Are Fruits and Vegetables Making You Sick?

Do you suffer from stomach pain, diarrhoea, constipation, bloating, wind or nausea? Have you also been told that you don’t have lactose intolerance, coeliac disease and IBS?

You may suffer from fructose intolerance or malabsorption.

Fructose is a sugar found in fruits, vegetables and processed foods. It can exist in food as a free sugar, a disaccharide (sucrose) and/or in a polymerised form (fructans) and relies on a facilitative transport system (GLUT5) for uptake from the small intestine.

Up to half of the population are unable completely absorb any more than 25g per day, this is equal to 2 apples and one banana.

Over the last few decades, fructose intake – in fruits, juice, and high fructose syrup – has increased in the Western diet to the point where the amounts commonly consumed in a day may cause mild gastrointestinal distress in normal people and severe symptoms in sensitive people.

These days, such symptoms are frequently diagnosed medically as fructose malabsorption.

Unabsorbed fructose travels to the bowel where it can ferment and cause bloating and flatulence. Other common adverse effects can include diarrhoea, reflux, abdominal pain and dysbiosis.

The gastrointestinal tract then becomes more permeable and inflamed, causing mucous in the stool and a constant feeling of tiredness.

Although fructose is a fruit sugar, other sugars can have a positive and negative effect on how fructose is absorbed.

Glucose helps with fructose absorption by stimulating GLUT5 to increase uptake in the small intestine. Therefore foods that contain more glucose than fructose are generally well tolerated (e.g. ripe bananas).

While glucose helps with fructose uptake, sorbitol reduces it. Sorbitol intake should be limited to under 5g per day.

Fructans can also pose a problem with fructose absorption. As fructans are commonly present in wheat products, many IBS suffers respond well to a wheat free diet, even though testing negative to coeliac disease.

As many of the symptoms of IBS are similar to fructose absorption problems, it is common to be misdiagnosed with suffering from IBS. It is also common to go undiagnosed altogether.

How is fructose malabsorption diagnosed?

Fructose malabsorption is diagnosed via a hydrogen breath test. It is a similar test as used to diagnose lactose intolerance.

Breath hydrogen measurements are taken fasting, 25 grams of fructose is administered and breath hydrogen levels are monitored regularly for 2-3 hours.

Hydrogen exceeding 20 points above baseline indicates fructose malabsorption.

The consequences of Fructose Malabsorption is damage to the lining of the gut.  This results in the inability to absorb nutrition from your food and the potential to develop sensitivities to other foods.

The integrity of the gut lining can be measured via an Intestinal Permeability Test. This test will indicate specific factors such as pore size and the extent of malabsorption.  You will therefore be able to gauge how “leaky” your gut has become as a result of the damage.

Invest in an Intestinal Permeability Test and begin the healing of your gut wall.  Click here for more information.


Emeds Comment

If you suffer from fructose malabsorption, you may find it difficult to spot the foods that you need to cut out your diet. It may come as a surprise but packaged foods have the highest amounts of fructose, it is added as a cheap sweetener.

You will need to become an expert in reading the label. Fructose may be hidden as corn syrup, high fructose corn syrup (HFCS), crystalline syrup, fruit sugar, levulose, D-fructofuranose, just to name a few.

The most effective treatment for fructose malabsorption is a low fructose diet. Total avoidance is not recommended, as small amounts will still be tolerated. Foods in the below table are very high in fructose should be avoided:


What else can I do?

Since glucose has the ability to up regulate GLUT5, glucose powder can be added to fruit juices/drinks or high fructose foods whilst cooking. 

Inflammation has been found to influence GLUT5 expression. By taking an anti inflammatory approach to supplementation and diet, fructose absorption may be improved and the associated symptoms decreased. 

Fish oil has been shown to be an effective long term solution for inflammation. Click here for Emeds best fish oils.

Probiotics may also be beneficial in reducing inflammation while also restoring microbial balance to the gastrointestinal tract. Click here for Emeds best probiotics.


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