A groundbreaking study has found compelling evidence linking the consumption of small fish, eaten whole, with a lower risk of all-cause and cancer mortality in Japanese women. Spearheaded by Dr. Chinatsu Kasahara, Associate Professor Takashi Tamura, and Professor Kenji Wakai at Nagoya University Graduate School of Medicine, this research underscores the potential health benefits of habitually eating small fish. The findings were published in the journal Public Health Nutrition.
In Japan, it is customary to consume small fish like whitebait, Atlantic capelin, Japanese smelt, and small dried sardines whole—head, bones, and organs included. This practice ensures a high intake of essential micronutrients such as calcium and vitamin A.
“While previous research has indicated the health benefits of fish consumption, few studies have focused specifically on the impact of eating small fish on health outcomes,” explained Dr. Kasahara. “I have eaten small fish since childhood and now include them in my children's diet, which sparked my interest in this study.”
The study involved 80,802 participants (34,555 men and 46,247 women) aged 35 to 69 from across Japan. Researchers used a food frequency questionnaire to assess participants' small fish consumption at the study's outset and followed them for an average of nine years. During this period, there were 2,482 recorded deaths, with about 60% (1,495 deaths) due to cancer.
One of the study's most notable findings was the significant reduction in all-cause and cancer mortality among women who regularly consumed small fish. Women who ate small fish 1–3 times a month, 1–2 times a week, or three or more times a week had 0.68, 0.72, and 0.69 times the risk of all-cause mortality, and 0.72, 0.71, and 0.64 times the risk of cancer mortality, respectively, compared to those who rarely consumed small fish.
The researchers controlled for various factors influencing mortality risk, including age, smoking and alcohol habits, BMI, and intake of various nutrients and foods. The results showed that women who frequently ate small fish had a significantly lower risk of death from any cause, suggesting that incorporating small fish into the daily diet could be an effective strategy to reduce mortality risk among women.
For men, the reduction in all-cause and cancer mortality showed a similar trend but was not statistically significant. The researchers speculate that the lack of significance in men could be due to the smaller number of male subjects or other unmeasured factors such as portion size. Additionally, differences in cancer types between sexes might contribute to the sex-specific associations observed.
While the study focused on Japanese participants, Dr. Kasahara believes the findings have broader implications. “Although our results were based on Japanese people, they could be relevant to other populations,” she noted.
Previous research has emphasized the nutritional value of small fish, particularly in developing countries facing severe nutrient deficiencies. This study adds to the growing body of evidence supporting the health benefits of dietary practices that include consuming small fish.
Source: Nagoya University