( Originally Published 1913 )
Nutritive Value and Other Properties of Various Kinds of Fish Foods.
The doctrines of certain churches, as the Roman Catholic, the Greek Orthodox, as well as the Anglican Church, forbid the use of meat during certain weeks of each year, and also on one day of each week, and recommend the use of fish. This fact corroborates the correctness of the statement made in our work on "Old Age Deferred" that the practice of a religious faith has a good influence in prolonging our life. Fish is more easily digested and is much better, for certain reasons, than meat. When one has at different times eaten an equally ample quantity of meat and fish, he usually feels less weight in the stomach after the fish, and this when even a rather larger quantity of lean fish is taken than of the meat. Fish in general have a much more tender flesh, they contain more water than meat usually does, and, while their fiber is more tender, they are, nevertheless, nourishing. Some varieties of fish do not contain any less albumin; some, in fact, the salmon, perch, and pike, for instance, have even more than some kinds of meat. This form of albuminous food has the advantage that, with the exception of some few kinds of fish, such as the carp and salmon, the albumin is associated with other quite harmless substances, and, owing to the very limited amount of extractive substances, much fewer harmful products are formed than is the case with meat. In order, however, that fish outrank the meat as a diet, it is requisite that the fish be absolutely fresh, for there is no kind of meat which spoils so rapidly as fish. Owing to this, it is advisable in the hot summer weather to dis-pense with fish unless one has the good fortune to live near the water, so that one may be sure of eating the fish on the day it is caught. The Aztecs were well aware of the fact that fresh fish is a much more healthful food than meat; the Emperor Montezuma ate it daily, the fish being brought from distant shores by runners. It is much the best when the fish—which is possible in the fresh-water varieties—is brought to the kitchen alive, and is killed only a very short time before it is to be used. The meat of such fish has a different appearance from the others; the trout looks blue and the meat of the cod or haddock is firm. In Holland one may often see the fish dealer kill the fish just as he is delivering it, making deep incisions into the quivering body; this causes contraction of the flesh, which can only be seen in perfectly fresh cod or had-dock. The eel is treated even more barbarously, for, in the belief that the meat tastes better, the skin is pulled off while the fish is yet alive.
Just because fish contains much less flavoring substance than does meat, it is most important that it be fresh. Nowhere else is it possible to eat such good-tasting sea fish as in England and Holland, and in Sweden and Norway, because it goes directly into the hands and stomach of the purchaser. In Paris and in other cities of the Continent it is more difficult to obtain such fish, and the longer the fish travels on the ice the more it loses its taste. This does not mean that it loses any of its merit as a healthful food when well packed in ice and eaten soon after its arrival. Generally speaking, a fish diet is most healthful when the fish is eaten at not too great a distance from its home. The taste of the fish depends, as does that of meat, upon its food and its abiding place. Usually the fish living in deep water, and those of mountain streams, are the most healthful; those living in unclean, muddy water are much less so, and Galenus already decried the use of such fish, especially when they are caught in waters below a city.
The use of fish without scales was strictly prohibited by Moses, and it is very interesting to note that the same law exists among the Hottentots and the Bushmen in South Africa, who, like the Jews, do not eat pork. Certain fish found in tropical regions, as in Cuba, Florida, etc., are very poisonous. In these sections there is a phenomenal quantity of fish, as I was able to observe during a two weeks' stay in Miami and Palm Beach, in Florida, during the winter of 1906-1907. Owing to the fact that many of these fish eat poisonous medusae and other harmful substances, decomposed bodies, etc., their meat becomes poisonous. When, however, care is taken to at once remove the head and intestine when they are caught, the meat proper may be eaten without fear of untoward results.
Fresh fish is not only the best, but it is the most readily digested; it tastes best when fried or baked, as by boiling the savory elements are even more easily drawn out from the fish than they are from meat. Smoked fish is quite as digestible as boiled fish, but the same is not the case with the dried and salted varieties. Penzoldt found, in regard to the digestibility of fish, that 1/4 kg. of whitefish was digested in two and one-half to two and three-quarter hours, while the same quantity of meat took three and one-quarter hours. Herring required the most time,—about four hours. According to Rubner, Atwater, and others, fresh fish meat is quite as well assimilated as beef, as will also be seen in the writings of Langworthy, who found that, of the fish, only 5 per cent. of albumin and 10 per cent. of fat were lost. Slowzoff recently affirmed that freshly cooked fish was even better assimilated than meat; he also found that smoked fish was as well assimilated as that which was cooked, but the salted and dried kinds more poorly so than the cooked fish. He found that the nitrogen was the equivalent of that in meat.
