Diarrhea is typically defined as having three or more bowel movements per day than what is normal for you. Because cancer treatment affects all rapidly dividing cells, it can also cause changes to the rapidly dividing cells of the digestive tract. This can lead to diarrhea and affect the amount of nutrients and fluid that your body absorbs from food. When insufficient quantities are absorbed, dehydration and malnutrition can result.
Some people think that diarrhea is one watery bowel movement. But from a medical standpoint, you’re not considered to have diarrhea until you have four or more such bowel movements in a 24-hour period.
If this occurs, you should see your oncologist or primary-care provider as soon as possible, especially if you have any other associated symptoms, such as vomiting, abdominal cramping, fever, chills, an inability to eat or drink, weight loss, blood in your stool, or an inability to urinate.
Like pain, diarrhea may have a variety of causes. It can be a complication of radiation to the bowel, occur after gastrointestinal surgery to remove a tumor, result from certain chemotherapy drugs, or occur after taking various other medications used to treat cancer.
Diarrhea can also signify a potentially serious infection within the gastrointestinal system, such as may occur from a foodborne illness; stem from stress and anxiety; or be attributable to the cancer itself. For certain cancers, like those of the colon or pancreas, diarrhea may be the first indication of cancer.
Because the causes of diarrhea are so varied, your physician will need to carefully consider its potential causes before deciding on a particular course of action. However, even if you experience just one bout of diarrhea or are given a certain medication to help with your diarrhea, there are food strategies you can employ that might be helpful.
To prevent diarrhea and its complications, you can try these strategies:
Avoid foods that are irritants. Some foods and beverages may worsen diarrhea and should be avoided, including fried foods, fatty foods, caffeine, and alcohol. In addition, lactose (the sugar in milk and milk products) may become difficult to digest during treatment, causing diarrhea.
Try to limit dairy products, except for yogurt or kefir, which can help improve symptoms. If you enjoy milk, consider buying milk that has the enzyme lactase added or using lactase tablets to help with digestion. You can also try a milk alternative like soy, rice, or almond milk.
Avoid using sugar alcohols. Sugar alcohols like sorbitol, mannitol, xylitol, and maltitol are used to sweeten foods in place of sugar to reduce calories. But they can make diarrhea, gas, and bloating worse, so you should avoid using them or consuming foods and drinks that contain them until your symptoms improve.
Maintain hydration. When you have diarrhea, you won’t absorb as much water from your foods and fluids as you should, which can lead to dehydration if the diarrhea continues. Also, your nutrition intake may decline, which can further increase your risk of dehydration.
Sip on clear liquids throughout the day, including sports drinks, broths, decaffeinated teas, coconut water, and water. Room temperature liquids may be better tolerated than chilled liquids. Try to drink at least a cup of liquid after any loose bowel movement.
Eat potassium-rich foods. Potassium is critical for maintaining hydration. When you have diarrhea, you may not absorb enough potassium from your foods and fluids, and you’ll be losing this important mineral in your stool. Some potassium-rich foods that may be tolerated when you have diarrhea include bananas, canned or peeled ripe pears or peaches, applesauce, potatoes without skins, pulp-free orange juice, and cooked carrots.
Eat sodium-rich foods. Sodium is important for hydration. Although you normally wouldn’t want to take in too much sodium, when you have diarrhea, you won’t absorb as much of this mineral from your diet and you’ll also lose it in your stool. To restore sodium levels, try sipping broths and eating pretzels and salty crackers.
Balance your fiber intake. You may remember being told to follow the BRAT (bananas, rice, applesauce, toast) diet when you had diarrhea as a child, or your pediatrician may have recommended it for a sick child of yours. The BRAT diet foods are good sources of soluble fiber, which can help absorb some liquid from and form your stool.
Other good sources of soluble fiber are instant oatmeal, white rice, pasta, canned Mandarin oranges, and canned or peeled ripe pears and peaches. Fruit pectin, such as Sure-Jell (which is used to thicken jelly), is also a good source of soluble fiber and can be added to cooked cereals, soups, or smoothies with some of the aforementioned fruits and a little rice milk or lactase-treated milk.
While increasing your soluble fiber intake, you’ll also need to decrease your insoluble fiber intake. Insoluble fiber has a laxative effect and speeds up the passage of food and waste through your digestive tract. Therefore, you’ll want to avoid eating whole-wheat products, seeds, nuts, dried fruits, and the skin of vegetables and fruits. Gas-forming vegetables like broccoli, cabbage, beans, and onions may also be problematic during this time.
Eat probiotic-rich foods. Probiotics are bacteria that help keep your digestive system healthy. Cancer treatments like chemotherapy, radiation to the abdominal area, and even antibiotics used during cancer treatment can decrease the amount of healthy bacteria in your gut or eliminate them altogether.
Studies show that consuming foods that contain probiotics, such as kefir or yogurt without seeds, can help manage diarrhea. Try to consume two to three servings of these foods daily.
If you can’t tolerate probiotic-rich foods, ask your doctor or healthcare team about taking a probiotic capsule that contains Lactobacillus.
Ask your doctor about glutamine. Some studies suggest that glutamine taken in 10-g doses up to three times daily may help.