Vitamins And Their Importance In Health
( Originally Published 1938 )
LET us go back in imagination to the year 1250, when the Seventh Crusade under that noble king, Saint Louis, was invading the Near East. A happy, hopeful band it had left France a short time before, each member sure that he would win his heart's desire,whether it was wealth, fame, love or oblivion. Most of them were young and all were tightly bound together by two of the strongest ties religious fervor and vibrant health.
How the picture changes when once the deserts of Egypt are reached ! But let de Joinville, who was Louis' biographer, tell us the story.
"While we were in camp," he wrote, "the only fish we ate during the whole Lenten season were mudfish and the mudfish ate the dead. And because of this misfortune, as well as the evilness of the country where not a single drop of rain falls, we fell sick, with a sickness that made our flesh and limbs dry all up, and the skin of our limbs become spotted with black and the color of the soil, just like an old boot,and the gums rotted; and no one contracted this malady but that he had to die of it. When the sign of death came a bleeding nose one had to die there was so much dead flesh on the gums that the barbers had to cut it away so that our men could chew their food and swallow. It was horrible to hear the men moaning when their flesh was cut away, for they moaned like women suffering the pangs of childbirth."
This is one of the earliest descriptions of scurvy or scorbutus, a disease caused by the lack of Vitamin C. It was probably known in the northern parts of Europe and Asia ever since they were occupied by man and it still menaces us.
Our knowledge of beriberi, another vitamin-deficiency disease, goes back even further. In old Chinese chronicles written almost 4000 years ago we find vivid descriptions of that disease.
Nevertheless vitamins themselves remained undiscovered and a mystery until 1912. Indeed their magic and mystery haven't been yet fully solved; so that anything we say today may be disproved, or at least modified, tomorrow by further revelations of medical science.
The vitamins, like the proteins and other food essentials, are chemical compounds. They differ from the elements that build tissue and supply energy, however, in that there is a far greater difference in the proportion between their nutritional functions and the amount necessary to perform them adequately. A man weighing 160 pounds has been estimated to require about 70 to 100 grams of protein daily, but his vitamin requirement is expressed in terms of milligrams! Sir Francis G. Hopkins, who has done much to help the cause of vitamins, as we shall see, estimated that a single ounce of Vitamin C would be sufficient to prevent 500 human beings from getting scurvy for a whole year.
Today we know of at least ten vitamins, each of which has its own chemical structure and its own definite functions to perform in the human body. Taking them as a whole, however, their functions may be divided into three broad classes. They promote the normal growth and development of the body, they protect the body against diseases and then insure the proper functioning or regulation of the bodily processes, including metabolism. And when the diet is deficient in one or more of the vitamins for a sustained period of time, grave diseases develop which may result in death.
The discovery of the vitamins is a fascinating story, and as it is one that helps to clarify their significance, let us pause here to relate the history of the discovery of these tiny but supreme rulers of our bodies.
The first glimmering that we needed something more than proteins, fats, carbohydrates, minerals and water in our diet to maintain life came in the 1880's. Before then chemists and physiologists had devoted their time to the study and analysis of proteins, carbohydrates and fats and it was the prevailing belief that they alone were essential to maintain health. But as time went on and experimental methods improved, it became obvious that a diet may contain the correct amount of calories and the proper balance of proteins, fats and carbohydrates and yet fail to meet the full demands of nutrition. To be sure, it had been observed for centuries that a diet of preserved foods or old foods would cause scurvy amongst soldiers, persons on long sea voyages and inmates of prisons. Experience had proved, too, that if certain fresh vegetables or fruit, such as oranges and lemons, were added to the diet, scurvy disappeared or was pre-vented. It was observed also that beriberi developed amongst the rice eaters of the Orient. But no one had been able to find out why this was true and most persons still held to the belief that these diseases were caused by "germs".
