Many people (and their doctors) use A1C and fasting blood glucose levels to gauge their diabetes control. But those numbers only tell half the story. To prevent organ damage, we also have to keep glucose from spiking after meals. How can we do that?
Do You Spike?
If you just check your blood glucose levels in the morning and maybe at bedtime, you will miss these spikes. Say your numbers at those times usually run about 125 mg/dl. If your blood sugar levels were like that all day, your A1C would be about 6.0%. But maybe when the doctor tests your A1C, it might be closer to 7.6%. You know then you are spiking after meals high enough to raise your average sugar to 170, which means spiking well over 200. You can find a good calculator for converting A1C to average glucose here.
Glucose levels above 140 can lead to inflammation of blood vessels and organs. The higher the spike goes and the longer it lasts, the more damage there is likely to be. With any type of diabetes, we want to get those spikes down, and it takes a lot of monitoring and experimenting to get it right.
Gary Scheiner, MS, CDE, who has Type 1, wrote here that for Type 1s, it’s about managing your insulin so that it peaks when blood glucose is peaking and drops off when glucose levels do. You can only do that with fast-acting insulin injections or a pump. But even then, you have to know how much a given meal is likely to raise your sugar to know how much to give and when to give it. Scheiner recommends testing about an hour after completing a meal or snack. That’s when sugar levels tend to be highest.
Jenny Ruhl at Diabetes Update says different people and different foods spike differently. So to find the very highest spike, you might have to try different times. “Meals heavy in fat digest more slowly than those that are made up mostly of starches and sugars,” she says. “Large meals of any composition may produce a slightly delayed spike.” High protein meals may spike even later. It will take some experimenting to find out.
It’s also valuable to learn how fast blood sugar levels come back down, and how low. So you might want to check again an hour after the peak. Ruhl says that, “When you take a second reading is up to you and depends on how many strips you have and what [you already know] about how your blood sugar works. Most of us will find it informative to [check] an hour after the peak occurs to see how fast our blood sugar is dropping from its peak.”
For many people, after-breakfast spikes go the highest. It may be that insulin resistance is worse in the mornings because you haven’t been moving around much.
Shrinking the Spike
You can do many things to reduce after-meal (also called “postprandial”) spikes. Most important is eating fewer, less-refined carbs. More vegetables, more fiber, so that glucose gets into the blood more slowly. Including some protein at each meal also slows the rise in glucose. (This includes breakfast!) If you’re Type 2, your natural insulin might be able to keep up with this slower drip of glucose into the blood.
You can also check the glycemic index (GI) of your foods. Low-GI foods put glucose in your system more slowly, reducing spikes. This page has a good glycemic index chart.
Gary Scheiner recommends mild physical activity after eating to reduce insulin resistance and get glucose into cells. “The key is to avoid sitting for extended periods after eating,” he says. He also gives many tips on working with insulin boluses and basal rates here.
There are reliable natural ways to reduce spikes. One of the best is vinegar (apple cider, rice, or wine). Take a couple of teaspoons as part of a dressing or drink or in a capsule before or near the beginning of a meal. Dozens of readers commented here that vinegar had lowered their blood sugar levels.
Cinnamon also has been found to reduce glucose spiking. A study in The Journal of Clinical Nutrition found that, “Inclusion of cinnamon in the diet lowers the postprandial glucose response, a change that is at least partially explained by a delayed gastric emptying rate.”
One study found that mulberry leaf reduced spikes by 44%, probably by slowing carbohydrate absorption, (like the starch-blocker drug acarbose (brand name Precose.) Other studies show that mulberry reduces insulin resistance. Most of these studies come from Korea and Japan. Here mulberry leaf extract is marketed as the main ingredient in Glucocil, a popular supplement. Glucocil is a little pricey (though not compared with brand name prescription drugs), but straight mulberry leaf extract is available for less than $10 a month.
So it seems not too hard to reduce postprandial spikes, and well worth the effort. How has that gone for you?