- Mar 13, 2018 -
Canned tuna is a popular food worldwide. It is used, for instance, on top of salads or as part of an afternoon snack.
On the one hand, canned tuna seems like a healthy food choice, due to its many essential nutrients and its beneficial effects on normal physiology, optimal fetal neural development, and general health in pregnancy.
On the other hand, canned tuna contains methylmercury and other heavy metals, from polluted waters, chemicals, the lining of the cans, and histamine, from inappropriate handling of fish. (1)
People often underestimate the dangers of these chemicals and metals, but consuming too much canned tuna may lead to some serious health problems.
The nutritional and toxic contents of canned tuna, and, therefore, the potential positive and negative health effects of consuming it, differ depending on the:
Tuna variety (e.g. light tuna has less mercury than albacore tuna.)
Tin content besides the fish component, such as vegetable oil versus spring water
For instance, the fat content varies between 3% and 33%, canned tuna in water contains more omega 3 fatty acids than tuna in oil.
Material used for lining the cans
Method of storage after the tuna is caught
In addition, various brands produce different quality products.
There is an optimal amount of canned tuna that you can eat per week. This will enable you to get the most health benefits but at the same time won’t reach the maximum safe level of methylmercury, which is the most abundant, illness causing toxin in canned tuna.
The following sections describe the “good and bad” aspects of eating canned tuna and a summary of how much canned tuna you can eat per week and which type to pick. The calculation is based on upper safe limit recommendations of methylmercury. (2)
What types of tuna do we usually eat?
The most common type of fresh tuna available in stores comes from large and older fish varieties such as Bluefin tuna.
Canned tuna is usually found in two varieties, a small tuna variety called “light tuna” (mainly skipjack tuna) and a large tuna variety called “white tuna” (albacore tuna).
Albacore tuna has the highest methylmercury content of all canned fish, but at the same time it is richer in omega 3 fatty acids DHA and EPA.