| | Flesh-forming.| Heat-producing.|
|----------------+---------------+----------------+
| Rice | 10 | 123 |
| Potatoes | 10 | 115 |
| Barley | 10 | 57 |
| Oatmeal | 10 | 50 |
| Wheaten Flour | 10 | 44 |
| Milk | 10 | 40 |
| Fat Pork | 10 | 30 |
| Fat Mutton | 10 | 27 |
| Beans | 10 | 22 |
| Beef | 10 | 17 |
| Hare | 10 | 2 |
| Veal | 10 | 1 |
+----------------+---------------+----------------+
In the tropics, where little exercise can be taken, the waste of
tissues is small, so that little nitrogenous food is required, and
only a moderate amount of fat is taken; the need of heat-producers is
comparatively small, so that starchy products, as millet and rice,
are the principal articles of food. But gradually as we come north
there is a marked increase both in the fatty and nitrogenous articles
of food, until in the Arctic zone oily substances and animal food
are the staple articles of existence, the amount of them that an
Esquimaux will eat being something almost incredible, yet necessary
to resist the severe cold.
The vegetable kingdom alone can supply all that is necessary for
the human body both of flesh-forming and heat-producing substances,
and we must not for a moment imagine that animal food is the only
source of flesh-formers, as the world’s population is supported to a
large extent on vegetable products, especially in tropical regions,
while in colder climates, where vegetable products are hardly to
be obtained, flesh and fat are indispensable. Thus man is clearly
omnivorous; while men may be advantageously almost vegetarians in one
climate, mixed eaters in another (as with us), and almost exclusively
flesh eaters in a third, as in the Arctic regions. But there are some
people who live exclusively on a vegetable diet (vegetarians) in our
country, believing that such a diet is right in principle. Only those
are true vegetarians who exclude milk, butter, eggs and cheese, as
these are the very essence of animal food.
Man is capable of deriving all that is required for living and
working from the animal or vegetable articles of food, either
separately or combined. The question, therefore, is whether a purely
vegetable diet or a mixed diet of vegetable and animal food is the
better suited for our existence. To judge the question we have some
facts to go upon. (1) We are so physically constructed as to be
able to derive our nourishment from both animal and vegetable food.
(2) In the Arctic regions hardly any vegetables are to be obtained.
(3) Man alone has the intelligence to obtain food from all sources,
and, by cooking, to render it fit for nourishment. It apparently
follows, therefore, that while we are suited for either diet, or
rather a combination of both, we may also select to some extent our
diet according to our individual taste, habit of body, and other
circumstances, as work and climate, experience having taught us that
for the enjoyment of good health our diet must be regulated by the
circumstances we have mentioned.
_Nutritive values of Foods._--The following tables, based on those
published by Letheby,[2] show the nutritive values (per lb.) of
various food-stuffs, with their composition.
(_a_) ANIMAL FOOD-STUFFS.
+-------------------+---------+----------------+----------------+
| | Value | Carbon. | Nitrogen. |
| | per lb. | | |
+-------------------+---------+----------------+----------------+
| | _d._ | Grains per lb. | Grains per lb. |
| Butter, fresh | 16 | 6456 | -- |
| Butter, salt | 12 | 4585 | -- |
| Lard | 9 | 4819 | -- |
| Bacon, dry | 9 | 5987 | 95 |
| Cheese, cheddar | 8 | 3344 | 306 |
| Beef | 8 | 1854 | 184 |
| Bacon, green | 8 | 5426 | 76 |
| Suet | 7 | 4710 | -- |
| Pork, fat | 7 | 4113 | 106 |
| Dripping | 6 | 5456 | -- |
| Mutton | 5 | 1900 | 189 |
| Herrings, red | 4 | 1435 | 217 |
| Cheese, skim | 3 | 1947 | 483 |
| Liver, bullocks’ | 3 | 934 | 204 |
| White fish | 2 | 871 | 195 |
| Milk, new | 2 | 599 | 44 |
| Milk, skimmed | 1 | 438 | 43 |
| Buttermilk | ½ | 387 | 44 |
| Whey | ½ | 154 | 13 |
+-------------------+---------+----------------+----------------+
(_b_) VEGETABLE FOOD-STUFFS.
