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.