Fact Checked

What are the Different Types of Sugar Intolerance?

Christine Hudson
Christine Hudson

Sugar intolerance describes any condition in which the body is unable to absorb basic sugars. Different kinds of sugar intolerance include fructose intolerance, a sugar allergy, and even lactose intolerance.

The main cause of sugar intolerance is a deficiency of the enzyme lactase. This enzyme is meant to break down sugars into digestible forms so they can be digested of absorbed by the body, and a deficiency makes this very hard or even impossible. When this enzyme is gone, a bacterium that resides in the digestive tract can ferment into gases, resulting in many uncomfortable symptoms.

A deficiency of lactase commonly causes sugar intolerance.
A deficiency of lactase commonly causes sugar intolerance.

Fructose intolerance is a fairly rare condition that affects about one in every 10,000 individuals. Many people confuse it with sugar or fructose malabsorption, but they are two very different conditions. Fructose intolerance is a condition in which the enzymes for breaking down sugars are not being produced. This intolerance can be passed genetically and will last a lifetime. Fructose malabsorption is far more common and affects over 30% of the population. This happens when epithelial cells are not available to help with digestion. Almost one in three people experience some type of sugar sensitivity, but many have no symptoms.

Flatulence and oily stools are common symptoms of fructose malabsorption.
Flatulence and oily stools are common symptoms of fructose malabsorption.

The symptoms of a sugar allergy may include diarrhea, bloating, and excessive gas. These symptoms will appear a few hours after consuming drinks or foods that contain simple or even complex sugars. An individual can avoid this condition by staying away from common foods which contain sugar or fructose. Fruits, juices, and soft drinks contain large amounts of these ingredients and should be avoided.

Lactose intolerance occurs when the lactase level is too low or non-existent and the molecule, which consists of two sugar molecules joined together, cannot be broken apart and digested. Those who have this form of sugar intolerance are commonly advised to take a lactase supplement before consuming any foods that contain sugars. Many also choose to substitute normal milk for soy, nut, or lactose-free milk. There are many kinds of food which may contain lactose or sugars that may need to be avoided or eaten very sparingly.

Most who believe they may have a sugar intolerance can go to a medical professional for diagnosis. If a professional diagnosis reveals a sugar intolerance of any kind, then the patient may be advised on how to combat the problem. Medication or supplements may be issued, and typically the patient will work closely with doctors or nutritionists to develop a dietary plan. The most effective way to live with a sugar intolerance, if it is not treatable, is to learn which foods to avoid.

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Discussion Comments


But how is sugar intolerance diagnosed?

I think that I have an intolerance to sugar, specifically to fructose, because I have bloating, cramping, nausea and diarrhea after I eat fruits. But my doctor thinks that I have irritable bowel syndrome (IBS). IBS causes some of the same symptoms, so how can I find out if I have sugar intolerance or not? Is there a test for it? Do I have to do an elimination diet?

If I do get a diagnosis, will the doctor tell me that I just have a sugar intolerance or will I get to know what type of sugar intolerance I have as well? Does anyone here know?


@fify-- No, they're not the same thing. The only things that sugar intolerance and diabetes have in common are that they're both hereditary and they're both metabolic disorders.

Diabetes is when the body doesn't produce insulin or the insulin that's produced doesn't recognize the sugar molecules in blood. There is no such issue in sugar intolerance. Sugar intolerant people have insulin and the insulin recognizes the sugar molecules. It's just that the sugar cannot be metabolized.

Sugar intolerance is much like gluten and lactose intolerance. It causes very similar digestive symptoms.


What's the difference between sugar intolerance and diabetes? Isn't diabetes a type of sugar intolerance too?

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    • A deficiency of lactase commonly causes sugar intolerance.
      By: sumire8
      A deficiency of lactase commonly causes sugar intolerance.
    • Flatulence and oily stools are common symptoms of fructose malabsorption.
      By: Ana Blazic Pavlovic
      Flatulence and oily stools are common symptoms of fructose malabsorption.