What is Carbohydrate Malabsorption?

Felicia Dye

Carbohydrate malabsorption, sometimes also known as “carbohydrate intolerance,” is a medical condition that makes it very difficult for people to properly digest some or all carbohydrates. Many different foods fall into this category, though breads, pastas, and fruits are some of the most common. Enzymes like lactose, which occurs in milk, are also considered carbohydrates. People who suffer from malabsorption either aren’t able to tolerate these sorts of foods or else digest them poorly. The condition often causes a significant amount of gastrointestinal distress, including gas, bloating, and stomach cramps. In some cases it will go away on its own, but it’s more common for people to change their diets to avoid “problem” foods and, in some cases, begin taking medication to control symptoms and flare-ups.

A person with a carbohydrate malabsorption can not properly digest starches and sugars.
A person with a carbohydrate malabsorption can not properly digest starches and sugars.

Carbohydrate Basics

Carbohydrates are often referred to simply as “carbs,” and they are one of the primary building blocks of human fuel. They include most starches and sugars. The body is able to metabolize them fairly quickly, converting them into almost instantaneous energy in the bloodstream. Some dieticians warn that these nutrients can have negative health effects if consumed in excess, in large part because they don’t usually provide any sort of lasting or sustained energy. Most experts agree that people need at least some carbs in order to stay healthy and keep up proper biological functions, though.

Gas is released by the unabsorbed material in the colon causing the sufferer to feel bloated.
Gas is released by the unabsorbed material in the colon causing the sufferer to feel bloated.

People who aren’t able to absorb starches and sugars don’t break them down or else break them down only partially during digestion. This usually means that they aren’t getting any of the quick energy, and are also usually hampering the digestion of other nutrients that the body is also processing. Unprocessed carbs passing through the digestive tract can cause a number of problems ranging from mild cramps to severe blockages.

Cramps can be a symptom of carbohydrate malabsorption.
Cramps can be a symptom of carbohydrate malabsorption.

Main Causes

There are a couple of different reasons why people develop this condition. Sometimes they’re born with it, but it can also develop over time, in much the way that food sensitivities or allergies can. It’s usually connected to intestinal enzymes, which are proteins that help with the digestive process. People who don’t have enough sometimes aren’t able to keep up with the demand, particularly when a lot of carbs are consumed at once.

In most cases a person will only have a problem digesting certain carbohydrates, such as lactose. Lactose intolerance is one of the most common forms of carbohydrate malabsorption. Low enzyme levels play a big role in this particular condition, and drinking fruit juices that contain sorbitol, which is a specific sugar alcohol, can also exacerbate it.


Symptoms of this condition can include cramps, diarrhea, and gassiness. These usually happen when undigested carbohydrates eventually make their way to the colon. Fluids tend to pool around the fibers, and the unabsorbed material begins to ferment. This frequently creates gases that can make a person feel bloated and uncomfortable.

Some experts and researchers believe that the malabsorption of certain carbohydrates, such as lactose and fructose, may also be linked to depression. The effects seem to be most profound in women; in men, however, the condition doesn’t always have the same intersection with mental health. It can, but it isn’t as common. Malabsorption can also cause delayed growth and low weight in children, and may also have an effect on brain development and cognitive activity.

Diagnosis and Treatment

Actually diagnosing carbohydrate intolerance can be somewhat difficult, since the symptoms often overlap with a number of bowel and digestive problems. Care providers who suspect a carbohydrate-specific problem may conduct a breath test, in which the patient breathes into a special machine that breaks down the chemical composition of each exhalation. The goal is usually to measure hydrogen levels, which are typically low when carbs are being properly digested; when they’re not, the digestive tract often has excess hydrogen that is trapped and often makes its way out through the breath. People usually have to eat cabohydrate-rich food just before being tested in order to get accurate results.

The easiest treatment is usually dietary. People are often encouraged to limit or reduce their intake of certain carbs, and to space out how often they eat food containing these sorts of starches. Enzyme replacements can be prescribed in some cases, and certain other medications can help, too. It’s uncommon for the condition to ever truly be cured, but it can generally be managed such that people who have it can lead mostly normal lives.

People with carbohydrate malabsorption should avoid potatoes.
People with carbohydrate malabsorption should avoid potatoes.

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Discussion Comments


I get bowel pain/cramps esp after eating potatoes, semolin and coconut. Could this be what I have? I also get very alkaline stools.


@MissMuffet - sorry to hear about your health problems. I wonder if you have a problem with the sugar in fruit, as my college roommate had similar issues.

You could ask your doctor to run a fructose intolerance test to be sure. If this turns out positive you will need to watch out for hidden sugars, which seem to be in everything these days.


I suffer a lot from stomach aches and gas and my mother is always telling me to eat less fruit. Is it possible that I am suffering from carbohydrate malabsorption syndrome?

I can't imagine quitting my fruit habit for very long. Apples and bananas are convenient to eat and low in calories, two things which are really important to me in my daily life.


I'm happy to read this article because many people don't realize they have some kind of malabsorption syndrome. Even the doctor may make a mistake when trying to diagnose the problem, as many of the symptoms are similar to those of irritable bowel syndrome.

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