Then, about 1880, a quiet young scientist, but one with imagination, who was working in the laboratory of Dr. Bunge at the University of Basle in Switzerland, began experimenting with mice on a diet of milk. He fed some of the animals on natural milk and others on synthetically prepared milk containing all the elements in exactly the proportion as they occur in natural milk. The mice fed on the natural milk thrived but those fed on the chemically prepared milk soon died. He repeated the experiments, only to get the same results. He came to the conclusion that natural milk contained some mysterious, elusive substance a substance which was absolutely indispensable to life and which was undoubtedly destroyed in the process of preparing the synthetic milk. While these experiments of Lunin did not create much excitement, they reawakened an interest in nutrition and it marked the beginning of a series of dramatic discoveries that have offered new life and hope to humanity.
Such was the beginning of the discovery of what was first called "accessory food factors" by the chemists. The medical profession, however, especially in the East, was constantly coming in contact with gruesome, death-causing diseases which were apparently due to dietary deficiency. About the time that Lunin was working in Switzerland, Takaki, the medical inspector-general of the Japanese navy, was making a study of beriberi which was playing havoc with the Japanese navy. Beriberi is characterized in its initial stages by a catarrh and swellings and pains in the limbs which soon become paralyzed. As the paralysis gradually creeps over the whole body breathing becomes very difficult and before long the victim dies.
Takaki, firmly believing that the disease was not an infection, as was generally believed in his day, but was of dietary origin, made a comparison of the diet of the Japanese navy when it was on long voyages and those of the European nations. He found that the Japanese diet, consisting largely of "polished" rice, contained a much greater amount of carbohydrate and a much smaller amount of protein than those of the Europeans. He therefore recommended that the Japanese cut down on the polished rice ration and substitute unpolished rice and a larger complement of foods richer in proteins. Of course, his advice was scorned. He bided his time, however, for an opportunity to put his theories to a crucial test. The opportunity soon came.
While taking a nine months' cruise twenty-five men died on board a Japanese training ship. Shortly after another ship was sent on a cruise over the same route. This time the navy acceded to Takaki's earnest pleas. The ration contained fresh milk and meat and unpolished rice that is, rice not deprived of the husk. As a result, during the whole ten months. that the crew was at sea only fourteen cases of beriberi developed and only in those men who had refused to accept the changed diet. Needless to say Takaki became a national hero.
Takaki, however, believed that protein as con tained in milk and meat was the cause for the decrease of beriberi. He had missed this important fact, that it was the unpolished rice which contained "the preventive factor".
Then, in 1897 a startling discovery was made by a Dutch physician, Eijkman, who was stationed in the island of Java in care of prisoners. Among his prisoners Eijkman had many patients suffering from nervous disorders, strange swellings on their limbs and a certain incoordination of movements, symptoms similar to those of the Japanese sailors. It happened that he had a large number of fowls which he was using for some experiments. One day they all fell sick with much the same symptoms that his patients had. He called the disease polyneuritis to distinguish it from the form found in human beings. Learning that they were being fed cooked rice left over in the hospital kitchen, he replaced their diet with one of raw, unhusked rice and the fowls quickly recovered.
Eijkman then tried substituting unpolished rice for the polished rice amongst his patients who were suffering from the same disease, with the same result. He came to the conclusion missed by Takaki that the outer covering of the rice kernel contained some substance which acted as a protector against poly-neuritis, although he did not know it as a vitamin.
In succeeding years further studies were made by physiologists and biochemists in addition to the research done by doctors.
In the meantime, however, this latter group of scientists continued their researches and as early as 1905, Pekelharing of Holland observed that if a little natural milk was added to a diet which contained well balanced proportions of proteins, carbohydrates, fats and minerals, mice would not only live but would achieve a remarkable growth. The following year, Hopkins of England wrote that some minor factors in the diet were essential to life and the prevention of diseases such as scurvy. Six years later he published an account of his findings and called the substances in milk which were necessary for life, "accessory food factors". The year before, however, a German by the name of Funk, who was making a study of polished rice as a cause of beriberi, gave the name to the missing factor, "vitamine", derived from the Latin word for life and amine, because he thought the missing factor had something to do with protein and nitrogen. The word was soon accepted by the world of science and the factor necessary for the prevention of beriberi became known as Vitamin B. It was soon discovered that protein had nothing to do with vitamins, so, in 1922 Drummond suggested that the "e" be dropped in order to avoid confusion.
