Nutritional yeast might very well seem a strange product to eat. It comes in the form of yellow flakes with an unusual smell that some identify as “cheesy” and others call “the smell of old dirty socks”. Why would one want to eat such a substance? Let’s find out.
Nutritional yeast has a strong flavour that is described as nutty, slightly sweet and cheese-like and indeed, it does make a flavourful plant-based substitute for cheese. Nutritional yeast consists of strains of a family of yeast known as Saccharomyces cerevisiae. The same family of yeast is found in both baker’s yeast and brewer’s yeast although they each emphasize different strains. The yeast in nutritional yeast has been deactivated so that it is no longer alive and has no power to grow or produce gases as it does when it is used to make bread rise or to ferment beer. Nutritional yeast is specifically cultivated as a food crop. It is grown on a medium such as sugarcane or beet molasses for several days and then deactivated (killed) by heat, harvested, washed, dried and packaged.
Nutritional yeast is a significant source of B vitamins and can actually provide from 35% to 100% of vitamin B1 and B2 daily requirements. It also contains trace amounts of other vitamins and minerals. A serving of unfortified nutritional yeast contains about 5% of the recommended daily value of iron. Some nutritional yeast is fortified with extra iron and also with vitamin B12. On average, two tablespoonsful of nutritional yeast provide 60 calories and 5 gm of carbohydrates (4 grams of which is fiber). This serving also provides 9 grams of a complete protein, one that contains all of the nine amino acids that the human body cannot produce on its own.
So what is this “beast” than might be tamed by nutritional yeast? It is the common cold, so named because it occurs so often in human beings. Adults tend to get a cold a few times a year; children contract a cold once a month on average. Much suffering could be avoided if there was a way to circumvent these respiratory infections.
Nutritional yeast and the common cold
It has been discovered that nutritional yeast can strengthen our immune system. There is a unique component of fungal cell walls called beta-glucan that naturally stimulates our immune system. In other words, our body recognizes this component as a threat and rightly so. Fungal infections such as those caused by a species known as Candida can be a powerful menace to our health. Beta-glucan is also a part of non-disease-causing yeasts like Saccharomyces cerevisiae, the yeast found in baker’s yeast, brewer’s yeast and nutritional yeast (1,2).
Most of the human immune system is concentrated in our intestinal wall, the first contact point of our inner self with the outer world. Eating a source of beta-glucan such as nutritional yeast can boost our immune system to such a degree that it actually can protect us from the common cold. A 2016 randomized, double-blind, placebo-controlled trial performed a twelve-week study on healthy children, giving them a daily source of beta-glucan sourced from baker’s yeast. During the course of the study, 85% of the children taking the placebo experienced at least one episode of respiratory illness and, on average, the placebo-taking children endured 1.5 episodes of respiratory infection. Conversely, children taking beta-glucan were infected by an average of 0.5 to 0.7 respiratory illnesses, cutting their sickness rate in half. Additionally, those taking yeast that did come down with a cold suffered for an average of only three days compared to an average of nine days for those in the placebo group (3). Other earlier studies found similar results. In 2012 a placebo-controlled, double-blind, randomized clinical trial studied 100 healthy adult participants over 26 weeks. 15.6% of the placebo group experienced a common cold during the study compared with only 2% of the group receiving the beta-glucan source (from brewer’s yeast in this trial). The decreased rate of infection in the treated group as compared to the placebo group was especially significant during the first thirteen weeks of the study (from November to March) when most of the common cold episodes occurred. The beta-glucan-treated group also showed reduced symptoms such as sore throat, hoarseness, cough and runny nose if they did contract a common cold (8). In another 2012 placebo-controlled study only 10% of the participants taking beta-glucan reported upper respiratory symptoms compared to 29% of those taking the placebo. The beta-glucan taking subjects also reported better overall well-being (6). A 2013 double-blind, randomized, placebo-controlled 16-week study on over-stressed women resulted in a 25% reduction of cold incidence in the group receiving beta-glucan sourced from brewer’s yeast. They also reported a 15% lower symptom score including reduced sleep difficulties (7).
Other randomized, double-blind, placebo-controlled trials have shown that children who regularly suffered respiratory infections were able to increase the lysozyme level of their saliva after eating the equivalent of about ½ teaspoon of nutritional yeast daily. Lysozyme is an important first-line immune component present in our eyes, nose and mouth (4,5).
