Fitness

In the small intestine, both vitamin A and carotene must combine with bile salts before they can pass into the blood. If the diet is low in fat, little or no bile reaches the intestine, and 90 per cent of both carotene and vitamin A may be lost in the feces. Not all the carotene which reaches the blood is changed into vitamin A. Unless the vitamin-E intake is adequate, any vitamin A reaching the blood is destroyed, and any already stored is quickly used up. Vitamin A cannot be stored if the B vitamin, cholin, is undersupplied. When one considers all of these points, one wonders how people have obtained enough vitamin A to stay alive.  If you plan carefully, however, you can probably buy 50 times more vitamin A with the same amount of money this week than you did last; some of it will certainly be absorbed, and there may even be an excess for storage. Select your fruits and vegetables for their yellow or green color. Serve liver, kidneys, cheese dishes, or an egg souffle more often than roasts, chops, and steaks. Use storage butter and eggs rather than winter products. Grow carotene-rich vegetables in your garden and freeze them for winter.  Since carotene and vitamin A dissolve in fat, and since fat can be stored in the body, this vitamin is stored, provided an excess is absorbed and not destroyed. The vitamin is stored largely in the liver; the amount can be doubled if the intake of vitamin E is adequate. This stored vitamin A can be called upon to meet your needs whenever your diet is inadequate. Experimental animals, given an excess of the vitamin A, store a hundred times more than is necessary to produce all appearances of good health. Analysis of human livers indicates that the same is true of people. Animal experiments show that a generous storage of vitamin A is advantageous during both health and disease.  Toxicity to massive doses of this vitamin has been reported when halibut-liver oil has been taken by tablespoon rather than by drops. The toxic amount appears to be approximately 10,000 times the daily need. Physicians have frequently recommended curative doses of 200,000 units daily for months, and children have been given 300,000 units daily 5 over long periods without apparent harm. Even when toxic doses are taken, the damage can be prevented or corrected by an increased vitamin-C intake (ref. 2, p. 36). The only food known to contain a toxic amount of this vitamin is polar-bear liver. (If you are served polar-bear liver, watch yourself.)  There is little if any evidence that vitamin-A deficiencies can be more quickly overcome by taking amounts larger than 100,000 units daily; much research indicates that no more than 50,000 units per day can be well utilized. The addition of vitamin E in amounts of 100 units (not milligrams) daily has been found to double the curative effect of vitamin A.  Doses of vitamin A are also more effective if taken in small amounts twice or three times daily rather than at one time. The Council on Pharmacy and Chemistry of the American Medical Association 6 has approved the following therapeutic doses: 25,000 units three times daily for prolonged or chronic deficiency; 25,000 units twice daily for two months for general treatment. They have not approved any single dose larger than 25,000 units.  The amount of vitamin A needed by healthy persons varies widely with each individual. Adults require more vitamin A than do children because the vitamin is needed in proportion to body weight; men usually require more than do women. Aged persons often utilize their food less well and therefore appear to need more of most vitamins than do younger adults. The requirements also vary with intensity of light, use of eyes, season, source, amount absorbed, and intake of vitamin E. One individual may thus require two or three times more than another of the same weight and degree of health. Moreover, when the vitamin is supplied by carotene, twice as much is needed as when it is supplied by vitamin A itself. Obviously no exact rules can be laid down. Since an excess can be stored to great advantage and only massive doses are toxic, it seems wiser to err by obtaining slightly too much rather than too little.  Dr. Henry C. Sherman, when at Columbia University, carried on experiments to determine the amount of vitamin A used advantageously by animals. A certain quantity of the vitamin allowed the animals all the appearances of goqd health. When that quantity was doubled, tripled, and quadrupled, signs of greater health, greater resistance, and greater vigor were evident, and with each increase the life span was lengthened. Beyond that point, increases brought no further improvements. Based on these experiments, Dr. Sherman recommends 20,000 units of vitamin A daily for adults, or four times the amount which usually gives the appearance of good health.  Considering that the vitamin-A content of foods varies widely and that the absorption is undependable, I see no way by which one can be reasonably sure his vitamin-A intake is adequate without taking a supplement. I believe that recurring symptoms of vitamin-A deficiency can be expected in the majority of persons who fail to take this precaution. Any fish-liver-oil concentrate should be taken immediately after the meal containing the largest amount of fat. Capsules of vitamin-A acetate are now available which can be absorbed without the presence of fat; these may be superior to other forms. The amount of vitamin E needed to prevent the destruction of vitamin A is not known; I have recommended 50 units of vitamin E as mixed tocopherols for each 25,000 units of vitamin A. I usually recommend capsules of fish liver-oil supplying 25,000 units each; they are economical and can be taken daily, every other day or even every fifth day, depending on the amount of vitamin needed. You alone must make the choice, depending upon how high your ideals for health are.  