+-------------------+---------+----------------+----------------+
| | Value | Carbon. | Nitrogen. |
| | per lb. | | |
+-------------------+---------+----------------+----------------+
| | _d._ | Grains per lb. | Grains per lb. |
| Sugar | 5 | 2955 | -- |
| Cocoa | 4 | 3934 | 140 |
| Oatmeal | 2 | 2831 | 136 |
| Pearl barley | 2 | 2660 | 91 |
| Rice | 2 | 2732 | 68 |
| Flour, seconds | 1½ | 2700 | 116 |
| Bread, bakers’ | 1½ | 1975 | 88 |
| Rye meal | 1¼ | 2693 | 86 |
| Peas, split | 1 | 2698 | 248 |
| Maize meal | 1 | 3016 | 120 |
| Barley meal | 1 | 2563 | 68 |
| Carrots | 1 | 508 | 14 |
| Parsnips | 1 | 554 | 12 |
| Beer and porter | 1 | 274 | 1 |
| Treacle | 1 | 2395 | -- |
| Potatoes | ½ | 769 | 22 |
| Turnips | ½ | 263 | 13 |
| Vegetables, green | ½ | 420 | 14 |
+-------------------+---------+----------------+----------------+
_Digestibility of Foods._--There cannot be the least doubt that in
the matter of digestion no rule holds good for all stomachs alike,
and it is absurd to attempt to lay down a hard and fast line. At
the same time, some idea of the relative period required to digest
various substances may be gained from a study of the published
results of experiments, though one very doubtful element is left
out of the case altogether, namely, the quality of the cooking,
which every one knows influences the digestibility of the food. The
most complete list is that by Dr. Beaumont, from observation of the
process in the stomach of a wounded soldier.
------------------------+---------------+-------
Articles. | Preparations. | Time.
| | h. m.
------------------------+---------------+-------
Rice | Boiled | 1.0
Pigs’ feet, soused | Boiled | 1.0
Tripe, soused | Boiled | 1.0
Trout, salmon, fresh | Boiled | 1.30
” ” ” | Fried | 1.30
Apples, sweet, mellow | Raw | 1.30
Venison, steak | Broiled | 1.35
Sago | Boiled | 1.45
Apples, sour, mellow | Raw | 2.0
Cabbage, with vinegar | Raw | 2.0
Codfish, cured, dry | Boiled | 2.0
Eggs, fresh | Raw | 2.0
Liver, beef, fresh | Broiled | 2.0
Milk | Boiled | 2.0
Tapioca | Boiled | 2.0
Milk | Raw | 2.15
Turkey, wild | Roasted | 2.18
” ” | Boiled | 2.25
” domesticated | Roasted | 2.30
Potatoes, Irish | Baked | 2.30
Parsnips | Boiled | 2.30
Pig, sucking | Roasted | 2.30
Meat hashed with | Warmed | 2.30
vegetables | |
Lamb, fresh | Broiled | 2.30
Goose | Roasted | 2.30
Cake, sponge | Baked | 2.30
Cabbage-head | Raw | 2.30
Beans, pod | Boiled | 2.30
Custard | Baked | 2.45
Chicken, full-grown | Fricasséed | 2.45
Apples, sour, hard | Raw | 2.50
Oysters, fresh | Raw | 2.55
Bass, striped, fresh | Broiled | 3.0
Beef, fresh, lean, rare | Roasted | 3.0
” steak | Broiled | 3.0
Corn-cake | Baked | 3.0
Dumpling, apple | Boiled | 3.0
Eggs, fresh | Boiled soft | 3.0
Mutton, fresh | Broiled | 3.0
Mutton, fresh | Boiled | 3.0
Pork, recently salted | Raw | 3.0
Soup, chicken | Boiled | 3.0
Oysters, fresh | Roasted | 3.15
Pork, recently salted | Broiled | 3.15
Pork, steak | Broiled | 3.15
Corn-bread | Baked | 3.15
Mutton, fresh | Roasted | 3.15
Carrot, orange | Boiled | 3.15