Nutritional yeast and exercise
Regular exercise can also improve immune function but, if taken too far, exercise has the opposite effect. It appears that excessive exercise overstresses the body and increases infection rate. The immune boosting effects of nutritional yeast can come in handy in this situation too. It seems our level of circulating white blood cells, an important part of our immune system, can be maintained even after exhaustive exercise by consuming a daily source of beta-glucan from yeast (9). This increase in white blood cells does translate into fewer infections. In 2009, a placebo-controlled, double-blind study of elite runners after a marathon found that those taking beta-glucans from yeast cut their upper respiratory infections in half and felt less tense and fatigued after completing the marathon compared with those runners taking the placebo (10).
How can I incorporate nutritional yeast into my diet?
Beta-glucan is concentrated in the cell walls of yeasts. The beta-glucan used in the studies discussed here was a concentrate derived from brewer’s yeast. Nutritional yeast in its dry state contains between 15% and 30% cell walls which themselves contain 50% to 60% beta-glucan. Daily doses in the studies discussed in this article averaged about 100 mg of pure beta glucan which can be found in about 0.6 to 1.3 gm of nutritional yeast. This is an amount equivalent to about ¼ of a teaspoonful (11).
The addition of nutritional yeast complements many dishes. It is a tasty replacement for parmesan cheese (see our recipe in a previous post). It adds pizzazz to pizza, lasagna and other pastas. It can be easily added to stews or rice dishes. It is a hidden ingredient of delicious savoury gravy. A mixture of raw cashews and nutritional yeast can be sprinkled on bread and toasted for a scrumptious open faced sandwich. The verdict is provided by your satisfied taste buds. The limit is your own imagination.
1 Rubin-Bejerano, I., Abeijon, C., Magnelli, P., Grisafi, P., Fink, G.R. Phagocytosis by human neutrophils is stimulated by a unique fungal cell wall component. Cell Host Microbe. 2007 Jul 12; 2(1):55-67.
2 Lavigne, L.M.1 Albina, J.E., Reichner, J.S. Beta-glucan is a fungal determinant for adhesion-dependent human neutrophil functions. J Immunol. 2006 Dec 15; 177(12):8667-8675.
3 Meng, F. Bakers Yeast Beta-Glucan Decreases Episodes of Common Childhood Illness in 1 to 4 Year Old Children during Cold Season in China. J Nutr Food Sci June 2016; 6(4): 518.
4 Vetvicka, V., Richter, J., Svozil, V., Dobiášová,, L.R., Král, V.K. Placebo-driven clinical trials of yeast-derived β-(1-3) glucan in children with chronic respiratory problems. Ann Transl Med. 2013 Oct; 1(3): 26.
5 Richter, J., Svozil, V., Král, V., Dobiášová, L.R., Stiborová, I., Vetvicka, V. Clinical trials of yeast-derived β-(1,3) glucan in children: effects on innate immunity. Ann Transl Med. 2014 Feb; 2(2): 15.
6 Talbott, S.M., Talbott, J.A. Baker’s yeast beta-glucan supplement reduces upper respiratory symptoms and improves mood state in stressed women. J Am Coll Nutr. 2012 Aug; 31(4):295-300.
7 Auinger, A., Riede, L., Bothe, G., Busch, R., Gruenwald, J. Yeast (1,3)-(1,6)-beta-glucan helps to maintain the body’s defence against pathogens: a double-blind, randomized, placebo-controlled, multicentric study in healthy subjects. Eur J Nutr. 2013 Dec; 52(8):1913-8.
8 H J Graubaum, R Busch, H Stier, J Gruenwald. A Double-Blind, Randomized, Placebo-Controlled Nutritional Study Using an Insoluble Yeast Beta-Glucan to Improve the Immune Defense System. Food and Nutrition Sciences. 2012;3(6):738-46.
9 Carpenter, K.C., Breslin, W.L., Davidson, T., Adams, A., McFarlin, B.K. Baker’s yeast β-glucan supplementation increases monocytes and cytokines post-exercise: implications for infection risk?
Br J Nutr. 2013 Feb 14; 109(3):478-486
10 Talbott, S., Talbott, J. Effect of BETA 1, 3/1, 6 GLUCAN on Upper Respiratory Tract Infection Symptoms and Mood State in Marathon Athletes. J Sports Sci Med. 2009 Dec 1; 8(4):509-515.
11 Rodrigo Valenzuela Baez (Editor); Lipid Metabolism (ISBN 978-953-51-0944-0 ); Chapter 12, Page 267: Besana Waszkiewicz-Robak. Spent Brewer’s Yeast and Beta-Glucans Isolated from Them as Diet Components Modifying Blood Lipid Metabolism Disturbed by an Atherogenic Diet. Published January 23, 2013.