What are the benefits of brewer’s yeast?

Reminder: what is brewer’s yeast?

Brewer’s yeast is a microorganism which, like baker’s yeast, is part of the Saccharomyces cerevisiae family. Produced in a controlled environment conducive to its growth, it plays a role in the fermentation of beer, where it converts sugars into alcohol and carbon dioxide. Sugar cane molasses and other nutrient substrates can also be used to cultivate brewer’s yeast.

Once collected and dried, this microscopic fungus is converted into powder, dehydrated flakes (for sprinkling on salads for example) or dietary supplements in tablet or capsule form. Inactive brewer’s yeast will have been heated to 40°C to ensure its stability without altering its nutritional profile.

Brewer’s yeast: key health benefits

Brewer’s yeast and hair

It’s no coincidence that naturopaths recommend brewer’s yeast for restoring strength and radiance to dull, damaged or thinning hair! This nutritionally-rich food contains a wide range of B group vitamins, which are involved in energy metabolism and cell regeneration: B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), and especially B8 (biotin), the famous ‘beauty vitamin’ which helps maintain healthy hair (1).

Brewer’s yeast’s high protein content, particularly the sulfur-containing amino acids, facilitates restructuring of the hair fibre, which is made up of 95% keratin (2). This is in addition to its significant content of zinc, an essential trace-element and pillar of good hair health (3).

Brewer’s yeast and skin

Taking brewer’s yeast is typically recommended for those with skin imperfections, because of its combination of vitamins B2, B3 and B8, all of which help maintain healthy skin. Its potential for regulating sebum production and skin inflammation (both key factors in acne) is often mentioned too, though studies are still needed to confirm this (4). Meanwhile its content of zinc, which plays a role in normal DNA synthesis and the protection of cells against oxidative stress, helps to brighten the complexion and delay the first signs of ageing (5).

Brewer’s yeast and nails

Together with hair and body hair, the nails are part of the integumentary system – a protective physical barrier characterised by high keratinisation. Again, it seems the protein in brewer’s yeast, aided by the biotin which supports normal protein metabolism, is able to strengthen brittle or damaged nails by contributing to keratin production.

Brewer’s yeast and the liver

Murine (mouse model) studies suggest that brewer’s yeast is able to modulate the activity of hepatocytes (liver cells). This research has highlighted changes in cholesterol metabolism, attributable to a specific yeast fraction (nicotinamide riboside), as well as in glucose tolerance (6-7). Scientists have also looked at the effects of yeast extracts on alcohol-induced liver damage in rats (8).

Brewer’s yeast and sleep

Is it true that brewer’s yeast can help you sleep better? While there’s limited scientific literature on the subject, brewer’s yeast is one of the best dietary sources of vitamin B1 (10g provides 100% of the recommended daily intake). Supporting normal nervous system and psychological function, this vitamin is involved in the production and absorption of serotonin, a neurotransmitter responsible for regulating mood and precursor of melatonin (the sleep hormone) (9). So why not!

Brewer’s yeast and immunity

Brewer’s yeast also contains specific polysaccharides able to interact with our immune system. A study on elderly mice supplemented with brewer’s yeast showed an astonishing ‘reactivation’ of immune mechanisms, with an upsurge of lymphocytes in the blood, thymus and spleen (10). A clinical trial involving 162 subjects prone to recurrent infections (colds) suggested promising effects from the beta-glucans in brewer’s yeast on the body’s ability to fight pathogens (11).

What downsides or side-effects are associated with brewer’s yeast?

Despite its many benefits, brewer’s yeast also has certain disadvantages to bear in mind.

In susceptible individuals, its fermentation activity can cause digestive problems: bloating, flatulence, etc., though these are mainly observed when the yeast is in its active form. It is not recommended for those with inflammatory bowel disease (Crohn’s, ulcerative colitis) or irritable bowel syndrome as it may make symptoms worse. It should also be avoided by anyone highly-sensitive to biogenic amines (which trigger migraines).

As it contains tyramine, brewer’s yeast should not be taken in conjunction with MAOI anti-depressants or meperidine (a narcotic), as this can increase the body’s adrenergic response, causing sudden surges in blood pressure (12).

And as it remains ‘live’, active brewer’s yeast should not be taken by immunocompromised individuals as there is a theoretical risk of septicaemia when fungi cross the intestinal barrier and enter the bloodstream (13).

Active or inactive brewer’s yeast, which is best?

Unlike the inactive version, active brewer’s yeast retains probiotic activity which may be beneficial in cases of gut flora imbalance. However, it is less well-tolerated by the digestive system and is in principle riskier for those in more delicate health.

Despite the fact it is heat-treated, inactive brewer’s yeast retains all its nutrients (vitamins, minerals, antioxidants…) and essential properties, including cosmetic ones. It’s worth noting that in some supplements targeted at tired or damaged hair, positive effects on the scalp are boosted by the addition of zinc, vitamin B6 and biotin (as in the product Brewer's Yeast Hair Boost, which has a high dose of inactive brewer’s yeast with a minimum 40% protein, and is enriched with the above-mentioned nutrients) (14).