Gut-lung axis is crucial in lung cancer

Gut-lung axis is crucial in lung cancer

There is a Gut-Lung axis which links the two microbiomes and the two immune systems and any dysbiosis or deficiency in the gut microbiome is soon reflected in the lungs - infection can then result in asthma, chronic pulmonary disease and even lung cancer; worse, chemotherapy drugs can worsen the situation and heighten the risk of severe and even fatal illness.

Lung damage can start early

New research published in JAMA (1) has shown that antibiotics given to infants greatly increases their risk of allergies, skin problems and asthma later in life. The researchers concluded that this was due to early damage to the gut microbiome. The research was a large scale study involving almost 800,000 medical records. Although ‘expert’ paediatricians in the USA claimed ‘surprise’ at the findings, they had only their ignorance to blame.

A Canadian study (2) showed exactly the same finding 5 years ago, even naming four bacteria in the gut of babies that were protective - faecalibacterium, lachnospira, veillonella and rothia.

It has been long-established that a poor microbiome in young children is linked to increased risk of asthma and allergies. For example a 2007 study from the University of Alberta showed that children under 12 and living on farms had a two year incidence of asthma of 2.3%, compared to their rural peers at 5.3% and their urban peers of 5.7%. The gut microbiome of farm children is populated with more strains of bacteria.

Studies (3) comparing Amish and Hutterites two farming communities, have shown that Amish (who have the cow sheds as part of the house) have 6.8 times more ‘farm dust’ in their houses, and levels of asthma were four to six times lower. Certain protective bacteria that shaped the Innate Immune System (your first line of defence) were found in the farm dust.

All these findings show clearly that a loss of important gut bacteria can be linked to problems in the lungs.

The Gut-Lung axis

Indeed, a Gut-Lung axis has been established and confirmed several times including a 2015 review of the subject (4). The researchers state that, ‘Advances in respiratory immune system also broaden our knowledge of the interaction between host and microbiome in the lung. Increasing evidence indicated the intimate relationship between the gastrointestinal tract and respiratory tract’. 

The composition of the microbiome in the gut is similar in composition to that in the airways.

The researchers go on to talk about the immune system and infection. ‘We discuss the impact of gut and lung microbiota on disease exacerbation and progression, and the recent understanding of the immunological link between the gut and the lung, the gut–lung axis’.

People with IBS have been shown to exhibit poor lung function (5), and that there was even ‘cross-talk’ between the gut and the lung microbiome in Inflammatory Bowel Disease (6).

Your microbiome strengthens immune response

In the top 6 articles on the immune system on Google, not one mentions the microbiome, yet it is firmly established that your microbiome of some 90 trillion members prompts both the innate and the Adaptive Immune system to be clearly stronger and more able to deal with new invading pathogens. Not surprisingly, people who eat the highest levels of soluble fibre – known to be loved by commensal bacteria and boost their numbers – have the strongest immune systems. Some 85% of the immune memory is produced in response to the membership of your gut microbiome.

A poor diet will reduce the strength of your microbiome, as will other factors such as drugs (including antibiotics and omeprazole), parasites which can ‘knock out strains of commensal bacteria, and smoking, binge drinking and stress. And these factors also reduce your immune response.

If the good, commensal bacteria are depleted in terms of volume and diversity, not only is your immune system compromised, but there is a loss in the production of health proving compounds such as B vitamins, vitamin K, melatonin, serotonin, cholesterol-restricting esters and more. Finally, your good bacteria may lose the ability to control the pathogens in your body. And pathogens make toxins and micro-RNA which can compromise your own health-producing micro-RNA and lead to chronic illness.

Infection regularly found prior to lung cancer

In a study from scientists in Ferrara, Italy involving 96 patients with a lung tumour, 42 micro-organisms were isolated of which 50% were gram-negative. Typically gram negative bacteria cause infections and include Klebsiella, Acinetobacter, Pseudomonas aeruginosa, and E. coli.

In other studies it would seem that infection is not just likely before the cancer appears, but can be the result of treatment itself, even resulting in death.

Different studies have shown figures from 30% to 70% of people with Lung cancer having an infection at some point. Gram-negative pathogens such as Haemophilus species, members of Enterobacteriaceae, and Pseudomonas aeruginosa, predominated and notable gram-positive pathogens were viridans streptococci, Staphylococcus aureus, and Streptococcus pneumoniae.

A thorough review (7) as long ago in 2005 was clear on the role of infection in terms of cause of lung cancer and subsequent mortality and morbidity.

Whilst oncologists may respond to infections later in the progression of the cancer, little action is taken at diagnosis.

Go to: Overview of Lung cancer – symptoms, causes and treatment alternatives





2. Antibiotics use in infants raises Asthma risk



5. S. Keely, N. J. Talley, and P. M. Hansbro, “Pulmonary-intestinal cross-talk in mucosal inflammatory disease,” Mucosal Immunology, vol. 5, no. 1, pp. 7–18, 2012.

6. H. Wang, J.-S. Liu, S.-H. Peng et al., “Gut-lung crosstalk in pulmonary involvement with inflammatory bowel diseases,” World Journal of Gastroenterology, vol. 19, no. 40, pp. 6794–6804, 2013.



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