It’s that time of year when our bodies are challenged with low vitamin D, colder temperatures and subsequent immune system hurdles. Besides the obvious strategies to boost immunity during this time like getting fresh air and eating vitamin C rich foods, taking care of your gut bugs may just provide that key extra ingredient to avoid getting sick this winter. And don’t forget, your immune system is much more than a barrier between you and the common cold, research is now pointing the finger at the immune system as being one of the root causes of disease.

Many of us have heard the statistic that the microbial cells in our body outnumber our own cells by up to 10 to 1, but did you know that genetically speaking, microbes contribute around 99% of gene expression and your own cells only 1%! The huge number of microbial cells which make up the microbiome, in the form of bacteria, yeast, parasites, viruses and protozoa, have an overwhelmingly significant impact on the health outcomes you experience each and every single day, particularly the immune system.

To set the story here, I want to go way, way back to when you were born. You see during the early stages of life, your immune system goes through some crucial development, and much of this is dependent on the microbiome which you receive from your mother at birth (and even in the womb, too!). As the baby moves through the vaginal canal, he or she picks up a sort of ‘seedling sample’ of Mum’s microbiome. These initial microbes begin to inhabit baby’s skin and most importantly enter the mouth and gut; the initial stages of a very delicate developmental microbiome project! 

In 2015, 32% of Australian children were delivered via C-section. Studies show that C-section delivery poses health risks for babies including higher risks of allergies, asthma and overweight, and this is most probably due to the fact that babies born this way receive very little, if any, of Mum’s microbiome. Although C-sections are a necessary birth intervention in some circumstances, the World Health Organisation states that no region should exceed a 10-15% rate as doing so offers no increase in important statistical measurements like infant & mother survivability (these rates stay the same regardless of how high above 10-15% C-section delivery rates go). Importantly, a process known as seeding is becoming more popular and is being studied heavily, whereby a swab is taken of Mum’s vaginal canal and used to inoculate baby manually.

The birthing process is an essential part of immune development. Mum’s microbiome is a reflection of her environment, for instance she may have certain parasites & viruses which help her thrive against other microbes which may be present in the area or food supply. These are passed on to baby to, presumably, help baby thrive in that same environment. Once birth has taken place, the colostrum in Mum’s breastmilk will also contribute important information for the immune system and for the gastrointestinal tract, and will slowly increase in sugar content to provide nourishment for the gut microbes. Amazingly, specific cells in Mum’s body will carry microbes from her gut into her breast tissue, and these will also be passed on to baby during breastfeeding.

For three to five years the baby’s microbiome will fluctuate and be a little unstable as it learns and adapts to changes in diet & environment. If antibiotics are taken a significant reduction in microbiome diversity (a key marker of microbiome health) can be expected and some species may be lost forever (see Dr Martin Blaser’s work). During this time the microbiome is digesting baby’s food, providing essential nutrition elements and, according to Dr Natasha-Campbell McBride, is an essential factor for healthy neural and immunological development. 

Your microbiome is in constant communication with your immune system. Your microbiome can activate, perpetuate and deactivate inflammation throughout the body to the point where even diseases like diabetes and Alzheimer’s are being attributed to the gut. As you may have heard, around 80-90% of the immune cells are located around the gut! Presumably, through complex communication pathways and a process called Quorum sensing, the microbiome acts as a messenger for the body’s own immune cells, indicating what is happening in the hosts’s outside environment. A low fibre diet for instance may cause a reduction in certain microbes who normally provide important anti-inflammatory molecules like butyrate, resulting in higher levels of inflammation throughout the body and higher immune cell activation as the host cells try to take over the job. 

Studies have shown that specific microbes have specific effects on the immune system. Asthma in mice can be reversed with probiotic supplementation, for instance. Autoimmune conditions such as psoriasis and arthritis are heavily attributed to the gut. In an interview with microbiologist John Ellerman, he explained to me that when the gut is ‘too leaky’, then macro food molecules enter the bloodstream and stimulate the production of antibodies which, through a process called molecular mimicry (where identical proteins are present in both the food and the body part), can cause the body to attack itself! These antibodies might attack the thyroid, skin or joints and we would translate these symptoms as Hashimoto’s, psoriasis or arthritis. Professor Mimi Tang at the Murdoch Children’s Research Institute has recently had success in reversing peanut allergies in children using probiotic therapy, but is it a case of simply switching over from the traditional pharmaceuticals to probiotic pills? Or should we be more focused on a holistic approach?

As Professor Andrew Holmes at Sydney University says about the microbiome,It’s more like a rainforest restoration. You don’t restore a complex system by adding or subtracting a few species.’ 

This is where the application of a good gut nourishing diet and a holistic microbiome approach become paramount in the immune system picture. Avoiding unnecessary use of antibiotics, consuming an unprocessed, wholefoods, gut-nourishing diet (like the one I outline in The Gut Healing Protocol) and taking probiotic supplements is across the board a fantastic way to start. When we provide these ideal conditions for the body, a natural state of homeostasis is much more likely to be discovered as opposed to prodding in the dark with pharamaceuticals or complementary medicines.

The gut and the immune system are intricately linked and if keeping on top of your health is important to you this winter, now is the time to start looking after your tummy.

Now, I’m off for some vitamin Sea (ehehe) and D 😉


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Kale Brock The Gut Healing Protocol

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