Sausages, fresh | Broiled | 3.20
Beef, fresh, lean, dry | Roasted | 3.30
Bread, wheat, fresh | Baked | 3.30
Butter | Melted | 3.30
Cheese, old, strong | Raw | 3.30
Eggs, fresh | Hard boiled | 3.30
” ” | Fried | 3.30
Flounder, fresh | Fried | 3.30
Oysters, fresh | Stewed | 3.30
Potatoes, Irish | Boiled | 3.30
Soup, mutton | Boiled | 3.30
” oyster | Boiled | 3.30
Turnip, flat | Boiled | 3.30
Beets | Boiled | 3.45
Corn, green, and beans | Boiled | 3.45
Pork, recently salted | Raw | 3.0
Beef, fresh, lean | Fried | 4.0
Fowls, domestic | Boiled | 4.0
” ” | Roasted | 4.0
Veal, fresh | Broiled | 4.0
Soup, beef, vegetables | Boiled | 4.0
and bread | |
Salmon, salted | Boiled | 4.0
Heart, animal | Fried | 4.0
Beef, old, hard, salted | Boiled | 4.15
Pork, recently salted | Fried | 4.15
Cabbage, with vinegar | Boiled | 4.30
Ducks, wild | Roasted | 4.30
Pork, recently salted | Boiled | 4.30
Suet, mutton | Boiled | 4.30
Veal, fresh | Fried | 4.30
Pork, fat and lean | Roasted | 5.15
Suet, beef, fresh | Boiled | 5.30
Tendon | Boiled | 5.30
------------------------+---------------+-------
This may be compared with the following table of precedence in
digestibility of some animal foods, on the authority of Chambers:--
Sweetbread and Lambs’ Trotters.
Boiled chicken.
Venison.
Lightly Boiled Eggs, New Toasted Cheese.
Roast Fowl, Turkey, Partridge, and Pheasant.
Lamb, Wild Duck.
Oysters, Periwinkles.
Omelette (?), Tripe (?).
Boiled Sole, Haddock, Skate, Trout, Perch.
Tripe and Chitterlings.
Mutton.
Roast Beef.
Boiled Beef.
Rump Steak.
Roast Veal.
Boiled Veal, Rabbit.
Salmon, Mackerel, Herring, Pilchard, Sprat.
Hard-boiled and Fried Eggs.
Wood Pigeon, Hare.
Tame Pigeon, Tame Duck, Goose.
Fried Fish.
Roast and Boiled Pork.
Heart, Liver, Lights, Milt, and Kidneys of Ox, Swine, and Sheep.
Lobsters, Shrimps, Prawns.
Caviare.
Smoked, Dried, Salt, and Pickled Fish.
Crab.
Ripe Old Cheese.
The contradictions are sufficiently glaring.
From some recent experiments by Jessen it would seem that raw meat is
more digestible than cooked, which is perhaps not astonishing when
due allowance is made for the way in which that operation is often
performed. Thus the times required for digestion were:
Raw beef, shaved fine 2 hours.
” mutton 2 ”
” veal 2½ ”
Boiled beef, half done, shaved fine 2½ ”
Raw pork 3 ”
Boiled beef, well done, shaved fine 3 ”
Roast beef, half done, shaved fine 3 ”
Roast beef, well done, shaved fine 4 ”
Klenze, experimenting on 18 kinds of cheese, found that cheddar was
digested in the shortest time (4 hours), while unripe skim Swiss
cheese required 10 hours for solution. There is no difference in
the digestibility of all sorts of hard cheese, or all soft cheese,
but all fat cheeses are dissolved the most rapidly, because, being
open by reason of the fat, they are the more readily attacked by
the solvent. There is no connection between the digestibility and
the percentage of water present in the cheese, but there is some
connection with the percentage of fat and the degree of ripeness.
