This section is from the book "Practical Dietetics With Special Reference To Diet In Disease", by William Gilman Thompson. Also available from Amazon: Practical Dietetics with Special Reference to Diet in Disease.
Nuts contain protein, with some starch and more or less fat, and very little water. From 50 to 65 per cent of the common nuts is shell. With the exception of the cocoanut, chestnut, almond, and English walnut, the varieties eaten in this country furnish but little nutriment. Their chief value is to stimulate the appetite and afford variety in the diet. Excepting chestnuts and cocoanuts, they are usually eaten raw, as dessert, but they are much used in confectionery. A few nuts are used in salads and as dressing for fowl. As a rule, they are to be proscribed from invalid dietaries, but, with the exception of chestnuts and peanuts, they may be allowed to diabetics. A preparation of malted nuts which may be obtained in market is both nutritious and digestible. It contains emulsified nut fat, maltose, and vegetable protein.
Almonds contain a ferment called emulsin and much fat, and sweet almonds have 3 to 5 per cent of sugar, but no starch (Bauer). This low percentage of sugar makes them of service in the treatment of diabetes, in which disease they are sometimes used as a substitute for bread after being ground into meal. (See Diabetic Breads).
Macaroons are a digestible form of cake for convalescents and children composed chiefly of almonds and sugar.
Almonds are wholesome and nutritious. They should not be eaten in cases of gastric irritability, but occasionally dyspeptics in whom gastric digestion is slow derive benefit from eating a few salted almonds with meals. They should be soaked and peeled or "blanched," otherwise their skins may set up gastric irritation.
The bitter almond contains hydrocyanic acid, sugar, and oil, and is not used except for flavouring cough mixtures. Almonds are imported chiefly from Italy, France, and Spain, but of recent years they have been extensively grown in California.
English walnuts eaten liberally between meals may assist in overcoming constipation through the bulk of insoluble residue which they leave, and possibly also from the oil which they contain.
Cocoanuts are very indigestible even when thoroughly desiccated and grated. The cocoanut contains a proteolytic ferment which converts meat into albumoses with considerable activity. The cocoa-nut has been successfully grown in Florida.
Brazil nuts, pecan nuts, beechnuts, butternuts, filberts, etc., all hold much oil, and are difficult of digestion. Butternuts easily become rancid after being shelled.
Chestnuts contain 15 per cent of sugar with so much starch that they are very nutritious, and in some parts of Italy they are made into cakes and eaten by the peasants as a substitute for potatoes. Raw chestnuts are wholly indigestible, but if thoroughly roasted or, better still, if long boiled, they become much less so. They should, however, not be given to invalids.
The pistachio, a native nut of Syria, has a greenish, almond-like kernel. It is chiefly used in confectionery and ices for both its colour and delicate flavour.
Peanuts are described under Legumes, p. 168.
Composition of Nuts and some Other Food Materials (C. F. Langworthy)
COMPOSITION AND FUEL VALUE OF THE EDIBLE PORTION
Fuel value pound.
Pine nuts or pifions (Pinus edulis)
"The meat of nuts, excepting chestnuts and cocoanuts, contains nearly 50 times as much fat and less than one fifth as much carbohydrates as wheat flour, and has about double the fuel value - i. e., energy-producing power. A pound of unshelled nuts will furnish about half as much protein and the same amount of energy as a pound of flour. Owing to their high fuel value and low protein contents, nuts would not make a well-balanced food when eaten by themselves" (C. F. Langworthy). Eaten with fruit, however, they are an excellent form of food, and if carefully selected and thoroughly masticated their coefficient of digestibility is high for persons in health, and they furnish very little residue of waste. The relatively high price of nuts as a food is offset by the fact that they demand no expense for cooking. A number of savage tribes live almost exclusively upon fruits and nuts, and M. E. Jaffa has shown at the California Agricultural Experiment Station (1901-1902) that such a diet is not incompatible in civilised man with maintenance of vigour and body weight.