This section is from the book "The Potato: A Compilation of Information from Every Available Source", by Eugene H. Grubb, W. S. Guilford. Also available from Amazon: The Potato: A Compilation Of Information From Every Available Source.
Definite knowledge in regard to, the world's greatest food crop is very meagre. This is true not only of the mass of consumers, but even doctors and cooks, who should be well informed on every subject pertaining to food.
One of the greatest authorities on food in the world is Dr. J. H. Kellogg, superintendent of the Battle Creek Sanitarium, Battle Creek, Mich. He has spent a lifetime in the study of the various articles of food, his investigations covering all possible sources of information, not only in America, but in Europe. The following article on "The Special Dietetic Virtues of the Potato," by this foremost authority, is one of the best ever written about the potato:
Soon after the potato was introduced into Europe in the sixteenth century the ridiculous notion somehow got afloat that the use of the potato was the cause of leprosy, which at that time was quite prevalent in most European countries. The prejudice which was thus created against this most valuable of all garden vegetables has never been quite overcome. Various malicious libels against the good name of this most innocent and wholesome of foodstuffs are still afloat. Multitudes believe the potato to be difficult of digestion. Even physicians often prohibit its use on the supposition that it is likely to ferment in the stomach - a mistaken notion, as the writer will show. The belief is quite general that the potato especially promotes fat-making, and hence that its use must be avoided by persons who have a tendency to obesity. This is also an error. All foods tend to produce obesity when taken in excessive quantity; that is, more than the individual needs to maintain his nutrition on equilibrium. No foods produce excess of fat when limited in quantity to actual daily bodily needs." The potato is truly a most remarkable product.
It contains within its aseptic covering a rich store of one of the most easily digestible of all forms of starch. The observations of Mosse, Von Noorden and others have shown most conclusively that the starch of the potato is more easily digested and appropriated by the body than the starches of wheat, corn, and most other cereals. In laboratory tests made by the writer it was found that potato starch digested in less than one sixth of the time of cereal starches. The experience of hundreds of physicians in the treatment of diabetics has shown that in many cases the starch of the potato is more easily assimilated or better utilized than other forms of starch.
Potato gruel made from specially prepared potato meal or the pulp of baked potatoes has been found in Germany of very great service in the feeding of infants and invalids. Potato starch is far better for this purpose than cornstarch, arrowroot and similar substances which are pure starch and cannot be properly considered as foods. The long continued use of these starches in the feeding of young infants often results most disastrously.
Dr. J. H. Kellogg.
Battle Creek Sanitarium, Battle Creek Mich.
Illustration shows desirable and undesirable types of potatoes before paring.
Same potatoes after paring. At the left is shown Dalmeny Challenge potato. The unpared tuber weighed 13.4 oz. and the parings 1.7 oz. or 12.6 per cent. In the centre is shown the Mc-Cormick potato. The unpared tuber weighed 13.9 oz., and the parings 3.2 oz., or 23.2 per cent. At the right is shown Red Peachblow potato. The unpared tuber weighed 9.5 oz., and the parings 1.2 oz., or 12.4 per cent.
The potato is not only an easily digestible foodstuff but possesses much higher nutritive value than is generally supposed. According to Gautier, about one fourth of the weight of the potato is food substance, consisting chiefly (nine elevenths) of starch. Of the remainder, three fifths are protein, the tissue-building element, and two fifths alkaline salts in combination with citric and malic acids, the acids of the lemon and the apple.
From a dietetic standpoint, the potato is perhaps slightly deficient in protein, though this statement would be disputed by some physiologists whose experiments appear to demonstrate that the amount of protein contained in the potato is quite sufficient for ordinary bodily needs.
The potato is certainly deficient in fats, of which it contains almost none, because of the fact that it is not, like so many of our vegetable foods, a seed, but a curiously modified and enormously fleshy tuber. This deficiency in fat must always be remembered in the use of the potato, and the lack must be made up by the addition of cream, butter, or some other foodstuff rich in fat.
