What is yeast and what is it used for?
Yeast is a single-celled fungus that naturally grows in soil and on plant surfaces.
There are hundreds of strains of yeast, and while some of them are harmful to humans, others can serve beneficial functions.
For instance, yeast can help foods, such as bread, beer, and wine, ferment or leaven. It can also be used to add flavor to foods or enhance their texture, as is often the case in the cheesemaking industry.
Yeast is naturally rich in B vitamins and sometimes fortified with additional vitamins and minerals. Therefore, certain varieties can be used to enhance the nutritional content of foods or meals.
Finally, it can be used as a medium to research, produce, or test pharmaceutical drugs intended to treat a range of medical conditions.
Why most vegans include yeast in their diet
Given that yeast is a living organism, some people wonder whether it can be included in a vegan diet.
However, unlike animals, yeasts do not have a nervous system. This means that they don’t experience pain — which completely differentiates them from animals.
Since eating yeast does not cause it to suffer and involves no animal exploitation or cruelty, yeast is typically considered a vegan food. Although, a very small minority of vegans may still avoid it, as it is a living organism.
Certain types, such as nutritional or torula yeasts, are particularly popular additions to a vegan diet, as they help add an umami, meaty, or cheesy flavor to meals without the use of animal products.
Plus, nutritional yeast is packed with B vitamins, which are among the nutrients that vegan diets often lack.
Types of yeast
Yeast comes in a variety of types, but only a few are currently used to make, flavor, or increase the nutrient content of foods, including:
This live culture of S. cerevisiae yeast is typically used to brew beer. The yeast cells are killed during the brewing process and sometimes consumed as a vitamin- and mineral-rich supplement.
This live S. cerevisiae yeast culture is used to leaven bread and other baked goods. The yeast is killed during cooking and provides bread with its characteristic yeasty flavor.
This inactive S. cerevisiae yeast culture can be used to add a savory, cheesy, or nutty flavor to foods. Nutritional yeast is deactivated during manufacturing and often fortified with additional vitamins and minerals.
An inactive culture of C. utilis yeast, which is used to turn wood into paper, torula yeast is typically used in the manufacturing of dog food. That said, it can also add a meaty, smoky, or umami flavor to human foods.
This food flavoring is made from the inactive cell contents of S. cerevisiae yeast. Yeast extracts are used to add umami flavor to packaged foods or make spreads like Marmite and Vegemite.
Consuming raw yeast is generally discouraged, as it can lead to bloating, cramps, constipation, or diarrhea. It may also increase the risk of fungal infections, especially in people who are critically ill or have a compromised immune system.
Suggested read: Are nitrates and nitrites in foods harmful?
One exception is the probiotic yeast S. boulardii, which most people can safely consume live in probiotic supplements.
Otherwise, yeasts that are made inactive through cooking, fermentation, or their manufacturing process can be safely used to boost the flavor or nutritional content of foods.