In addition to the albumin and considerable quantities of gelatin, fish also contains valuable mineral salts in not inconsiderable quantities; some varieties contain much phosphorus. Slowzoff states that these nutrient salts are also better assimilated than those of meat, and that more phosphorus and magnesia are absorbed. It will be seen from the above that a fish diet is a very advantageous form of nourishment, and that from it we get large quantities of nutritive substances. We shall show in the following list by Kdnig how many calories are obtained from a fish diet, and how much of the various nutrient salts is found in the kinds of fish which are chiefly eaten.
As this table shows, fish meat is characterized by a high content of soda and a low amount of potash. The quantity of common salt is naturally quite considerable in sea fish. When the fish are salted down, the amount of salt is greatly increased ; the fish are placed in tubs and are covered with brine. The longer they remain in the brine, the more salt they absorb. This influences their digestibility in a very unfavorable way, as has been already stated; it may be imagined how injuriously the kidneys will be affected when such large quantities of salt pass through them. Such fish are, therefore, certainly not healthful.
The best method of preparing the fish with regard to their digestibility is by boiling or frying. Since, however, the flavoring elements are so readily given off, and there is, consequently, very little taste left, possibly the only way to retain it is by steaming.
It will be necessary, as previously. emphasized, to see that the fish is always fresh. There is no article of food in which this is more important, particularly in the summer. The decomposition processes occurring in fish may, otherwise, give rise to the much-dreaded ptomaine poisoning.
The Indian tribes of Oregon had the habit of burying salmon in the ground, and, the more it was decayed, the better they liked it. The inhabitants of Greenland and the other Eskimos do the same with seals. Dried and strongly smelling fish seem also to be a favorite food with the Chinese and Malays in Java and in the Archipelago. In Java, trassi, the meat of dried shrimps, is eaten after having been kept for many months. While I was the guest of a family in the Hague who had possessions in India, I had the opportunity of tasting this. It had a most unpleasant odor, but did not taste badly. It might be here mentioned that trassi, as has been stated by Jebbink, is very rich in phosphorus, probably as much so as any article of food; its total content of phosphoric acid amounts to 2.27 per cent., and, of this, 2.21 per cent. is soluble and digestible.
While fresh fish, in general, does not keep very well, this is particularly the case with fatty fishes, for very soon, some-times after one day, the quality of the fat undergoes a change and it has a rancid taste, as in the eel and the salmon. Yet, these two kinds of fish are the best flavored among them all, and have, likewise, the greatest nutritive value. They have the disadvantage, however, and the eel most particularly so, of being very difficult to digest not only on account of the great quantity of fat contained in the eel, but also because of its very unappetizing habits. I would call it the pig among fishes. It likes to roll in the mud, and in water containing waste products of all sorts ; where the water is stagnant and cannot run off, as in the Dutch canals, the eel tastes the best. The variety living in clean water has not nearly so good a taste as the river eel, and particularly that living in the ditches and canals in Holland. It is said of this fish that it eats the most unclean things, and it was stated that the eels caught near the Dutch Lazarettos, in the Dutch Indies, fed upon the bodies of the dead, together with refuse of all sorts, and that, with it all, their meat had a wonderfully good taste! Something of the same nature has been recorded in history of Vadius Pollonius, who fed his murænce, a kind of eel, with the flesh of slaves who had been killed just for this purpose, in order that they should have a better taste. That the meat of the eel sometimes causes toxic disturbances may no doubt be referred to its unclean mode of living, and we may find in this instance an exception to the rule that everything which has an agreeable taste is good, and agrees with one. The meat of the eel can in no way be regarded as a healthy food. The salmon might rather be recommended for a normally healthy person, since it is not quite so fat as the eel, and always lives in clean water. Owing to its fat content and its very compact meat, salmon is not easily digested, and is not indicated for people suffering from stomach and intestinal disorders. According to some authors, who found that salmon contained considerable quantities of purin bodies, it is not to be recommended in gout and arteriosclerosis. Lately, however, Bessau and Schmidt found in both the eel and the salmon much smaller quantities of purin bases; in 10o grams of each fish there were 0.024 gram (salmon) and 0.027 gram (eel).
