impossible for her to hold herself erect except for a few strained moments, but at last her desire had been achieved.
Another case which I found astonishing was that of a three-year-old boy: his chest was sunken; he had an enormous pot belly and feet as flat as a table top. Three months later this child had a high chest, beautifully arched feet, and a total absence of protruding abdomen. The rarity of good posture and a rhythmical, graceful stride tells of our widespread protein deficiency.
Since hair and nails are made of protein, this nutrient must be adequate to maintain their health.
Like the muscles, hail which lacks elasticity and resiliency and perhaps breaks or refuses to take a permanent will often change to healthy hair after a few weeks of improved nutrition. Nails which break, peel, or crack can likewise change when the diet is improved.
Advantages of an adequate protein intake are that energy is readily produced and sustained, and life is made easier. Although a major cause of fatigue is low blood sugar, there are other causes resulting from protein deficiency which are less quickly corrected: low blood pressure, anemia, and the body's inability to produce the enzymes necessary for the breakdown of foods into energy.
Blood pressure means the push or force of the blood against the walls of the blood vessels. Only when the tissues of the vessel walls are strong can the blood pressure be maintained at its normal level. If these tissues become flabby and weak, they expand, making more room in the vessels. Since the volume of blood remains the same, the blood presses with decreased force against the walls; less blood plasma, carrying all nutrients, is pushed into the tissues. Adequate supplies fail to reach the cells; thus fatigue results. Since relaxation is greatest during the night, the person with low blood pressure finds that he is especially exhausted in the early morning; getting out of bed is a chore, and he is usually irritable and sluggish until his blood pressure has been increased by the stimulus of strong coffee. After a diet has been made adequate, however, low blood pressure usually becomes normal in one to three weeks.
Another cause of fatigue, particularly common among women and children, is anemia, or lack of red corpuscles, which are made almost wholly of protein. Without adequate protein anemia quickly results and persists until the nutrition is made normal. Anemia, however, can result from any number of nutritional inadequacies.
All energy is produced by means of enzymes, organic substances whose principal component is protein. Vitamins are important only because they form part of certain enzymes. When protein is inadequate, however, none of the enzymes can be formed in adequate quantities. Fatigue is only one of many abnormalities which result.
If protein is abundantly supplied and the diet is otherwise adequate, we can expect high resistance to diseases and infections. Although there are many mechanisms which help to protect the body against infections, two are particularly dependent upon the protein intake: antibodies and white blood cells. Under normal circumstances, the liver produces proteins known as gamma globulins, or antibodies, whose purpose it is to combine with and make harmless various bacteria, bacterial toxins, and presumably virus. Studies of persons suffering from almost every type of infection, including polio, show that the gamma globulins of the blood are undersupplied. These globulins might be thought of as a militia guarding your health.
Within recent years, it has become medical practice to take blood globulins from the plasma of healthy persons who have built up immunity and to inject these globulins into malnourished persons; such a treatment has been widely publicized as a means of preventing polio. If your nutrition is adequate, your body can produce all the antibodies it needs and more, but that simple fact is not given publicity. Experimental work has shown that when a low-protein diet is replaced by one high in adequate proteins, the antibody production is increased a hundredfold within a single week.
Another marvelous mechanism which helps to protect our bodies from infections is the production of cells known as phagocytes. Plago means to eat; cyte means cell. Some of these white blood cells circulate in the lymph and blood. Other phagocytes are stationary and remain in the walls of the blood vessels, in the tiny air sacs of the lungs, and in other tissues where they, like the antibodies, stand constant guard. When bacteria invade the body, the phagocytes mobilize, surround the enemies, and digest them. These valuable cannibals are made of protein and are produced in adequate amounts only when proteins of high quality are obtained in the diet.
