If you experience unpleasant or uncomfortable symptoms after eating food that contains fructose, such as fruit, sweets or bread, you may have a fructose intolerance, also known as fructose malabsorption. Often mistaken for an allergy, fructose intolerance can have a range of symptoms that range from mild to severe, but it can be managed if you have confirmation.
In this post, we’re going to explore what a fructose intolerance is, including the symptoms, which foods contain fructose and what you can do to find out for sure whether or not you have one.
What is fructose intolerance?
Fructose is a natural sugar found in many fruits and vegetables. The body converts fructose into glucose, which is the body’s main source of energy. When the body struggles to do this it doesn’t absorb all the fructose, and this is known as a fructose intolerance, or fructose malabsorption. This then leads to a series of symptoms that can be painful and unpleasant.
There are two types of intolerance to fructose:
- Dietary fructose intolerance (DFI) – when the intestine finds it difficult to process fructose.
- Hereditary fructose intolerance (HF) – when the body amasses sugars that it cannot process, which can lead to severe symptoms and complications.
What are the symptoms of fructose intolerance?
Fructose intolerance symptoms can show in babies as soon as they’re introduced to food or baby formula, which often contains fructose. Symptoms in babies can be similar to galactosemia, including:
- Lethargy
- Jaundice
- Cataracts
- Refusing to eat
- Sepsis
In adults, fructose intolerance symptoms have a lot in common with liver disease. These include:
You may also have a dislike of sweet foods, such as fruit.
How common is fructose intolerance?
Fructose malabsorption is relatively common, and it affects around one in three people. Between 1970 and 1990, the consumption of fructose grew by over 1,000%, which is thought to be the reason so many people experience symptoms when eating fructose-containing foods today.
Thankfully, hereditary fructose intolerance is far less common. Despite the name, it is possible to develop HFI if neither parent has it, and it will usually develop in infancy. However, fructose malabsorption can develop at any stage of your life.
It’s also worth noting that those with HFI are 10 times more likely to have celiac disease than those without.
How do you test for fructose intolerance?
The main way to test whether you’ve developed fructose intolerance is with a breath test. This is something we recommend you speak to your healthcare provider about, who may be able to organise this for you. If you’ve developed symptoms as an adult, you’re more likely to have DFI than HFI. But, as with most things health-related, it’s always best to speak to a doctor if you’re not sure.
If you suspect you may have an intolerance to something but you’re not quite sure what, you can take a food intolerance test to test 970 key food and drink items.
Can you have a fructose allergy?
Because the symptoms of fructose intolerance have crossover with symptoms of an allergy, many people confuse the two. However, fructose malabsorption isn’t the same as an allergy. An allergy is caused by the body’s immune system overreacting to certain foods, whereas an intolerance is caused by the body struggling to process it.
What to eat and what not to eat with a fructose intolerance
If you have fructose intolerance, you’ll need to avoid food and drink that’s high in fructose. This includes:
- Apples
- Honey
- Baby food
- Baby formula
- Bread
- Fruit juice
- Yoghurt
- Sweets/candy
- Fizzy drinks
- Orange
- Strawberries
- Pears
- Mango
- Grapes
- Pineapple
- Watermelon
- Prune
- Onion
- Some salad dressings
- Raisins
- Apricot
It’s important to pay attention to food labels to ensure food doesn’t contain:
- Fructose
- High-fructose corn syrup
- Molasses
- Maple-flavoured syrup
- Agave syrup
- Invert sugar
- Palm sugar
- Coconut sugar
- Sorghum
If you have an intolerance, you may be able to eat some low-fructose fruits and foods, such as:
- Bananas
- Carrots
- Avocados
- Lettuce
- Green beans
- Apricots
- Raspberries
- Blackberries
- Nectarine
- Plums
- Peaches
- Honeydew
- Cantaloupe
Test to see if you have an allergy or intolerance
If you experience symptoms after eating any type of food, you may have an allergy or intolerance. To find out for sure, a food intolerance blood test or food allergy test can tell you accurately and conveniently in just one week.
References
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2. Nair R, Maseeh A. Vitamin D: The “sunshine” vitamin. J Pharmacol Pharmacother. 2012;3(2):118-126.
3. Vitamin D2 vs. D3: Which Should I Take for Bone Health?. Cleveland Clinic. URL. Accessed February 15, 2021.
4. Jetty V, Glueck CJ, Wang P, et al. Safety of 50,000-100,000 Units of Vitamin D3/Week in Vitamin D-Deficient, Hypercholesterolemic Patients with Reversible Statin Intolerance. N Am J Med Sci. 2016;8(3):156-162.
5. On call: Vitamin D2 or D3? Harvard Medical School. URL. Accessed February 15, 2021