In many books on nutrition including my own, there are tables of food analysis, giving quantities of nutrients in standard servings. Years ago I read a criticism of such tables; the writer held that they should not be published because foods grown on different soils and under different conditions, harvested, handled, and processed by different methods contained different amounts of nutrients. At the time I disagreed violently with the writer; now I agree as violently with him. When I read the statement that apricots or other foods are rich in such nutrients as vitamin A, iron and copper, my only reaction is: Which apricot? Grown where?

Studies have been made of the mucous membranes of animals fed different amounts of vitamin A. It was found that harmful bacteria were always present. The animals deficient in this vitamin had millions of bacteria feeding off their dead cells, however, and 98 per cent showed infections; those fed adequate vitamin A harbored few bacteria and showed no infections. Microscopic studies of the mucous membranes of hundreds of humans dying from accidental death or infection show similar correlations; there is freedom from an accumulation of dead cells and from infections; or the number of dead cells parallels the severity of the infections. Furthermore, the liver tissue of adults meeting accidental death has been found to average 20 times more vitamin A than that of persons dying from infections or infectious diseases.

The absorption of adequate vitamin A will correct deficiency symptoms, the length of time depending on the amount of vitamin given, the severity of the deficiency, and the tissues affected. Studies have shown that improvement in mild eye symptoms has occurred in as little as one hour after 50,000 to 100,000 units of vitamin A have been given. On the other hand, when the deficiency is severe and the vitamin dosage small, normal night vision may not be recovered for weeks or even months. In correcting mild visual abnormalities, the vitamin need merely be absorbed into the blood and carried to the ocular fluid. Recovery from corneal ulcers or changes which have occurred in the skin and mucous membrane, however, means that new tissue must be grown to replace the unhealthy tissue produced during the deficiency. It has been reported that the dryness of skin has disappeared and the lubricating oils have returned in as short a time as two weeks after dietary improvement; it has been my experience, however, that a longer interval is needed for recovery.

Some years ago a physician referred to me a woman whose face was covered with hundreds of large warts. A number of reports had pointed out that warts often disappeared when the diet was made adequate in vitamin A. I therefore planned a nutrition program for her, making it as adequate in all nutrients as I possibly could, and suggested that she take 100,000 units of vitamin A daily. When her skin showed no change after four months, we both became discouraged. A week later she came to see me, greatly excited. Not a wart remained, nor has one returned since then. This case convinced me that it takes approximately four months for unhealthy tissue to be replaced by healthy tissue, although probably wide individual variations should be expected.

Aside from helping to maintain normal vision and resistance to infections, adequate vitamin A is essential to the development of bones and the tooth enamel, good appetite, normal digestion, reproduction, lactation, and the formation of both red and white blood corpuscles. It appears to delay the onset of senility and to promote longevity. Vitamin A also has a profound influence upon development before birth.”

The National Research Council has recommended that an adult have 5,000 units of vitamin A daily to maintain health. A table of food analysis would show that the richest sources of carotene, averaging about 12,000 units per serving (100 grams), are green leaves such as chard, kale, spinach, and other greens. Even one serving of string beans, broccoli, carrots, yellow squash, apricots, sweet potatoes, or yams would supply 5,000 units, all one supposedly needs for a day. A serving of tomatoes, peas, unbleached celery, lettuce, and asparagus averages nearly 2,000 units. Except for apricots, most yellow fruits offer little more than 400 units per serving. Vegetables which have lost their color or have never been green lack this vitamin.

Such a table would show that liver may be extremely rich in vitamin A and that kidneys and sweetbreads contain appreciable amounts. Since this vitamin is not stored in muscles, such meats as roasts, chops, and steaks lack vitamin A. Eggs and butterfat contain it, the amount depending upon the animals’ food. Whole milk varies from 500 to 7,000 units per quart but usually averages 2,000 units. Most of the vitamin A may be destroyed by oxygen when milk is homogenized, although this problem appears not to have been studied. Winter butter, produced when the cows are given dry feed, may contain only 2,000 units per pound, whereas summer butter averages 12,000 units. Butter substitutes usually have 12,000 units of the vitamin added per pound.

Fish-liver oils are the richest commercial sources of vitamin A. The vitamin content of livers, however, depends on the animals’ food and age. Aside from polar-bear liver, the richest source ever determined was the liver oil of a python estimated to be 100 years old when killed in a London zoo. Halibut-liver oil is richer in vitamin A than is cod-liver oil because halibut is elderly when marketed, whereas cod is a mere adolescent; the halibut has had more years to eat green sea algae. For the same reason beef and mutton liver usually contains more vitamin A than do calf and lamb liver.