The salmon usually prefers the northern waters; in Europe it is found in large numbers in the Norwegian and Swedish waters, and when in very cold winters the seals come farther south they eat up all the salmon of the Swedes and Norwegians; it is for this reason that in these regions there is an actual massacre of seals. Whoever likes good salmon fishing should go to Canada, where the lakes in the province of Quebec are full of these fish. Wonderful stories were told me of the size and quality of the salmon while I was in Quebec, four years ago, during the winter.
Another very popular fish, the herring, also prefers the waters of the North. We unfortunately only get this fish, which is so excellent when fresh, in the salted or pickled form, and then it is not quite so good, nor is it a healthy food sub-stance. I have eaten very good fresh herring in England. In the Lake of Garda there is also a variety of that fish which is excellent. The amount of salt contained in salted herring is often very considerable after it has been in the brine for some time. König states that herring which has been lying in brine for three days contains 9.5 per cent. of salt; after nine weeks it contains 17.7 per cent., an amount which is certainly prejudicial for the kidneys.
The value of fresh herring is increased when it contains the roe or the milt. Of the fatty fishes, the one most easily digested is the whitefish, which the English (Pavy) call the "sea chicken."
The best-tasting and probably also the most easily digested among the fat fish varieties is the carp. In Berlin, particularly, great quantities of this fish are consumed. Unfortunately, however, the carp contains—it is unfortunate that so often with the best goods there must be a "but"—a large amount of extractive substances. According to the latest analyses of Bessau and Schmidt, the carp contains more purin bases than either the eel or salmon, 10o grams containing 0.054 gram. The herring contains more extractive substances : 0.064 gram. Small fish in general, such as anchovies and sprats, contain the greatest number of purin bases ; also the sardine, which has the large amount of o.118 gram purin bases in 10o grams. While the carp, however, gives off a portion of its extractive sub-stances during cooking, this is naturally not the case with the sardine. Another fish which is considered as one of the most healthy as food, the trout, contains, according to these authors, a like amount of purin bases. There is probably no fish which is so well liked in our Carlsbad diet as the trout, and, as a matter of fact, the meat of this fish is quite easily digested. When we consider that, just as is the case in meat, a hard, tough condition prevents the elimination of the extractive sub-stances through cooking—as in beef, for example—the opposite condition probably exists in the trout; for just as the tender meat of the calf gives off its extractives in cooking, so does also the soft, tender trout. A fresh, well-cooked trout has very little of the flavoring substances left, and may without hesitancy be recommended as a food for arteriosclerotics and gouty patients, as well as in diabetes.
With regard to the digestibility, the sole, which also has a tender fiber, resembles the trout ; also the plaice, which is eaten in large quantities in England and in Holland, and is of a fine quality. The turbot would probably come next. The haddock is rather more indigestible, owing to its tough and hard fibers. This fish is best eaten in Norway. It has an excellent taste and, when perfectly fresh, is not so hard to digest ; so that we can readily understand the predilection of the Norwegians for this fish, and the current saying, "Jeg aer Norsk, Jeg spiser Torsk." On the other hand, the same fish, when I ate it in Barcelona, where it is called "baccalau," did not taste nearly so good; neither did I care for the "cabillaud" in Belgium and France. The salted codfish, because of the salt, has very hard fibers, and might be rendered more palatable if the salt were first well washed out in plenty of water, and the fish cooked for some time. It will then not only taste better, but it will also be more readily digested. The cod is, in itself, not a very easily digested fish, owing to its tough flesh. It might probably represent beef among the fish varieties, particularly since it contains more albumin than the plaice and sole. Kanianizin made a series of experiments on the digestibility of this fish in the prisons of St. Petersburg, and found that it was quite as well digested and assimilated as beef. While hearty eaters make the objection that they have nothing in their stomachs after having eaten fish, I can affirm, by my own experience, that such is not the case as regards codfish.