In the meantime in the United States two groups of experimenters were working independently on "the unknown substances essential to life". Osborne and Mendel at Yale devised a preparation of "protein-free" milk to which they added mixtures of pure starch, sugar and fat. They fed this mixture to white mice who kept alive for a longer period of time than ever before. But after a period of about 100 days, it was impossible to induce any increase in weight in the animals. When whole milk powder was substituted for the protein-free milk, the animals survived two generations.
They concluded that the difference was in the milk fat and substituted butter for lard. Those fed on butter-fat attained normal size.
While Yale scientists were proving that milk fat contained an element essential to growth, McCollum and Davis at the University of Wisconsin were experimenting along the same lines, and found that animals fed on purified casein, carbohydrates, lard and various salt mixtures were stunted in their growth, but that the same animals regained their vigor and normal growth when fed on egg-yolk fat or butter. They called this essential accessory food factor "Fat-soluble A". It is now generally known as Vitamin A. Many long and weary years had been consumed in the search for this unknown, but the scientists were amply rewarded: it was now established beyond doubt that butter fat and egg-yolk contained something necessary for normal growth that was not found in lard and the common vegetable fats.
Two years later the same experimenters, McCollum and Davis, discovered that if they replaced the milk sugar in their ration with starch, the animals no longer continued to grow, in spite of the fact that the diet contained sufficient butter fat. Moreover, the animals developed a paralysis which closely resembled the polyneuritis of the fowls with which Eijkman had experimented. When natural foods were added to the diet, the paralysis disappeared and the animals assumed their normal growth. The scientists discovered this time that the curative substance could be extracted with alcohol from the wheat germ or embryo. They called it "Water-soluble B" to distinguish it from Fat-soluble A. It was soon found that it was identical with Funk's substance and is, as we have said, now known as Vitamin B. Since that time, it has been found that Vitamin B is in reality a complex made up of more than one substance, each of which, as we shall later see, having its chemical characteristics and functions.
Oddly enough it was not suggested, however, that scurvy was due to a lack of a third essential food factor until 1913, and not until two years later was it pointed out by Dr. Alfred F. Hess that this potent factor was also contained abundantly in tomatoes. Some years passed and in 1919 it was definitely established that there really was a third accessory food factor Vitamin C.
During this time research was being carried on in another direction research on the relation between bone growth in children and their diet. This led to the identification of Vitamin D in 1922. The following year Vitamin E, necessary for reproduction, was discovered. Since then many new important discoveries have been made about the nature of the vitamins and their functions, such as the discovery of the pellagra-preventing vitamin G or B-2 by the late Dr. Joseph Goldberger in 1926. Nevertheless, there is still much to be learned, and probably much to be unlearned. Bearing in mind what has just been said, let us examine each of them in turn and see what, in light of present knowledge, they do for us and where we can best find them in our foods.
As all-efficient as man likes to believe himself to be, he could not exist without the aid of plant life, for the ultimate source of all vitamins and other necessary organic substances is the plant. This is true even when we eat the flesh of an animal or fish, or butter or milk.
The cow, for instance, eats the fresh sweet meadow grass that contains the vitamins or their precursors and then metabolizes them in a concentrated, convenient form for us. Neither we nor the vast majority of animals can synthesize the vitamins or other organic substances necessary for the maintenance of life. We are therefore entirely dependent on the plant world for our very existence.
Vitamin A perhaps illustrates this point better than any others. One of the five substances from which Vitamin A is formed is known as carotene, a yellow pigment found in most vegetables and fruits and which is particularly noticeable in green leafy vegetables and deeply colored ones such as the carrot. Indeed the very name carrot calls to mind the word carotene. When any of the precursors are eaten by man or any other member of the animal world, they are converted into the vitamin in the liver.
Vitamin A has a potent influence on general growth and vigor and is believed to increase the span of life. It helps to preserve the normal vitality of epithelial tissue, aids in maintaining a normal functioning of the glands, and what is very important it helps to build resistance against many dread diseases, such as xerophthalmia, a horrible disease of the eyes which results in blindness; tuberculosis, influenza and other respiratory diseases.
