Prostate cancer could be prevented by eating yoghurt enriched with good bacteria, according to new research. The wrong gut bugs fuel the growth of tumours - and may make them resistant to therapy, say scientists.
A study identified dramatic differences in the microbiome of men with the disease compared with those who had benign biopsies. It opens the door to a screening program and development of personalised probiotics or prebiotics - good bacteria and the plant fibres that nourish them, respectively.
The findings also shed light on the link between lifestyle effects and geographical anomalies in prostate cancer cases.
Lead author Professor Peter Bostrom, of the University of Turku, Finland, said: "There are significant variations in prostate cancer rates around the world, which could be due to genetic factors or differences in healthcare policies, but also variance in lifestyle and diet.
"The difference in gut microbiota between men with and without prostate cancer could underpin some of these variations. More research is needed to look at the potential for using gut microbiota for both diagnostic and preventive strategies."
A huge 100 trillion microorganisms live in the human belly - good and bad. The immune system is affected by the balance.
They have been linked to many conditions - even in organs that are far from the intestines. But their role in prostate cancer is not understood.
The Finnish team sequenced intestine samples of 181 suspected prostate cancer patients. They were collected during biopsies after MRI scans.
Gut bacteria of the 60% diagnosed with the disease was strikingly unlike that of the others found to be cancer-free. They had increased levels of Prevotella 9, members of the family Erysipelotrichaceae, and Escherichia-Shigella, a pathogen that causes diarrhoea. There were also fewer bugs known as Jonquetella, Moryella, Anaeroglobus, Corynebacterium and CAG-352.
Prostate cancer is the most common male cancer globally. In the UK, more than 52,000 men are diagnosed annually. It claims around 12,000 lives a year. The disease is common in most Western countries and less prevalent elsewhere. It is known to run in families.
There is also evidence men who emigrate from low to high-incidence areas have an increased risk of prostate cancer in their lifetimes. Their offspring are also more prone.
Prostate cancer expert Prof Lars Andersen, of Aarhus University, Denmark, who was not involved in the study, added: "This is a striking finding from a large well-conducted trial. We should be careful with observed associations when it comes to complicated epidemiology, and no cause-and-effect measures can be determined based on this.
"But certainly the gut microbiota could be an important area to investigate further to enhance our understanding of prostate cancer risk."
The study was presented at a European Association of Urology meeting in Amsterdam.
