Scurvy, Past and Present

by Alfred F. Hess

VEGETABLES

It is everyday knowledge that fresh vegetables are of great value in the protection from, and cure of, scurvy. The first experimental investigation of this subject was that of Holst and Froelich, published in 1907, and continued in a series of papers extending to 1916. These investigators tested the potency of a large number of vegetables by feeding them in varying quantities to guinea-pigs. They found that all vegetables have antiscorbutic value but to a markedly varying degree. Cabbage, sorrel leaves, endive, head salad, and dandelion leaves, were found to be of most avail in protecting against scurvy, whereas carrots, cooked potatoes and cooked turnips, and cauliflower proved to be of less value. In general, it may be stated that the leafy vegetables have more antiscorbutic power than the roots or the tubers. This generalization, we shall see, is not without exception, e.g., the swede. Similar experimental work has been recently carried on by a group of investigators at the Lister Institute, who have added considerably to our knowledge in this field. In all this experimental work cabbage has been found to be the most potent of the vegetables, and therefore experiments have centered about it just as in considering fruits the work has centered about orange juice or lemon juice. We shall, therefore, discuss in detail its reaction to heat and dehydration.

Cabbage.—Holst and Froelich found that 1 g. daily of fresh cabbage afforded nearly complete protection to guinea-pigs, and Delf has corroborated this work. This amount is sufficient to prevent the development of manifest scurvy, although it does not induce satisfactory growth. In this respect it is comparable to giving 1.5 c.c. of orange juice daily. If guinea-pigs take only 0.5 g. of raw cabbage, scurvy will develop; whereas 2 g. or more will promote satisfactory growth and no scorbutic changes will be found on microscopic examination.

Effect of Heating.—Vegetables are of decidedly less antiscorbutic value when cooked than raw; cabbage, for instance, on being boiled is weakened about one-half. Heating to 110° C. for an hour destroys almost all of its antiscorbutic factor. Delf’s tests did not show so great a loss. She came to the conclusion, of theoretical and practical value, that slow cooking at a low temperature is much more deleterious than rapid cooking at a higher temperature. Hess and Unger found that carrots lost much of their antiscorbutic power after boiling, and that this was the result of a true destruction, the vitamine not having been merely dissolved in the water of boiling; for if guinea-pigs consumed 40 c.c. per capita of this water, they were not protected against scurvy ([Fig. 11]). Acidulating the water with 10 per cent. vinegar did not reduce the loss, an experience similar to that of others using citric acid or lemon juice.

Vegetables cannot be considered from an antiscorbutic standpoint as a standard and uniform foodstuff, as they vary in their content of this factor according to their freshness and age. This was demonstrated by means of feeding experiments with carrots. For example, 35 g. of old carrots, such as were used for feeding the laboratory animals, afforded but little protection after having been cooked in an open vessel for about 45 minutes, whereas the same amount of young carrots cooked this way protected the guinea-pigs. It is obvious that this distinction is of importance in evaluating the antiscorbutic content of the various foods, and in considering whether individuals and groups of individuals are receiving an adequate quota of antiscorbutic vitamine. It will be noted later that it is also of importance in connection with the potency of dehydrated vegetables. Recent experiments indicate that not only age, but the degree of ripeness must be considered in appraising the food value of vegetables. Feeding experiments showed that tomatoes which were fully ripe were more potent than those which were slightly green. Probably many other factors play a rôle in determining the richness of vegetables in vitamine. It may not be immaterial whether they are allowed to ripen on the vine or shrub, or mature subsequently. The nature of the soil may also affect the antiscorbutic quality of the vegetables or fruit. So that it is evident that we must not be schematic in considering this question, and must realize that a table of antiscorbutic values, such as accompanies this text ([Table 3]), does not furnish definite and inflexible values.