By influencing and preserving the normal growth of epithelial cells, Vitamin A acts as a first line of defense against the invasion of disease bearing bacteria. When there is a deficiency of this vitamin, the epithelial cells not only begin to lose their power as defenders against disease, but they also become hard and horny and offer an ideal opportunity for the growth and development of germs. The delicate mucous membrane linings of the mouth, the alimentary canal, the nose and sinuses, the kidneys and gall bladder are among the first to suffer. The tear glands, too, no longer produce tears and as a result the eyeball and tissues of the underlying glands dry up. Xerophthalmia develops and if the cornea is attacked, the victim becomes blind.
Fortunately there are but few instances of xerophthalmia in the United States, although cases of night-blindness caused by a mild deficiency of Vitamin A are frequent. Children especially seem to be victims of night blindness, but when a carefully selected, well balanced diet to which cod liver oil is added, is given them, they may be cured within a few days.
It is believed that when there is a great deficiency of Vitamin A in a woman's diet sterility develops because the creation of the mother cell in the womb ceases. Likewise, in the case of a man, the epithelial cells lose their vitality and degenerate and in the end there may be a permanent impairment of the sexual functions. Moreover, Mellanby found that fifty percent of women who did not have a sufficient amount of the vitamin stored in the liver, developed a bad fever after childbirth, while among those treated for such a deficiency only three out of two hundred developed fever.
Before continuing the discussion of Vitamin A, we should give a word of warning regarding the popular misconceptions of the rôle that Vitamin A plays in the warding off of respiratory infections and in the promotion of normal growth and vigor. These misconceptions are largely due to advertising, probably the principal source of the average person's knowledge of vitamins. It is rarely, particularly in the wintertime, that one can pick up a newspaper or magazine without seeing glaring headlines commanding us to eat such-andsuch food if we wish to go through the season without catching cold, or if not commanding us, threatening us with this uncomfortable nuisance or even worse. As a result most of us get the erroneous idea that Vitamin A acts more or less like an antitoxin for diphtheria or smallpox. This is far from the truth.
For the present, at least, we can only say that Vitamin A merely aids in establishing bodily resistance to infections. And it only aids when the supply of Vitamin A stored in the body has been exhausted and the intake is inadequate.
"It certainly has not been shown to be a specific in the prevention of colds, influenza and such infections," observes the American Medical Association, "nor has it been demonstrated that ingestion of Vitamin A far in excess of that necessary for normal body function and readily obtained from a properly selected diet is an aid in preventing various types of infections."
The same erroneous conceptions are met with concerning the growth promoting powers of Vitamin A. While it is true that a deficiency of Vitamin A slows up normal growth when the body store of it has been exhausted, it is also true that the other vitamins, the food elements and amino acids are equally important in the attainment of normal growth.
"Statements conveying the impression that Vitamin A is more important in promoting growth than any other food essentials are therefore considered misleading and objectionable," is the verdict of the American Medical Association.
We have briefly summarized the functions of Vitamin A and the symptoms which result from its deficiency in the diet. They are mighty serious, of course, but don't be alarmed if perchance you haven't had your weekly quota, for xerophthalmia or sterility won't result right away. You'd have plenty of warning to correct the deficiency before these tragedies would occur. You'd first experience a loss of appetite and a lack of vigor, accompanied by diarrhoea; your skin would become dry and your body would offer poor resistance to infections; night-blindness would develop and if you were still in the growing state, your growth would show signs of retardation. Not until the deficiency became very marked would xerophthalmia develop and the various infections entering through the epithelial tissues. Loss in weight, debility, sterility and the atrophy of the glands are also the result only when the vitamin deficiency is very marked.
While the ultimate source of Vitamin A is the green leaves of plants, it was first discovered in combination with fats butter, egg yolk and cod liver oil, all of which are rich in Vitamin A. Other animal products which are excellent sources are cheese, cream and milk, fish roe, halibut liver oil and liver. Animal products ranked as good sources are beef fat, kidney, sweetbreads, the heart, herring and oysters.
In the vegetable kingdom we find kale, escarole, green lettuce, string beans, spinach, watercress, Brussels sprouts, broccoli, and parsley. All yellow fruits and vegetables are rich in this vitamin yellow turnips, corn and sweet potatoes. White or pale colored vegetables are a poor source and with the exception of the carrot, roots and tubers are likewise a poor source. Among the fruits the apricot and tomato have a high Vitamin A content, the latter having almost eight times as much as the orange.
