We don’t know for sure whether sourdough bread definitely has health benefits.

But dietitians like Lizzy Traxler, MS, RDN, also a diabetes educator at University Hospitals, say: “Over time, and in combination with other healthy lifestyle choices and a balanced diet, choosing sourdough over regular bread may provide numerous health benefits.”

These, she told University Hospitals, may include improved digestion. “The improved mineral absorption from the fermentation process supports cardiovascular function,” they add (this might be especially true of sourdough rye bread).

And the British Heart Foundation says sourdough bread may make your blood rise more slowly, too.

So why did Dr Karan Rajan, an NHS surgeon and author, advise we “check the ingredients list” on sourdough loaves before buying?

Quality wholegrain, sourdough, and high-fibre breads may contribute to the “replacement of hyper-palatable baked goods, which are high in sugar, fat, and salt,” which can be beneficial to our health, a 2023 paper reads.

But, they add, one of the reasons sourdough research is so tricky is because “there is no established and internationally recognised legal definition of sourdough bread”. In fact, they found, the artisanal products usually included in trials may differ from the sorts found on most shelves.

“Analysis of bread samples purchased in the market showed that most of these had pH levels of >5.0, substantially above desired levels of pH 4.5 to obtain desired changes in composition,” they wrote.

This paper did not say that this difference definitely meant one was better than the other, or that the higher pH versions were sourfauxs ― though traditional sourdoughs tend to have a lower pH, which is linked to their sour taste.

But if you would like to eat sourdough made from traditional starter, Dr Rajan advises you look at the labels of sourdough breads in search of “added yeast”.

“Authentic sourdough doesn’t mention any added yeast,” he explained, “because it uses a natural fermentation process.”

He added, “Imitation sourdough, or ‘sourfauxs,’ often contain commercial yeast like baker’s yeast and even chemical raising agents like baking powder in addition to, or instead of, live sourdough starter culture.”

To be clear, the doctor didn’t say there’s anything wrong with eating non-sourdough bread.

It’s just that he felt it was important consumers know what they’re really buying (especially considering sourdough bread could be easier for people who usually struggle to digest food to eat).

The Real Bread Campaign has called for more research into the topic. For now, though, the group, which is against “sourfaux” breads, list some studies which suggest the real thing might have some health benefits.

“Sourdough” is not a legally-protected term, Swie Joo, head baker at The Palmerston restaurant in Edinburgh, told The Independent (like Dr Rajan, by the way, the chef advised customers to check for the word “yeast” on packages if you want a traditional sourdough loaf).

That means you can add commercial, or non-fermented, yeast to “sourdough” breads.

This can make the rise of bread more predictable and easier to replicate. It can be cheaper and less time-consuming, too.

The combination could make mass production a lot easier.

The Real Bread Campaign write that their campaign “is to better protect us from the risk of being misled by cynical marketing and to allow us all to make better-informed choices about the food we eat”.