_Animal Foods._--There is surely no need to insist on the value of
animal foods. At the same time there can be no doubt of a general
tendency among town dwellers to eat too much meat. Twice a day is
quite often enough for a meat meal, and then it should not form
more than about ⅕ of the whole meal. Fresh fish is an excellent
and wholesome substitute for meat, especially in the case of brain
workers. Cheese is highly nutritious, but digestible only by those
living out of doors; this does not apply, however, to the soft
cream-cheeses. Lard, dripping, butter, and even butterine or bosch,
have great value as heat-producing foods.
_Vegetable Foods._--Few people rightly estimate the true value of
vegetables, apart, that is to say, from the starchy products of the
vegetable kingdom, such as potatoes, sago, rice, &c. Many people
hardly think of eating cabbage or spinach with their meat, yet
there is no more wholesome food as an adjunct to the dinner table.
The same may be said of many other vegetables. On the authority of
the _Medical Record_, asparagus is a strong diuretic, and forms
part of the cure for rheumatic patients at such health resorts as
Aix-les-Bains. Sorrel is cooling, and forms the staple of that
_soupe aux herbes_ which a French lady will order for herself after
a long and tiring journey. Carrots, as containing a quantity of
sugar, are avoided by some people, while others complain of them
as indigestible. With regard to the latter accusation, it may be
remarked, in passing, that it is the yellow core of the carrot that
is difficult of digestion--the outer, a red layer, is tender enough.
In Savoy the peasants have recourse to an infusion of carrots as a
specific for jaundice. The large sweet onion is very rich in those
alkaline elements which counteract the poison of rheumatic gout. If
slowly stewed in weak broth, and eaten with a little Nepaul pepper,
it will be found to be an admirable article of diet for patients of
studious and sedentary habits. The stalks of cauliflower have the
same sort of value, only too often the stalk of a cauliflower is
so ill-boiled and unpalatable that few persons would thank you for
proposing to them to make part of their meal consist of so uninviting
an article. Turnips, in the same way, are often thought to be
indigestible, and better suited for cows and sheep than for delicate
people; but here the fault lies with the cook quite as much as with
the root. The cook boils the turnips badly, and then pours some
butter over it, and the eater of such a dish is sure to be the worst
for it. Try a better way. What shall be said about our lettuces? The
plant has a slight narcotic action, of which a French old woman, like
a French doctor, well knows the value, and when properly cooked is
really very easy of digestion.
_Fruits._--There are few who cannot enjoy fruit in one form or
another. For diabetics only the least desirable kinds, as certain
nuts and almonds, are available, all others, as containing sugar,
being forbidden. Sufferers from acid dyspepsia must select carefully,
and limit their consumption to the least irritating--a few
strawberries or a few grapes. Diarrhœa and dysentery preclude the
use of all fruit. On the other hand, for constipated persons it is
sometimes the only trustworthy remedy which they can use continuously
with comfort; it is also of benefit in renal diseases, by its action
on the bowel. Atonic persons generally take it well, and feel the
better for its digestive property Those in normal health may eat
almost any ripe fruit. The bland varieties are the most wholesome and
nutritious--strawberries, apples, pears, grapes, and gooseberries.
