Yeast is a general name for about 1500 types of tiny, single-celled fungi. Some yeasts can cause disease. Many, however, provide us with nutrition plus the natural tools we need to produce some of our favorite foods. For example:
- Brewer's yeast, which produces carbon dioxide, is used to make beer. It's also a powerhouse of essential nutrients including protein, vitamin B, and chromium.
- Baker's yeast is a similar organism that feeds on sugars to produce carbon dioxide. It's the ingredient that causes bread to rise.
- Deactivated or nutritional yeast has been killed by heat and can no longer produce carbon dioxide or reproduce. It does, however, maintain its flavor and nutrients. As a result, nutritional yeast can be used to add protein to foods or shakes. It's also a common flavoring agent. There are many different strains of deactivated yeast, and each has a somewhat different flavor. Some are "nutty," some are "creamy," some are "meaty," and so forth.
Edible torula yeast grows on wood alcohols. When deactivated and dried, it looks like a tan powder and can be packaged and sold in health and nutrition stores.
Since it is rich in glutamic acid, torula yeast lends a smoky, savory umami taste-profile to foods. It is an increasingly common flavoring additive in processed specialty foods such as chips, seasoning blends, and crackers.
Due to its meaty taste, it's often used as an additive to pet food, and since it contains high levels of nutrients such as zinc, vitamin B, and amino acids, it is sometimes used as a supplement for puppies.
As veganism and vegetarianism have grown in popularity, food producers began using torula yeast to mimic the flavor of meat (in veggie burgers, for example) without adding any animal products.
Torula yeast has also become a popular replacement for the flavor enhancer monosodium glutamate (MSG) among manufacturers marketing "all-natural" products. MSG, in powdered form, was used for decades to enhance the flavor of meats, sauces, and other dishes. It's a chemical additive with no nutritional value, making it a questionable food for many people interested in natural nutrition. Perhaps more significantly, it can also cause mild or severe allergic reactions including headaches and disorientation.
Torula yeast does many of the same things that MSG did for many different foods. It ensures that flavor and aroma are not lost during the cooking process. It also improves the texture and flavor of many foods ranging from sauces to chips to soup.
Like all yeasts, torula also adds a good deal of nutrition to foods. It can also thicken foods such as protein shakes and dips.
Torula yeast is a food-grade product, which means that, for the vast majority of people, it is safe and tasty. It also provides a significant source of nutrition.
There are, however, questions about the value of using yeast, in general, as a nutrient. According to some research, there is a very slight possibility that yeast in food could actually cause problems such as vaginal yeast -- but there is very little evidence to support this claim.