Nutritional & Brewer's Yeast - History, Uses, and Benefits
Nutritional yeast is rich in vitamins, mineral, fiber, and protein. You may expect nutrient-packed bacteria to taste like dirt but nutritional yeast actually has a light cheesy flavor.
Related: Peppermint Essential Oil - History, Uses, and Benefits
The yeast strain saccharomyces cerevisiae must undergo five key steps to be packaged and sold as nutritional yeast. Since yeast is a living organism it must first be grown in a sterile environment free of impurities and bad bacteria. After growing in this sterile environment it's transferred to large stainless steel fermentation tanks where it's fed a diet of air and glucose derived from sugar cane or beet molasses.
The yeast feeds on this sugar and air for a predefined number of days before passing through a centrifuge to eliminate impurities, bathe, and extract the yeast cells. This process creates a liquid called nutritional yeast cream.  At this point the yeast is still alive and activated.
This next steps defines the difference between brewer's yeast and nutritional yeast. Manufacturers then pasteurize the yeast cream to deactivate the yeast.  This heat kills the yeast and prevents it from continuing to grow. Some manufacturers add vitamin B-12, a vitamin commonly under-consumed by vegans and vegetarians, to further improve the nutritional profile.
The final step involves running the yeast cream through drum dryers.  This method runs the cream slowly dries the yeast at a low temperature until it reaches a yellow flake or powder form. The yeast is then packaged and sold at supplement retailers, grocery stores, and specialty food shops.
Three tablespoons (15 grams) of nutritional yeast provides 60 calories, 0.5 grams of fat, 0 milligrams of cholesterol, 25 milligrams of sodium, 5 grams of carbohydrates, 3 grams of fiber, and a whopping 9 grams of protein.  This breaks down to a macronutrient ratio of 7% fat, 33% carbohydrates, and 60% protein.
A 15-gram serving of nutritional yeast also contains 1.08mg of iron, 2.7mg of zinc, 8.1mg thiamin (B1), 8.2mg riboflavin (B2), 42mg niacin (B3), 8.4mg vitamin B6, and 7.20mcg vitamin B12.  This equates to 6%, 18%, 683%, 630%, 263%, 560%, and 120% of your recommended dietary allowance (RDA) for each vitamin and mineral listed in the previous sentence, respectively, per three-tablespoon serving.
Nutritional yeast is also one of the best vegan sources of selenium, second only to Brazil nuts.  Selenium is critical for normal thyroid function.
Nutritional & Brewer's Yeast UsesNutritional yeast is most commonly sold as a standalone bulk supplement but it may also be included in protein bars, powders, and baked goods. The subtle cheesy taste will take your sauces, scrambles, crackers, bread, and biscuits to the next level.
Those looking to bump up protein content without having to bake can sprinkle nutritional yeast on vegetables, potatoes, pasta, and popcorn. Throwing in a few tablespoons into your superfood smoothie or shake will increase the protein, vitamin, and mineral content without the subtle cheesy flavor overpowering your palate and ruining the beverage.
Unlike most supplements nutritional yeast does not have a clinically-backed recommend dose. Nutritional yeast is technically a food product so while I wouldn't recommend eating pounds of the deactivated bacteria, there's virtually zero risk of overdosing or ingesting toxic quantities.
Most folks consume anywhere between one teaspoon and three tablespoons per day to bump up their protein, vitamin, mineral, and fiber intake. Nutritional yeast is a versatile and reasonably priced all-natural food product that can add both flavor and nourishment to your diet.
Nutritional & Brewer's Yeast BenefitsThe quantity of placebo-controlled research on nutritional yeast consumption in humans is limited since it's treated more like a food and less like a supplement. Examination of the micronutrient and macronutrient content of nutritional yeast supports some claims pertaining to its health benefits.
Nutritional yeast is an excellent food-based supplement for those deficient in vitamin B12, a water-soluble vitamin critical for normal red blood cell formation, neurological function, and DNA synthesis.  A vitamin B12 deficiency is most common in those eating vegan or vegetarian diet since animal protein and seafood, on average, are the richest sources of this critical vitamin.
