NASHVILLE: Even among smokers, people who eat more fibre and yoghurt may be less likely to develop lung cancer than those who don’t consume much of these foods, a research review suggests.
Researchers examined pooled data from 10 previous studies that included a total of almost 1.45 million adults in Asia, Europe, and the United States. After following people for an average of 8.6 years, 18,822 cases of lung cancer were documented.
Compared to people who never ate yoghurt, those who consumed the most yoghurt were 19 per cent less likely to develop lung cancer, the analysis found.
People who had the most fibre in their diets, meanwhile, were 17 per cent less likely to develop lung cancer than those who ate the least fibre.
And individuals with the highest fibre intake and highest yoghurt consumption were 33 per cent less likely than those with the lowest consumption of both to develop lung cancer, the study team reports in JAMA Oncology.
“Our study suggests a potential novel health benefit of increasing dietary fibre and yoghurt intakes in lung cancer prevention,” senior study author Dr. Xiao-Ou Shu of Vanderbilt University Medical Center in Nashville, Tennessee, and colleagues write.
While the study wasn’t a controlled experiment designed to prove yoghurt or fibre protects against lung cancer, it’s possible these kinds of foods might lead to changes in the gut microbiota – the bacteria living in our digestive tract – that help protect against cancer, the study authors hypothesise.
It’s also possible fibre and yoghurt might help protect against inflammation, which in turn helps reduce the potential for tumors to develop, the researchers note.
Fibre-rich foods typically have lots of prebiotics, nondigestable compounds that can be fermented in the gut and serve as food for beneficial bacteria, the authors note. Yoghurt has lots of those beneficial bacteria, or probiotics.
Considerable research links the gut microbiota to the immune system overall. And some recent studies have suggested that the gut microbiota may play a role in lung inflammation, the study authors point out.
The reduced risk of lung cancer associated with fibre and yoghurt in the study persisted even after researchers accounted for smoking habits.
For people who never smoked, the lung cancer risk reduction associated with the highest levels of yoghurt and fibre consumption was 31 per cent, while for smokers it was 24 per cent and for former smokers, 34 per cent.
The researchers point out that they didn’t know what type of fibre people consumed or which types of foods they ate to get their fibre, or the type or fat content of any yoghurt people ate.
They also lacked data on some other risk factors for lung cancer, including low income or limited education levels as well as any history of chronic obstructive pulmonary disorder.
Even so, the authors conclude it’s worth considering the potential protective effect of yoghurt and fibre.
“For the first time to our knowledge, a potential synergistic association between fibre and yoghurt intakes on lung cancer risk was observed,” the study authors write.
“Although further investigation is needed to replicate these findings and disentangle the underlying mechanisms, our study suggests a potential novel health benefit of increasing dietary fibre and yoghurt intakes in lung cancer prevention.”