White bread may be healthier than whole — for some

White bread may be healthier for some people than whole, according to a new study from Israel’s Weizmann Institute.

The findings, published in the journal Cell Metabolism, follow a study of 20 healthy adults, divided into two groups.

Every participant was asked to make bread a quarter of their calorie intake for a week.

One group ate processed white bread made from mostly refined wheat, while the other consumed sourdough-leavened bread made in an artisan bakery from freshly stone-milled whole grain wheat flour and baked in a stone hearth oven.

After a two-week break, the groups switched, and for a week the group that had eaten white bread ate the sourdough bread, and vice versa.

Subjects were told not to consume any other wheat products, such as pasta, during the test periods.

While tests showed that both breads influenced blood sugar levels, minerals, liver enzymes and other substances, the researchers were surprised to discover that there were no significant links to the type of bread consumed.

In one finding, about half of the participants had higher blood sugar after eating white bread, while the other half had higher blood sugar after eating sourdough bread.

Prof. Eran Segal, who headed the study with Prof. Avraham Levy and Dr. Eran Elinav, speculated that the findings were “probably because the body’s response to bread is a highly personal matter, so the differences between people in the study averaged themselves out.”

It was possible, the scientists propose, that different people respond differently to bread not because of the type of bread they consume, but rather due to each person’s unique ecology of intestinal microbes.

The researchers concluded that dietary recommendations related to consumption of types of bread, among other advice, should be personalized.

Bread accounts for around a tenth of the calories consumed by Westerners.

Common wisdom and advertising campaigns say that whole grains are healthier because they contain germ and bran, making them excellent sources of dietary fiber, B vitamins, iron, magnesium, and zinc. These elements are removed in the milling process that refines flour.

Some studies link consumption of whole grains to reduced risk of cancer, cardiovascular disease and improved cholesterol and blood pressure readings. Others show insignificant effects, and a couple have even claimed that eating whole grain bread may lead to a reduction in mineral absorption.

Susan Jebb, professor of diet and population health at the University of Oxford, told the Independent newspaper that the lack of a control group meant other factors may have contributed to the results, and that while the findings were clear, the test group was possibly too small to detect potentially small differences.

Dr. Elizabeth Lund, an independent nutrition and gastrointestinal health consultant, told the newspaper, “It should not be forgotten that the health benefits of whole grains may be much longer-term than a one week study can show, especially in relation to gut health and prevention of conditions like bowel cancer.”