Posted on 13 Jan 2014 15:08
Yeasts are microscopic fungi organisms that use alcoholic fermentation to produce energy. The type of yeast that most people are familiar with is baker's yeast, which is based on different strains of Saccharomyces cerevisiae.
Bakers mix this yeast with sugar and as the yeast use the sugar, they release carbon dioxide gas that expands the dough, thus making it rise. Yeast is important for the rising, flavor, and texture of bread.
Brewers also use S. cerevisiae yeasts in the brewing of beer, which are known as ale yeasts because they feeds on the bottom of the fermentation vat and settle to the bottom near the end of the brewing process. Another type of yeast, S. carlsbergenis ferment on the top and are used in brewing lager type beers.
There are many different strains of yeast that are used according to their various properties and alcohol tolerance and they may be used to brew not only beer, but also whiskey and some wines. Occasionally moonshiners use store-bought baker's yeast to brew their moonshine.
The yeast used for brewing has given rise to a confusing dietary supplement product called Brewer's yeast, and sometimes nutritional yeast. This product is frequently found in health food stores, where it comes in yellow flakes or powder. It is called Brewers yeast because it was once a byproduct of the brewing industry. This product was originally the dead yeast cells and other byproducts left over after beer or other brewed beverages were filtered. Today, however, products sold as Brewer's yeast or nutritional yeast are no longer brewing byproducts, but are grown specifically as a nutritional product, by companies specializing in producing them. This eliminates some of the other by-products, such as hops, that would give an unpleasantly bitter taste to the Brewer's yeast byproduct. These yeast, again, are dead, so do not bother trying to brew beer using "Brewer's yeast" you bought at a health food store.
Brewer's yeast is often recommended as a very nutrient-dense food for vegans and vegetarians. It is highly nutritious, with a very wide range of micro-nutrients. It is extremely high in all the B vitamins, including B1 (thiamine), B2 (riboflavin), B3 (niacin), and B6 (pyridoxine), and folic acid. Plus, it is can be a good source of B12, important for vegans. It is rich in minerals like potassium, sulfur, manganese, and magnesium, as well as trace minerals like copper, chromium, and selenium. At 50 to 60 percent protein by weight, although you would have to consume a lot of the product to make it contribute significantly to protein intake, it is a fairly good source of protein.
The most frequent way nutritional yeast is consumed is as a condiment sprinkled on top of other foods before eating. It can be served on grain and rice dishes, vegetables, or even soups and salads. It is sometimes put on popcorn, as well, and can be used as a breading, for frying. Vegan cookbooks often have a recipe for tofu breaded with nutritional yeast. There are, of course, many other ways it might be used.
The taste is a bit nutty and reminiscent of cheese. However, the "yeasty" flavor is definitely quite noticeable. People that do not like the taste, but wish to use it as a supplement, sometimes purchase it in the form of capsules and tablets. If you are a vegan using nutritional yeast as a supply of vitamin B12, be aware that the B12 is often added, or is encouraged by growing the yeast on a medium that is high in B12. Some nutritional yeast products, therefore, may not contain B12, so you should check the label to be sure. Also, if you buy the yeast from a bin at the health food store, you may want to inquire as to its level of B12. Other nutrients may also be added, such a calcium, to offset the high phosphorous content.
While it is true that Brewer's or nutritional yeast is nutritious and healthy, there are many sensationalistic claims about its many healing properties. These are entirely without scientific merit.
However, while nutritional yeast is not a miracle healing food, neither should it be seen as dangerous. It has been reported in hundreds of publications that high intake of yeast containing foods, including nutritional yeast, could promote yeast infections in the body. This is absolutely absurd.
There is a type of yeast called Candida albicans that colonizes certain parts of the body in low amounts, such as the gut, mouth, and the vagina in females. The other natural flora, with the help of the body's immune system, normally keeps the population of this organism in check. However, if the population of this flora is disrupted, such as from the use of wide-spectrum antibiotics, or immunity is compromised, Candida can sometimes multiply, resulting in a local yeast infection.
Many holistic medical practitioners believe that it is possible for humans to develop systemic Candida albicans infections, where the infection is found throughout the body's tissues, including the blood. Medical science does not show this to be a real condition, and most doctors consider it to be poppycock. Many of those that do believe in it, however, advise people to avoid yeast containing foods and beverages, and also Brewer's or nutritional yeast, as these may encourage such a Candida overgrowth. This is absurd, and not only because these systemic infections have not been shown to actually exist. The yeasts used in bread baking and brewing, as seen above, have no relationship to Candida albicans, and consuming the one in no way will contribute to the growth of the other. As well, the yeast cells in nutritional yeast are dead.
To be fair, some of the advise actually concerns avoiding very high carbohydrate foods such as bread, so as to withhold this energy source from Candida albicans organism in someone suspected of having a Candida infection, and some people have assumed that the yeast is the problem. Regardless, the whole thing is quite ridiculous and based on quack science.