Since the temperatures used in canning do not destroy appreciable amounts, the Vitamin A content of most canned foods is practically the same as that of the fresh foods. It is moderately sensitive to oxidation and when butter is exposed to sunlight for a long period, much of its Vitamin A content is destroyed. Likewise, the Vitamin A content of cod liver oil becomes unstable when exposed to sunlight, especially in the presence of oxygen. It is for this reason that it is sold in dark bottles and stored in a dark place.
As to the amount of Vitamin A one should eat, don't bother your head about the puzzling "units" and milligrams. If you eat plenty of fresh vegetables and fruits and eggs and milk, you'll get all you need. Just remember to eat a balanced diet with plenty of fresh, appetizing fruits and vegetables that are to your liking and the vitamins will take care of themselves. But remember, too, that Vitamin A can be stored and that when you are storing Vitamin A, you're storing vigor, resistance to disease and consequently happiness.
In the history of beriberi, polyneuritis and the discovery of Vitamin B, we alluded to the fact that this vitamin is often called "the Vitamin B complex". This is because it has been recently discovered that what was once thought of as a single vitamin, can be divided into at least six different substances, all of which, incidentally, are found in fresh yeast. These factors are similar in their chemical structure and properties, but the most important are the beriberi and pellagra preventing factors which are known sometimes as B1 and B2 and sometimes as Vitamin B and Vitamin G. In this discussion we shall call the beriberi preventing factor Vitamin B and that associated with pellagra, Vitamin G. In order to avoid confusion they will be treated separately, but it must be kept in mind that they are present in many foods in an undifferentiated degree and proportion.
Vitamin B is necessary for the maintenance of the normal condition and functioning of nervous tissue and in this respect acts as a preventative and corrective for beriberi which is a degenerative disease of the nervous system. It is also of great value in securing optional growth in infants and children. It stimulates the appetite and aids the processes of digestion and assimilation, There are also indications that it has an influence on intestinal motility or peristalsis and neuritis of various types. It is also believed that Vitamin B is related to carbohydrate metabolism and that its requirements are greatly increased when the metabolic rate is higher as in various types of neuritis, hyperthyroidism and infections.
One of the first signs of a deficiency of Vitamin B intake is a poor appetite and accompanying digestive disturbances. When the appetite fails no amount of forced feeding seems to help, for the digestive glands do not secrete the proper amount of the digestive juices. As a result the time required for the passage of food through the stomach and intestines is twice as long as under normal conditions.
Recently some English investigations showed that a deficiency in Vitamin B produces an abnormal slowness of the heart beat. It was proved that this was actually produced by a specific lack of the vitamin, and by an insufficient food intake.
Other symptoms of a mild deficiency of Vitamin B are nervousness accompanied by trembling hands, a hesitant outlook on life and a general debility, decreased lactation or milk production and poor glandular functioning in general.
The lack of Vitamin B may also cause paralysis and polyneuritis, convulsions, loss in weight, intestinal infections such as colitis, weakening or atony of the stomach and atrophy of the glands. With respect to the last, deficiency of Vitamin B causes the male's interest in the female to wane and the tissues of the sex glands to degenerate. In women it results in a failure to produce healthy offspring or a failure to produce at all. Ovulation ceases and as in the case of the male, the sex glands degenerate.
The richest sources of the vitamin are brewers' dried yeast and cereal germs and bran. The liver, heart, kidney, egg yolk, milk, mutton, pork, fish roe and oysters are good sources from the animal kingdom. Asparagus, peas, peppers, peanuts and the soy bean are very good sources from the plant world. Other good sources are cabbage, carrots, spinach, watercress, Iettuce, tomatoes, cauliflower, kale, beets, onions, apricots, apples, berries, grapefruit, pineapple, dates and various nuts such as hazel nuts, almonds and Brazil nuts.
