What to eat to prevent metformin diarrhea (or metformin-induced diarrhea)

Key takeaways:

• Metformin is the first-line drug for treating type 2 diabetes mellitus in adults and children above 10 years. 
• Although it is the first-line treatment for diabetes, metformin has some gastrointestinal side effects, including diarrhea, nausea, vomiting, stomach discomfort, and flatulence. 
• Some meal options, such as dairy products and fatty and fried foods, can worsen diarrhea while taking metformin. In contrast, other options, such as soybeans and sweet potatoes, can reduce the chances of having diarrhea while taking metformin. 

Metformin is under a class of drugs known as biguanides, and it is the first-line treatment for type 2 diabetes mellitus because of its safety, tolerance, and cost-effectiveness.

Although metformin is the first drug that comes to mind in treating this condition, according to research, 75% of people who take metformin will have gastrointestinal-related side effects. Diarrhea is one of them.

Researchers believe metformin typically causes diarrhea because of the following: 

• Changes in the gut microbiome (Gut microbiome refers to all the microorganisms in your digestive tract, including viruses, bacteria, fungi, and other organisms)
• Increased intestinal glucose
• Increased bile acid concentration in the intestine
• High levels of the hormone glucagon-like peptide 1 (GLP-1) concentration (a hormone produced in the gut)

Foods to avoid to prevent diarrhea while on metformin

As previously mentioned, metformin-related diarrhea can be caused by changes in the gut microbiome. This means that to prevent diarrhea while on metformin, you have to avoid foods that upset the gut because this could worsen the side effects of metformin.

Here are some foods to avoid while on metformin:

1. Diary products

For some people, absorbing the sugar in dairy products, known as lactose, may not be easy. This condition is known as lactose intolerance. People with this condition often show signs related to the side effects of metformin, which include diarrhea, bloating, gas, nausea, and vomiting.

When taken together, foods under this category can worsen diarrhea while on metformin and should be avoided. (5) Dairy products are foods made from or containing milk. They include:

• Milk 
• Cheese 
• Ice Cream
• Butter
• Yogurt

2. Fatty foods

Meals that have excessive fats are not always easily absorbed in the body. They affect the body's absorption cycle and the intestinal microbiome, triggering diarrhea. Foods that fall under this category include;

• Butter 
• Cheese 
• Ice cream
• Red meat

These foods should be taken in small quantities or avoided when taking metformin as they may worsen diarrhea.

3. Fried foods

Although fried foods may seem palatable and pleasant, they may not be very healthy for your gut. They can lower the amount of microbes in your gut, leading to many problems,, including diarrhea. To reduce the side effects of metformin, avoid or limit eating fried foods while taking this drug. 

4. Alcohol

Generally, taking alcohol with medications is not advised because of the adverse effects it may have with certain medications. Alcohol may affect muscle movements in the small and large intestines, causing diarrhea. Because of the effect of alcohol on the body, it is not advised to be taken alongside metformin. 

5. Spicy foods

Consuming foods that contain too much chili can upset the stomach and cause diarrhea. Because of this effect, it is not advisable to take excessive chili alongside metformin, as it can worsen metformin-related diarrhea. To reduce this, you can reduce the quantity of chili used in preparing your meal or avoid it completely.

6. Caffeinated drinks

Drinking drinks full of caffeine, like coffee, may seem cool and be an early morning routine. However, research has shown that taking caffeinated drinks causes the secretion of an enzyme called gastrin (an enzyme responsible for enhancing gastric motility). When gastric motility is increased, there may be loose stool or diarrhea.

7. Excess Protein

As important as protein is in our everyday meals, too much may cause diarrhea. Excess protein affects the absorption of this food into the body, affecting the balance of intestinal microbiota (microorganisms in the intestine) and causing diarrhea.

This does not mean that protein foods should be cut out of your diet entirely; however, because metformin can cause diarrhea, you may want to limit the quantity of protein you take in during this period. 

Herbs and supplements to avoid while on metformin

Drug-to-drug interactions are normal, especially when taking supplements or herbs alongside another medication. However, current available scientific evidence has not shown significant side effects of taking metformin with herbs or supplements. Notably, there has not been much research on this particular cause, but future discoveries may exist.

Although little or no research exists on this topic, the herb berberine has been discovered to increase the amount of metformin in the system, which may also increase its effects and side effects. The effect occurs when berberine is taken around two hours before metformin and does not occur when taken at the same time as metformin.

What to eat while taking metformin

While some foods may increase the chances of metformin-induced diarrhea, some other food options may help reduce the chances of having diarrhea when taking metformin. Below are some food options to explore while you are on metformin.

Dietary fiber

Dietary fiber is essential for your health because of its protective factor. They have numerous benefits, including increasing the time it takes for food to move from the mouth to the end of the intestine (anus), increasing the feeling of being full, and reducing diarrhea.

With all these benefits, it is obvious that a fiber-filled meal can greatly decrease your chances of having diarrhea while taking metformin. Examples of fiber-rich foods include vegetables, whole grains, legumes and fruits.

A rice-based diet

Rice is a refined grain and contains low dietary fiber levels. Because it has low fiber, it is not easily digestible; instead, it bulks up the feces, reducing the chances of diarrhea.

Consider opting for brown rice instead of white rice, as the former contains more fiber and has not been stripped of most nutrients.

Soya beans

The main cause of metformin-induced diarrhea is an impaired gut microbiota. Research has shown that fermented soy beans can replenish and modulate the gut microbiota and relieve diarrhea. . Soya beans may help reduce the chances of diarrhea when taking metformin.

Sweet potatoes

Sweet potatoes are another way to reduce the chances of diarrhea when taking metformin. They contain phytochemicals (chemical compounds produced by plants that play various roles in the human body) like trifostigmanoside 1, which makes them beneficial in treating several illnesses, such as diarrhea and other stomach disorders. 

Soups

Taking soup broth is a good way to replenish your body with necessary electrolytes and fluids and reduce dehydration. Opt for soup broths that contain chicken, vegetables, or beef.

Fluids

Taking liquids also prevents dehydration and replenishes electrolytes in the body. Liquids you may take include water, fresh apple, and grape juice, cranberry juice, and tea (without caffeine).

Other gastrointestinal side effects of metformin

Aside from diarrhea, other common side effects of metformin include:

1. Nausea
2. Vomiting
3. abdominal discomfort
4. Flatulence

When to seek medical care

Although metformin is the first-line treatment in treating type 2 diabetes mellitus, if you notice that the gastrointestinal issues are too much to bear, even after following the advised precautions and dietary options, you should seek proper medical attention from your doctor to prescribe an alternative option. 

Wrap Up

Due to its safety and cost-effectiveness, metformin is a very beneficial drug when treating diabetes mellitus. However, the fact that it is an important drug does not exempt its severe gastrointestinal side effects, and diarrhea is one of them.

Although metformin causes diarrhea, there are meal options that worsen this particular side effect, while some may decrease the chances of diarrhea occurring. If you follow these dietary options, the chances of curbing metformin-induced diarrhea may be high.