Consuming too many rice and raw fish foods, especially tuna, would expose you to high levels of heavy metals and pollutants like arsenic.
- Sushi containing tuna has a high concentration of mercury and methylmercury, and those containing rice have high levels of arsenic.
- Significant concentrations of lead and nickel were also observed, although these remain within established safety limits.
Lovers of sushi, maki and other sashimi, be careful not to consume it too often!
This is the conclusion reached by researchers from the Universitat Rovira i Virgili and the Pere Virgili Health Research Institute (Spain). In a study published in the journal Food and Chemical Toxicologythey have analyzed the concentration of various toxic elements in these foods and assessed the risk associated with their consumption in infants, adolescents and adults.
High concentrations of arsenic and heavy metals
To reach this conclusion, the researchers analyzed the concentrations of various toxic elements (cadmium, nickel, lead, mercury, inorganic arsenic and methylmercury) and iodine in around a hundred pieces of sashimi (raw fish), maki (roll of stuffed with rice, raw fish or other ingredients) and nigiri (balls of rice covered with fish or seafood). The researchers also calculated the dietary exposure to all these contaminants in different population groups (infants, adolescents and adults) and assessed the health risks.
The results show a significantly higher concentration in maki and nigiri due to the presence of rice. They also show higher levels of mercury and methylmercury in sushi that contains tuna, due to the bioaccumulation and biomagnification of this metal.
A worrying concentration of methylmercury
The scientists also wanted to know how the consumption of this foodstuff varied in different groups of the population. So they looked at an average consumption of 8 pieces of sushi in adults and teenagers and an average consumption of 3 pieces in babies. They then found an increase in exposure to nickel and lead, although this remains within the established safety limits.
However, explains Montse Marquès, one of the authors of the study, the analyzes revealed the presence of methylmercury, “a highly neurotoxic compound, for which there was an estimated exposure of 0.242 μg per kg body weight in adolescents, a value above the daily safe limit established by the European Food Safety Authority (EFSA)”.
The preferred menu
Finally, the researchers wanted to determine which combinations of sushi present little or no risk to health. “We recommend that people combine 8 pieces of maki, nigiri or sashimi made with salmon or maki containing unagi (eel) and limit their consumption of any type of sushi containing tuna”concludes Professor Marquès.
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