I have just been reading about the rationale for the
GAPS (gut and psychology syndrome) diet and the very similar
SCD (
specific carbohydrate diet), the latter which dates back to 1924. I understand that the GAPS diet is the same as the SCD in terms of food restrictions; but in GAPS, some extra food types are added, which are thought beneficial for intestinal health.
The main restrictions of the SCD (and the GAPS diet) are the avoidance of certain carbohydrates, specifically:
disaccharides (eg sucrose, lactose, maltose) and most
polysaccharides (grains, potatoes, rice, maize) are not allowed, because these cannot be directly absorbed in the small intestine: they first need to be broken down into monosaccharides (simple sugars) before they can be absorbed into the bloodstream.
The theory is that if these disaccharides and polysaccharides are not fully broken down into monosaccharides and absorbed in the small intestine, some disaccharides and polysaccharides will pass partially digested into the colon, where they get eaten (fermented) by the bacteria in the colon (by both the good and bad bacteria).
This will tend to cause gas and bloating, as bacterial fermentation releases gases such as hydrogen, methane and carbon dioxide. But moreover, if you have pathogenic bacteria in your colon, these partially digested carbohydrates may nourish the bad bacteria and allow them to proliferate (bacteria ferment these carbohydrates to obtain energy).
So the rationale for the SCD and GAPS diet diet is to eliminate disaccharides and polysaccharides from the diet, so that there is very little food for the bad bacteria to eat. Presumably it would be a good idea to add prebiotics to the SCD and GAPS diet, as prebiotics are defined as food that the friendly can eat, but that bad bacteria cannot make much use of.
The SCD allows you to eat
monosaccharide sugars (eg glucose, fructose, galactose), as these are directly absorbed in the small intestine, and so will not pass into the colon to feed the bad bacteria. So fruit is fine on the SCD, as this contains fructose. And honey is fine, as the main sugars in honey are glucose and fructose.
Here is a list of legal and illegal foods in the SCD.
The
Paleolithic diet (stone age diet) is similar to the SCD, but is not quite as strict (allows some carbohydrates that are not allowed on the SCD). The low
FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) diet also follows the same basic rationale as the SCD: it restricts any carbohydrates that can pass partially digested into the colon, where bad bacteria may feed on them.
An Easier Alternative to the SCD, FODMAP and GAPS Diets?
It occurs to me that instead using these hard to follow SCD, FODMAP and GAPS diets, a much easier shortcut to obtaining the same results might be to take a supplement that provides all the appropriate enzymes needed to digest the disaccharide and polysaccharide carbohydrates. That way, you could still eat the normal range of carbohydrate foods wihout any restriction, but the supplemental enzymes should ensure that all these carbohydrates are fully digested and absorbed in the small intestine, and that no partially digested carbohydrates reach the colon, where they may feed pathogenic bacteria.
The most important enzymes for digesting carbohydrates I have listed and detailed below. These enzymes include
amylase (secreted by the
pancreas),
glucoamylase,
maltase,
isomaltase,
sucrase and
lactase (all secreted by the
brush border in the small intestine).
I looked at dozens different digestive enzyme supplements, and the following have the highest levels of enzymes that break down carbohydrates (brush border enzymes and the pancreatic enzyme amylase):
Enzymedica, Digest Gold with ATPro
Source Naturals, Essential Enzymes Ultra
Healthy Origins, Digestive Enzymes, Broad Spectrum
Garden of Life, O-Zyme, Digestive Enzyme Blend
Garden of Life, O-Zyme, Ultra, Ultimate Digestive Enzyme Blend
Enzymedica, Digest Spectrum
Swanson Ultra BioCore Optimum Complete Ultimate Full Spectrum Enzymes
It may be that such carbohydrate-digesting enzyme supplements will not be as effective as the SCD diet; but it may be worth trying them, as it will be so much easier than the diet.
Further discussion in
this post.
Digestive Enzymes That Break Down Carbohydrates
In the small intestine, the following enzymes break down carbohydrates (via hydrolysis):
- The pancreatic enzyme amylase (which is also found in the saliva) breaks down carbohydrates into the maltose, maltotriose and dextrins (dextrins are polymers of glucose).
- The brush border enzyme glucoamylase (also called amyloglucosidase) breaks down dextrins into the monosaccharide maltose (which is then absorbed) and the trisaccharide maltotriose.
- The brush border enzyme maltase breaks down maltose and the trisaccharide maltotriose into glucose, which is then absorbed.
- The brush border enzyme isomaltase breaks down polysaccharides which cannot be broken by amylase or maltase.
- The brush border enzyme sucrase breaks down sucrose into glucose and fructose, which are then absorbed.
- The brush border enzyme lactase breaks down lactose into galactose and glucose, which are then absorbed.
Another enzyme sold as a supplement for the purpose of digesting carbohydrates is
alpha-galactosidase (this enzyme is naturally secreted by the saliva glands).
