A few months ago the news of the change in the recommendations of consumption of certain jumped fish contaminated by mercury. Specifically, we were referring to the ban on consumption for pregnant women, breastfeeding women and children under three years of age and restrictions for older children.
But then a controversy arose, because canning associations argued that canned tuna did not have to be included in these restrictions. We wanted to delve a little into this issue, and we see that the issue of whether canned tuna yes or no, it is not clear.
Let's see what AESAN says about it, along with what the canning associations and even Greenpeace point out, to see if we clarify this issue a bit.
What canneries say
On the one hand, the National Association of Canned Fish and Seafood Manufacturers (Anfaco) issued at the time a press release in which the association was aware of its huge disgust and worry for the news published in the press media. In this note, they clarify the following points:
- The news is based on a recommendation of the AESAN (Spanish Agency for Food Safety and Nutrition) that never refers to canned tuna but to large-scale bluefin tuna.
- They point out that when talking about bluefin tuna, the AESAN limits the problem to the product from the Mediterranean and consumed fresh, frozen and filleted, preparations to which the conserve is totally foreign.
- That the prohibitions and restrictions for not consuming these products referred to very specific population groups.
- The same report of the Scientific Committee of the AESAN, underlines the importance of risk / benefit studies of fish consumption (especially blue fish), since EPA and DHA fatty acids from fish fat have a very important role in the development of the fetus and nervous system of children.
- Canned tuna in its different presentations such as Tuna, Light Tuna and Northern Tuna or White Tuna, is made mainly with tropical tunas from the Pacific, Indian and Atlantic Ocean and totally away from this problem.
We haven't found a way to know where do tuna from the cans we buy come from, but personally I can say that when I read "nice of the north" I never thought they would be fished in the Tropics. Nor am I sure that the problem of mercury is exclusive to some seas, in fact the articles consulted indicate that it is a global issue.
What the AESAN says
The AESAN in its section of frequent questions links to what is referred to in our previous posts, that is, the restrictions in the different population groups. There is also a specific section: What are the recommendations for consumption of fresh bluefin tuna and canned tuna? Here is the answer:
It is a single species, bluefin tuna. This can be verified in the recommendations we make on our website, specifically mercury (more clearly in the pdf file. Which can be downloaded from the page). There it is specified that bluefin tuna is the species Thunnus thynnus (large species, normally consumed fresh or frozen and filleted) exclusively. The species that canned (canned) are of a much smaller size, so their mercury content decreases considerably.
That is, according to this section canned tuna would have less mercury content, although it is the same species and not a different one as claimed by the Anfaco. We have not found the reference to the danger of contamination being exclusively from Mediterranean fish.
What tuna canned?
Inquiring a little more about tuna species, we find that Thunnus thynnus is the Atlantic bluefin tuna, and that other species exist within the Thunnus genus: northern or white tuna (T. alalunga), bigeye (T. obesus), Pacific bluefin tuna (T. orientalis), southern bluefin tuna (T. maccoyii) and yellowfin tuna (T. albacares).
As explained by the World Health Organization, albacore and bigeye are the two most commonly used species for canned markets. Do these accumulate the same amount of mercury?
According to a study developed by the National Institute of Oceanography (IEO), within the framework of a collaboration agreement with the General Secretariat of Maritime Fisheries in order to know the concentrations of heavy metals in fish of commercial interest, albacore and yellowfin have mercury concentrations far from the established limit.
But nevertheless, some bigeye specimens exceeded that limit, and a clear relationship was found between the level of mercury and the size of tuna.
What Greenpeace says
I was surprised to find several Greenpeace articles about canned tuna that do not leave the product very well (or rather to the process of fishing and preserves), specifically to the species caught in tropical areas, which is where most of the preserves according to Anfaco come from.
Greenpeace has found irregularities after analyzing tuna cans of different brands in several European countries, including Spain. There is no reference to the issue of mercury, but we are transferred to the tropical waters of the Indian and Pacific Ocean, which is where these tunas are fished. Some irregularities detected are:
- Presence of two different species in the same can, illegal practice in the European Union.
- Different cans of the same product with different species; Some cans contained species other than what was indicated on the label.
- In Spain, the analysis of tuna cans of the Calvo and Campos brands revealed the presence of two different species in the same can (yellowfin tuna and bigeye tuna).
Overfishing or unsustainable fishing techniques are other aspects that GreenPeace denounces, although we are left with the mixture of species (and large and small tunas) in the same can of canning.
In short, canned tuna, yes or no?
The truth is that after all this, I realize how little we know about what we eat, and I think that by investigating a little more about each food we would find many unpleasant surprises.
That without counting the contradictions and gaps in information that will be presented to us, due to the conflict of interests of the organizations and companies involved in the production and marketing of food.
Does that mean we can't eat anything? Obviously, no, but we can look for the most natural products possible and inform ourselves about their composition and the risks of each food.
Populations with restrictions and prohibitions regarding bluefish (women of childbearing age, pregnant women, breastfeeding and children) should opt for other fish that do not involve the risks seen.
For our part, we will not stop putting a can of tuna in olive oil for the salad, although I am more and more inclined to mackerel, which has the properties of blue fish but is small and goes by pieces (fish are not mixed). Of course, fear gives me research on mackerel because surely someone else but exists ...
Photos | TheGiantVermin, FotoosVanRobin on Flickr-CC
In Babies and more | Mercury in fish, Fish, a limited food in pregnancy, Beware of eating panga and perch, Fish in infant feeding, Recommendations of fish consumption during childhood, pregnancy and lactation