Scientists as well as laymen have been led to the conclusion, from studying tables of food analysis that we easily obtain all the vitamin A we need from foods. Surveys in which thousands of persons have kept records of foods eaten for a month or more, however, show that three-fourths of our population obtains only about 2,000 units of vitamin A daily. In these surveys the assumption has been that all the vitamin A obtained from food is absorbed into the blood.

Unfortunately, there is many a slip between the lip and body cells. Vegetables analyzed in a laboratory perhaps grew on excellent soil and received the optimum amount of rain and sunshine; possibly they contained a hundred times more vitamin A than those grown under less ideal conditions. Carrots, for example, have been analyzed which contain no carotene whatsoever. Losses of the vitamin occur during shipping, storage, freezing, canning, and cooking. Milk from cows feeding on a luxuriant growth of alfalfa has been found to lack vitamin A; the alfalfa, when analyzed, was found to contain no vitamin E, necessary to prevent the destruction of vitamin A in the body. The liver you perhaps ate, believing that you were obtaining vitamin A, may have come from an animal whose only food for months was dried hay.

Even if vegetables are rich in carotene, there is no insurance that it will be absorbed. The carotene in vegetable foods is held inside cell walls made of cellulose, a substance which cannot be digested by humans. Carotene cannot dissolve in water; therefore it cannot pass through these walls. Only when the cell walls have been broken by cutting, chopping, cooking, or chewing is it freed to pass into the blood. Approximately 1 per cent of the carotene from raw carrots has been found to be absorbed,” whereas cooking increases the absorption from 5 to 19 per cent.’ Studies show that the absorption of carotene from most vegetables averages from 16 to 35 per cent; the softer the texture, the larger the amount of carotene which reaches the blood. Presumably all the carotene is absorbed when vegetables are liquefied or juiced, but if the juice is not drunk immediately, much of the vitamin is destroyed by oxygen.

Through the years I have been consulted by dozens of girls whose faces are covered with pimples; often they tell me they have never had skin trouble until recently. Invariably I find they are doing office work, usually under fluorescent lights, and the continuous use of their eyes, together with the glare and reflection from white paper, has greatly increased their need for vitamin A. I can often tell them how long they have been in their jobs-approximately four months previous to the onset of the pimples.  When vitamin A is undersupplied, the hair becomes dry and lacks sheen and luster. Dandruff usually accumulates on the scalp. The nails may be affected and peel easily or become ridged.  Simultaneously with the visual difficulties and the changes in the skin, a vitamin-A deficiency allows abnormalities to occur in the tissues spoken of as mucous membranes. These tissues line the body cavities such as the throat, nose, sinuses, middle ears, lungs, the gall bladder, and the urinary bladder. If the diet is adequate in vitamin A, these membranes continuously secrete a liquid, or mucus, which covers the cells and prevents bacteria from reaching them and also cleanses the surface. Furthermore, bacteria cannot live in mucus, Worn tissues are digested by enzymes, and the wastes are removed; therefore healthy tissues contain no accumulation of dead cells. Because of substances known as antienzymes which counteract the effect of the enzymes produced by bacteria, live cells can protect themselves from bacterial destruction. Millions of bacteria find their way to these healthy tissues but cannot reach the cells because of the mucus covering or are made ineffective by the mucus; they are offered no food and/or are rendered harmless by the antienzymes. Since they cannot get a foothold, no infection occurs.  Individuals deficient in vitamin A allow conditions ideal for bacterial growth to be set up in their bodies; bacteria Can grow only when they are provided with warmth, moisture, and food. Dr. Wolbach of the Harvard School of Medicine points out that during vitamin-A deficiency the cells of the mucous membranes grow more rapidly than usual but quickly die. These cells are crowded forward by other rapidly growing cells which likewise die until there accumulates a cheesy-like surface of layer upon layer of packed, dead cells. Since dead cells cannot secrete mucus or produce antienzymes, their surface is no longer washed and their self-protective mechanisms are gone. Heat, moisture, and a continually replenished food supply combine to set up conditions ideal for bacterial growth; bacteria themselves are ever present. Infections are usually the result.  Changes in the mucous membranes occur early in the bronchial tubes and lungs, where air sacs may be completely plugged with dead cells, and in the middle ears, sinuses, kidneys, urinary bladder, and prostate gland. What has been described as an “accumulation of profuse debris” may cause irritation or obstruct narrow ducts, such as those from the salivary gland or the pancreas; the mouth may become dry; the pancreatic juices may fail to reach the intestine. Dead cells from the uterus and vagina may slough off, causing leucorrhea, often accompanied by profuse menstruation. Cysts may be formed around the accumulated dead cells in almost any part of the body.