Vitamin B is comparatively stable to dry heat, but when food is cooked in water, more than one-half of the anti-neuritis factor is dissolved. This may be remedied in several ways. From the French, who are famed as the best cooks in the world, we have learned to utilize the water in which vegetables have been cooked. Not only does it make the various vegetables far more delicious, but it gives us the benefits of the vitamins and the minerals. Or, if such a procedure does not suit your fancy or the particular dish of the moment, the loss may be reduced by steaming or using very little water.
The effect of canning is variable, although generally speaking there is no appreciable loss. Commercially canned tomatoes, peas, carrots, peaches and pineapple have shown little diminishment in their Vitamin B content.
Children apparently need more of this vitamin than adults. Not only does its deficiency cause a chronic loss of appetite which is known technically as "anorexia" and digestive disturbances, but also the stoppage of growth and eventually death. Clinical evidence has proved that the lives of many children have been saved by the proper and timely administration of foods containing large amounts of Vitamin B, such as liver, kidney and wheat embryo and brewer's yeast. While it still must be demonstrated to what extent Vitamin B lowers infant mortality, it has been valuable in correcting "summer diarrhoea", that dread of all parents, since 20 to 30 per cent of all infants die yearly from digestive disturbances.
Vitamin G or Vitamin B2 is sometimes called the antipellagric vitamin for it is believed that it is related to the cure and development of this disease.
This disease is characterized by skin lesions, a sore mouth, red tongue and digestive disturbances. In its final stages, lesions of the spinal cord develop which spread throughout the entire nervous system, causing insanity and very often death. It has been known in Spain and northern Italy since the beginning of the eighteenth century. An Italian physician of this period gave it its present name which means "rough skin". In the beginning of this century it appeared in the United States where it still reaches alarming proportions in the cotton belt of the South.
In addition to probably preventing pellagra, Vitamin G has a definite rôle in improving growth, promoting good health and prolonging the plan of life. A mild deficiency is characterized by digestive disturbances, general lassitude and impaired growth. With regard to the latter, recently experimental evidence has been produced to the effect that Vitamin G is in reality two dietary factors one which prevents pellagra and the other which promotes growth, tentatively called Vitamin Y. Poor lactation in the female, impairment of the respiratory tissues and a shortened life are other effects of a partial deficiency.
Pellagra and the accompanying symptoms which we have already described are in all probability the result of an extreme deficiency. Such a deficiency also causes cataracts, anemia, loss of hair, loss in the body weight of the intestines and general atony.
The best sources of Vitamin G are milk, the liver, kidney, heart, pork, eggs, cheese, brewer's yeast, beet tops, broccoli, kale and the wheat germ. Other good sources are beef, veal, salmon, tomatoes, asparagus, cabbage, cauliflower, spinach, and other green vegetables.
Vitamin G is stable to heat and therefore little of its potency is lost in canning and cooking.
Eat as much as you like of this vitamin and the more the better for it is stored in the liver and muscles and is eventually utilized in some way. If this seems like a vague order, one quart of milk or a half-pound of lean meat or an ounce of yeast daily will certainly give you enough protection. But remember, as far as yeast is concerned, its effects on the human body in concentrated form are not yet fully known and many of the claims made for it may be utterly unfounded so, therefore, except under the guidance of your doctor, it is best to stick to the more usual foods.
You are probably still shuddering over de Joinville's lurid description of scurvy, so there is no need to dwell further on this dread disease due to the lack of Vitamin C. The absence of scurvy, however, by no means signifies that you are well supplied with, this vitamin for scurvy is the result of extreme deficiency. It is believed to have many other functions. For example, there is evidence that it is essential for a healthy, normal condition of the endothelial cells, that it improves the appetite and stimulates growth. It is necessary for proper tissue respiration and for glandular functions. It protects the vascular system and in some way is involved in the defense mechanisms against bacterial attacks. Many authorities believe that it favors good tooth development and acts as a safeguard against pyorrhea which may be related to scurvy bleeding gums, it will be recalled, was one of the first symptoms of scurvy.
A mild deficiency of Vitamin C is connected with weakness, restlessness, poor resistance to infections,digestive disturbances, headaches, defective teeth, retarded growth, lesions in the endothelial tissue and tender joints.
Effects of extreme deficiency are hemorrhages, swollen joints as well as gums, loose teeth, fragile bones, paralysis, sterility, respiratory and intestinal infections, as well as scurvy.
