Nuts enter but little into the invalid's dietary, but as more attention is being paid to means of rendering them digestible, a word concerning them is not out of place.

Composition

The edible substance of nuts is concentrated food, containing little water, and with few exceptions, much fat. In general, nuts are also rich in protein. The average composition is as follows:

Water .................'........... 1-4%

Protein ........................... 6-15%

Fats.............................. 40-50%

Carbohydrates ..................... 6-10%

The only common nut containing much carbohydrate is the chestnut, which contains 73 per cent. The pignolia, peanut, butternut, almond, beechnut and pistachio contain over 20 per cent. of protein. The pecan, brazil nut, butternut, filbert, hickory nut and walnut contain over 60 per cent. of fat.

The ash content is comparatively high. Walnuts, almonds, etc., are rich in phosphoric acid.

Cooking Of Nuts

Nuts are more often eaten raw than cooked. But the peanut is not considered palatable when raw, and the chestnut is very indigestible unless the starch is cooked, when it becomes very easily digestible. Almonds are widely used in confectionery.

Nuts may be used as staple articles of diet, in salad, soups, desserts, etc.

To insure the best utilization of nuts they must be thoroughly prepared for digestion by grinding or mastication. Nut butters offer much less resistance to digestion than raw nuts hastily eaten. On account of the high fat content, these products must be fresh, or the fat is likely to decompose (become rancid) and be irritating.

Nut flours and meals are made into bread or porridge. Almond meal (containing no starch and very little sugar) is often utilized as a bread for diabetics. The chestnut cannot be so used, on account of its high content of starch. The peanut contains about 11 per cent. of carbohydrates, and hence is undesirable for this purpose.

1 For further information, note " Nuts and Their Uses as Food," Fanner's Bulletin No. 332, U. S. Dept. of Agriculture, Washington, D. C.

Digestibility

Nuts have been considered very indigestible. This is due largely to improper mastication or other preparation for digestion; to the fact that they are a very concentrated food, and are often eaten when not needed. While nut protein, as nuts are ordinarily eaten, is not so easily nor completely digested as meat protein, there are experiments showing that on the whole, they are as thoroughly digested as an ordinary mixed diet. No experiments have been reported on the ease or rapidity of nut digestion.

Nutritive Value

Nuts are a concentrated food. This is clearly shown by the following figures:

1 lb. of Almonds .......... yield 2895 Calories.

1 lb. of Brazil nuts ........ yield 3120 Calories.

1 lb. of Filberts ........... yield 3100 Calories.

1 lb. of Hickory ........... yield 3345 Calories.

1 lb. of Peanuts ........... yield 2610 Calories.

1 lb. of Walnuts ........... yield 3075 Calories.

The high fuel value is due to the absence of water and the large amount of fat present. Nuts can be most advantageously used along with bulky foods, such as fruits and vegetables, and those lacking in fat, such as bread. In a vegetarian diet they become a valuable source of protein.