The health benefits of eating more fish have been well documented, from the heart-healthy properties of omega-3-laden fatty fish to the copious benefits of a fish-rich Mediterranean diet. And now, a new study is adding even more evidence to the case for eating more fish—and this time, it’s whole fish, bones, organs, and all.
Japanese people habitually eat small fish, such as whitebait, Atlantic capelin, Japanese smelt, and small dried sardines. Importantly, it is common practice to consume small fish whole, including the head, bones, and organs, which are rich in micronutrients, such as calcium and vitamin A. With that in mind, a team of researchers from the Nagoya University Graduate School of Medicine set out to investigate the potential health benefits of this time-honored dietary pattern.
“Previous studies have revealed the protective effect of fish intake on health outcomes, including mortality risks. However, few studies have focused on the effect of the intake of small fish specifically,” said the lead researcher, Chinatsu Kasahara, PhD. “I was interested in this topic because I have had the habit of eating small fish since childhood. I now feed my children these foods.”
The results of Kasahara’s study were published in the journal Public Health Nutrition.
To determine the health benefits of eating small, whole fish, the team analyzed data collected from participants enrolled in the Japan Multi-Institutional Collaborative Cohort (J-MICC) Study, comprising 80,802 adults (34,555 men and 46,247 women) aged 35 to 69 years nationwide in Japan, who were followed for an average of nine years.
The participants’ frequency of the intake of small fish was assessed using a food frequency questionnaire at baseline. During the follow-up period, 2,482 deaths from people included in the study were recorded, with approximately 60% (1,495 deaths) of deaths being cancer-related.
After controlling for factors that can affect mortality risk, such as participants’ age, smoking and alcohol consumption, BMI, and diet, the researchers found that women in the study who ate small fish frequently were significantly less likely to die from any cause. Specifically, women who ate small fish 1–3 times a month, 1–2 times a week, or 3 times or more 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, compared to those who rarely eat small fish.
The risk of all-cause and cancer mortality in men showed a similar trend to that in women, although it was not statistically significant. The reasons for the lack of significance in men remain unclear, but the researchers believe that factors not measured in the study, such as the portion size, may matter.
Conclusions
Previous studies have highlighted affordable small fish as a potentially important source of nutrients, especially in developing countries that suffer from severe nutrient deficiency. This study adds to the growing body of evidence supporting the health benefits of dietary practices that include eating small fish, suggesting that incorporating small fish into their daily diet could be a simple but effective strategy to reduce the risk of mortality, especially among women.
Although acknowledging the need for additional research Kasahara is enthusiastic about these results. “Small fish are easy for everyone to eat, and they can be consumed whole, including the head, bones, and organs,” he said. “Nutrients and physiologically active substances unique to small fish could contribute to maintaining good health. [While] we suspect that the intake of small fish…may be revealed as a way to prolong life expectancy, [f]urther evidence is necessary to elucidate the potential role of the intake of small fish in mortality risk.”