The tomato is one of our chief sources of Vitamin C and the tomato juice cocktail now graces the breakfast table of almost every American home, as well as the menu of the finest hotels and of the humblest drugstore soda fountain. Oranges, grapefruits and lemons are also excellent sources. Indeed, most of the foods that are low in calories seem to have a high Vitamin C content a godsend to all those bent on reducing. Cabbage, cantaloupe, watermelon and berries, spinach, peppers, and sprouted grains and legumes are all rich in Vitamin C. Apples, bananas, potatoes, the liver and brain are considered good sources, too.
Vitamin C is generally destroyed by drying and open kettle cooking, but not so much by steam cooking. Short cooking at a high temperature is much better than slow cooking at a low temperature. Commercially canned foods have a much larger amount of this vitamin preserved than home canned foods.
There has been no evidence that large amounts of Vitamin C produces ill effects on the human organism, so that you can consume as much as you like without fear.
It is wonderful to think that the sun, 93 million miles away, is the source of all things living on earth the trees, the flowers, the birds, the animals and us human beings. Without the sun the earth would be a cold and lifeless planet. It is still worshipped by many peoples as the giver of life and of health, yet not until a few years ago did it become known that the sun is the creator of Vitamin D, the "sunshine" vitamin so plentiful in cod liver and haliver oil and so necessary for the prevention of rickets, the commonest of nutritional diseases amongst children of the temperate zone.
Rickets may appear as early as the third month after birth. It is characterized by constipation, irritability, restlessness and loss of sleep in its earlier stages. The muscles of the legs, arms and abdominal region become lax. Later the ribs develop knobs or beads and "pigeon" breast develops. The head acquires a peculiar square shape and the long bones become bowed and curvatures of the spine develop. The sufferers from rickets are usually very sensitive to touch, they may have a slight fever and perspire profusely. They are stunted in their growth and are susceptible to respiratory infections which may lead to death. After the third year rickets are no longer active in form, although still active in effect.
While rickets is a disease of childhood, there is a similar disease known as osteomalacia (softening of the bones) which may develop in adults. It exists almost entirely among Mohammedan women in the East and is the result of the secluded life they practise. It is characterized by softening of the bone, hysteria and extreme muscular pain. It is soon curbed by the administration of cod liver oil.
In addition to the prevention of rickets, Vitamin D has an important part in tooth formation and in the maintenance of normal, healthy teeth. However, the cause of dental caries is in all reality still unknown and there is little evidence to prove that Vitamin D insures normal tooth formation or will actually prevent decay. All that can be said is that it is apparently a favorable influence towards normal teeth.
Vitamin D is also a potent factor in calcium and phosphorus metabolism and is therefore needed even after full growth is attained and the danger of rickets is long passed.
The principal source of this vitamin is sunshine itself. The ultraviolet rays of the sun fall on the skin and convert the tiny deposits of ergosterol, a component of cholesterol, a substance found in all animal tissue. Ergosterol is now considered a precursor of Vitamin D and is sometimes called "pro-Vitamin D", Vitamin D has been produced in a crystalline form by ultraviolet irradiation. The natural vitamin has not been isolated as yet and it is not known whether it is wholly identical with the artificially produced article.
Irradiated ergosterol is produced for medicinal purposes from yeast and is known to the medical profession as "Viosterol" "bottled sunshine". It is used for rickets as well as for pregnant and nursing mothers and premature babies. However, it cannot be used except by the advice of physicians.
There is very little Vitamin D in natural foods but a few green vegetables contain it. In addition to cod liver oil and halibut liver oil, it is found in butter, liver, salmon and sardines. Whole milk, egg yolk, beef fat, clams and oysters also are good sources of this vitamin. It may also be ingested in foods such as bread, ice cream, milk and even beer, which have been reinforced either through irradiation or by the addition of the concentrated form.
Vitamin D can be cooked or stored since it is unusually stable to heat, alkalis and acids and is quite stable to oxidation.
