Brewer’s yeast is the yeast, principally Saccharomyces cerevisiae, used to ferment beer wort into alcohol and carbon dioxide, harvested afterwards as a by-product of brewing. Dried and debittered, it is sold as a nutritional supplement rich in B vitamins, including thiamine, riboflavin, niacin, and folate, as well as protein, chromium, and selenium. It has a savoury, slightly bitter taste and is sprinkled on food or taken in tablets. Nutritional yeast is a related deactivated product grown specifically for food use. Brewer’s yeast should not be confused with live baking yeast, and people with yeast allergies or on certain medications should seek advice before using it.