According to recent research looking at how bread affects certain biomarkers in the body, that artisanal sourdough loaf you pay a small fortune might not be any better for you than mass-produced white bread.
Those metabolic markers has showed no significant differences whether study volunteers ate a traditionally made whole grain sourdough or an industrially produced white loaf, which is suggesting that personalised diets could be more important for our health than sticking to certain universal ‘food rules’.
According to a team from the Weizmann Institute of Science in Israel, the generalisations about which type of bread is better for our guts don’t actually apply to individuals. What is healthy for us to eat is a much more personal question which is related to our own unique biology.
“We were sure that the sourdough bread would come out a healthier choice, but much to our surprise, we found no difference between the health effects of the two types of bread,” says one of the researchers, Eran Segal.
Sourdough is made using microbes dating back to ancient times – it’s what provides that distinctive tang – whereas white loaves are baked with strains of yeast that date back just 150 years.
That kind of heritage and a lack of artificial processing have lead many to believe that sourdoughs are healthier and better for our bodies. But as this study suggests, maybe not.
Segal and his team recruited 20 participants, and by observed them over the course of two weeks, 10 spent a week eating sourdough bread and then a week eating white bread, while the other 10 did the reverse.
This experiment found that levels of blood sugar, minerals, and liver enzymes were all affected by eating bread, but the type of bread made no real difference.
Take the level of blood sugar, which whole grain bread is often said to help moderate – about half the volunteers ended up with higher blood sugar levels after eating white bread as expected, but the other half had higher blood sugar levels after eating the sourdough.
A member of the team, Eran Elinav says: “That’s probably because the body’s response to bread is a highly personal matter, so the differences between people in the study averaged themselves out.“
To make it clear, the researchers aren’t saying whole grain bread is suddenly not a healthy choice – but they are suggesting that each person’s body responds to bread types differently.
The study also looked at the microbiome of the participants, and found that the particular make-up of each person’s gut bacteria could actually predict some of their reactions to the two types of bread.
The study relied on a very small sample size, and ran for a short period of time, so it’s too early to apply these findings universally.
The researchers suggest that further studies look at using microbes in the body as a way of personalising healthy eating plans.
In the meantime, don’t be so sure that buying a whole grain sourdough loaf is going to be any better for your overall health than sticking to a cheap white one – pay attention to how your body responds to a varied diet, and try to base your eating habits on whatever gives you the best result.
As chef Anthony Warner, who wasn’t involved in the research, writes for New Scientist: “Healthfulness is defined by chemical composition, not by the price tag or the kitchen or factory in which it was made.”