Nutritional yeast

Dried, inactive yeast flakes with a nutty, cheesy taste for pasta, soups, dips, roast veg and popcorn. Whether there’s B12 in them depends on fortification.

What is nutritional yeast? The cheese trick

Thinking of those soft, sticky blocks of fresh yeast that make pizza dough rise? Forget them. Nutritional yeast (fans call it ‘nooch’) is the same species, Saccharomyces cerevisiae, but a different strain. The bright, butter-yellow flakes are grown on dark molasses and then inactivated with heat. The cells are dead: they can’t ferment in bread dough or anywhere else. And the taste of these pale yellow flakes? Pure umami. They smell and taste remarkably like aged Italian parmesan.

What’s in it: filling gaps in a vegan diet

Nobody sprinkles nutritional yeast over popcorn or mac and cheese just because they’ve run out of cheese:

• A whole range of B vitamins: The flakes contain B1 (thiamin), B2, plenty of niacin (B3) and folate. Some producers also fortify them with vitamin B12 (cyanocobalamin) – especially useful if you’re vegan. Check the pack.
• Protein: A serving of flakes provides all 9 essential amino acids, and protein makes up around 50 % of the dry flakes.

What researchers look at: beta-glucans and B vitamins

Beta-glucans in the cell walls (beta-1,3-glucan)

The tough cell walls of the yeast contain a type of fibre called beta-glucans. Your body can’t digest them. Researchers are studying how these molecules interact with receptors on cells in the lining of the small intestine and with white blood cells. The popular idea that a sprinkle of flakes knocks out a cold before it starts goes well beyond what these studies show.

Thiamin and riboflavin

Flagging on a grey office afternoon and reaching for a can of energy drink? Worth knowing: your cells use vitamin B1 (thiamin) and vitamin B2 (riboflavin) in the chemical reactions that release energy from food, including carbohydrates. Nutritional yeast flakes contain both.

Important: don’t bake it for an hour

The most common mistake: stirring the golden flakes into a wet pasta bake or lasagne and baking it for 45 minutes at 200 °C. Many B vitamins are sensitive to heat, and a long bake breaks down a large part of them. Instead, scatter the fluffy flakes **as a cold ‘cheese’ topping right at the end, over pasta that’s already steaming on your plate**.