You may be able to lower your risk of developing lung cancer by 33 per cent if you maintain a diet rich in fibre and eat yoghurt every day, according to the results of a new study published in the journal JAMA Oncology.
This study looked at the pooled data of over 1.4 million people living across the United States, Europe and Asia to explore how the amount of fibre and yoghurt people consumed could impact the level of risk.
The research showed that people who ate around one tub of yoghurt a day had a risk of lung cancer that was almost 20 per cent lower than those who did not consume yoghurt. Meanwhile, participants who had an overall high-fibre diet reduced their risk of lung cancer by around 15 per cent.
The most interesting finding was what resulted when individuals combined both dietary strategies, eating yoghurt every day while maintaining a high-fibre diet; they reduced their risk of lung cancer by 33 per cent.
"Our present findings indicated that the combination of prebiotics (fibre) and probiotics (yoghurt) may be stronger against lung cancer than either component alone."
Prebiotics and probiotics at work
The researchers say the health benefits of fibre and yoghurt combined may be rooted in their prebiotic and probiotic properties.
"Our present findings indicated that the combination of prebiotics (fibre) and probiotics (yoghurt) may be stronger against lung cancer than either component alone,” the study reads. “This finding suggests a potential role of increasing both prebiotic and probiotic consumption in lung cancer prevention.”
This study explored high and low-risk factors only and not cause. The fibre and yoghurt links to lung cancer risk were significant in people who had never smoked and were consistently observed across sex, race/ ethnicity and tumour type.
The research did not take into account the type of fibre (insoluble or soluble) or kind of yoghurt (detailing the type of bacterial strains contained, flavour or sugar-content) people were consuming.
Lung cancer: not just a smoker's disease
Cancer Australia estimates that lung cancer was the fifth most commonly diagnosed cancer in Australia in 2015, and in 2016 it was the most common cause of cancer death in Australia. The organisation also states that 18 per cent of all cancer deaths in Australia result from lung cancer.
Contrary to common belief, people who do not smoke can still develop lung cancer.
Cancer Council explains that exposure to other toxic substances, a family history of the disease, or a history of various lung diseases can also increase your risk of lung cancer. Within this study, the high-fibre diet and yoghurt consumption links to reducing the risk of risk were significant in people who had never smoked and this was consistently observed across sex, race/ ethnicity and tumour type.
How do yoghurt and fibre have anything to do with lung cancer?
Accredited Practising Dietitian, Nicole Dynan, stresses that the study does not prove yoghurt and a high-fibre diet causes a protective effect against lung cancer. As an observational study, it simply shows a link between the foods and lung cancer risk, opening the door for further research into the subject.
But, given the study’s sample size was so large and culturally diverse, Dynan says its findings are significant.
“It covers people with a broad range of different eating patterns and cultures, making the study much more robust than those using data from one single demographic type,” explains Dynan, a spokesperson for the Dietitians Association of Australia.
“So if we are adding populations of good bacteria [to our gut] through food, then technically it should help reduce inflammation in the body."
The study was unable to determine why yoghurt and fibre may impact your lung cancer risk. However, the authors hypothesise that it could be to do with the anti-inflammation power of probiotic strains in some yoghurt and prebiotic fibre types, which may help inhibit lung metastasis or enhance natural killer cell activity.
“That could make sense because if you think of it in simple terms, bad bacteria causes inflammation and good bacteria reduces inflammation,” Dynan says. “So if we are adding populations of good bacteria [to our gut] through food, then technically it should help reduce inflammation in the body. But [the impact] is only as good as the food that’s available to you.”
Dynan recommends that people consume plenty of high-fibre, plant-based foods like vegetables, fruits, wholegrains, legumes, nuts and seeds to promote good health overall.
“Also the fermented dairy foods like yoghurt, kimchi and sauerkraut are beneficial to eat as they can help boost populations of good bacteria in the gut.
“Having that balanced diet with lots of wholefoods and fermented products is important for everyone’s health.”