Processed white bread is often shunned by those looking to live a healthier lifestyle, but new research suggests that it may be just as healthy as brown bread.
Researches from the Weizmann Institute of Science analysed the levels of fat, cholesterol and key vitamins and minerals in participants eating different breads and found very little difference between the two.
Surprisingly, the investigators found the bread itself didn’t greatly affect the participants and that different people reacted differently to each bread type.
During the study, 20 healthy individuals were divided into two groups and advised to incorporate a specific bread into their diet.
Half the participants were given whole wheat sourdough bread to consume while the others were given the same portion of processed, packaged white bread.
Whole-wheat sourdough is a type of brown bread made through the natural fermentation of the yeast and bacteria found in flour.
The study participants were instructed to consume a higher-than-usual amount of bread (around 25% of their calories, compared to the average bread consumption of 10%).
The participants ate their first bread type for a week, before a two-week resting period where no bread was consumed. After this, the breads for the two groups were reversed.
Before the study and throughout the time it was ongoing, many health effects were monitored.
These included wakeup glucose levels; levels of the essential minerals calcium, iron, and magnesium; fat and cholesterol levels; kidney and liver enzymes; and several markers for inflammation and tissue damage.
The investigators also measured the makeup of the participants’ gut bacteria before, during, and after the study.
“The initial finding - and this was very much contrary to our expectation - was that there were no clinically significant differences between the effects of these two types of bread on any of the parameters that we measured,” said Eran Segal, a computational biologist at the Weizmann Institute of Science and one of the study’s senior authors.
“We looked at a number of markers, and there was no measurable difference in the effect that this type of dietary intervention had.”
Surprisingly, the researchers found that different people responded to different breads in contrasting ways.
About half the people had a better response to the processed, white flour bread, and the other half had a better response to the whole wheat sourdough. The lack of differences were only seen when all findings were averaged together.
“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,” said Eran Elinav, a researcher in the Department of Immunology at the Weizmann Institute and another of the study’s senior authors.
“To date, the nutritional values assigned to food have been based on minimal science and one-size-fits-all diets have failed miserably.”
He added: “These findings could lead to a more rational approach for telling people which foods are a better fit for them, based on their microbiomes [a group of microorganisms such as bacteria and viruses].”
Avraham Levy, a professor in the Department of Plant and Environmental Sciences and another coauthor, added a caveat to the study: “We know that because of its high fibre content, people generally eat less whole wheat bread. We didn’t take into consideration how much you would eat based on how full you felt. So the story must go on.”