The last named, however, with currants and raspberries, are less
wholesome than the others. Stone-fruits are apt to disagree with
the stomach; but the more watery, as peaches and large plums, are
better than the smaller and drier, as apricots and damsons. The pulp
of oranges renders them heavy. Among other foreign fruits, bananas
are wholesome. Dried fruits and the skin of fruits in general are
indigestible. Nuts, the edible part of which is really the seed,
contain much albumen and some fat in a condensed form, and are
particularly difficult of digestion. Fruit may be taken with a meal
or on an empty stomach. In the former case it promotes digestion by
its gently irritating effect on the mucous membrane of the stomach
and intestine. If an aperient effect be desired, it had better be
taken in the morning before breakfast or between meals. A succulent
and pleasantly acid variety is best for both of these purposes,
while it is also a food. The quantity of fruit which should be
taken depends on the kind. If it belongs to the bland nutritious
class, a healthy person may now and then partake of it as freely
as of any other wholesome food; but he will gain most benefit if
he take only a little, and take it regularly. The same may be said
of the invalid with whom fruit agrees. Cooking removes much of the
acidity from crude fruit, and renders it lighter as well as more
palatable. So treated, it is productive of good and no harm; but it
is a fundamental principle that whatever fruit is eaten uncooked
must be fully ripe and not over-ripe. This may sound trite, and
indeed the principle is commonly admitted, but not, it would seem,
by all, for we still find people, and not a few, who will themselves
deliberately take, and worse, will give to their children, green
gooseberries, green apples, &c., the very hardness of which, apart
from their acid pungency, suggest their unfitness for digestion. Such
people use as food an acid irritant poison, whose necessary action
is to cause excessive intestinal secretion, with more or less of
inflammation. Hence arises diarrhœa. On the other hand, fruit which
is over-ripe, in which fermentation has begun, is a frequent cause
of this disorder, and equally to be avoided, and perhaps also more
difficult to avoid because the insidious beginning of decay is not
easily recognised. It should never be forgotten by any who incline to
follow the season in their feeding, that the want of such precautions
as the above may produce that dysenteric form of diarrhœa, “British
cholera,” which is occasionally as rapidly fatal as the more dreaded
Asiatic type of that disease. (_Brit. Med. Jour._)
_Bread and other Grain Foods._--Arguments on the bread question
threaten to be endless, probably because the champions on both sides
have just enough scientific knowledge to enable them to misstate
the case. The most reasonable review of the whole circumstances is
contained in one of Prof. Church’s papers in _Nature_. He deals first
with variations in composition in the grain itself. These variations,
chiefly affecting the percentage of nitrogen, depend upon hereditary
qualities in different strains of the wheat-plant; upon climate and
season: and, to some extent, but not so largely as is often stated,
upon cultivation, soil, and manure. The hard translucent wheats,
_blés durs et glacés_, are of high specific gravity, about 1·41,
and, owing to their lengthened and wrinkled shape, of low weight per
bushel; these wheats are rich in nitrogen. The soft opaque wheats,
of less specific gravity, about 1·38, and, owing to their rounded
and plump form, of high weight per bushel, are poor in nitrogen.
The hard wheats grown in Poland, in Southern Russia, in Italy, and
in Auvergne, are used in the manufacture of macaroni, vermicelli,
semolina, and pâtés d’Italie. The softer and more starchy wheats
are especially appropriate for the production of fine white flour.
According to the most recent analyses, the percentage of nitrogen in
different varieties and samples of air-dry wheat may range from 1·3
up to 2·5--numbers corresponding to 8·23 and 15·83, respectively, of
gluten or flesh-forming substances. But the same variety of wheat may
give a grain having 3 per cent. more gluten in a bad season than when
matured in a fine summer. More than this, one may select from the
same field, the same plant, or even the same ear, individual grains
which shall show quite as wide a variation in gluten as that just
cited.
Church next considers “how much flour and how much bran will 100
parts of ordinary soft wheat yield on the ordinary system of
low-milling adopted in England?” As the averages from an immense
number of independent estimates we may put down the flour at a
total of 80, the bran at 17, and the loss at 3. Thus, from an
economical point of view, we appear to lose ⅕, or 20 per cent., of
our wheat by submitting it to the numerous treatments involved in
the manufacture of flour. But is this really the case? We think not.
For much of the nitrogen in the rejected parts is not in the form of
flesh-forming matter, and much that does so exist in the bran passes
unaltered and unused through the alimentary canal, because of its
close incorporation with fibre. But on the other side we must not
forget that bone-forming materials are clearly deficient in wheaten
flour, and that those phosphatic compounds present in bran are
readily soluble to a large extent, not only in the several digestive
secretions with which they come in contact in the body, but also in
pure water.
