Traditional Japanese diet cuts breast cancer incidence, mortality

A traditional Japanese diet (TJD) appears to reduce breast cancer incidence and mortality, suggest the results of a longitudinal analysis.

A TJD consists of a staple food (steamed rice or soba, ramen, or udon noodles), soup (miso, vegetable, or noodle), main dish (fish, seafood, tofu, or natto with small amount of meat, poultry, or egg), and side dishes (vegetables, wild plants, seaweed, and raw or pickled fruit). [https://bit.ly/3wrI4T5]

In this study, the investigators assessed the longitudinal association between TJD score and the incidence and mortality of breast cancer in an ecological study. They obtained food supply and breast cancer incidence and mortality by country from an international database.

TJD score by country was calculated from nine food groups, with the total score ranging from –9 to 9: higher scores indicated greater adherence to a TJD.

The investigators analysed longitudinal associations of interaction between TJD score and fiscal year on breast cancer incidence and mortality in 139 countries with populations of 1 million or more. They evaluated the associations using four linear mixed-effects models with different adjustment covariables.

From 1990 to 2017, many countries with high TJD scores demonstrated lower distributions of breast cancer incidence and mortality.

In longitudinal analysis using a linear mixed-effect model controlled for socioeconomic and lifestyle covariables, the interaction between TJD score and fiscal year showed a significant correlation with a decrease in breast cancer incidence (–0.453±0.138; p<0.01) and mortality (–0.455±0.135; p<0.001).

“The traditional Japanese diet is considered one of the important factors of health and longevity in Japanese people,” the investigators said, noting that breast cancer remains the most common cancer among women across the globe.