I am currently in Tokyo for the day, heading to Kathmandu, Nepal for the holidays and then Thailand for a week in the new year. In Japan, my priority was to eat sushi. In British-Columbia where I live, Vancouver is surrounded by the water, thus why it has some of the best sushi served in the entire country because the fish is fresh out of the sea. Sadly, many Japanese restaurants in Canada are very westernized and do not always serve the most authentic sushi or maki. That being said, I wondered with all of the environmental initiatives warning us to reduce our fish intake because of the high mercury concentration in the sea, what could be the benefits and disadvantages of eating raw fish?
Since I am currently in Japan, let’s begin by understanding the history behind its foods. Sushi as a style of food began as a way of preserving fish. In the 7th century, the mountain people of Southeast Asia invented the technique of pickling. The Japanese acquired this same practice that consists of pressing cleaned fish between rice and salt by a heavy stone for a few weeks and subsequently using a lighter cover for the packing process until the fish was considered ready to eat. During the process of fermentation, the rice produces a lactic acid, which in turn caused the pickling of the pressed fish. The finished edible product that results from this early method of sushi processing is known as naresushi, a sushi made with carp, (Cindy Hsin-I Feng, 2012).
For starter, fish contain both beneficial nutrients such as fish oils like omega-3 (chemistry: long-chain omega-3 polyunsaturated fatty acids n-3 PUFA), (Amelia Granier et al., 2010). The benefit of omega-3 is that it reduces high levels of triglycerides; blood fat which are risk factors for heart disease. Some researcher speculate that foods with high levels of omega-3 are associated with antidepressants boosters, improved maternal nutrition and neonatal and infant brain development. Whilst, a huge disadvantage with eating fish, particularly raw; is the high contaminates such as methyl mercury (Ch3Hg). Such high concentration of mercury can cause poisoning, compromise fetal development and cause neurological damage, particularly in young children, and possibly cause cardiovascular disease. Thus monitoring levels of fish intake is very important, especially for women of childbearing age and those who are pregnant or nursing about the risks of eating any shark, tilefish, swordfish and king mackerel and advised that other fish consumption should be limited to 12 oz/week and albacore tune to 6 oz/week, (Amelia Granier et al., 2010).
Speaking as someone who loves fish, more importantly sushi and maki rolls (salmon is always my favourite), knowing all associated environmental factors that comes with eating such foods is very important. Trying to buy low to no mercury fish, and knowing the type of water the fish comes from ( freshwater or marine), geographic variation and differences based on the consumer (pregnant women or fishermen), these are important factors that should not be overlooked when delighting in some delicious fish.
- Amelia Greiner, Katherine C. Smith and Eliseo Guallar. (2010). Something fishy? News media presentation of complex health issues related to fish consumption guidelines. Public health Nutrition: 13 (11), 1786-1794.
- Cindy Hshin-I Feng. (2012). The Tale of sushi: history and regulations. Comprehensive reviews in Food Science and Food safety, Vol. 11.