More and more mercury in tuna
Heavy metal contamination of Pacific fish is increasing 3.8 percent annually
In addition to microplastics, toxic mercury in particular accumulates in tuna meat. This comes from industrial pollution of the seas. The side effects of mercury poisoning include various symptoms of cognitive impairment, coordination problems, Parkinson’s and many more
A California boy, the star of a cover story in the Wall Street Journal, went from a star athlete and honored student to a boy who couldn’t concentrate, let alone catch a football, because he regularly ate canned tuna. Even if he had only eaten half a can of albacore tuna a week, it would still have ingested 60 percent more mercury than is considered “harmless” by the US government.
Tuna get really big
The largest tuna are bluefin tuna, which can reach a body length of 4.5 meters and a weight of more than 800 kilograms. Even “small” tuna species such as the yellowfin and albacore tuna can reach a body length of almost a meter and a weight of several hundred kilograms. Tuna are very active – they can cover more than 160 kilometers per day – with a top speed of 65 kilometers per hour.
Mercury poison harmful to your heart
Eating fish is not good for your heart either! In tuna, which are high up in the food chain, heavy metals accumulate, which they ingest by eating smaller fish. Because of this, tuna contains large amounts of heavy metals that can attack the heart muscle.
According to a study published in the Journal of the American Heart Association, the risk of heart disease in men with high mercury levels increases by 60 percent and the risk of dying from a heart attack is 70 percent higher.
Cruel fishing methods
Tuna are hunted mercilessly. Large swarms are encircled in a net. Some fish will suffocate from the weight of all the other fish or be crushed in the mass. Large tuna are fished with longlines. These are up to 100 kilometers long and have up to 30,000 hooks. These nets stay in the sea for days.
Dolphin death from tuna fishing
Tuna fishing is about as “dolphin-friendly” as the slaughterhouse is for the cow. Even if dolphins are not “accidentally” caught in tuna nets, they are deliberately killed by Japanese tuna anglers because tuna are among their prey. Whole schools of whales and dolphins are rounded up and led into shallow waters, where all but the youngest (which are caught and sold to aquariums) are butchered with knives.
Methyl mercury is particularly toxic
Methyl mercury is the predominant form of mercury in fish and other seafood and is particularly toxic to the developing nervous system, including the brain. So far, the estimates of the amount of toxic heavy metal in the oceans have been based largely on model calculations, as the scientists from the Oceanic Institute Woods Hole write. The release of mercury into the environment had increased significantly with mining and fossil fuel use in the past. The metal is currently used for neon tubes, energy-saving lamps and batteries, among other things. The majority of the input into the environment is caused by the production of heat and electricity from coal, oil or gas as well as by small-scale gold mining.
Mercury in fish
The level of mercury exposure is highly dependent on the species of fish: Predatory fish at the end of the food chain contain particularly high concentrations of mercury. Among the fish species popular in Austria, trout, carp, char, sardine, sprat, herring, salmon and the “Alaska pollock”, which is often made into fish fingers, are only slightly contaminated. According to current data, seafood such as shrimp, squid and mussels are also little contaminated. If the maximum levels for methyl mercury are exceeded, z. B. in tuna, swordfish, snapper, marlin and butterfish, which is contained in certain sushi dishes on.
Overview of mean values of methyl mercury in fish from the Austrian food tests for the years 2007-2015:
- Trout, char, carp, salmon, Alaskan pollock, sprats, sardines, herrings, pangasius and tilapia are only slightly contaminated with an average of 10 – 40 µg / kg.
- The mercury contamination of seafood (shrimp, squid and mussels) is also low at 18 – 24 µg / kg
- For zander, cod, mackerel, anchovies, plaice, sea bream, halibut and sea bass, the mean values are in the range of 45 – 100 µg / kg
- High mean mercury levels occur in tuna (184 µg / kg) and snapper (256 µg / kg) as well as in butterfish (677 µg / kg)
- In domestic fish, trout (20 µg / kg), char (33 µg / kg) and carp (26 µg / kg) are only slightly contaminated. In pikeperch the levels are on average 93 µg / kg
Mercury and fish consumption
If the average mercury content of fish is compared, the following examples of the weekly tolerable intake for children and adults can be calculated:
Data based on the mean values of methyl mercury from the Austrian food tests from 2007-2015.
* Mean value for tuna from the current EFSA opinion (EFSA, 2012). For tuna there was a big difference between the Austrian (184 µg / kg) and the European mean (290 µg / kg). As a precaution, the higher European value was used for this calculation.
Alternatives to tuna
When adhering to the recommendations for fish consumption, care should be taken to firstly consume as little animal products as possible and secondly, if not, predatory fish such as tuna, swordfish, halibut, pike, butterfish, snapper, shark, marlin, swordfish, king mackerel , Brick fish and butter / snake mackerel. Babies, toddlers, pregnant women, breastfeeding women and women who want to have children should avoid these predatory fish entirely.
In this way, the positive nutritional effects of regular fish consumption can be achieved without the ingestion of dubious amounts of methylmercury. Those who do without fish can cover their omega-3 (DHA, EPA) requirements with fish oil capsules.
People who are in good health can eat a corresponding small or large amount of fish. Light, white fish meat generally contains less fat than those types of fish with red meat or blue skin. Rivers are often cleaner than the world’s oceans. The difference between “wild-caught fish” and “farmed fish” is important, however.
You should also make sure that you eat smaller fish, such as mackerel or sardine. These small fish are much less contaminated with heavy metals than the large predatory fish.
