Monday, July 24, 2017

When to Measure Postmeal Glucose Levels

What's the best time to test your blood glucose (BG) after meals?

Of course that depends on what you want to learn from testing after meals. If you want to know the after-meal peak, then you should test about an hour after you eat. The peak will differ a bit with different foods; fats slow down gastric emptying, and liquids pass through faster than solids. It also can differ with different people.

So if you want to know where your own peaks are, you should test every 15 minutes or so starting about 45 minutes after eating and continuing until the numbers start coming down.

If you want to know if you're able to return to normal, or close to normal, BG levels within a few hours, then you should test at 2 or 3 hours.

"After eating" is also ambiguous. Should you test X minutes after you start to eat or after you stop eating? Again, it depends on your habits. If you wolf your meal down, it doesn't much matter. If you eat leisurely and take 30 minuts to finish a meal, then it does. What you really want to know is differences between different meals, so the important thing is to test about the same way every time. Don't compare one meal you ate in 4 minutes with another one that you took an hour to finish. Most people measure the time after starting to eat.

If you ask CDEs or your doctor when to test, they'll usually tell you to test at 2 hours. This is because most research papers about postprandial (after meal) BG numbers use the 2-hour reading. But this may not be the best.

One researcher, Antonio Ceriello, recently published a paper proposing that it's time to switch to a one-hour postprandial measurement. He kindly sent me a copy of the full text of the paper.

Ceriello says that there's evidence that the one-hour measurement has even stronger power than the two-hour measurement for identifying impaired glucose tolerance. He said this number is also related to the risk for cardiovascular complications. In vitro experiments have shown that just one hour of high BG levels is enough to cause endothelial dysfunction that can then lead to coronary vascular disease, as well as reactive oxygen species (strong oxidants), he said.

Endothelial function is worse at one hour than at two hours both during oral glucose tolerance tests and after meals, he said.

If all this isn't enough, Ceriello said short-term high BG levels can impair beta-cell function.

When I've measured BG levels in nondiabetic friends and relatives, I've sometimes found one-hour readings of 160 or so, but the numbers come down to baseline by two hours. Testing only at two hours wouldn't identify these people, who might be at risk of developing diabetes in the future.

Ceriello's recommendations apply to clinical studies, but there's no reason you couldn't measure at one hour if you so chose. The best, of course, would be to measure at both one hour and two hours if you could afford enough strips. Then you'd know which time made most sense for you.

Even if most clinicians accept Ceriello's recommendations, it will take time before they become standard. So for now most studies will continue to use the two-hour numbers. But when  you see a study mentioning postprandial (or postmeal) numbers in the future, you should check to see what they mean, if you can (abstracts may not specify).

If anyone wants references to the studies Ceriello was citing, let me know and I'll send them to you. If I get tons of requests, I'll just edit this post to put the links in.

Saturday, July 8, 2017

Of Mice and Humans

"New Research Describes the Differences Between Mice and Humans" screams a headline of an article in Eurekalert. 

Golly. I guess I'm ahead of my time because I've known the differences between mice and humans for decades. The mice are the furry ones with long tails, and the humans are the larger ones who fight and kill each other because they don't agree on politics or religion.

But once you get past the headline on Eurekalert, you find that researchers are finally accepting that mouse research often doesn't translate into human treatments. Mice have been cured of diabetes hundreds of time, but the drugs the researchers used just don't seem to work when they try them on humans. 

The problem is that it would be unethical to try new drugs on humans without some evidence that they might do something beneficial. Mice are relatively cheap to maintain, and we already know a lot about them. If we used only larger animals like pigs or dogs or monkeys, the cost of research would be even higher than it is now, and animal rights groups would protest. Very few people object to mistreating rodents.

Now researchers are beginning to find out why mouse research doesn't always translate into human cures. These researchers looked into a class of receptors found on beta cells in both mice and humans. They are called G-protein-coupled receptors (GPCRs), but the names don't matter.

What they found was that some of these receptors are found in both mice and humans, but others are not. Some are found only in mice, and others are found only in humans. If they know which ones are found in both mice and humans, future researchers can limit their research to those receptors. There's no point in spending millions of dollars on some drug that affects a receptor found only in mice! That money could instead be used to study drugs that affect both species.

Of course not all drugs target GPCRs. But a large number do. Let's hope these findings channel research into fruitful drugs, and not duds.

Thursday, July 6, 2017


I know what ravenous hunger is.

More than 20  years before I was Dx'd with type 2 diabetes, I used to get reactive hypoglycemia, although I didn't realize that's what it was. At the time, I was working at a daily newspaper, and I occasionally did the wire desk, which mean I had to arrive at work at 7 a.m.

I normally didn't eat breakfast, and I wasn't especially hungry for lunch. But because I was a night owl and hated getting up early enough to get to work by 7, I'd reward myself with a chocolate doughnut, in addition to the strong black coffee I usually had.

Then, almost exactly 4 hours later, I'd get the shakes and a feeling that if I didn't eat something immediately, I was going to die. So I'd rush to the candy machine and get a candy bar, and that got rid of the shakes and the feelings of doom.

Now if I go low, which doesn't happen often but it does happen, I have that same feeling that if I don't eat I'm a goner. And because I want to get rid of that feeling that I'm doomed, I sometimes overtreat and then go high for hours.

Of course the official recommendation is to eat 15 grams of carbs, wait 15 minutes and retest, then eat a little more if you're still low. But one thing I really miss on my low-carb diet is fruit. When I was a kid I remember telling my mother, "What I really like is meat and fruit." So I keep canned sugarfree peaches in the cupboard to eat if I go low. They have about 6 grams of carbs in a cup, which is often just right when I'm not very low, and I wolf them down.

So I was wondering if this same 15/15 approach would work not just for lows but for weight loss.

I suspect that many people who have weight problems have something wrong with their appetite controls. When everyone else is feeling just hungry before a meal, they may feel ravenous. And when you're ravenous you tend to wolf down whatever you can reach. It takes about 20 minutes before your body lets you know you've had enough, and if you eat fast, by that time you've eaten a lot more than you need.

It's not enough to tell people to eat slowly. What exactly does that mean? Would it work better to measure out a small amount of food, eat it, and then wait 15 minutes? If you were still hungry, you could eat a second small amount of food. You'd keep doing this until you were no longer hungry.

Of course, if you have only 30 minutes for lunch, this would be difficult. Even with an hour it might be hard if it took four small portions and until you felt full. If so, you could increase the portions until you found an amount that filled you up with one or two servings.

So would this work? I really don't know. I'd try it myself but I no longer get ravenously hungry except when I'm very low, and that doesn't happen very often. I've always had a big appetite. One time a waiter at a Chinese restaurant remembered me two years later. He said they'd all been talking about me, "Because we'd never seen anyone so small eat so much." (This was in the days before they let you take extra food home and I hated to waste food, so I ate my whole meal, including the rice, and then finished what my brother couldn't eat.)

But as I get older my appetite seems to have abated, and "normal" portions now seem dauntingly large. So I no longer have that urge to stuff myself. I sometimes even stop eating when there's still food on my plate and heat it up and eat it at the next meal. So my weight has been steady for a long time.

It's nice to have a normal appetite after all these years, but I do understand what it's like to feel ravenous. I wish we could figure out how to fix that.