Virgin extra olive oil is not exactly the enemy of our diet. A flag-bearer of Mediterranean cuisine, olive oil has long been regarded as one of the healthiest fats at our disposal. Yet there is sometimes fine print. Even when we delve into canned foods, a topic THE OBJECTIVE has often covered, a clear case arises with tuna and mercury and the health recommendations surrounding it.
First, when talking about olive oil, we should prioritise extra virgin olive oil—or virgin olive oil—if we want to maximize its nutritional benefits. This is the message of numerous studies. Choosing extra virgin olive oil is especially advisable if we also seek the highest organoleptic purity.
But what happens when we reach for the oil that comes, for example, in tuna cans? Doctor Isabel Viña explained it on her social networks. Known for being one of the most popular science communicators on Instagram or TikTok, Viña outlined what we should do to make the most of the potential of these commonly used canned products, particularly if we want to avoid mercury.
How does mercury get into our canned goods?
It is common to fear the mercury that cans or fish can accumulate and that eventually reaches our body. In the case of fish, AESAN reminds that there are certain species, located at the top of the marine food chain, that accumulate it in larger amounts.
These include, for example, bluefin tuna, swordfish, sharks, and pike. In this regard, for pregnant or lactating women, children, the elderly, and immunocompromised individuals it is wise to limit consumption of these species. For other age groups and populations, the restrictions are somewhat less strict, but it is still prudent not to make them a daily staple.
Less problematic are other fish that are equally common in canned form. This includes bonito, for instance, or light tuna, which we see so often in supermarkets because they are smaller species. In any case, mercury reaches canned fish through two routes. On one hand, mercury released from human and natural emissions ends up in the sea, where it becomes methylmercury, which then travels through the marine food chain to our diet.
@isabelvinabas Canned tuna: natural or in oil, which is better?
♬ sonido original – Isabel Viña
Additionally, although in a very small proportion, mercury also ends up in the tuna cans themselves, as explained by AESAN. We reiterate that it is present in a tiny amount but it exists, so it is worth paying attention to Isabel Viña’s recommendation to avoid certain types of canned products or certain oils used in the cans.
What is the best way to consume canned tuna?
Well, according to Isabel Viña, the prudent choice is to select tuna canned in natural form if we want to avoid mercury. It is not a whim, but pure and simple chemistry. “In any fatty medium, such as extra-virgin olive oil, sunflower oil, or in brine, mercury accumulation is favored,” she explained, which means you end up “taking more mercury per can.”
Not by much, but a little more. Nor is it something to worry about excessively because, as numerous studies show, the amount is microscopic. Still, Viña noted that a can of tuna “in any kind of oil or in brine contains between 80 and 10 micrograms more mercury than natural tuna.” This is why we might prefer natural tuna. After all, there are other factors to consider so as not to demonize oil-based canned tuna.
The organoleptic aspects also matter in canned tuna
Gemma del Caño, a food technologist, pharmacist and well-known on social networks as @farmagemma, explained that “the tuna used is usually in small pieces, so these values are far from the established limits.” In any case, the recommendation also has an organoleptic dimension that matters.
Making use of the oil from the cans is not inherently bad. However, its quality—even if the can is packaged in extra-virgin olive oil—will not be the same as a bottle you buy yourself. Therefore, in terms of taste, you may notice the difference. Thus, whether to avoid mercury or to enjoy a higher-quality oil, Isabel Viña recommended that, even if it seems tedious, “pour off the oil and then dress it with a good quality virgin extra olive oil yourself.”
Similarly, let us not forget that, as healthy as oil may be, it is a highly caloric element. If we also want to limit our overall calorie intake, natural-toned canned options become preferable when seeking that reduction. It’s true that it won’t be our worst dietary foe, but every drop counts.
