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Boosting sIgA Mucosal Immunity against Virus Infections

Updated: May 4, 2022

Earlier I briefly spoke about the role of sIgA and some basic nutrients to support our mucosal immune defence.

Some of you may want to understand a little deeper how it works and want to know more helpful nutrients that would boost our immunity against virus infections.

A Nature magazine review spoke about “The role of secretory antibodies in infection immunity”(Strugnell and Wijburg, 2010) and how it reduces the severity of virus infections.

As the virus enters our body, the sIgA has three main ways to protect us

1. By preventing the virus from penetrating into our lungs

2. By neutralizing the virus replication

3. By removal of the virus from the mucous layers

With prolonged exposure of the virus, the sIgA would call upon the next levels of defence to actively target the specific virus.

Adapted from “The role of secretory antibodies in infection immunity”(Strugnell and Wijburg, 2010)

It is well known that a deficiency in IgA may lead to insufficient activation of our second level of defence (Arulanandam et al., 2001) and a prolonged period of ill-health following an infection.

How do we boost sIgA levels and our immunity

Beta-glucans are isolated from natural materials such as mushrooms, grains, yeast and seaweed, and found to have an immune-enhancing effect (Vetvicka et al., 2019).

In a study they found beta-glucans stabilised the sIgA levels of children with the flu and chronic respiratory problems and improved their immunity and health status (Richter et al., 2015).


1. Mushrooms such as Shitake and Maitake

Maitake, a common mushroom found in regular supermarkets in Singapore, is rich in Beta-glucans. Shitake is higher in alpha-glucans. However, researchers found consuming them together enhanced the immune activity of humans after two weeks of intake (Josef et al., 2017).

Mushrooms are a favourite vegetable added to stews and braised meat. A favourite dish we make at home is sesame oil braised chicken with ginger, soy sauce and a medley of mushrooms.

2. Oats and Barley

Cereals such as Oats and Barley contain Beta-Glucans as part of their endosperm. Therefore you would need to select the organic and unrefined options such as rolled oats vs. instant or baby oats, to get the immune-enhancing benefits (Volman, Ramakers and Plat, 2008).

Some ways to add them to your diet include having overnight soaked oats in water and have it in the morning with cinnamon, stewed apples and greek yoghurt. And if you prefer savoury dishes, you could cook the oats on the stove with organic chicken stock and top it with an egg, shallots and chives as breakfast chicken porridge. Cooked barley with minimal sugar is a common drink that is well-liked by Asians.

3. Saccharomyces Boulardii

A well-studied yeast-based probiotic has been found to increase sIgA levels likely due to the presence of beta-glucans (Hudson et al., 2016).

I hope you find the information enlightening and beneficial in supporting your health and that of your loved ones with the power of Functional Nutrition.


Arulanandam, B. P. et al. (2001) ‘IgA Immunodeficiency Leads to Inadequate Th Cell Priming and Increased Susceptibility to Influenza Virus Infection’, The Journal of Immunology. The American Association of Immunologists, 166(1), pp. 226–231. doi: 10.4049/jimmunol.166.1.226.

Hudson, L. E. et al. (2016) ‘Characterization of the probiotic yeast Saccharomyces boulardii in the healthy mucosal immune system’, PLoS ONE, 11(4), pp. 1–21. doi: 10.1371/journal.pone.0153351.

Josef, R. et al. (2017) ‘Glucan Supplementation Regulates Secretory Immunity and Stress’. doi: 10.3844/ajisp.2017.81.85.

Richter, J. et al. (2015) ‘β-glucan affects mucosal immunity in children with chronic respiratory problems under physical stress: clinical trials’, Annals of Translational Medicine, 3(4), p. 52. doi:

Strugnell, R. A. and Wijburg, O. L. C. (2010) ‘The role of secretory antibodies in infection immunity’, Nature Reviews Microbiology. Nature Publishing Group, 8(9), pp. 656–667. doi: 10.1038/nrmicro2384.

Vetvicka, V. et al. (2019) ‘Beta Glucan: Supplement or Drug? From Laboratory to Clinical Trials’, Molecules. MDPI AG, 24(7), p. 1251. doi: 10.3390/molecules24071251.

Volman, J. J., Ramakers, J. D. and Plat, J. (2008) ‘Dietary modulation of immune function by β-glucans’, Physiology and Behavior, 94(2), pp. 276–284. doi: 10.1016/j.physbeh.2007.11.045.

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