This nutritional supplement has a pleasant nutty-cheesy flavor and is packed with protein and B vitamins. It comes in flakes or powder and is popular with vegans and health buffs who use it to make cheese substitutes, gravies, and many other dishes. It's also a great topping for popcorn. Nutritional yeast is very similar to brewer's yeast, which is also used as a nutritional supplement and is made from the same strain of yeast. The difference is that brewer's yeast is a by-product of beer production and retains some of the bitter flavor of hops. Don't confuse nutritional yeast, which is deactivated, with active forms of yeast, like the kinds bakers, brewers, and winemakers use. If you eat them, active yeasts will continue to grow in your intestine, robbing your body of valuable nutrients. Look for nutritional yeast at health food stores. Get fortified nutritional yeast if you're taking it as a source of vitamin B12.