Slow Digestion Can Explain Odd Readings

I received emails this week from three different correspondents that asked about strange blood sugar readings several hours after eating. In my replies I mentioned slowed digestion as a possible cause. As I did so I realized this is a blood-sugar related problem that isn't often discussed in mainstream media, so it isn't familiar to all of us.

I first learned about it in reading Dr. Bernstein's landmark book,Dr. Bernstein's Diabetes Solution. Bernstein explains that delayed digestions, which he calls by its medical name, gastroparesis, results when neuropathy affects the nerves of the autonomic nervous system that control the opening and closing of the valve at the bottom of the stomach.

If the valve stays shut after eating, your food does not get to the upper part of the gut where much of it digests. As a result, starch and complex sugars don't turn into glucose and your blood sugar stays low after eating. Eventually, of course, the valve does open, and when it does your food digests and your blood sugar rises.

If you aren't using insulin, this merely will give you odd readings. You'll see good readings an hour or two after eating, only to discover your blood sugar soaring the third hour.

However, if you use fast-acting insulin at meals this effect can be dangerous, because your insulin will peak at about an hour after you eat whether or not your blood sugar is high. If you inject enough insulin at the time you eat to cover a significant amount of carbohydrate, you may end up with a hypo if that carbohydrate doesn't digest into glucose in time to meet the insulin.

And even if you don't hypo, if digestion is delayed, by the time your food does digest you may not have any insulin left to cover it, so you will end up with a very high blood sugar.

Delayed stomach emptying can be very hard to deal with because there may be no pattern to how the valve behaves. It may open at different intervals after every meal. Fast one meal, very slow the next. You may eat lunch and not have it digest until you eat your dinner.

Dr. Bernstein's book contains a long section that lists various treatments he's found helpful when treating patients with the slow stomach emptying that results from autonomic diabetic neuropathy. It's well worth reading if you suffer from this problem.

Since the autonomic neuropathy that causes delayed stomach emptying is a late diabetic complication that occurs only after long exposure to very high blood sugars, most of the people with Type 2 diabetes who are reading this blog because they are devoted to keeping their blood sugar normal aren't likely to experience it.

But--and Dr. Bernstein does not discuss this--there are other conditions besides autonomic diabetic neuropathy that can also cause delayed stomach emptying. So slowed digestion does occur in otherwise healthy people with normal blood sugars.

A friend of mine experienced this problem--confirmed by gastroscopy--after suffering a severe bout of stomach flu. It lasted for more than five years until for no discernible reason it finally went away.

People who have other medical conditions that affect the functioning of their nerves or muscles may also experience this phenomenon, regardless of their blood sugar status. It may also come on with age, when the digestion seems to slow down for many people. It may even be a response to the inflammatory reactions associated with conditions like gluten sensitivity.

This is why some people with diabetes who have kept good control over of their blood sugars or who are recently diagnosed will still see readings that don't make sense to them. Delayed stomach emptying keeps their blood sugar from peaking at the average time--75 minutes after eating--and they see surprise blood sugar highs at some other time, anywhere from one to four hours after eating.

If this is your pattern, especially if it occurs in an unpredictable manner, you will have to be extremely careful when injecting insulin to cover a meal. If your meal delay is predictable--for example, if you always see a peak after eating at two hours rather than one, you can just inject your insulin an hour later. But if it isn't predictable, using insulin according to some "one size fits all" dose schedule your doctor handed you may become dangerous.

One helpful rule to use when dealing with this problem--one that is a lot easier to follow if you are eating a relatively low amount of carbohydrates--is to never inject more insulin before a meal than your body could handle even if there was no food coming in at all. This may not be enough to fully cover the meal, but if you don't know when your meal will digest, it's better to shoot less than too much. Then, an hour after you eat, test your blood sugar, and based on what you see then, inject an additional corrective dose.

Never injecting more insulin than you can handle on an empty stomach is a good practice to follow even if you don't have stomach issues, because things sometimes come up that keep you from eating a meal, after you've injected--like a sudden attack of vomiting or a family emergency. So it's never a good idea to inject more insulin than your body can handle without a lot of carbs in it.

However, in order to use this kind of strategy where you inject partial doses and calculate a correction dose, you will have to have a very good understanding of how to match insulin to carbohydrates. If you are injecting the same amount for each meal because that's what you were taught by the "diabetes nurse" at your doctor's practice, you need to get yourself some more education before you try it.

A good place to start is to read Dr. Bernstein's book or John Walsh's Using Insulin.If you don't understand how to match your insulin dose to what you ate after reading up on the subject, don't guess. Demand that your doctor hook you up with someone who can explain it properly. The combination of poorly calculated or generic insulin doses and unpredictable stomach emptying is dangerous and may be one erason why so many older people with diabetes end up with hypos that put them in the hospital.

Many people with Type 2 can avoid having to use insulin at meals if they cut back on their carbohydrate intake enough. If you haven't tried a lowered carb diet you might be surprised how well it works. The strategy described HERE can help you find out just how low you need to go to see results. An intake somewhere near 100 grams a day or 30 grams a meal is very helpful to many people with diabetes without being so low that they find it onerous to stick to it.

Cutting out all products containing gluten is worth a try, too, because so many people find that persistent digestive problems clear up when they do this.

However, if you jump on the currently fashionable gluten-free bandwagon, take care. I'm seeing a disturbing trend, now that this way of eating has become mainstream. The "health food" groceries are filling up with "gluten free" products that are extremely high in carbohydrates, which are being promoted as if they were good for you. They aren't. They are just expensive blood sugar bombs, filled with fast, refined carbs, both starches and sugars. They are a poor choice for anyone who is interested in preserving their health, and for people with diabetes they are dangerous since the high starch and sugar content is guaranteed to raise blood sugar very high.

Have you had experience with delayed stomach emptying? Any tips for dealing with it? Post them in the comments section if you do.