Fermentable carbohydrates
Gut fermentation is the process whereby gas and other things are produced as food is being digested (broken-down into smaller parts) by bacteria. It is similar to what happens when beer is being brewed or indeed, in a garden compost heap!
There are several different food components that are fermented by bacteria in the gut. One of the by-products of fermentation is gas, which can cause tummy pain (by stretching the gut), bloating and excess 'wind'. Another by-product is fatty acids that can act like a laxative, because they can be an irritant to the cells of the gut wall.
Lactose
This is the sugar naturally present in milk and milk products (whether cow, goat, sheep or human milk). As babies, all of us have an enzyme tool (called lactase) in our small bowel wall which breaks up the lactose chain of molecules, so that it can be absorbed. The lactase enzyme
works as 'scissors, cutting up the lactose into smaller pieces that can be handled by the cells lining the gut.
As we grow into adulthood, our ability to make lactase can become less, particularly if we are of Chinese or Japanese heritage. Not making enough lactase makes lactose indigestible. This means that it cannot be absorbed in the small intestine, so it ends up in the colon where bacteria ferment it.
During a bad episode of food poisoning, gut cells that make lactase can be 'stripped' away and then only partially re-grow, which will compromise a person's tolerance to milk and milk products - sometimes this change can be permanent.
Fructose
Fructose is sometimes referred to as 'fruit' sugar – fructose is actually one of several different types of sugar in fruit. Very importantly, fructose may also be present as a sweetener in a range of foods and drinks.
The process that helps us to absorb fructose in the small intestine is complex and gets easily overwhelmed, which results in fructose not getting absorbed. So, consuming too much fructose in one go can result in a lot of this sugar ending up in the colon, where it is fermented.
This is not a problem for many, but for some of us, fermentation of fructose can cause excess 'wind', bloating, tummy pain and loose
/ frequent stools.
One key "hidden" ingredient to look out for as a possible cause of bowel symptoms such as gas or diarrhoea is High Fructose Corn
Syrup (HFCS) which is increasingly found in soft-drinks, breakfast cereals and other foods.
Fructans
These are related to fructose and actually are a string of pure fructose molecules strung together in a chain like a string of beads. We can't break up the links in these chains (i.e. digest them), which means that we can't absorb them, so fructans end up in the colon, where they get fermented.
Foods that are high in fructans include artichokes, asparagus, leeks, garlic, onions and wheat - wheat also contains gluten.
Galactans
These are galactose (another type of sugar) molecules linked together in a chain like a string of beads (much like fructans).
We can't digest the galactan chains and so they also end up in the colon, where they are fermented. Galactans are found in pulses e.g. baked beans, kidney beans, chick peas.
Sugar alcohols
We cannot digest or absorb these food components, so they too end up in the colon, where they are fermented. Sugar alcohols
include sorbitol, mannitol and xylitol and are naturally present in some fruits and vegetables. Importantly, they are also used as low-calorie sweeteners in a range of foods, drinks and confectionery such as sugar-free gum and snack-bars. They are very definitely something that you need to look out for if diarrhoea, bloating or gas are the problem.
Gut fermentation is the process whereby gas and other things are produced as food is being digested (broken-down into smaller parts) by bacteria. It is similar to what happens when beer is being brewed or indeed, in a garden compost heap!
There are several different food components that are fermented by bacteria in the gut. One of the by-products of fermentation is gas, which can cause tummy pain (by stretching the gut), bloating and excess 'wind'. Another by-product is fatty acids that can act like a laxative, because they can be an irritant to the cells of the gut wall.
Lactose
This is the sugar naturally present in milk and milk products (whether cow, goat, sheep or human milk). As babies, all of us have an enzyme tool (called lactase) in our small bowel wall which breaks up the lactose chain of molecules, so that it can be absorbed. The lactase enzyme
works as 'scissors, cutting up the lactose into smaller pieces that can be handled by the cells lining the gut.
As we grow into adulthood, our ability to make lactase can become less, particularly if we are of Chinese or Japanese heritage. Not making enough lactase makes lactose indigestible. This means that it cannot be absorbed in the small intestine, so it ends up in the colon where bacteria ferment it.
During a bad episode of food poisoning, gut cells that make lactase can be 'stripped' away and then only partially re-grow, which will compromise a person's tolerance to milk and milk products - sometimes this change can be permanent.
Fructose
Fructose is sometimes referred to as 'fruit' sugar – fructose is actually one of several different types of sugar in fruit. Very importantly, fructose may also be present as a sweetener in a range of foods and drinks.
The process that helps us to absorb fructose in the small intestine is complex and gets easily overwhelmed, which results in fructose not getting absorbed. So, consuming too much fructose in one go can result in a lot of this sugar ending up in the colon, where it is fermented.
This is not a problem for many, but for some of us, fermentation of fructose can cause excess 'wind', bloating, tummy pain and loose
/ frequent stools.
One key "hidden" ingredient to look out for as a possible cause of bowel symptoms such as gas or diarrhoea is High Fructose Corn
Syrup (HFCS) which is increasingly found in soft-drinks, breakfast cereals and other foods.
Fructans
These are related to fructose and actually are a string of pure fructose molecules strung together in a chain like a string of beads. We can't break up the links in these chains (i.e. digest them), which means that we can't absorb them, so fructans end up in the colon, where they get fermented.
Foods that are high in fructans include artichokes, asparagus, leeks, garlic, onions and wheat - wheat also contains gluten.
Galactans
These are galactose (another type of sugar) molecules linked together in a chain like a string of beads (much like fructans).
We can't digest the galactan chains and so they also end up in the colon, where they are fermented. Galactans are found in pulses e.g. baked beans, kidney beans, chick peas.
Sugar alcohols
We cannot digest or absorb these food components, so they too end up in the colon, where they are fermented. Sugar alcohols
include sorbitol, mannitol and xylitol and are naturally present in some fruits and vegetables. Importantly, they are also used as low-calorie sweeteners in a range of foods, drinks and confectionery such as sugar-free gum and snack-bars. They are very definitely something that you need to look out for if diarrhoea, bloating or gas are the problem.
