Fermented bread could help prevent asthma

By Lisa Marie Basile | Fact-checked by Jessica Wrubel
Published June 26, 2024

Key Takeaways

  • A recent animal study published in Current Developments in Nutrition found that adding Saccharomyces cerevisiae UFMG A-905 (a strain of brewer’s yeast) to bread could potentially attenuate the effects of allergic asthma.

  • Findings included partially reduced airway inflammation and a reduction in eosinophils as well as Interleukin 5 and Interleukin 13 concentrations. The researchers found that when bread also contained microcapsules of the live yeast, the results were more pronounced, with less airway hyperresponsiveness and an increase in Interleukin 17A. 

  • The study is limited in a few key ways. Experts say human trials are needed.

Researchers in Brazil have developed a probiotic-rich functional bread fermented with Saccharomyces cerevisiae (S. cerevisiae)—otherwise known as brewer’s yeast. Its use? To potentially help prevent allergic asthma.[]

The S. cerevisiae UFMG A-905 strain is biologically unique for a few reasons, including its “fermentation capacity, accompanied by the production of alcohol and CO2 and its resilience to adverse conditions of osmolarity and low pH,” according to AIMS Microbiology.[]

Asthma—marked by inflammation and tightening around the airways—is a global health concern, affecting an estimated 262 million people in 2021(with more than 3,500 deaths in the US alone). It is the most common chronic disease in children. Its causes are multitudinous, from urbanization impacts to early life events like prematurity or exposure to tobacco smoke.[]

The team published their findings in Current Developments in Nutrition, writing, “Probiotics are administered using dairy-based matrices, but other vehicles (e.g., fruit juices, biscuits, candies, and breads) can be used.” Probiotics are living microorganisms that offer therapeutic qualities.

Study takeaways

The researchers conducted an animal study using pathogen-free male Balb/c mice between six and eight weeks old. The mice, they write, “were sensitized and challenged with ovalbumin. Breads were administered 10 d before the first sensitization and during sensitization and challenge protocol. Yeast fecal count, in vivo airway hyperresponsiveness, and airway and lung inflammation were assessed,” the researchers write.

They treated the mice with three different kinds of fermented breads—one made with commercial yeast, one with S. cerevisiae UFMG A-905, and one with S. cerevisiae UFMG A-905 and alginate microcapsules with live S. cerevisiae UFMG A-905. The goal was to compare the breads' effects for preventing asthma in mice. The team noted that, for the study, S. cerevisiae UFMG A-905, was isolated from a Brazilian sugarcane-distilled alcoholic beverage.

Marcos de Carvalho Borges, study author and professor in the Department of Clinical Medicine at the Ribeirão Preto Medical School, explained to The Microbiologist that the live yeast capsules were added to “improve probiotic viability and activity at the high temperature reached during the baking process.”

The researchers also cited previous research, noting that S. cerevisiae has been shown to prevent bacterial infections, colitis and mucositis, and food allergies—in addition to asthma. It works, they say, by acting on “cell signal transduction, pathogenic bacteria cell adherence, and local and systemic immunomodulation.”

Findings revealed that bread fermented with S. cerevisiae UFMG A-905 partially reduced airway inflammation due to a reduction in eosinophils and Interleukin 5 (IL-5) and Interleukin 13 (IL-13) concentrations. IL-5 plays a critical role as a pathogenic mediator in eosinophilic asthma,[] while IL-13 IL-13 is associated with hyperresponsiveness, mucus production, airway remodeling, subepithelial airway fibrosis, infectious asthma, allergic asthma, and aspirin-exacerbated respiratory disease, according to the World Allergy Organization Journal.[]

More so, the bread enhanced with live S. cerevisiae UFMG A-905 microcapsules resulted in diminished airway hyperresponsiveness and increased concentrations of Interleukin 17A (IL17A). The authors note that IL17A seems to play a “controversial” and “dual” role in asthma: While some studies have shown that an increase in IL17A may be associated with severe asthma, other studies have found that “exogenous administration of IL17A reduced the recruitment of pulmonary eosinophils, bronchial hyperresponsiveness, and allergic response,” they say.

Although the findings are promising, the study has some key limitations. Not only were all the different breads not evaluated with the additional microcapsules, but the asthma was induced only with ovalbumin—and only in mice. “Although it is a classical model of asthma, it would be important to evaluate it in another model with a different allergen or even in a clinical trial. Finally, we did not assess microcapsule shelf life,” the authors write.

The Asthma and Allergy Foundation of America (AAFA) agrees that the study is limited and that its results aren’t exactly exciting—just yet. “This is really quite a modest effect—and it is in a mouse model,” the organization tells MDLinx.

The AAFA also says that—as the authors state—there are already several other animal studies exploring probiotics and allergic diseases and asthma. “We’re withholding further comment until human trials are done,” the AAFA says.

What does this mean for you? Additional research is needed before fermented bread becomes a viable prevention or treatment method for your patients. While the researchers have demonstrated promising asthma-reduction potential in bread made with S. cerevisiae UFMG A-905, the study is limited.

Share with emailShare to FacebookShare to LinkedInShare to Twitter