Canned Fish – A Nutritious Alternative to Fresh Fish
While it is always best to have foods as close to their natural, whole forms as you can, there are exceptions when the more processed form of the food offers more benefits. A great example of this is tuna.
Canned light tuna, generally prepared from skipjack tuna, in fact poses a considerably lower risk in terms of mercury exposure than fresh albacore or yellowfin tuna. Therefore, this type of (canned light) tuna is the best for you to have if you wish to eat tuna quite often, like around one meal in a week. While canned light tuna may not supply you with more nourishment than fresh light tuna, an easy canned fish pate recipe is still possibly saving you nutrients by letting your body keep away from processing unwanted mercury, in addition to providing convenience and palate satisfaction.
Another type of fish which can offer some surprising advantages upon canning is salmon. As canned salmon is usually packed in its own oil, you are likely to get the advantage of some additional omega-3 fatty acids. Canned salmon even has the bones (which get softened during the process of canning and so, are safe to eat) which provide you some added nutritional goodness as well. A serving of 3 oz of salmon has more than half the calcium you get in 8 oz of cow’s milk.
However, when taking into account these potential benefits, it is important to consider that canning process can bring about a loss of nutrients. This is because it generally involves two steps of heating. They are namely “pre-treatment” and “retorting”. During the step of pre-treatment, the can is typically heated, before the fish is placed in it. This is often done by with the help of steam (approx. 100°C/212°F) for a duration of 1 to 8 hours, based on the size of the fish. After the addition of fillers, salts, brines, oils and other components to the can together with the fish, the second step of heating, i.e. retorting is done. Based on the size of can and other factors, approx. 1 to 3 hours are needed at a temperature of around 116°C/240°F. These numbers are characteristic to tuna and would be different for canning of other types of fish.
But amount of heat and duration of heating process are important factors which affect nutrient loss not only in the canning of fish, but also in case of cooking of all foods. If a fish contains colorful pigments, such as carotenoids (component of pre-vitamin A in salmon), they will decrease totally with cooking. The level of vitamin A restored in cooked salmon may seem to be higher than that found in raw salmon in certain nutrient databases, but if you get the gram weight and sizes of edible part identical, you will know that the raw salmon contains more nutrients. If you consider the canning factor, you often get another 15% to 35% decrease.
Skipping the Heating
The two-fold process of heating can considerably damage some of the nutrients contained in fish. To overcome this drawback, some companies skip the first step of pre-treatment and place the fish in fresh form in the can. When cooking of fish takes place only in the sealed can, the loss of nutrients is less.
Almost all the companies which cook only in cans put emphasis on wild-caught fish and consider both health and environmental issues. You may require to search for this kind of canned fish online because not many stores stock them regularly. Another aspect is, though it may offer nutritional advantages, its cost may be remarkably higher.
Though no specific data is available on fresh versus canned sardines, it can be expected that extra calcium nourishment would be the case also for sardines same as for salmon or any other canned fish having bones. However, because the bones of sardines are pretty small and several people eat them when fresh fish is cooked, the canned variety might not become that much practical regarding calcium advantage.
Since tuna is not canned with bones, you cannot consider these factors same as canned salmon or sardines, in case of canned tuna regarding calcium supply. But most people won’t look to tuna for calcium supply in the first place since a serving of 6 ounces of freshly broiled tuna provides only around 7 mg of calcium (which is less than 5% of our daily requirement).
Therefore, canned fish can be considered as a satisfactory, convenient and nutritious alternative to fresh fish, the later not always being readily available.