Part 4

FRUITS

The term "fruit" in a strictly botanical sense includes a very wide range of vegetable articles--the reproductive product of trees, or other plants, such as grains, legumes, nuts, berries, apples, peaches, plums, etc. In this lesson, however, I will apply the popular meaning to the term.

The common succulent or juicy fruits, including both tree fruits and berries, have many properties in common. The chemical composition of these typical fruits consists of from 80 to 85 per cent water, 5 to 15 per cent sugar, 1 to 5 per cent organic or fruit-acids, and small quantities of protein, cellulose, and the numerous salts, a portion of which may be combined with the fruit-acids. Some unripe fruits contain starch and various other carbohydrate substances, many of which are distasteful and unwholesome. On the other hand, when fruits become over-ripe, and decay sets in, the sugar is changed into carbon dioxid, alcohol, and acetic acid, and the fruit rapidly deteriorates in nutritive value and unwholesomeness. These changes, together with the loss of water, account for the sponginess and the tastelessness of cold storage and other long-kept fruits. All varieties of fruit are best when they have been allowed to ripen naturally on the trees, but modern commercial conditions demand that fruits for shipping purposes be picked slightly immature, and allowed to ripen in transit to the markets.

The fruit-acids are composed of carbon, hydrogen, and oxygen, and are burned in the body the same as sugar, or fats. The actual energy-producing content of fruit is not large, and depends almost entirely upon the sugar content. The nutrient elements of fruit consist of fruit-sugar, combinations of salts, organic acids, and various flavoring or aromatic substances. These same salts, acids, etc., purchased at the drug store, and administered separately, would be of no particular value, and might produce harmful results, but in the various combinations of fruits they have very important places in the diet.

One of the most important functions that fruit performs in the body is that of an artificial solvent, or an aid to digestion. To make food serve this purpose well would require some knowledge in regard to chemical harmonies, quantity, etc. To illustrate: If the stomach does not secrete a sufficient quantity of hydrochloric acid, fruit-acid should be absolutely omitted, as any acid, except hydrochloric acid itself, tends to inhibit the formation of the normal stomach acid. And this in turn tends to fermentation of the sugars and starches--causing acid fermentation and all the symptoms that accompany this condition.

So it is very important to prevent all the causes and sources of fermentation if we would prevent the development of all the various diseases that arise from acid conditions of the stomach, and autointoxication. This explains why people of rheumatic tendency cannot take acid fruit. Citrus fruits, however, and limes, lemons, oranges, grape-fruit, etc., are beneficial in rheumatism and conditions of lowered blood alkalinity, because they are changed to alkalis in the system, and reinforce the blood alkalinity. People of rheumatic tendency, therefore, should confine the diet as nearly as possible to starchless foods, omitting all but the citrus fruits.

In the lesson on "Vieno System of Food Measurement" I give the energy value of various fruits, and also the nitrogen factor. These tables consider fruits in the same light with other foods; that is, as sources of energy and nitrogen. In the table which follows, the more important fruits are grouped according to their total acidity. The figures represent the volume of acidity, not strength:

ACID FRUITS SUBACID FRUITS SWEET AND NON-ACID FRUITS

Limes 95 Raspberries 16 Grapes 8 Lemons 78 Plums 14 Prunes 7 Grapefruit 39 Cherries 13 Raisins 6 Cranberries 37 Peaches 12 Bananas 6 Pineapples 22 Blackberries 12 Persimmons 4 Oranges 20 Apples 11 Figs 4 Apricots 18 Pears 3 Strawberries 18 Dates 3

The fruits in the above table are all reasonably wholesome, and the particular fruits to be used depend as much upon convenience as upon the nature of the food substances. The above groups, however, will be given much attention in dietetic prescriptions, and the food scientist should become thoroughly familiar with this classification.

Of the acid fruits, oranges are the best and most desirable, and cranberries perhaps the least.

Acid fruits are responsible for much stomach and intestinal trouble. Food was prior to life. Animal life on this globe has been fitted into, and is the net result of food; therefore, in the wonderful adaptations of Nature, it is evident that life will develop higher and better by subsisting upon the food that grows in its respective country.

Acid fruits, such as lemons, limes, grapefruit, pineapples, and oranges, are grown in the tropical and semi-tropical countries, where the climate is warm, and where people subsist largely upon native vegetables. These fruits supply the acids and the fruit-sugars which the system requires in a warm climate.

In the tropics the people live out of doors, the pores of the skin are kept open, and the effete matter produced by acids can be cast out of the body.

In northern countries people live largely indoors, and are heavily clad except during a very short term in midsummer, therefore they do not eliminate freely. They subsist largely upon the heavier foods, such as flesh and grains, both of which require a large amount of hydrochloric acid for digestion, hence when the acid of fruits is added to the hydrochloric acid, of which most people have a deficiency, serious acid fermentation may result.

Acid fermentation is the beginning of nearly all stomach trouble, and is the primary cause of many other ills. (See "Fermentation," p. 424.)

Practically all the fruits of the subacid group are excellent; however, on account of the mechanical irritation of the seeds, berries should not be used in cases in which the stomach and the intestines are irritated or catarrhal. In such cases the juice should be pressed from the fruit and the seeds discarded.

Of the non-acid fruits, raisins, figs, and dates are excellent foods from the standpoint of furnishing a large amount of sugar in its very best form. Very ripe bananas and ripe persimmons, especially the large Japanese variety, are fruits which have a distinct nature, and are suited to a particular purpose in dietetics. These pulpy fruits are especially desirable in all cases of digestive irritations and disorders, because of the amount of nourishment contained in them, which is greater than that contained in the juicy fruits. In my practice I seldom, if ever, find a stomach so weak that it cannot digest ripe persimmons and very ripe bananas. I attribute much of my success in treating such cases to the skillful use of these products. The persimmon and the banana as remedial and nutritive articles, are the most valuable fruits grown.

Raisins, prunes, figs, dates, apricots and peaches are common types of fruit preserved by the process of evaporation, and when soaked in clear water may be restored to almost their original condition. Evaporated fruit should not be cooked. This is perhaps the most palatable and wholesome method of preserving fruit. Next in purity and importance are the methods of canning, as practised by the housewife. The ordinary commercial preparations of canned fruits, together with the many jams, marmalades and jellies, are generally of doubtful, if not inferior quality. The Pure Food Law has accomplished much to establish honesty in the preserving and the labeling of food, but these products are still far from ideal, and are not to be considered where fresh or evaporated fruits are obtainable.

VEGETABLES

In this group we may conveniently class all food products not elsewhere discussed.

Beans, peas, and corn, when taken in the immature state, are classed as vegetables. The importance of this group of food products is not their great food value per pound (succulent vegetables contain anywhere from 75 to 95 per cent of water); it is the great variety of nutritive substances which they contain. Lettuce contains cellulose, proteids, active chlorophyl, pentoses, sugars and starches, representing carbohydrates in various processes of transformation; small quantities of fat, and a relatively large per cent of mineral salts, besides numerous flavoring materials. All other edible plants contain many of the same elements in different proportions.

Edible vegetables may be conveniently grouped according to that portion of the plant which we consume. These groups are:

a Above ground b Roots and tubers c Leafy or succulent d Cucurbita family

Melons, cantaloups, and tomatoes are on the border line between vegetables and fruits. The following groups of vegetables are made up according to these classifications:

VEGETABLES

(a) Above Ground

Beans-- Dried Green Beets Brussels sprouts Cauliflower Corn Eggplant Lentils (dried) Okra Peas Dried Green