Nutrition and diet experts say the
fish protein is of high biological quality and that its
content in essential amino acids is the same as red meat
or beef, making it more digestible, because it contains
less connective tissue. In general, fish meat has a
composition equivalent to that of red meat, except that
the protein content is somewhat lower and the amount of
water it contains is higher. It has no fat and very
little fat in it is rich in polyunsaturated fatty acids,
especially marine fish, these fats are an essential
component in human nutrition because the body can not
synthesize itself and has to take them through the diet.
The fat content is higher in marine fish such as cod,
sole, sardines and anchovies, than in fresh water, such
as carp or catfish.
There are two main types of polyunsaturated fatty acids,
the omega-3 (linolenic acid) and omega-6 (linoleic acid),
and both play important roles in the body, forming an
important part of cell membranes and to be precursors
various chemical messengers.
These are polyunsaturated fats lower the levels of
certain lipoproteins that are directly associated with
cardiovascular disease risk, maintaining and enhancing
those lipoproteins commonly called "good cholesterol",
which avoids the formation producing the dangerous
arteriosclerosis plaques. Important sources of omega-3 (polyunsaturated
fats) are found mainly in marine fish such as salmon,
herring, tuna, sardines or trout, usually called blue
fish. The concentration of these omega-3 is higher in
the body of the fish that live in cold sea water,
because fat need to have fluid, with plenty of double
bonds, and low freezing point.
Fish is a source of vitamins and minerals, such as fat-soluble
A and D, soluble B12, and elements such as phosphorus,
magnesium, selenium and iodine, especially marine fish.
Vitamin B5 or pantothenic acid is synthesized in
bacteria and in green vegetables, and stored in animal
tissues, so their distribution is very broad in
Sardines canned in oil and dried salted cod, and other
canned products are also rich in calcium, or vitamin B3
niacin, riboflavin or vitamin B2, vitamin A and iron,
though less than the animal flesh.
Marine fish contain more sodium than fresh water, and
canned, salted and smoked foods are those that have more
sodium. The fish meat has a characteristic whitish
color, which is related to the color of blood is white,
but there are red-blooded fish, like salmon. The fish
meat is mainly characterized by its high proportion of
water off the fat and very digestible.
The shellfish meat has had throughout history, except in
certain geographical areas, less important than that of
other animals, but the flavor is very popular today.