Fructose – also referred to as fruit sugar – is a monosaccharide. Just like glucose and galactose, fructose also gets absorbed directly into the blood after consumption. Fructose is generally:

 · Sweet;
· White;
· Odorless;
· Water-soluble;
· Comes in the form of solid crystals.

Every single year about 240,000 tons of crystalline fructose are produced. These massive amounts of crystalline fructose are added to countless products – for a variety of purposes – from candy to sauces and way more. This is also why it’s important to make sure that fructose isn’t used as a sweetener, when consuming processed foods – if fructose is one of the FODMAP’s that triggers your IBS and / or SIBO.

Malabsorption

‘Fructose malabsorption [is prevalent in] about 22% of patients with IBS. Taking on a low-fructose diet is one of the possible treatment strategies. Research – looking into fructose malabsorption – shows that ‘symptoms occurred after an [average] delay of 62 min after fructose intake, but their early onset – within the first 30 min of the test – was reported by 44% of the patients.’ 1

Studies show that fructose is not completely absorbed in the small intestine and thus gets transported into the larger intestine.

In the larger intestine it gets fermented by the gut bacteria (also known as colonic flora). During this process hydrogen ‘is exchanged across the lungs and is measurable by the hydrogen breath test.

The colonic flora also produces carbon dioxide, short-chain fatty acids, organic acids and trace gasses in the presence of unabsorbed fructose.’ 2

But, what about that process causes all the symptoms?

Why fructose causes symptoms

‘The presence of gasses and organic acids in the large intestine causes gastrointestinal symptoms such as bloating, diarrhea, flatulence and gastrointestinal pain.’ 2

For more information about monosaccharides and why they cause the symptoms they do, click here!