Bread is a popular commodity and billions of people around the world consume it. Although most nutritionists recommend eating whole-grain bread instead of white bread, a new study indicates that the type of bread that you like best might have more to do with your body than with the bread itself.
In the study, which was published in the journal Cell Metabolism, 20 people consumed whole-grain fermented dough or refined white bread for a week. After a two-week break, each participant began to consume the other bread for a week. Both breads had the same amount of carbohydrates.
The researchers measured weight and blood pressure and did other blood tests before and after consumption of each type of bread, but did not find significant differences in these indicators. In other words, as for health, it did not matter if they consumed white bread or whole wheat bread.
"We originally thought that white bread and whole wheat bread were totally opposite in health benefits, but to our surprise, we found no difference in the effects of those two loaves on the markers we measured", Said study author Eran Segal and professor at the Weizmann Institute of Science in Israel.
Bread consumption was compared with improved cholesterol levels as well as markers of inflammation. It was also related to the reduction of the concentration of certain minerals in the blood.
However, the effects of both pieces of bread were similar. Moreover, although whole wheat bread has more fiber and in theory its content enters the bloodstream at a slower rate than white bread, not all participants in the study yielded these results.
Half of the participants had higher glycemic reactions to white bread as expected, but the other half had higher responses to whole-wheat bread. In fact, the glycemic response was more related to the microbiome composition of people's digestive tract and not so much to the bread itself.
"We showed that we could have predicted, with a good degree of precision, which bread induces low glycemic responses in each subject and that we could have done based on the initial configuration of their microbiome", Segal said.
One bread for each microbiome?
The researchers found that the presence of two species of bacteria served to predict which bread caused the highest glycemic response.
"We need more research and larger studies to validate this approach, but we envision a future in which each person's microbiome is tested for later personalized nutrition advice", Segal said.
In other words, nutritional recommendations for bread could be made subjectively, based on your microbiome, and not on the objective nutritional values of breads.
"We do not know which bread is better and in fact, we give evidence that there might not be a better bread", said Segal. "Maybe what we should be wondering is not which is better, but which is better for you".
Segal and others in the study are taking advantage of these preliminary findings, literally. They are consultants to a company that offers personalized nutritional recommendations based on the DNA sequence of your microbiome.
Although they trust their findings, they are not the only ones who share this position regarding nutrition.
Angela Poole, an assistant professor in the Division of Nutrition Sciences at Cornell University in the United States, is studying microbioma and starches and believes there is growing evidence that nutrition is more subjective than most People believe.
"These intriguing findings indicate that each person's intestinal microbiome may serve as biological markers for predicting that person's glycemic response to certain foods, which coincides with his impressive previously published study", he said.
Whole wheat bread, the winner?
Despite these findings, some experts are convinced that most people should choose to eat whole wheat bread.
"As far as nutritional composition is concerned, whole wheat bread is the winner", said Angel C. Planells, a registered dietitian and spokesperson for the United States Academy of Nutrition and Dietetics.
"Because of processing (white bread), whole wheat is the best option because it has fiber, vitamins such as folic acid, B6 and E, and minerals like chromium, magnesium and zinc".
The study also had limitations: it was reduced and was carried out for a short period. The long-term effects of exposure to each type of bread were not taken into account even though it might have yielded different results.
"We should not forget that the benefits that whole grains bring to health could be in the longer term and would not be shown in a one-week study, particularly in relation to the health of the digestive tract and the prevention of disorders such as bowel cancer. This study does not imply that people should stop eating whole grain foods based on these results", said Elizabeth Lund, an independent consultant in nutrition and gastrointestinal health and former Food Research UK researcher United.
"These results do not necessarily point to the numerous and long-term benefits of increased fiber consumption, including satiety", added Poole. "You need to consider a number of physiological effects, both short and long term, before labeling a 'good' or 'bad' food. Personalized nutrition is an attainable and valuable goal, but there is still much to learn".
SOURCE: CNN
