The benefits of yeast for human health

Key factors for fermentation, yeasts also possess other nutritional bonuses and properties worthy of interest for human health. Professor Pierre Desreumaux, gastroenterologist at the Claude Huriez Regional Hospital in Lille, provides an overview of their therapeutic effects.

The microorganism Saccharomyces cerevisiae is a well-known ingredient in food, and in particular bread-making. Employed for its role in the phenomenon of bread dough rising, this single-celled microscopic fungus also has incredible nutritional qualities, which make it an excellent food supplement. However, as with other yeasts, its properties do not end there.

Present on skin and mucous membranes, as well as in the digestive tract, yeasts actively contribute to local microbiota1 and stimulate the immune system. “In the past few years, huge progress has been made in the understanding of intestinal flora and its composition,” explains Prof. Desreumaux. “We now know that intestinal flora is made up of a veritable microbial community, comprising bacteria, yeasts and phages2. And that the balance between these different populations has a significant impact on the resistance to colonization of certain pathogenic agents.”

Yeasts working to prevent infectious diarrhea

One interesting case in point in which yeasts operate, is with Escherichia coli infectious diarrhea. “Yeasts such as Saccharomyces boulardii are capable of attaching themselves in a spherical shape around these pathogenic bacteria and thus arresting their spread,” stresses the gastroenterologist. “Yeasts can also directly line the intestinal epithelial cells, thereby blocking all bacterial attachment points,” which leads to a neutralization of bacterial infections caused by infectious diarrhea.

Yeast efficiency in the treatment of vaginal or oral mycosis

Yeasts can also tackle the very resistant pathogenic agents that are fungi.

Though the pathogen Candida albicans is a benign colonizer of mucosal surfaces (insofar as it lives there but does not cause damage), it is responsible for invasive surface infections, sometimes fatal. Among them, vulvo-vaginal mycosis that affects 75% of child-bearing age women. Yet, explains Prof. Desreumaux, “an Italian team in Perugia showed, in a pre-clinical study3, the virtues of using inactive Saccharomyces cerevisiae yeast in pessary form in conjunction with an oral treatment.” This resulted in reduced frequency and duration of the mycosis, more specifically known as candidiasis. Similar results were observed with yeast mouth washes for oral candidiasis. A bonus for future patients, reveals the specialist, is that the “Saccharomyces cerevisiae-based treatment costs less, is more effective and above all is more environmentally friendly compared to the untimely use of medication.”

Yeasts to improve digestive comfort

Another hope: the effect of probiotics made from Saccharomyces cerevisiae in the reduction of intestinal pain and discomfort. “Used as a probiotic, the CNCM I-3856 compound, selected from the Lesaffre yeast collection, eases abdominal pain and bloating after five days,” attests the specialist. This treatment, recommended for three months, leads to an increase in the patients’ pain threshold. A veritable natural analgesic specifically for the digestive tract!

Prof. Desreumaux is the co-founder, with Lesaffre and Roquette, of the Digest Science foundation, which is dedicated to research and the care of patients suffering from chronic intestinal inflammatory conditions and irritable bowel syndrome, He stresses the added value of partners such as Lesaffre, which “is a true patron, ready to financially support research in the interest of patients, and which holds the largest yeasts store in the world, and has incredible access to all the sector’s scientific data.”

New fields of application for yeasts

A global specialist in the use of probiotics for human health, Lesaffre effectively spearheads an approach that enables it to innovate endlessly and to discover new applications for yeast every day. And there are still numerous sectors to explore! The most meaningful, according to Prof. Desreumaux, are to be found in dermatology and ophthalmology. The focus is on “local applications, such as drops or ointments, based on their pain-relieving, anti-inflammatory, wound-healing and antibacterial properties,” explains the specialist.


  1. Microbiota or human intestinal flora. These are all the microorganisms in the human digestive tract.
  2. Phages or bacteriophages. These are viruses that only infect bacteria, naturally present in the environment and in our body.
The therapeutic effects of yeast for human health can still be further multiplied and can reach an optimal effect by pairing them with other microorganisms, such as bacteria or phages. That is exactly what happens in Nature and, above all, in the mysterious ecosystem that is our digestive tract!
Pr. Desreumaux
Gastroenterologist at the Claude Huriez Regional Hospital in Lille

Nutritional yeasts, allies of choice to protect our health

Although active yeast makes bread rise, nutritional yeast is an inactive yeast, which has been warmed. It is obtained from the microorganism Saccharomyces cerevisiae, cultivated on sugar cane or beet molasses. “Yeasts produce numerous vitamins that contribute to the general good health of skin appendages and easily-absorbed trace elements (chromium, selenium, silica, and magnesium). Certain carefully-selected strains are capable of producing more selenium, folic acid or vitamin B, thanks to the know-how of yeast producers in controlling the process and cultivating microorganisms,” explains Prof. Desreumaux. “It is a great way to correct nutritional deficiencies in humans.” And also, to reinforce our natural defenses and combat oxidative stress. Easily tolerated by older people, yeasts also produce different types of sugar, which can be beneficial to them. “The third element of nutritional interest in these yeasts is to give a particular taste to foods,” states Prof. Desreumaux. “As with the taste of cheese, like for example bacon that you can taste in certain crisps.” As such, the strain of yeast will be selected according to the desired taste. Sold in powder or flake form, yeasts can now be bought in health food shops, organic grocery stores and also in the health food section in supermarkets.