The daily intake requirements of this vitamin is small and varies. It is known that infants require more than adults, but beyond the age of infancy, the amount necessary for good health is not known. However, there is no danger from too much Vitamin D as long as it is taken in the form of natural or artificially reinforced foods, but it should not be taken in a concentrated form without the advice of a physician.
Ten years ago scientists were greatly puzzled by the fact that experimental animals who were apparently fed on a well-balanced diet and who were lively and healthy failed to produce offspring. Finally H. M. Evans of the University of California solved the mystery certain foods contained a special fertility factor which is now known as Vitamin E. It was also revealed that Vitamins A and B played a vital part in fertility. The absence of the former interferes with ovulation while the lack of the latter causes the sex glands to degenerate. In animals a deficiency of Vitamin E caused the destruction of the germ cells in the male and impaired the placental function in the female. As yet, however, there is no evidence to indicate that Vitamin E corrects sterility in human beings, and it must be remembered that not one of the vitamins related to reproduction provide fertility they merely serve as aids to fertility and the prevention of sterility. Whether Vitamin E is related to human fertility is a matter which should not give you much concern, for this vitamin is so widely distributed in nature that it is seriously doubted that human sterility could ever be attributed to it. Besides it can be stored up by the body. It is found in nearly alt green leaves and whole cereal grains, as well as in meat and eggs.
It is quite stable to heat, light and air, but is highly susceptible to oxidation under certain conditions, such as the changes which occur in fats when they become rancid.
You probably feel by this time that you'll never be able to eat a mouthful of food without thinking of vitamins and wondering whether you are developing some of the various dreadful symptoms we've just described perhaps you feel that you have them this very minute. In reality, vitamins per se should not be taken too seriously by the average person. Living in an era when fresh food is abundant all year round and scientific methods of preserving retain almost the full value of the various components of foods, you are sure of getting all the vitamins you need if you eat a well balanced diet containing plenty of fresh vegetables and fruit, meat, fish, eggs and milk. Besides the vitamins would be of no avail without energy producing foods and their component minerals. And no food is going to do much good if you don't see to it that your whole alimentary canal, from your mouth to your colon, is in good condition.
And by no means take it upon yourself to take vitamins in a concentrated form not even through a so called sun lamp. If you feel tired, have no appetite or can't sleep, or have more serious symptoms, consult your physician and not your well meaning neighbor or friend. It takes years of study and practice to diagnose diseases or functional disturbances, and it is more than likely that the lack of vitamins providing your diet is correct is not the source of your trouble.
As we pointed out in the beginning of our discussion on the vitamins, new discoveries are being constantly made. Even since the writing of this chapter the results of more recent experiments have been published.
"Vitamin F," for example, is a comparatively recent new-comer. But whether it is really a vitamin or an unsaturated fatty acid, only further research will tell. It may be associated with Vitamin B in certain cereals and it may be present in milk and codliver oil. At any rate, it is now incorporated in some soaps, face creams and even permanent wave lotions on the grounds that it might be of value in maintaining normal skin and other epithelial tissue and in preventing certain skin lesions.
Vitamin H is another recently discovered vitamin. Clinical studies point towards a possible value of this vitamin in a type of baldness called alopecia arcata, as well as in psoriasis, status seborrhoicus and eczema of an allergic origin. The liver and kidney are the richest sources of Vitamin H and it is also found in dried yeast. It is not commercially available as yet, the only concentrates reported being used for research purposes.
Vitamin K is a fat soluble vitamin which has been found in cereals, some vegetables, hog liver and hempseed. Green vegetables at present seem the richest sources and concentrates have been prepared from dried alfalfa. Research indicates that it is possible that certain diseases which are characterized or followed by a retarded clotting power of the blood, such as hemophilia, may be related to a lack of Vitamin K.
A group of scientists recently isolated a substance from lemon juice called "citrin". Clinical tests showed that citrin was responsible for beneficial effects obtained in the treatment of patients suffering from diabetes, myxederaa, vascular purpura and infectious diseases. Because in many diseases the permeability of the walls of the capillaries to albumin is controlled by citrin, it was given the name of Vitamin P, the "P" referring to permeability.
Much work has also been done on the skin absorption of vitamins. Many authorities are convinced, for example, that Vitamins A and D are not only absorbed, but are directly utilized by the skin.