Previous research has identified bread, especially bread made from refined white flour, as a food that can raise blood sugar and insulin levels rapidly. This is considered a food with a high glycemic index. Over time, a diet that raises blood sugar too readily has the potential to contribute to a variety of health problems, including diabetes, obesity and heart disease. So what bread is best?

It seems that the obvious solution to a diet with high-glycemic index bread would be a switch to wholesome whole-grain bread. Israeli scientists have found, however, that the obvious solution isn’t necessarily correct.

What Bread Is Best for Blood Sugar?

Twenty volunteers participated in a study comparing industrial white bread made from refined flour to sourdough bread baked of stone-milled whole-wheat flour in an artisanal bakery. The investigators chose sourdough as one of the options because it may raise blood sugar less than ordinary bread. The volunteers were randomly assigned to eat one type of bread during the first week and the second type during another week. In between, there was a break period of two weeks to “wash out” any effects.

No Overall Differences in Blood Sugar:

The scientists found no significant differences in wake-up glucose responses to the two different types of bread. They also detected no differences between groups on the oral glucose tolerance test, a way of determining blood sugar response to food. They theorize that the differences between individual responses averaged themselves out in the groups.

What Bread Is Best Depends on Your Gut Microbes:

About half the participants had higher blood sugar levels on the white bread diet; the other half had their blood sugar rise more on the sourdough bread diet. The scientists also studied the volunteers’ intestinal microbes. Variations in the abundance of certain species were linked to the different glycemic responses to the two types of bread.

Korem et al, Cell Metabolism, June 6, 2017 

Learn More:

We interviewed one of the senior researchers on this project about related work a few years ago. That experiment determined that “glycemic index” is not one-size-fits-all. Eran Segal, PhD, explained it to us in Show 1017: How to Avoid Weight Gain Over the Holidays.

If you would like guidance on fixing food that is more likely to be low in glycemic index, you’ll find tips in our book, Recipes & Recipes from The People’s Pharmacy.

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  1. Mary Katheryn
    Stuart, FL

    Can you verify the chemical “Round-Up” is being used to harvest wheat in this country; and thus those folks who think they are gluten intolerant are actually reacting to the poison in “Round-Up”?

  2. G

    I think you have a typo in the last paragraph unless you have two books with recipes.

  3. Bruce Higginbotham

    I believe Ezekiel Sprouted Grain bread from Food For Life is the best available bread. It’s in the orange wrapper. It does take some bother because there are no preservatives, so you can’t leave it out at room temperature. It is not gluten free. But it is special.

  4. Frances

    This is yet another fascinating piece in the groundbreaking Israeli research into the microbiome’s effect on everything to do with health and its individual basis.
    It’s not clear whether the wheat used is traditional European wheat or older Middle Eastern strains – probably not the “new” short wheat we use in America called out by, for instance, the book WHEAT BELLY, for its negative health effects. It’s also not clear whether any of the test subjects were harboring large candida populations. And wild yeasts are different everywhere, of course.

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