What the potato lacks in fat and protein, however, it makes up in salts, which constitute nearly 5 per cent, of its dry substance and are perhaps its most characteristic quality from a dietetic standpoint and one of its chief excellences. These salts consist chiefly of potash, arid in the ordinary form in which they are supplied do a most important service in maintaining the alkaline condition of the blood, which is essential to good health and resistance to disease. Meats contain a very great excess of acid-forming elements and tend to acidify the blood. Cereals have some tendency in the same direction. The lowering of the alkalinity of the blood by acid-forming foods, especially by the free use of meat, is unquestionably one of the chief causes of the rapid increase in chronic diseases, the mortality from which has doubled within thirty years, causing a loss annually of 350,000 more lives than would occur if the average citizen was as healthy as he was thirty years ago. This is probably also one of the chief causes of arteriosclerosis, or hardening of the arteries, gout, rheumatism, Bright's disease, apoplexy, and other degenerative maladies. The alkaline salts of vegetables are needed to balance the dietary. If the consumption of potatoes in this country could be quadrupled, the result would undoubtedly be the saving of many thousands of lives annually and an incalculable amount of suffering from disease.
The great nutritive value of the potato, notwithstanding the fact that it is three fourths water, may be best shown by comparing it with other known foods. A study of the nutritive value of various common foodstuffs shows that one pound of baked potato is equivalent in total nutritive value to the quantities of various foods shown in the following table:
Food Equivalent in Total Food Value to One Pound of Baked Potato.
1 1/5 pounds of boiled potato.
5 7/8 ounces boiled beef.
1 pound of chicken.
1 1/2 pounds of codfish.
2 1/4 pints of oysters (solids)
4 pints of clams (in shell)
4 1/2 pints of beef juice.
10 pints bouillon or beef tea.
1 1/2 pints whole milk.
3 pints skimmed milk.
9 ounces baked beans 7 ounces bread.
1 3/4 pints oatmeal or corn meal mush.
1 1/3 pints hominy (cooked).
1 pint boiled rice.
1 pound of bananas.
2 pounds parsnips (cooked).
1 pound green peas (cooked).
3 pounds beets (cooked.)
4 pounds boiled cabbage.
4 pounds radishes.
5 pounds tomatoes.
5 pounds turnips (cooked).
6 1/2 pounds cucumbers.
From the above table it will readily appear that the potato is one of the most nourishing of our common foods. Its value is still further emphasized by the fact that steamed or mashed potato digests in two or three hours, whereas roast beef requires four to five hours, or double the time (Gautier).
As already noted, the potato is not rich in protein, although the amount of this element in the baked potato reaches the Chittenden standard of 10 per cent of the total nutritive value, a proportion which in feeding many thousands of persons, those in health as well as invalids, at the Battle Creek Sanitarium, we have found amply sufficient. The writer adopted personally a very low protein standard in early life and has adhered to it for more than forty-six years, and with great benefit. Nevertheless, if a larger amount of protein is required, it may easily be obtained by the addition of milk or eggs, substances which while increasing the proportion of protein also add the fat necessary to render the potato a complete food. Half a pint of rich milk will thus balance a pound of baked potato; or an equally good balance may be made by adding to a pound of potato two ounces of white bread (two ordinary slices) and an ounce of butter.
Bunge, the world's greatest authority on the chemistry of foods, has called special attention to the importance of the alkaline salts that are found in vegetables, and in a much larger proportion in the potato than in any other vegetable used as food, the potato containing nearly forty times as much of this useful element as some cereal foods. No farmer would think of feeding his horses or cattle on grain alone. Cereals of all sorts contain a considerable excess of acid-forming elements. Grass and herbage of all sorts, as well as fresh vegetables, contain an abundance of alkaline salts, and hence are a necessary part of the diet of animals. Human beings, as Bunge has clearly shown, require such vegetables for the same reason, and the potato is the most valuable of all known foods as a source of these essential elements. This is perhaps the reason why the potato is an almost invariable accompaniment of meat dishes. Meat contains an enormous excess of acid-forming substances, which are to some extent neutralized and anti-doted by the basic salts of the potato.
Graham bread with butter, or beans with butter, however, are much better combinations with potato than meat, for the reason that both meat and potato are lacking in lime. The body requires about thirteen grains of lime a day. Meat contains but half a grain of lime to the pound. The potato contains only about a grain and a half to the pound. Wheat flakes and other whole wheat preparations contain four grains of lime to the pound, and peas and beans contain eight grains of lime to the pound. Cow's milk contains fourteen grains of lime to the pint. The American people are losing their teeth, and bone diseases are increasing, as a result of this deficiency of lime. Professor Sherman of Columbia University declares that half the people of the United States are suffering from lime starvation. This is in part because of the meat diet and free use of cane sugar. Less meat, a larger proportion of potatoes, combined with wheat preparations and other cereals, beans, peas, and cow's milk would help to check this degenerative tendency.