The consumption of dietary fiber and yogurt has been shown to be associated with a reduced risk for lung cancer after the adjustment for known risk factors among never-smokers. A pooled analysis of 10 prospective cohorts was conducted, which included 1,445,850 adults from studies performed in the United States, Europe, and Asia. Results of the analyses were published in JAMA Oncology.

Recognizing that dietary fiber (the main source of prebiotics) and yogurt (a probiotic food) confer a variety of health benefits, investigators sought to evaluate the individual and joint associations of dietary fiber and yogurt consumption with risk for lung cancer. In addition, they aimed to assess the potential modifications of any associations by lifestyle and other dietary factors, including smoking status and saturated fat intake. The data analyses were conducted between November 2017 and February 2019. Those participants with a history of cancer at enrollment or who developed any cancer, died, or were lost to follow-up within 2 years after enrollment were excluded from the study.

The main study outcome was incident lung cancer, which was subclassified according to histologic type (eg, adenocarcinoma, squamous cell carcinoma, and small cell carcinoma). The sample population being analyzed included a total of 627,988 men and 817,862 women. The mean participant age was 54.8±9.7 years. “During a median follow-up of 8.6 years, 18,822 incident lung cancer cases were documented,” the authors wrote.

The intake of both fiber and yogurt was inversely associated with the risk for lung cancer after adjusting for status, pack-years of smoking, and other risk factors for lung cancer (hazard ratio [HR], 0.83 [95% CI, 0.76-0.91] for the highest vs lowest quintile of fiber intake and HR, 0.81 [95% CI, 0.76-0.87] for high vs no yogurt consumption).

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Study findings demonstrated that the fiber or yogurt associations with lung cancer were significant among never-smokers and were observed consistently across sex, race/ethnicity, and histologic type of tumor. When taken into account jointly, high yogurt consumption with the highest quintile of fiber intake demonstrated a >30% reduced risk for lung cancer compared with nonyogurt consumption with the lowest quintile of fiber intake (HR, 0.67 [95% CI, 0.61-0.73] in the total study populations and HR, 0.69 [95% CI, 0.54-0.89] in never-smokers), which implies potential synergism.

The investigators concluded that the results from this study suggest a possible protective role of prebiotics and probiotics against lung carcinogenesis. The consumption of dietary fiber and yogurt may be both individually and jointly associated with a decreased risk for lung cancer.

Reference

Yang JJ, Yu D, Xiang Y-B, et al. Association of dietary fiber and yogurt consumption with lung cancer risk: a pooled analysis [published October 24, 2019]. JAMA Oncol. doi:10.1001/jamaoncol.2019.4107