But in comparing and contrasting bread made from flour with that
made from whole wheat, Church considers other points. We shall find
it impossible to make, by means of leaven or yeast, a light spongy
loaf from whole wheat finely ground, the so-called _cerealin_ of
the bran inducing chemical changes which result in a moist, clammy,
dense product. Even whole wheat merely crushed into meal, and not
ground, partakes of the same defect. Fine flour, on the other hand,
yields a bread which is light enough before mastication, but which,
when masticated, possesses a marked tendency to become compacted into
dense lumps which may never become penetrated by the gastric and
intestinal juices, and which are a frequent cause of constipation.
Whole-meal bread cannot be charged with this defect; indeed it acts
medicinally as a laxative, and by reason of its mechanical texture
is hurried rather too quickly along the digestive track, so that the
full virtue of such of its nutrients as are really soluble becomes in
part lost. Yet there is no doubt that for many persons, especially
those who have passed middle age and are engaged in sedentary
occupations, whole wheaten meal in the form of bread, biscuits,
scones, &c., forms an invaluable diet.
The following analysis may present some of the foregoing statements
in a cleared light, and may add some additional particulars of
interest. They represent, so far as a couple of sets of average
results can do so, the percentage composition of ordinary white bread
and of the whole-meal bread made by Hill and Son:--
---------------------------------------+--------+--------------
| White. | Whole meal.
---------------------------------------+--------+--------------
Water | 40·0 | 43·5
[a]Albuminoids or flesh-formers | 7·0 | [b]10·5
Starch, dextrin, and sugar | 50·7 | 40·6
Oil and fat | 0·6 | 1·6
Cellulose and lignose | 0·5 | 1·8
[c]Ash or mineral matter | 1·2 | 2·0
---------------------------------------+--------+--------------
(Church.)
[a] Calculated from total nitrogen present.
[b] As much as 12·5 in some samples.
[c] Includes common salt added.
Another writer who has worked out the facts arrives at closely
similar conclusions. He sums up thus:--(_a_) The carbohydrates of
bran are digested by man to but a slight degree. (_b_) The nutritive
salts of the wheat grain are contained chiefly in the bran, and,
therefore, when bread is eaten to the exclusion of other foods, the
kinds of bread which contain these elements are the more valuable.
When, however, as is usually the case, bread is used as an adjunct
to other foods which contain the inorganic nutritive elements, a
white bread offers, weight for weight, more available food than
does one containing bran. (_c_) By far the major portion of the
gluten of wheat exists in the central four-fifths of the grain,
entirely independent of the cells of the fourth bran-layer (the
so-called “gluten cells”). Further, the cells last named, even when
thoroughly cooked, are little if at all affected by passage through
the digestive tract of the healthy adult. (_d_) In an ordinary mixed
diet, the retention of bran in flour is a false economy, as its
presence so quickens peristaltic action as to prevent the complete
digestion and absorption, not only of the proteids present in the
branny food, but also of other foodstuffs ingested at the same
time. (_e_) Inasmuch as in the bran of wheat as ordinarily roughly
removed there is adherent a noteworthy amount of the true gluten of
the endosperm, any process which in the production of wheaten flour
should remove simply the three cortical protective layers of the
grain would yield a flour at once cheaper and more nutritious than
that ordinarily used.
On this same subject the _Lancet_ remarks that bread which contains
all the constituents of the wheat, except the outer, insoluble and
irritating portion of the seed, seems, when the appetite for it has
been obtained, to be more satisfying and digestible than the white
and fashionable product which is found on most tables, of rich and
poor alike. It is believed, too, that for children, the whole meal
is the best for sustaining growth and for building up the skeleton
strongly and in perfect form. The supply of whole-meal bread is now
much facilitated by the improvements that have been introduced in
the decorticated or granulated flour, to which Lady John Manners
called public attention in her paper on Wheat-meal bread. In the
decorticated whole meal the extreme outer coating of the wheat grain
is, by a special process of abrading, to the perfection of which
Dr. Morfit has rendered able service, cleverly removed. After the
abrading process is completed, the whole of the grain is reduced to
a fine flour, in which there is retained all the substances that are
nutritious and digestible. Considering the fact that the whole-meal
bread, when properly manufactured, is easily assimilated, we are led
to the conclusion that it must be more nutritious generally than any
other bread, in which starch predominates.