Yes, scientists are now saying that white bread may not be that unhealthy for everyone.
According to research published in the journal Cell Metabolism, investigators from the Weizmann Institute of Science in Israel found that people have varied reactions in blood sugar levels when consuming white and whole wheat bread. In fact, out of the 20 study participants, nearly half were shown to have a better glycemic response to the processed white flour while the other half of the volunteers had a healthier response to the whole wheat sourdough.
Before and during the study, the researchers monitored a number of health effects, including: wakeup glucose levels, fat and cholesterol levels, kidney and liver enzymes, several markers for inflammation and tissue damage, and levels of the essential minerals calcium, iron, and magnesium. The authors theorize that the differences in the gut microbiome — also known as the gut flora, which are the microorganisms that reside in the intestines — might explain for the different reactions.
“The findings for this study are not only fascinating but potentially very important, because they point toward a new paradigm: Different people react differently, even to the same foods,” senior study author Eran Elinav said in a press release. “To date, the nutritional values assigned to food have been based on minimal science, and one-size-fits-all diets have failed miserably.”
“I find the study interesting, but not surprising,” registered dietitian Katherine Brooking, co-founder of Appetite for Health, tells Yahoo Beauty. “Increasingly studies are showing that different people react differently to the same foods.”
However, Brooking quickly adds that glycemic response should not be the only factor taken into consideration when choosing bread. “Whole grains — including 100 percent whole wheat bread — generally provide more fiber, iron, and B vitamins,” continues Brooking. “This is why the USDA’s Dietary Guidelines for Americans recommend that we eat at least half our grain as whole grains.”
She further explains that whole grain items — such as whole-wheat flour, bulgur (cracked wheat), oatmeal, whole cornmeal, and brown rice — contain the entire grain kernel, which is comprised of the bran (the outer layer), endosperm (the middle layer), and germ (the inner layer).
On the other hand, refined grains — the white foods, like white bread, pasta, flour, and rice — have been milled, a process that removes the bran and germ in order to extend the food’s shelf life, along with giving the grain a finer texture. “But it also removes dietary fiber, iron, and many B vitamins,” states Brooking.
“The size of this study is small and the response was studied over a short period of time,” Palinski-Wade tells Yahoo Beauty. It had also “not looked at the long-term health implications of a diet rich in white flour.”
And although these results do not warrant changes in recommendations on whole grain consumption at this time, she continues, “it does suggest more research should be conducted on the impact gut bacteria have on diet and digestion.”
For now, both experts continue to advise holding off buying that loaf of white bread.
“Keep in mind that this study was conducted on a small sample of otherwise healthy individuals without impaired insulin resistance or diabetes,” says Palinski-Wade. “For individuals with diabetes, many see a greater elevation in blood glucose levels after consuming low fiber, refined grains.”
She adds that research also indicates “a diet rich in refined grains may increase insulin resistance over time, making diabetes harder to manage.”
Brooking suggests that anyone who requires a personalized diet for any type of health condition should consult with a registered dietitian. As for a general rule: “Follow the Dietary Guidelines’ advice and make at least half of your grains whole.”
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