Who really needs non-dairy bread?

Who is who?

When we talk about yeast contained in food products, we most often mean the various strains of the species Saccharomyces cerevisiae (in bread, wine, beer, kvass, kefir, tvorog, on the surface of fruits and berries). Also – Saccharomyces pastorianus (in beer) and some species of Kluyveromyces, Debaryomyces and Yarrowia (in hard cheese varieties). Accordingly, if subjective beliefs lead you to boycott yeast and products based on them, be prepared to give up not only baking, which will be discussed further, but also kefir, cheese, beer, wine, and kvass. Is it really worth it? And if so, who would you sacrifice for?

When can yeast be dangerous?

In scientific literature there isn’t a single publication claiming that yeast causes cancer. Of course, all-knowing naturopaths without formal higher medical education, journalists who disregard primary sources, and even perceptive grandmothers on a bench might try to persuade you otherwise. But they are unlikely to cite a credible scientific source.

At the same time, let’s be honest: there have been cases where yeast cells were isolated from the focus of mixed fungal infection in patients, note carefully — in people with severe immunodeficiency, including elderly smokers with chronic inflammatory lung conditions, and patients with inflammatory bowel conditions in hospital settings. However, it is fair to note that in severe immunodeficiency, from infectious foci, other microorganisms could just as well be isolated with the same safety concerns for those organisms—lactobacilli or bifidobacteria, for example. Therefore, these facts should not be treated as arguments. There are also certain species of conditionally pathogenic yeasts, such as Cryptococcus neoformans, and the well-known Candida albicans, but they have nothing to do with the food products discussed above: the former can be contracted from pigeons, and the latter is a component of our microbiota transmitted by contact.

However, sometimes yeasts in products can still work against us and cause digestive disturbances if consumed in excess — a phenomenon of bloating after overindulgence in sour milk cheeses, large amounts of grapes, or overly lively beer — though this is not related to bread yeast!

So who actually needs non-dairy bread?

The answer is simple — primarily those who bake and sell it; in other words, it is nothing more than a marketing trick. And there would be nothing wrong with that if people called things by their proper names, for example, bread made with a mixed starter. Because in reality, the starters on which “non-yeast” loaves are baked contain the same yeasts, just with lactic acid bacteria. And homemade sourdough, which some brave housewives practice, contains an unknown mix, but, trust me, yeast is definitely there! It is the yeasts that for thousands of years have formed those nice holes in bread, producing carbon dioxide and raising the dough, as well as enriching it with vitamins and amino acids.

For those who, despite what they read, still fear live yeast and have already mentally refused kefir and grapes, here is good news — yeast does not survive in baked bread! The temperature at which most yeasts live and reproduce is 27-30°C (15-35°C — depending on the strains), and the thermophilic yeast strains, which some naturopaths fear, maintain their activity at 40°C; some strains withstand up to 48-50°C, but not 100-200°C, at which bread is baked. The spores that sugar yeasts may form withstand a maximum of 55-60°C and serve a sexual reproduction function, not survival at high temperatures as in bacteria.

Thus, yeast in both living and baked forms does not pose a danger to our health. Any possible digestive problems after consuming some types of baked goods are usually linked to an excess of simple carbohydrates, poor-quality raw materials, and, in some cases, possible enzyme deficiency. Therefore, it is not the yeast that makes baking unhealthy.

Special thanks to senior researcher Olga Yanieva from the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine, candidate of biological sciences, a researcher who has been studying yeast for a long time, Olga Yaneyeva — for the fruitful discussion of this material.