Do you need to be careful of mercury in Tuna sushi?

Sushi is very popular around the world as a healthy food, but you may need to be careful with how frequently and how much of it you eat. Among the fish used for sushi, it has been found that the average content of methyl mercury is the highest in tuna.

Seafood contains high quality protein and various nutrients important for a healthy diet. On the other hand, some sea creatures towards the top of the food chain accumulate mercury found in nature. Therefore, it is very important to avoid excessive consumption of seafood containing high levels of mercury. Pregnant women and children in particular must pay special attention because mercury affects the development of the central nervous of fetuses and young children.

So, which fish contain high levels of mercury and how much can you eat and still have no negative effect on your health? The following is an overview of guidelines for various countries.

  • Seafood consumption guidelines from various countries (excerpts from the Ministry of Health, Labor and Welfare information)
Country Target Guidelines
Japan Pregnant women, women who may become pregnant Bottlenose dolphin: up to once (80g) in 2 months.
Short-finned pilot whale: up to once(80g) in 2 weeks.
Splendid alfonsino, swordfish, bluefin tuna, bigeye tuna, finely-striated buccinm, Baird's beaked whale, sperm whale: up to once(80g) a week.
Yellowback seabream, striped marlin, scorpionfish, southern bluefin tuna, great blue shark, phocoena dalli, Japanese bluefish : up to twice (160g) a week.
U.S.A. Women who may become pregnant, pregnant women, lactating women, infants Avoid consuming shark, swordfish, Spanish mackerel, tilefish.
Shrimp, canned tuna, salmon, codfish, catfish : 340g or less a week.
Longfin white tuna: twice a week 170g or less.
EU Women who may become pregnant, pregnant women, lactating women, infants Large predatory fish should be consumed once a week (100g or less) at a maximum.
Avoid eating large sized predatory fish more than one a week.
Do not eat tuna more than twice a week.
U.K. Pregnant women, women who are considering pregnancy Avoid consuming shark, swordfish, striped marlin.
Keep intake of medium-sized canned tuna to 4pcs (560g) or less or intake of tuna steak to 2pcs (280g) or less in one week.
Children under the age of 18 Avoid consuming shark, swordfish, striped marlin.
Canada Everyone Intake of Swordfish, shark, tuna should be less than one meal in one week.
Infants, women of childbearing age Intake of Swordfish, shark, tuna should be less than one meal in one week.
Ireland Women of childbearing age (women who are considering pregnancy), Pregnant women, lactating women, infants Avoid consuming shark, swordfish, striped marlin.
Keep intake Tuna steak to 1pc (8oz, 230g) or intake of medium-sized canned tuna to 2pcs (8oz, 230g) or less in one week.
Others Intake of Shark, swordfish, striped marlin should be less than one meal in one week. (restriction of eating tuna is not necessary)
Australia Pregnant women, women who are considering pregnancy, Children under the age of 6. Intake of shark, marlin should be a maximum of one meal in two weeks (without eating other fish in the same two weeks) or intake of orange roughy, catfish should be a maximum of one meal in one week (without eating other fish in the same week).
Intake of other fish should be 2-3 meal or less in one week.
Others Intake of shark, marlin should be at most one meal in one week (without eating other fish in the same week).
Intake of other fish should be 2-3 meal or less in one week.
New Zealand Pregnant women, women who are considering pregnancy Intake of shark, ray, marlin, barramundi, silver gemfish, orange roughy, pink cusk-eel, southern bluefin tuna, fish caught in geothermal waters should be 4 meals or less in one week.
Norway Pregnant women Do not eat whale, pike, perch (more than 25cm), perch and char (more than 1kg), shark, marlin, ray, tuna.
Lactating women Do not eat whale
Denmark Women who are considering pregnancy, pregnant women, lactating women, Children under the age of 14 Intake of tuna, Japanese seaperch, flatfish, oilfish, swordfish, mackerel shark, barracuda, perch should be 100g or less in one week.

Please note, we are not saying that people should reduce their intake of seafood.
Seafood is a nutritious food containing good protein, polyunsaturated fatty acids and minerals.
It is important to keep from consuming an excess of seafood with high mercury level.
Except for fish with high levels of mercury (tuna, swordfish, sharks, and deep-see fish) it is not necessary to reduce intake of other seafood.