Immunity in your gut

As the weather turns bleaker here in the southern hemisphere, we find ourselves feeling a little more vulnerable to the winter lurgie. So what do we do?

Sure, vitamin C is good. And reaching for a Codral is common place. But what if the key to heightened immune resilience lay in somewhere almost completely unexpected. Yes – you know what we are talking about. Somewhere like the gut.

The ultimate defense

70% of our immune system lies in your gastrointestinal tract – whoa!

Lining the gut is the gut-associated lymphoid tissue (GALT); our gut-immune system. It exists to block external toxins, microbes and contaminants from entering the blood. It is the largest mass of lymphoid tissue in the body, communicating with the rest of the immune system and our initial line of defence to decide if something entering our mouths is friendly to our human body or not.⁵

GALT and the microbes of our gut work together to keep us safe.

This means that the health of your gut can have a great impact on the health of your immune system, as an innate or adaptive immune response. When compromised, issues arise such as increased susceptibility to colds and flus, food intolerances and allergies, respiratory difficulties and allergies such as hay fever, and skin conditions such as eczema, among others.⁷

Leaky gut (a.k.a. intestinal hyperpermeability) is highly implicated in immune function (or dysfunction) and inflammation. Consider this – we have a barrier and defence force in our intestine that decide whether we let something pass through the gate between or through our gut cells. When compromised, the barrier function is lost and all manner of things can pass into the bloodstream.

It is at this point that the whole body immune system loses its mind.

Via a paracellular route, antigens are accessing the GALT, and in turn stimulating inflammatory and immune responses.⁴

Responding to the presence of foreign material, the immune system goes into action mode, creating inflammation as a protective mechanism to contend with large molecules that just shouldn’t be in our blood. That inflammation can spread through the body, damaging cells and long-term result in cardiovascular disease, cancer, diabetes, depression and anxiety, joint pain, gastrointestinal disorders and more.⁵

And these issues can all be intertwined.

Stressed out

A central factor in the immune function is our old mate stress. Shifts in cortisol production following extended periods of can stress alter immune response and function.

Because stress hormones and immune function act in opposite to each other (as who is concerned about fighting a cold when you are fighting a grizzly bear?), initially, the immune response is suppressed. After a while, cortisol production can slow down, letting the immune system run riot. Therefore the balance between two immune system cytokines, Th1 and Th2, is thrown out depending on high or low cortisol production.

The two scenarios respectively leave you with:

1. heightened susceptibility to colds, flus, allergies and the like (Th2 dominant)
2. immune dysfunction and possible development of autoimmunity (Th1 dominant).

Neither are good.

A fantastic and proven way to help mitigate stress is diaphragmatic breathing. This is deep inhalation, followed by long slow exhalation.

So if you feel your blood pressure rise, or that things keep piling up on your desk, or the incessant whine of your toddler is nowhere near end point, take 5-10 deep, conscious breathes, and help manage the fight or flight response and further surges in adrenal stress hormone output.

Your gut bugs will also thank you for it. They aren’t fans of chronic stress either.^1;2

Love your guts

Boosting immune health is great for anyone and everyone. In particular, those most vulnerable to colds and viruses, like the elderly, athletes, children and pregnant women, are in need of all the assistance they can get to build immune defence!

A critical component to boosting immunity is caring for your intestinal microbiome. We discuss ways to tend to the gut garden here and here. Diet is one of the most defining factors for creating optimal or compromised health, in part due to its impact on our gut bugs.³

So you want to eat for your health? Then eat for your gut! Get plenty of fibre, and a variety of seasonal veg and fruit, whilst ensuring your diet comprises mostly of unprocessed, real foods, to aid in the growth and production of microbiota. This aids nutrient absorption and toxin removal. On the flipside, limit high sugar, highly processed and pesticide-laden foods, use of medications like antibiotics (using only when necessary), and explore ways to manage chronic stress.

References:

1. Bailey, MT 2016, ‘Psychological Stress, Immunity, and the Effects on Indigenous Microflora’, in Microbial Endocrinology: Interkingdom Signaling in Infectious Disease and Health, 2^nd, vol 874, pp 225-246.
2. Bharwani, A, Mian, MF, Foster, JA, Surette, MG, Bienenstock, J, & Forsythe, P 2016, ‘Structural & functional consequences of chronic psychosocial stress on the microbiome & host’, Psychoneuroendocrinology, vol. 63, pp. 217-227.
3. Brown, K, DeCoffe, D, Molcan, E, & Gibson, DL 2012, ‘Diet-Induced Dysbiosis of the Intestinal Microbiota and the Effects on Immunity and Disease’, Nutrients, vol. 4, no. 8, pp. 1095-1119.
4. Drago, S, El Asmar, R, Di Pierro, M, Grazia Clemente, M, Tripathi, A, Sapone, A, Thakar, M, Iacono, G, Carroccio, A, D’Agate, C, Not, T, Zampini, L, Catassi, C, & Fasano, A 2006, ‘Gliadin, zonulin and gut permeability: Effects on celiac and non-celiac intestinal mucosa and intestinal cell lines’, Scandinavian Journal Of Gastroenterology, vol. 41, no. 4, pp. 408-419.
5. Harnett, J 2013, ‘Understanding the intricacies of intestinal immunity: Integral to nutritional medicine practice’, Journal of the Australasian College of Nutritional and Environmental Medicine, vol. 32, no. 2, p. 3.
6. Sekirov, I, Russell, SL, Antunes, LM, & Finlay, BB 2010, ‘Gut microbiota in health and disease’, Physiological Reviews, vol. 90, no. 3, pp. 859-904.
7. Vighi, G, Marcucci, F, Sensi, L, Di Cara, G, & Frati, F 2008, ‘Allergy and the gastrointestinal system’, Clinical & Experimental Immunology, vol. 153, pp. 3-6.