A significant source of some B vitamins, nutritional yeast is a great way to give foods a cheesy or savory flavor. Some brands are fortified with vitamin B12, making this a staple in many vegan households. I personally love the flavor of nutritional yeast and started using it years before I was eating vegan.
Nutritional yeast can also be helpful for people who want to give their food a cheesy flavor but are on a low sodium diet. One serving (1 tbsp) of nutritional yeast has 25mg of sodium while one serving (1oz) of cheddar cheese has 174mg.
One serving of nutritional yeast provides 9g of complete protein and is made from a single-celled organism called Saccharomyces cerevisiae. It is dried and inactive and therefore doesn’t grow like active dry yeast does, so you can’t substitute it in place of yeast in your bread recipes. Nutritional yeast is technically made from the same species of yeast as active dry yeast, but it’s a very different product.
But you can use nutritional yeast to amp up the flavor of many dishes including soups, sauces, egg substitutes (like this tofu scramble) or even as a popcorn topping. The umami flavor of nutritional yeast is from the amino acid glutamic acid. But don’t worry, this is a naturally occurring amino acid and is not the same as the additive monosodium glutamate (MSG).
NPR has a great piece on the history of nutritional yeast including it’s many rises and falls in popularity.