Fructose Intolerance: Causes, Symptoms, and Management

Jan 25, 2021 10:51 AM EST | By Staff Reporter

Fructose Intolerance: Causes, Symptoms, and Management

(Photo : Pixabay)

Are you always feeling tired and weak, even after eating a heavy, nutritious meal? Do you frequently complain of abdominal discomfort after enjoying your favorite fruit? If so, you could be a victim of fructose intolerance

This term may not be new to most people. However, in most cases, the diagnosis is made after years of suffering. So what exactly is fructose intolerance? Read on to discover more. 

What is Fructose Intolerance? 

Fructose is a sugar present in fresh fruits, some vegetables, honey, and other foods. When you suffer from fructose malabsorption, as it is colloquially known, your body cannot metabolize this sugar, severely compromising your general health. 

Typically, nutrients are absorbed in the small intestine. However, in a body intolerant to glucose, the undigested molecules pass on to the colon, resulting in abdominal discomfort, bloating, and gas. 


Fructose intolerance is quite common, affecting 1 in 3 people. Genes have primarily been blamed as the cause of fructose intolerance. However, multiple causes have been discovered, including;- 

  • Bacteria imbalance in your gut 

  • High intake of processed foods 

  • Inflammation 

  • Stress 

  • Pre-existing gut condition, such as IBS 



Digestion is a long process that begins in the mouth and ends in the small intestine. A person who suffers from fructose intolerance cannot break down the molecules. Instead, they move to the colon as undigested waste. 

Here, your gut bacteria use the molecules as fuel, releasing hydrogen gas that causes bloating. Consequently, one complains of abdominal discomfort and gas. 

Stomach Cramps 

Because the body has trouble digesting fructose, the molecules pass through the alimentary canal undigested. This movement of whole or minimally digested fructose molecules through the digestive tract causes pain and discomfort. The bloating and gas does not help the situation either. 


An increase in the number of undigested food particles results in excessive waste in the form of diarrhea. Besides, undigested fructose molecules trigger excessive reabsorption of water along the gastrointestinal tract. As a result, one complains of diarrhea after consuming particular foods.  

Chronic Fatigue 

Fructose is the body's primary source of energy. Persons suffering from fructose intolerance cannot convert fructose into energy, resulting in constant weakness and fatigue. 

Therefore it is not unusual to find individuals with undiagnosed fructose intolerance frustratingly trying to figure out why they are always tired. That is despite eating energy-rich foods. 

Iron Deficiency 

Iron is one of the crucial nutrients ingested in the form of fructose. With an unknown intolerance to fructose, iron goes unabsorbed, ultimately resulting in its deficiency. The body needs iron to generate hemoglobin, an oxygen-carrying molecule.

With inadequate oxygen transport, bodily tissues and muscles become fatigued, resulting in constant physical fatigue. Other symptoms include headaches, weakness, and lightheadedness. 


If you suspect you might be fructose intolerant, visit your health practitioner to get tested. The test is simple - avoid carbohydrates on the night before and the morning of the test. Your doctor will then give you a high fructose solution to drink, then analyze your breath for hydrogen every 20 to 30 minutes for about three hours. 


Fructose elimination from your diet is the ultimate cure for fructose intolerance. Foods such as honey, fruit juices, and particular fruits, such as apples, pears, plums, and cherries, should become a thing of the past. 

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