There is a marked difference between vegetables and vegetable juices in keeping quality, and in their reaction to heat and to acid. In general, it may be stated that the juices are much more sensitive. Holst and Froelich brought out this point in 1912 and enlarged upon it in their publication of 1916. The different juices vary greatly in this respect; for example, dandelion juice is acutely sensitive to heat, whereas sorrel leaves withstand high temperatures very well. In regard to these differences an analogy may be drawn to the fruit juices. Lemon, orange and raspberry juices are markedly thermostable, but lime juice is weakened markedly by heat. Many of these juices are protected by the addition of acid—5 per cent. of lemon juice increasing the thermostability of cabbage juice—whereas, as we have stated, little is gained by cooking vegetables in an acid medium.

Potato.—The civilized world is dependent for its quota of antiscorbutic foodstuff largely upon the potato. It might be thought, therefore, that this would signify that the potato is endowed with great antiscorbutic power. Such is not the case, however, as demonstrated both by laboratory tests and clinical experience. Considering its importance, there have been surprisingly few feeding experiments carried out with potato. Holst and Froelich (1912) found that 17 g. of potatoes, steamed at 100° C. for 30 minutes, afforded but slight protection, and that it required 20 g. to fully protect a guinea-pig. Givens and Cohen failed to ward off scurvy by means of cooked potatoes fed to the equivalent of 5 g. of the raw vegetable (guinea-pigs will not eat raw potatoes). There are no accurate figures as to the quantity of potatoes needed to protect a human being from scurvy. The statement of Doctor Guy, however, who after careful study of convicts’ diets, concluded that 14 ounces daily would protect them from scurvy (if the ration included one ounce of other fresh vegetable and 4 ounces of meat), is probably close to the mark.[41] With the experience that potatoes play such a significant rôle in the prevention of scurvy, how are we to interpret the fact that they are only mildly antiscorbutic? Potatoes are consumed in very large amounts; in the Temperate Zone probably twice as many pounds of potatoes are consumed during the winter as of all other vegetables combined ([Fig. 1]). It is evident, therefore, that in a practical evaluation of antiscorbutic foodstuffs, not only the intrinsic antiscorbutic potency must be considered, but also the quantity of the vegetable or fruit consumed.

Swede.—We cannot leave the consideration of vegetable antiscorbutics without adding a few words as to the value of swede juice,[42] which has been recently highly recommended by Chick and Rhodes, who found it comparable to the cabbage and the onion, and even to orange juice. For example, 25 c.c. of raw swede juice were equivalent to 1.5 g. of raw cabbage. It is, therefore, more potent than the juice of raw carrot, and far more efficacious than the juice of the beetroot ([Table 3]). Tests carried out with this antiscorbutic in infant feeding seemed to show that it is of value in this field. The authors believe that the potency of vegetables is closely associated with certain botanical species, and that in this way the marked virtue of the swede can be explained, as it belongs to the natural order of Cruciferæ, which includes also the cabbage, the scurvy grass and the cresses. If, however, this is a rule of nature, it is difficult to explain the marked difference between the lime and the lemon, which are both varieties of Citrus Medica.

Dehydrated Vegetables.—For hundreds of years fresh vegetables have been dried to serve as food during the winter months and have fulfilled a useful purpose on account of their small bulk and great food value. The question for us to consider, however, is whether dehydrated vegetables still retain their antiscorbutic quality and can be counted on to supply this factor in the dietary. At present this subject is engaging the attention of laboratory workers as well as of practical dietitians and food hygienists. The experience of the past is not happy in this regard. In the Medical and Surgical History of the War of the Rebellion we read as follows: “A scorbutic tendency was developed at most of our military posts during the winter season, after the troops had been confined to the use of the ordinary ration with desiccated vegetables. The latter in quantities failed to repress the disease.” In spite of this and similar military experiences[43] the employment of dehydrated vegetables was urged recently for rationing our soldiers, the claim being made that “by simply soaking in water and boiling in the same water these vegetables are brought back to the condition of fresh vegetables.” Both in this country and in England there was strong propaganda during the war to dehydrate vegetables on an enormous scale and to substitute them for the fresh food.