Last February I lectured about SIBO at grand rounds at my alma mater NCNM. I was pleased to see that the student evaluations were very positive considering the over-worked and under-slept state of the student body. Apparently it had more to do with my Lord of the Rings example for disaccharide absorption then anything else! Excellent- I’ll be keeping that in my future presentations.
So here are some basics about digestion, disaccharides and Balrogs.
So here are some basics about digestion, disaccharides and Balrogs.
Digestion
Digestion is the the breaking down of food into it's smallest possible elements so that it may be absorbed.
Fats are broken down into fatty acids and glycerol
Protein is broken down into single amino acids
Carbohydrates are broken down into single sugars
Fats are broken down into fatty acids and glycerol
Protein is broken down into single amino acids
Carbohydrates are broken down into single sugars
Enzymes
Chewing physically breaks apart food and then enzymes do the rest. Enzymes are in small amounts in the mouth and stomach, but mostly work in the small intestine (SI). Enzymes usually have the suffix ase (exceptions: pepsin, trypsin, chymotrypsin). They are secreted from the pancreas and embedded in the brush border, or lining, of the SI.
Pancreatic enzymes get all the press and we often forget about the brush border enzymes- peptidases and disaccharidases.
Peptidases break petides (very small proteins) into single amino acids
Disaccharidases break double sugars (disaccharides) into single sugars
Pancreatic enzymes get all the press and we often forget about the brush border enzymes- peptidases and disaccharidases.
Peptidases break petides (very small proteins) into single amino acids
Disaccharidases break double sugars (disaccharides) into single sugars
Absorption
Very small molecules are all that can be absorbed across the brush border. They absorb into and then pass out of a single layer of cells, called enterocytes, into the blood vessel underneath.
What can and can’t pass?
Amino acids (single proteins) pass the brush border
Di & Tri Peptides (very small proteins) pass the brush border
Single sugars pass the brush border
Disaccharides can’t pass brush border
(they need disaccharide enzyme digestion first)
What can and can’t pass?
Amino acids (single proteins) pass the brush border
Di & Tri Peptides (very small proteins) pass the brush border
Single sugars pass the brush border
Disaccharides can’t pass brush border
(they need disaccharide enzyme digestion first)
Problem
The problem in SIBO is that disaccharide enzymes are damaged and can't do their job. Then the disaccharide sugars, such as lactose (milk sugar), sucrose (table sugar) and isomaltose (starch), sit unabsorbed. This makes a perfect meal for the overgrown bacteria, who then rudely expel gas and acids into our SI, leading to all sorts of havoc such as bloating, constipation, diarrhea and brain symptoms.
Balrog
To illustrate, here's a picture of the “You Shall Not Pass” scene from the first Lord of the Rings movie (one of my favorite scenes). Here, the heroes have already crossed the bridge but Gandalf stays to fight off the fiery Balrog that’s been chasing them.
Gandalf (enzyme) will not allow the Balrog (disaccharide) to pass as is (across the brush border). It must be transformed first (obviously, who wants that coming across). For our body, it's just too big and must be broken into smaller pieces.
This is why the diets that treat SIBO avoid all but the single sugars (honey and ripe fruit) which can pass the brush border freely.
This is why the diets that treat SIBO avoid all but the single sugars (honey and ripe fruit) which can pass the brush border freely.
Conclusion
In the case of SIBO, disaccharides are like a Balrog.
For more on how disaccharides are problematic in SIBO, see The Gut/Brain/Food Connection, and/or Breaking the Vicious Cycle, both by Elaine Gottschall.
For more on how disaccharides are problematic in SIBO, see The Gut/Brain/Food Connection, and/or Breaking the Vicious Cycle, both by Elaine Gottschall.