Yeast, in powder or flake form, has long been a popular supplement. Brewer's yeast, a by-product of beer-making, tastes bitter and is not as rich in some nutrients as nutritional yeast, which is grown specifically for human consumption. Nutritional yeast is a good source of the B-complex vitamins, trace minerals, and some protein (which you do not need). It is not expensive. A heaping tablespoon of yeast will color your urine yellow (owing to its content of riboflavin) and may have enough vitamin B-3 to give you a niacin flush. If you like the taste of nutritional yeast, try sprinkling it on popcorn instead of butter, as an alternative to taking a B-complex pill. Smoked torula yeast is even tastier as a seasoning, but it is not as good a source of vitamins and minerals and probably contains some carcinogenic compounds.