How much tuna is safe to eat per week?

In this brief guide, we will answer the query “How much tuna is safe to eat per week?”. Furthermore, it presents what mercury is and how it gets into tuna, what are the risks of consuming mercury, and some of the best choices for low-mercury fishes.

How much tuna is safe to eat per week?

You can safely consume 3 servings (113 g each serving) a week if you are an adult. If the consumer is a child, you should adjust his/her intake by age as follows (1):

  • 56 g a week at 1 to 3 years
  • 112 g a week at 4 to 7 years
  • 170 g a week at 8 to 10
  • 226 g a week 11 or older

What is mercury, and how does it get into Tuna?

Mercury is a heavy metal naturally occurring in the environment and also produced as pollution from human industrial activities. It can be converted to methyl mercury. Unfortunately, it is present in the sea and oceans (2).

Methyl mercury is highly soluble and bioavailable for fishes and humans. That’s why large and carnivore fishes can accumulate methyl mercury when they feed with smaller fishes. Hence, we consume all the methyl mercury accumulated in those fishes (2).

What are the risks of consuming mercury?

The risks of consuming high concentrations of mercury are poisoning. This poisoning has neurological effects like poor control of muscle movements (ataxia) and limited visual and hearing senses (3,4).

Other symptoms are arrhythmia, and abnormalities in the heart contractions that can cause death (5).

Is there any way to remove mercury from Tuna?

No, unfortunately there is no way to remove mercury from tuna. However, there is evidence that farmed tuna could have higher concentrations of antioxidant minerals like Selenium, and lower concentrations of methyl mercury (3,6).

Maybe choosing farmed tuna and following the guidelines of international organizations, like the FDA, could be the best way of preventing poisoning. Nevertheless, the poisoning normally appears after long-term exposure to methyl mercury (for example, 20 years) (6).

What other fishes are high in mercury?

The fishes with higher concentrations of mercury are: King mackerel, bluefin tuna, marlin, swordfish, shark, tilefish, and orange roughy (1).

What are other healthier options to replace Tuna?

For a healthier option instead of tuna, you can decide the best choices of fish from the FDA guideline. In short, between the most known species, you can consume with lower concern (1):

  • Anchovy
  • Catfish
  • Crab
  • Clam
  • Lobster
  • Oyster
  • Pacific chub mackerel
  • Salmon
  • Sardine
  • Shrimps
  • Squid
  • Tilapia
  • Freshwater trout
  • Canned tuna

Conclusion

In this brief guide, we answered the query “How much tuna is safe to eat per week?”. Furthermore, it presented what mercury is and how it gets into tuna, what are the risks of consuming mercury, and some of the best choices for low-mercury fishes.

References

  1. Advice about eating fish [Internet]. U.S. Food and Drug Administration. FDA; [cited 2 May 2023 2023]. Available from: https://www.fda.gov/food/consumers/advice-about-eating-fish
  1. Özden Ö, Erkan N, Kaplan M, Karakulak FS. Toxic metals and omega-3 fatty acids of bluefin tuna from aquaculture: Health risk and benefits. Expo Health, 2020;12(1):9–18.
  1. Annibaldi A, Truzzi C, Carnevali O, Pignalosa P, Api M, Scarponi G, et al. Determination of Hg in farmed and wild Atlantic Bluefin tuna (Thunnus thynnus L.) muscle. Molecules, 2019;24(7):1273.
  1. Hirai T, Abe O, Nakamura M, Inui S, Uetani H, Ueda M, et al. Brain structural changes in patients with chronic methylmercury poisoning in Minamata. Brain Res, 2023;1805(148278):148278.
  1. Santos Ruybal MCP, Gallego M, Sottani TBB, Medei EH, Casis O, Nascimento JHM. Methylmercury poisoning induces cardiac electrical remodeling and increases arrhythmia susceptibility and mortality. Int J Mol Sci, 2020;21(10):3490.
  1. Ekino S, Susa M, Ninomiya T, Imamura K, Kitamura T. Minamata disease revisited: an update on the acute and chronic manifestations of methyl mercury poisoning. J Neurol Sci, 2007;262(1–2):131–44.