( Originally Published 1930's )
All vitamins are essential to good health. However, some are much more necessary than others. Some vitamins are used up daily as eaten, while others are stored within the body for future use. Vitamin A is one which we store. But, some people have an aversion for the foods which carry this vitamin. They never eat a sufficient amount of vitamin A foods to supply their daily need and to store against infectious attacks.
We store vitamin A within the liver. In fact, all animals store vitamin A in the liver. That is why all liver, particularly salt water fish livers, contain rich amounts of this essential vitamin.
Vitamin A is important, and necessary, for the correction of night blindness, a defect which makes it quite difficult for the eye to change from bright to dull light. When you enter a dimly lighted room and stumble over the furniture, it may be vitamin A deficiency.
Continued lack of vitamin A produces a hardening of the skin around the eyes and a dry, lustreless eyeball. However, this condition is usually one of semi-starvation and involves the lack of other food and other vitamins.
It is not definitely known whether vitamin A acts upon night blindness through the actual food deficiency, or whether it is due to the delicate coloring material supplied to the eye by vitamin A bearing foods. This coloring material supplies the rod-like genes with the necessary light refraction to adjust the eye to light and dark. The greenish yellow, amber, to dark yellow which vitamin A supplies, causes the facets of the color cells to reflect dim light. If you are up on vitamin A, you see better.
Vitamin A is also called the anti-infection vitamin. Perhaps, anti-infection is too strong a word for its ability. Vitamin A will not actually prevent infections, but if you have a sufficient reserve of this vitamin, an infection will not attack so quickly, nor be so severe. That is why vitamin A should be given as a food supplement in early fall, and throughout the winter, as a cold preventative.
As an anti-infective agent, vitamin A can be used with benefit for sinus, catarrh, and asthmatic conditions. Any condition of the system which causes a thickening of the mucus exudations of the body, indicates a degree of infection of some kind.
You will remember that the white blood cells are the police of your system. When they are killed in combat, they are thrown off as a thick white, or yellowish white, mucus. Vitamin A helps to increase the ability of your white cells, or police, to throw off infection.
The ordinary need for vitamin A to prevent night blindness, to promote and sustain growth, and to supply the skin with its smoothness, is approximately 1500 units a day. This amount can be sup-plied with one pint of milk, one egg, two pats of butter, and a serving of green leaf, or yellow vegetable. However, this does not allow sufficient excess to build up against infection, or for any other extraordinary need of your body for vitamin A.
Milk and butter supply less vitamin A in the winter months because the cows get less grass, a very excellent source of vitamin A. That is why most people would play safe by taking a small vitamin A capsule daily during the winter.
Let us see how easily you can become a victim of night blindness, and an easy prey to various body infections. We will give you what is apparently a lot of food to eat, but if you ate only those foods for one month your eyes would take twice as long as the normal person to change from light to dark. Not only that, but the first cold wind would blow you a cold that would stay with you most of the winter.
Here is a list of vitamin A deficient food:
Lean meats:—All kinds in abundance.
Vegetables:—Bleached celery, cabbage, asparagus, corn (white) , mushroom, onions, parsnips, white potatoes, cauliflower, and dried beans.
Fruits:—Apples, grapefruit, pears, lemons, cranberries, grapes, (white), and strawberries.
Miscellaneous:—Gelatin, honey, cocoanut, macaroni, egg white, cocoa, white flour, white rice, sugar, oleomargarine, tapioca, and vegetable oils.
The above group of foods contains meat, fruits, vegetables, and carbohydrates. This list would seem to supply food in plenty, but people who find their sustenance within this group, will be in for trouble of some kind. Eye and systemic infections could only be pre-vented if you add sweet potatoes, liver, carrots, oranges, butter, egg yolks, lettuce, and other green leafs. Or, you would have to take vitamin A in concentrate.
When deficient vitamin A conditions attack you, do not depend upon carrots, milk, and butter to replace your loss. The vita-min A in some of these foods is not really vitamin A; it is only potential vitamin A. Potential Vitamin A must be turned into real vitamin A within your own body. Under some conditions of your system, you may do this. On the other hand, you may not be able to convert potential to real vitamin A.
It is a reported fact that a cow does not convert all the potential A from grass into real vitamin A. Some of the cow's milk contains only potential vitamin A. You would have to convert this to real vitamin A yourself. This same thing is true of carrots, which produce carotene; also other vegetables containing vitamin A. That is why fish liver oils are given as a dietary supplement. They all contain rich amounts of real vitamin A.
You can see now, why most diets may be deficient in vitamin A. Thousands of allergic conditions, and millions of infectious colds could, perhaps be prevented, or at least eased if each person so attacked would take a large amount of vitamin A as a pre-seasonal immunization
How much vitamin A is necessary for any one person cannot be easily determined. It depends upon what kind and how much food containing vitamin A is consumed. The daily amount of vita-min A from food may vary from 800 to 4000 units. Less than 2000 units a day is not a safe bet for anyone. Therefore, to keep within the certain sure healthful group, you had best join the 4000 unit a day vitamin A crowd. You can do this by eating generously of all green and yellow vegetables, eggs, milk, liver, and fish.
You folks, who do not like the above foods, or do not eat them, which amounts to the same thing, should take vitamin A in its most assured form, fish liver oil capsules. 5000 to 10,000 units a day is a very cheap insurance against body infections and some types of eye trouble.
When you catch cold easily, or are the victim of some allergy, it is not unusual, indeed quite beneficial, to take 25,000, and up to 100,000 units per day of vitamin A.