Indicators of a B12 deficiency include but are not limited to diarrhea, dizziness, fatigue, appetite loss, rapid and irregular heartbeats, tingling, numbness, or burning in the extremities (e.g. feet, hands, arms, legs).  If you suspect a recently developed or mild vitamin B12 deficiency in the blood, then ask for a methylmalonic acid (MMA) test. MMA, critical for metabolism and energy production, is naturally produced by the body in small quantities.
If you're not consuming sufficient quantities of vitamin B12 then your MMA level will rise.  A blood or urine test can measure MMA levels.
49 individuals consumed the Hallelujah Diet, a raw plant-based vegetarian diet, for between two and four years. 76% of participants had low vitamin B12 levels in the blood (<221 pmol/l) and 47% had high MMA levels in the urine (> 4.0 microg/mg creatinine).
Those consuming nutritional yeast, a great source of vitamin B vitamins, significantly decreased their urine MMA levels compared to probiotic treatment group.  The group consuming a sublingual vitamin B12 supplement also significantly decreased their B12 blood levels.
These findings indicate that the all-natural nutritional yeast is equally as effective as a vitamin B12 supplement in treating a recent and mild deficiency as measured by decreased MMA levels.
As previously mentioned nutritional yeast is a great vegetarian source of the mineral selenium. This mineral plays important roles in reproduction, thyroid function, DNA synthesis, and protection against oxidative damage. 
Selenium and iodine work hand-in-hand to ensure normal thyroid and metabolism function. Failure to consume sufficient quantities of selenium alongside high amounts of iodine can lead to a number of dangerous side effects.
Those who fail to consume sufficient quantities of selenium are at a significantly increased risk of developing colon and lung cancer. This mineral also improves immune system function during bacterial invasions and infection, ramps up the formation of natural killer cells, slows the rate of tumor growth, and increases sperm motility in males. 
The recommended daily allowance of selenium for males and females greater than 18 years of age is 55 mcg.  Incorporating a few teaspoons or tablespoons of nutritional yeast into your daily diet will quickly bump up your selenium intake.
Nutritional yeast also contains potent antioxidants, polysaccharides, and disaccharides. Specifically, beta-1,3 glucan, trehalose, mannan, and glutathione.  The polysaccharide beta-1,3 glucan has powerful immune-boosting, anti-inflammatory, and antimicrobial properties verified through human, animal, and cell studies. 
Trehalose is a disaccharide can trigger programmed cell death, also known as apoptosis, which is useful in fighting infections and required for normal cellular function.  Mannan, a polysaccharide found in all varieties of yeast, improves immune system function in animal models through encouraging the growth of beneficial bacteria in the gut. 
Additional research is needed to see if these benefits are also true for a human subject. Glutathione is a potent antioxidant that protects against some of the harshest oxidative stressors, improves immune function, programmed cell death, and mitochondrial function. 
The mitochondria are the powerhouse of the cell and is responsible for both respiration and energy production. While the quantities of these compounds are not exceptionally high in nutritional yeast, chronic consumption over a long-term period of time can have significant positive effects on overall health.
Although not identical to nutritional yeast, one study on brewer's yeast found positive impacts on cold and flu symptoms. The randomized trial took a large group of adults who recently obtained the seasonal influenza vaccination and provided them with either EpiCor, an over-the-counter brewer's yeast-based product or placebo. Those receiving EpiCor had significantly fewer and shorter instances of cold and flu-like symptoms. 
While brewer's yeast is nowhere as effective in preventing the flu as a flu shot, it may help ease some of those undesirable symptoms accompany colds and the flu. It would be interesting to see if these results differed based on the use of nutritional yeast rather than brewer's yeast. Furthermore, it would be beneficial to compare the vaccine-only group to a yeast-only group.
Do you supplement with nutritional yeast? Have you noticed additional benefits no described above? Let me know in the comments below.
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