fructose intolerance

Fructose is a sugar naturally occurring in fruits, honey, and vegetables. When you cannot digest or absorb fructose in your body, you have fructose intolerance or malabsorption. When you have fructose intolerance, you may experience abdominal pain, bloating, and diarrhea whenever you eat foods with fructose. There is a more severe fructose intolerance known as hereditary fructose intolerance, whereby the symptoms develop early in infancy. When ignored, such a condition can develop into other complications like liver and kidney failure.

Forms of fructose intolerance

There are three forms of fructose intolerance: fructose malabsorption, essential fructosuria, and hereditary fructose intolerance.

Fructose malabsorption

When you have fructose malabsorption, your body cannot absorb or digest fructose properly, and therefore the fructose goes to the large intestine leading to painful digestion and gas. Additionally, some individuals with fructose malabsorption are sensitive to a category of foods that include FODMAPS ( fermentable oligosaccharides, disaccharides, monosaccharides, and polyols). FODMAPS comprises many types of sweeteners, both natural and artificial.

Fructose malabsorption affects about 40% of the people in the western hemisphere. Like other food sensitivities, it can be caused by a combination of factors, including lifestyle, exposure to fructose, and overall health condition. Symptoms of fructose malabsorption include gas, diarrhea, nausea, and bloating.

If you have fructose malabsorption, you should maintain a food log and stick to a low fructose diet. Many people with this condition can consume about 10-15gms of fructose a day without experiencing any symptoms. Reducing your intake of fructose can alleviate symptoms within 2-6weeks. 

Essential fructosuria

Also known as hepatic fructokinase deficiency, essential fructosuria is a harmless recessive disorder that you may unconsciously have. If you have essential fructosuria, you lack a liver enzyme known as hepatic fructokinase that breaks down fructose. 

The condition being recessive means that you inherited the gene from both of your parents. But if you inherit the gene from one parent and not the other, you are only a carrier. Essential fructosuria is asymptomatic; therefore, it is not harmful and requires no treatment.

Hereditary fructose intolerance

Hereditary fructose intolerance occurs when you cannot digest fructose and fructose precursors like brown sugar. That means your body lacks enough activity of an enzyme known as fructose-1-phosphate aldolase that helps digest fructose. Therefore the fructose builds up in the liver and kidney, which can cause severe and fatal conditions such as liver and kidney failure. 

Symptoms of hereditary fructose intolerance include impaired physical development, growth delays, jaundice, hyperventilation, vomiting, a strong dislike for sweets, liver or kidney failure. However, hereditary fructose intolerance is manageable.

No treatment guarantees a cure for hereditary fructose intolerance, so you should avoid consuming fructose altogether if you have this condition. That involves avoiding all fruits and other foods. But you need professional support to maintain a healthful diet to prevent nutritional deficiencies.

The takeaway

While eliminating fructose from your diet can be impossible, the most important thing is determining how much fructose you can consume without experiencing any uncomfortable digestive issues. You can seek help from a dietician to work out how much fructose you can tolerate and ensure a balanced diet to achieve better results.