Fruits are a colourful, delicious, and important food group and can mostly be expected to contain sugar. The sugars in fruit occur naturally, making them fundamentally different from processed sugars. One such sugar commonly found in fruits is fructose. It is a simple compound that is also found in juices, and sometimes even in other foods like honey and sugarcane or vegetables like artichoke, onion, mushroom, and even red pepper.
Complementing fructose is a sugar called sucrose. It occurs naturally in dates, honey, and sugarcane. It is half part fructose and half part glucose. When produced commercially, sucrose is made in large quantities for use in food.
Some people have digestive systems that cannot process fructose and sucrose, leading to a condition called hereditary fructose intolerance (HFI). What are its symptoms? How can it be diagnosed? Here’s breaking it all down.
Highlights
- Fructose is a simple, naturally occurring sugar found in fruit, juices, and other foods like honey, sugar cane, asparagus, and mushroom,
- Hereditary fructose intolerance (HFI) prevents one’s digestive system from processing fructose and sucrose. Symptoms include a lack of growth and weight gain in afflicted infants as well as abdominal pain, bloating, low blood sugar, and vomiting among others,
- By limiting foods with fructose and sucrose, one can navigate daily life with HFI.
Fruits are a colourful, delicious, and important food group and can mostly be expected to contain sugar. The sugars in fruit occur naturally, making them fundamentally different from processed sugars. One such sugar commonly found in fruits is fructose. It is a simple compound that is also found in juices, and sometimes even in other foods like honey and sugarcane or vegetables like artichoke, onion, mushroom, and even red pepper.
Complementing fructose is a sugar called sucrose. It occurs naturally in dates, honey, and sugarcane. It is half part fructose and half part glucose. When produced commercially, sucrose is made in large quantities for use in food.
Some people have digestive systems that cannot process fructose and sucrose, leading to a condition called hereditary fructose intolerance (HFI). What are its symptoms? How can it be diagnosed? Here’s breaking it all down.
What is HFI?
At its simplest, hereditary fructose intolerance (HFI) is a condition that prevents people from digesting fructose and sucrose sugars. Primarily, it causes low blood sugar in people with the condition who consume the two sugars. It can also cause toxic substance liver build-up. In terms of intensity, HFI can range from mild to severe, and is caused when one lacks an enzyme called aldolase B.
Fructose is a simple sugar that occurs with sucrose or other sugars in nature. It can also be added to foods during the manufacturing or processing stages. Fructose and glucose share the same chemical formula, even though their molecular structures differ. This differentiation makes fructose sweeter than sucrose, and it is believed to be the sweetest natural carbohydrate.
Those with HFI begin to show symptoms in the early parts of their life. As diets evolve to include fruit, juice, or other foods with fructose, those with the condition experience ill effects like abdominal pain, bloating, diarrhoea, and nausea. Other symptoms also include low blood sugar and vomiting. Infants or children with the condition may grow or gain weight below their expected pace.
What causes HFI?
HFI, which affects between 3,000 and 30,000 people in America, is an inherited metabolic disease. It can occur at any time period in one’s life. Its causes include the lack of an enzyme known as aldolase B, found primarily in the liver. It works to convert fructose into energy. Another cause changes in the ALDOB gene, which guide the making of the aldolase enzyme. The condition is passed on from parents to children in an autosomal recessive pattern. This means inheriting two mutations, or altered genes, one from each parent. While it may not affect the parent’s health, there is a 25% chance that their affected child has two altered genes and carries its effects.
What are the symptoms of HFI?
In infants, unidentified, undiagnosed, or untreated HFI becomes apparent when they come across fructose, sucrose, or sorbitol. HFI symptoms can be divided into two categories:
Metabolic disturbances (hyperalaninemia, hypermagnesemia, hyperuricemia, hypoglycemia, hypophosphatemia, and lactic acidemia)
Clinical findings (abdominal stress, nausea, vomiting; harmful growth limitations – whether in size or weight, as well as a lack of thriving)
Infants who consume meaningful amounts of fructose might demonstrate lethargy, progressive coma, or even seizures. HFI, when untreated, could also result in renal and hepatic failure. When the condition is detected, diagnosed, and treated before causing any irreversible organ damage, infants or adults with HFI can expect the typical quality of life as well as life expectancy.
Which foods cause fructose intolerance?
Fructose is present in fruits, juices, and even certain vegetables. If someone is diagnosed with HFI, it restricts their food options. Here are some food considerations to keep in mind for those with the condition:
Foods with generous fructose quantities should be consumed only in limited quantities. These include apple, asparagus, grape, juices, peas, watermelon, and zucchini.
Foods with lower fructose presence—like avocados, bananas, blueberries, carrots, green beans, and lettuce are best suited as meal accompaniments in modest quantities.
Avoid foods that contain these on product labelling: agave syrup, coconut and/or palm sugar, fructose, high-fructose corn syrup, honey, invert sugar, maple-flavoured syrup, molasses, and sorghum.
What is the treatment for HFI?
HFI is best treated through a simple approach: that of early detection and then living a fructose-free lifestyle. Avoiding fructose is the most effective way to lead a normal life for people with the condition. In addition, sucrose and sorbitol consumption is also meant to be avoided and minimized. While a lifestyle with this diet is challenging, it is possible. Long-term consequences of fructose exposure on the liver remain unknown.
However, there have been cases of liver transplant performed on people whose life is at risk from HFI-related complications. There are certain vaccine dose limitations for those with the condition. Typically HFI sensitivity is higher in children than in adults, and this is a factor to take into account while administering doses of vaccines that may contain fructose, sucrose, or other sugars.
Conclusion
Hereditary fructose intolerance (HFI) prevents people with the condition from processing fructose and sucrose, both of which are types of sugar. A key cause of HFI is the lack of a liver-concentrated enzyme named aldolase B. Its symptoms include metabolic difficulties as well as clinical consequences like nausea and vomiting. Fructose is found naturally in sweet foods like honey, fruits, juices, and even some unexpected vegetables like asparagus, mushroom, and peas. You can navigate life with HFI through effective detection and a fructose-free diet.
Disclaimer: The contents of this article are for general information and educational purposes only. It neither provides any medical advice nor intends to substitute professional medical opinion on the treatment, diagnosis, prevention or alleviation of any disease, disorder or disability. Always consult with your doctor or qualified healthcare professional about your health condition and/or concerns before undertaking a new health care regimen including making any dietary or lifestyle changes.
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