From the standpoint of cost, nuts, even at the present extraordinary prices, compare favorably with milk as a source of protein, because of the small quantity required to furnish the needed supplement of complete proteins. For example, shelled almonds, at a cost of $1.00 a pound (retail) supply for 19.2 cents the same amount of supplementary protein furnished by milk at a cost of 24 cents. Black walnuts supply the same amount for 15 cents, pine nuts (pinons) for 20 cents, hickory nuts 15 cents, and peanuts 4 cents.
The late Dr. Austin Flint more than fifty years ago prepared from almonds a milk for use by certain classes of patients. The writer, about thirty years ago, prepared from the peanut and other nuts a preparation known as malted nuts which much resembles malted milk in appearance and flavor, and which has been successfully used in place of milk by persons sensitized to cow's milk in hundreds of cases.
The preparation of milk substitutes from vegetable sources is not a new idea. When in Russia a few years ago, I found on sale in delicatessen shops a paste prepared from honey and almonds which with the addition of water made a very palatable emulsion much resembling milk in appearance as well as in flavor. I have been informed that the natives of the Philippines prepare from the litchi nut a vegetable milk for feeding infants deprived of their natural nourishment. These natural products have the advantage over the infant foods of commerce most of which are better fitted to destroy than to preserve life. They are complete foods, supplying the essential vitamines as well as other necessary elements.
The nut is not only the most concentrated form of nourishment known, but, contrary to the general view, is one of the most easily digestible. The supposed indigestibility of the nut is due to two things, eating when already satiated with food; that is, taking the nut as a surplus food, and second, neglecting to masticate the nuts thoroughly. Watch a monkey eating nuts and see how thoroughly he masticates each particle. Any particle not well crushed and emulsified is passed through the intestinal canal undigested and of course unabsorbed. But when crushed and converted into a smooth cream, the nut is one of the most easily digestible of all foods. Most nuts consist almost exclusively of two food principles, proteins and fats. The protein is one of the finest sort and more easily digestible in the raw state than is cooked protein of any kind. The fat is finely emulsified, and thus prepared for prompt digestion and absorption.
Experiments on human subjects conducted at the Battle Creek Sanitarius by an expert from the laboratory of Yale University, showed that the proteins of nuts are as easily digested and as fully utilized as the proteins of other foodstuffs.
The peanut produces an average crop of at least 40 bushels, or 900 pounds of shelled nuts to the acre, equivalent to 8,280 pounds of cow's milk, to produce which would require 4.6 acres. A grove of black walnuts, 40 trees to the acre, producing one hundred pounds of nuts to the tree, or one thousand to the acre, would afford as much protein as 8,500 pounds of milk, to produce which would require 5.3 acres. It is to be noted, also, that one pound of peanuts has a nutritive value nearly one-third greater than that of the 9.2 pints of milk containing an equivalent amount of protein, while the calory content of the one pound of nuts is more than ten per cent greater than that of the milk furnishing the same amount of protein. In the case of many nuts the disproportion is greater. For example, one pound of filberts has a food value double that of an amount of milk containing the same amount of protein.
The nut is evidently superior to milk as a source of protein. Like milk, nuts are rich in lime, doubtless due to the high protein content with which the lime is associated in vegetable products. Nuts, like milk, are deficient in iron, although in this respect they are considerably superior to milk. Hence when nuts are freely used as a source of protein care should be taken to supplement them by a liberal quantity of greens, which are rich in iron and lime as well as in the fat soluble vitamine which is also found in abundance in milk but in which nuts are rather deficient.
It thus appears that nuts, because of the superior quality of their protein, may not only take the place of meat in the dietary, but when properly combined with other vegetable foods, may to a large extent, at least, take the place of milk. In this respect they constitute a unique class of foodstuffs.
The soy bean, which like the peanut is a legume rather than a true nut, resembles the peanut in composition and like it affords a protein of a quality so closely resembling that of milk that a very excellent milk has been prepared from it. Its protein is also complete in character and may replace the protein of meat. The soy bean has, in fact, for many thousands of years been the chief source of complete proteins for the Chinese and the Japanese.
Aside from the soy bean and the peanut, nuts have no rivals in the vegetable kingdom. They are real plant aristocrats, the value of which will be more and more appreciated as scientific research and practical dietetic experience make clear their numerous points of superiority.