In my last column, we followed sugars and starches through the trail of digestion. We followed the carbohydrate foods through the mouth and down to the upper part of the bowel as they were broken into simple sugars by the action of enzymes produced in the mouth, the stomach, and the small intestine.
A Short Detour: Should We Take Supplemental Digestive Enzymes?
It was my intent, with this column, to continue right along in this discussion with the next part of the fascinating facts of carbohydrate absorption and utilization. But I received a question sent via email from a reader of these pages, and I think her question may also be in the minds of other readers. So we are taking a short detour to talk about the advisability of supplemental digestive enzymes.
As I pointed out last time, those of us who are trying to lose weight, sometimes lose track of the fact that the body wants to take in food and use it to our best advantage. It does this by digesting the food, thereby making it ready for transfer into the body’s tissue cells. The necessary factors are enzymes, which are produced in our bodies for this purpose. Only simple sugars can be absorbed into the cells of the body, and enzymes are necessary to break down the complex carbohydrates to the simple sugar stage.
As we learned last time, by the time the food has reached the end of the small intestine, the sugars have been made ready and the non-digestible fiber is in attendance, but there is nothing much else present, in so far as carbohydrates are concerned. However, if there are remaining undigested digestible carbohydrates (either because huge, pig-out amounts of carbohydrates were eaten, or because not enough enzymes were produced), the person will be an unhappy camper because there are not supposed to be large quantities of undigested digestible carbohydrates beyond a certain point in the intestine.
Since there are bacteria in the gut, the bacteria will act on these undigested carbohydrates in a process known as fermentation. This will result in symptoms such as nausea, intestinal gas, flatulence, abdominal swelling, possible diarrhea, possible constipation, and pain. Or, if the carbohydrates are mixed with undigested protein, the bacterial action may result in putrefaction in the gut, which can also result in the same, but often more severe, unpleasant symptoms.
Yes, No, and It Depends
The essence of the question posed by my reader was this: Should a person take supplemental enzymes in order to help the body digest carbohydrates more easily, as was recommended by some (unspecified) diet plan? And, if a person is deficient in digestive enzymes because his/her body does not make enough, is this deficiency a good thing for weight loss?
The answer, dear readers, is “Yes, no, and it depends.”
Yes: a person would benefit from taking supplemental carbohydrate-digesting enzymes if his/her body does not produce enough, as evidenced by the presence of the symptoms mentioned above.
No: a person seeking weight loss should not take supplemental enzymes in the absence of such symptoms because, if some of the carbohydrate passes unused from the body, so much the better.
Yes: a deficiency of carbohydrate-digesting enzymes is a good thing for weight loss, in theory, but the weight-loser will be sorry for it. Constant diarrhea is no price to pay for weight loss. Ask any sufferer of Irritable Bowel Syndrome.
No: a person should not try to interfere with their carbohydrate-digesting enzymes by taking such things as Carb Blockers because the resulting symptoms may be severe.
It Depends: taking a general mixture of enzymes as a supplement is only going to help if the proper enzymes are present in the mix. Remember that enzymes are very specific for what they act upon. If a person is deficient in lactase, and is therefore lactose intolerant, taking papain (an enzyme derived from papaya fruit) is not going to help. Papain is used as a meat tenderizer because it acts on protein; it is not a carbohydrate-digesting enzyme.
Back On Track: How Carbohydrates Are Digested
So, all that said, we are now ready to get back on the trail of sugars entering the system. We are in the small intestine and the sugars to be absorbed are all simple sugars. First, some new terms.
The term diffusion, as it pertains to carbohydrate absorption, means the transferring of the simple sugars, which are in solution (in water), through the walls of the intestine, and then through the walls of the individual cells of the body tissues.
When we talk about the walls of the cells, we use the term membrane because the wall is extremely thin. The simple sugars and the water diffuse through the membrane walls. But the membrane does not allow everything to flow in or out, otherwise there would be no reason for the membrane to be there at all.
The membrane has what is called selective permeability. That term means that certain things are allowed in and certain things are allowed out, but other substances are blocked passage. The mechanisms by which substance Y is allowed in while substance Z is refused admittance are very complicated.
Only Simple Sugars Are Permitted To Pass Through
For our purposes, suffice it to say that in the case of carbohydrates, the membranes only allow simple sugars to diffuse in, but they does not allow complex sugars or fiber to pass through. Any complex carbohydrates that are still present, all the fiber, and a lot of the water continue down the intestinal tract, where we will catch up to them in another article, some time in the future.
The sugars, meanwhile, pass through the membranes of the intestinal wall and enter the blood, where they are, for the most part, carried directly to the liver. And that is where we will leave it for today.
Next time we will be exploring what happens after the sugars reach the liver. It just gets better and better! I hope you’ll join our discussion.