reaches, and when aimed at the breast can sometimes reach the GI tract, especially if it’s a high dose.
Chemo belly and weight changes
Many people gain weight after a breast cancer diagnosis. Chemotherapy can bring on early menopause, which causes hormone changes that can lead to weight gain. Side effects like fatigue, as well as chemo belly symptoms like nausea, can make it harder to be active during treatment. And sometimes people with GI symptoms like nausea and indigestion may only find high-calorie processed foods appealing, which are more likely to promote weight gain, Bragagnini says.
But some people with breast cancer lose weight during chemotherapy. Chemo belly can cause weight loss by making people not want to eat food. “People will say things like ‘food just doesn't really appeal to me because I'm nervous that if I eat too much I'll end up having diarrhea or I might get constipated,’” Bragagnini says.
How to get rid of chemo belly
There’s no one-size-fits-all way to find relief from chemo belly, Bragagnini says. But there are some diet changes that may help:
Cut back on caffeine and alcohol.
Cut back on gas-producing vegetables and beans.
Avoid high-fat and spicy foods.
Avoid sugar substitutes.
Try cutting out dairy products.
Eat fewer acidic foods like citrus fruits.
Eat more prebiotic foods like garlic and onions.
Eat several small meals throughout the day.
Drink plenty of water.
Avoid carbonated beverages.
Don’t chew gum or drink from a straw.
Not all diet changes are right for all symptoms. For example, if you have constipation, eating more fiber may help. But adding more fiber could make issues like gas and diarrhea worse.
Your medical team may be able to prescribe medicine that helps, such as an anti-nausea medication, a stool softener, or a probiotic.
To help find a solution to chemo belly, Bragagnini recommends seeing an oncology dietician. Their job is to try to root out the main culprit behind someone's changing bowel habits, Bragagnini says. Many cancer centers have a dietician on staff, but they don’t always tell people getting treated. Bragagnini recommends asking to meet with the dietician — even before you have GI symptoms.
