Yeast has been used for fermentation and baking for thousands of years. Archeologists have found grinding stones and baking chambers for yeasted bread in ancient Egyptian ruins, as well as 4,000-year-old drawings of bakeries and breweries.
Despite yeast’s long history, today bread and other yeast-leavened products are sometimes viewed as unhealthy. Is eating yeast actually harmful to your health? There is no evidence to suggest that it is. In fact, dietary yeast has many nutritional benefits.
WHAT IS YEAST?
Yeasts are single-celled fungi. They feed on sugar and carbohydrates, converting them into carbon dioxide and alcohol. The carbon dioxide is what makes bread rise. While, beer and wine production uses yeast to produce the alcohol.
Four main types of yeast are used in food:
Nutritional Yeast – Available in the form of flakes or a powder, this yeast earns its name. Nutritional yeast is high in protein, fiber, zinc and many B-complex vitamins. It is also a complete protein that contains all nine amino acids that the human body cannot naturally produce. It has a cheese-like flavor and can be added to many different dishes.
Brewer’s Yeast – Brewer’s yeast has been grown and taken as a supplement for many years due to its high nutritional value. It is available as flakes, tablets, a powder or liquid. A mere 2 tablespoons of brewer’s yeast have 32 percent of your daily recommended intake of protein, as well as significant amounts of B vitamins, minerals and fiber. Brewer’s yeast is also used in beer brewing.
Baking Yeast – This yeast is primarily used to leaven dough for bread and other baked products. It’s not used as a supplement, although it contains various minerals and B vitamins, especially folate.
Torula Yeast – A derivative of molasses, torula yeast is a good source of B vitamins, chromium, amino acids and selenium. It is available as a powder that has a smoky, savory taste. It is sometimes used in vegetarian or vegan dishes to mimic the flavor of meat.
Certain yeasts may interact with medications, so always check with your doctor before adding yeast to your diet.
CAN YEAST BE HARMFUL?
Not all yeasts are beneficial. For example, Candida albicans is one of the most common pathogenic yeasts. It can cause oral, genital and intestinal yeast infections.
It’s sometimes suggested that eating yeast will encourage Candida growth in your body. There is actually no evidence to support this claim.
An important distinction to make is that Candida and other problem yeasts are completely different species than Saccharomyces cerevisiae, the main species of dietary yeasts. Saccharomyces cerevisiae is not known to cause any health problems in humans.
Also, dietary yeasts are typically dead when you eat them. Baking yeast has been cooked in bread, and nutritional and other supplemental yeasts are also heated to kill the yeast. When you eat inactive yeast like this, your body simply treats it like any other food. It’s digested and the nutrients are absorbed.
Whereas, if you have a Candida infection, the Candida is actively growing and spreading in your body. And it feeds on sugar like other yeasts do.
This means that eating sugar and highly processed, simple carbohydrates will feed a Candida infection, not eating dietary yeasts. Candida yeast overgrowth is also triggered by a high-fat and low-fiber diet, impaired immune function, stress and drugs like antibiotics, birth control pills and steroids.
So, are bread and baked products bad for you because of the yeast? Probably not. But the sugar and low-fiber, refined flour used in many baked goods have the potential to feed a Candida infection.