Yeasts in Foods- A Source of Immunity Enhancer

 By Dr. Parul Thapar

Introduction

Yeasts can be consumed mainly in two forms- active and dead form. Depending upon the form to be utilized, the active form is further available in dried (powder), compressed and liquid form. The active form of the yeast carries out the process of fermentation in various foods and also leavening during baking. The dead form of the yeast are the dead yeast cells thatdoes not have fermenting activity and is only available in dried (flakes) form (Figure 1). The different features of the active and dead forms of the yeasts are shown in the Table 1.

Fig.1. Forms of yeasts to be consumed

Table 1: Features of the active and dead forms of yeasts

Forms of yeasts
Features	Active form	Dead form (Flakes)
Purpose	Specifically used during fermentation of foods	Specifically used to improve food flavour and increase nutrition.
Commercially available as	·         Baker’s yeast (Saccharomyces cerevisiae); ·         Probiotics(Torula spp., Saccharomyces kefir, Torulakumiss); ·         Brewer’s and wine yeasts (Saccharomyces cerevisiae, Saccharomyces carlsbergensis, Saccharomyces vini, Saccharomyces sake)	·         Nutritional Brewer’s yeast (Saccharomyces cerevisiae); ·         Nutritional Whey yeasts (Kluyveromyceslactis, Kluyveromycesmarxianus).   These also called modified nutritional yeast
Food value	Rich in essential amino acid lysine which helps the body to absorb calcium, iron and zinc [4]. High in energy and minerals like phosphorus.	Rich in essential amino acid lysine which helps the body to absorb calcium, iron and zinc [4]. Excellent source of protein. Also rich in basic nutrients such as vitamin B, minerals like calcium, phosphorus, potassium, magnesium, copper, iron, zinc, manganese and chromium
Products	Bread/ Cake/ Biscuits; probiotic drinks like kumiss/ koumiss, kefir; beverages like beer, wine, rum; fermented whey drinks	Modified nutritional yeast flakes can be used to sprinkle over soups, roasted vegetables, salads or pasta.
Recommended intake (if consumed)	·         Bread:2 slices per day ·         Probiotic and fermented whey drinks: 60-100 ml per day ·         Red wine: 1-2 glasses per week ·         Rum, beer, vodka, ale: 1-2 units per week	Nutritional yeast flakes: 1-2 table spoon per day

 

Health benefits of consuming yeast based food products:

In view of the prevailing pandemic (COVID-19) caused by SARS CoV2 virus and scope of future viral infections, the diet containing yeasts as ingredients can provide major health benefits. The drawback of SARS CoV2 virus and other viral infections is that after attacking the host, they become deadly for the people with weaker immune system. Therefore, the yeast based food products can play a major role in boosting up the immune system and overall health of the human beings. These are mentioned below:

• Healthy Immune System:

Probiotic drinks– The probiotic drink like koumiss containing yeast provide natural defence system for the body. They prevent the growth of unwanted bacterial and viral species and strengthen the immune system from allergies. Yeast based probiotic drinks help the body to produce vitamins and minerals that act as antioxidants against infections.

Nutritional Brewer’s yeast dried flakes -The dried flakes of nutritional brewers’s yeast helps in the stimulation of B-cells and natural killer cells of the lymphatic system. This increases the initiation of salivary immunoglobulins A (IgA antibodies). These antibodies act against certain viral antigens causing symptoms like cold (by Rhino virus, corona virus) and flu (by influenza virus); thus enhancing the immune system.

EpiCor- EpiCor, a whole food fermentateis a nutritional brewer’s yeast based product that has been formulated recently and is also available online. Besides stimulating the secretion of IgA antibodies, EpiCor also contains macronutrients like fatty acids such as oleic acid and variety of soluble and insoluble dietary fibres. It contains vitamin B3 (niacin) and minerals like phosphorus, phytosterols and phenolic compounds like resveratrol. Resveratol is a natural antioxidant that also has anti-cancer properties inhibiting all carcinogenic stages, anti-inflammatory properties as well as cardio and neuro protective.

Yeast based products- All the yeast based products consist of essential amino acid-lysine. This amino acid is essential because the human body cannot synthesize it and one needs to take it from out sources. The percentage of lysine is highest in yeast based products. This amino acid helps to produce antibodies which enhance the immune system. Lysine also helps the body to absorb minerals like calcium, iron and zinc, thus promoting the growth of collagen in bones; production of enzymes and hormones and also lowering of blood pressure in patients of hypertension.

• Improvement of Diabetes mellitus-2 and Blood Pressure:

Nutritional Brewer’s yeast dried flakes – The nutritional brewer’s yeast contains glucose tolerance factor (GTF). GTF structure is composed of organic chromium (Cr+3) which is biologically active in association with amino acids- cysteine (cis), glutamine (glu), glycine (gly) and vitamin B3. GTF facilitates the binding of insulin to the target cells that reinforces the hypoglycemic activity of insulin and increasing the insulin functioning of maintaining blood-glucose level. This improves the glycemic index of patients of diabetes mellitus-2 and cardiovascular diseases.GTF contains macronutrients like potassium, magnesium, calcium and biological peptides containing lysine. The biological peptides along with these minerals reduces the activity of angiotensin converting enzyme (ACE) that converts the hormone angiotensin-I into an active form of angiotensin-II leading to hypertension. Due to reduced ACE activity, there will be reduced hypertension and hence improvement in blood pressure. GTF also reduces cholesterol and triglyceride levels (high density lipoproteins or HDL) in patients of diabetes mellitus-2, overall maintaining a normal blood pressure.

• Improves Digestion:

Probiotic drinks- The probiotic drinks like kefir and koumiss containing yeasts support healthy digestion by reducing constipation. They also improve lactose digestion (mainly for lactose-intolerant people).

Conclusion

There are diverse variety of organisms living on the earth. Among them, is the nature of the virus or any other pathogenic microbial species causing a particular infection, that they can change their strain every year causing a particular disease. This does not allow either the available vaccines to work or there can be delay in the development of new vaccines. Therefore, in order to avoid the havoc of any future infections or waiting for any kind of vaccine to develop, it is the right time is to make our immune system up to the level that can fight against any new pathogen. This can be done by bringing a change in the dietary habits. Due to the prevailing conditions of COVID-19 and considering other viral infections in future, the addition of yeasts in the diet will certainly enhance the immunity. The natural yeasts consist of numerous substances that are beneficial for human beings. Not only the market available yeast based products can be consumed, but active dry or liquid form of yeast can also be used as ingredient in fermented foods like dosa batter, dhokla etc. in recommended dosage. While using the yeast based products, only the recommended quantity should be kept in mind, as excess of yeast intake can also cause side-effects like yeast allergy. The yeast intake should be avoided by patients of organ transplant and pregnant women