Adequate protein is also necessary to maintain normal digestion. Since enzymes, necessary to change food into particles which can dissolve in water and pass into the blood, are made of protein, the stomach, small intestine, and pancreas can pour out enzymes only when adequate protein is supplied. The walls of the stomach and intestine are muscular and, like other muscles, contract and relax alternately, thus mixing foods with digestive juices and enzymes and bringing already digested food into contact with the intestinal wall where it may pass into the blood. Furthermore, the entire digestive system must be held in a normal position to work efficiently. When proteins are undersupplied, muscular walls and ligaments become flabby, and the "internal posture" suffers: the stomach may sag, the transverse bowel, or colon, may coil in snake-like fashion on the pelvic bone; the uterus or urinary bladder may be tipped; and other internal organs may be displaced. The flabby muscles of intestinal walls no longer contract normally; much food remains undigested. This food, on reaching the large bowel, supports the growth of billions of putrefactive bacteria; gas formation and flatulence result. Because flabby muscles are unable to push waste material from the body normally, constipation often occurs. Laxatives or cathartics may be used, causing food to be forced through the body before the protein it contains can be digested; or enemas may be resorted to which further break down the worn muscles. Only when the protein intake is entirely adequate does digestion become normal again.
Proteins help to prevent the body fluids from becoming too acid or alkaline; they can combine with and neutralize either acid or alkaline substances. They are the raw material from which most of the hormones are made. Proteins are also necessary in helping blood to clot. They have almost endless other functions without which life would be impossible.
In still another particular way proteins are immensely important in regulating body processes. A protein known as albumin, produced by the liver provided all the building stones are furnished by the diet, makes urine collection possible. As the blood cruises through the capillary beds, the force of the blood pressure pushes the plasma into the tissues; when the blood thus becomes concentrated, the protein albumin attracts fluids from the cells back into the blood. In these fluids are dissolved the waste materials, urea, uric acid, carbon dioxide, and others from the breakdown of tissues within the cells. These wastes are then carried to the kidneys and lungs.
When the diet is so inadequate that sufficient albumin cannot be formed, waste materials are not completely removed from the tissues. Many weeks or months of mild protein deficiency may occur without the accumulated water becoming noticeable; such a person merely thinks he is overweight and often tries to reduce by cutting down still further his protein intake. If the deficiency becomes more severe, the tissues are noticeably puffy, and the entire body is waterlogged. The ankles swell, especially toward the end of the day; swollen face and hands and puffy bags under the eyes are evident in the morning.
This condition is extremely common in persons of all ages. For example, most reducing diets are now fairly high in protein. It is Dot unusual for a person staying on 1,000 calories a day to lose 8 or 10 pounds during the first week; 3 pounds of this loss may be fat, and the remainder is usually water held because of previous faulty urine collection. Not long ago a young woman for whom I had planned a reducing diet lost 18 pounds the first week. Two women who came with legs and ankles badly swollen from waste-laden liquids lost 18 and 24 pounds respectively in two months, although neither was given a reducing diet.
Unfortunately, water held in the tissues gives the appearance of chubbiness often associated with health, especially in children; thus this abnormal condition may be looked upon as advantageous. Studies of youngsters suffering from polio and many other diseases show that the blood proteins, both the albumin and the globulins, or antibodies, are low and have been low long before the onset of the disease. Children entering the hospital with diarrhea or various infections or diseases are frequently so waterlogged that they appear to be fat; when a diet high in protein is given them and normal urine collection is resumed, they can be seen to be extremely emaciated.
It is my belief that only when the role of protein in building and maintaining health is understood will persons make the effort to select food with sufficient care to promote health.
Chapter 4, One Trick in Staying Young
WHEN all parts of the body are maintained by the absorption and utilization of adequate food, health and youthfulness are likewise maintained. Conversely, you grow old on the days your diet is inadequate. Since your body structure is largely protein, an undersupply can bring about aging with depressing speed.
The bodies of animals, like our own, are composed largely of protein; meats, fish, and fowl, therefore, are excellent food sources. Other superior sources are eggs, fresh milk, buttermilk, yogurt, powdered milk, cheese, soybeans, and powdered yeast. Nuts, beans, peas, and grains are fair sources. Plants can synthesize their own proteins; we cannot because certain parts of this substance cannot be made in the body.
Proteins are made of amino acids, all containing nitrogen which other foods lack. Twenty-two different amino acids are known. Just as thousands of words are made from the 26 letters of our alphabet, so are thousands of proteins made from different combinations of amino acids. Not only do the proteins in milk differ from those in soybeans, but the proteins in all parts of your body vary because of different combinations of amino acids which form them. Each protein may contain a combination of several thousand individual amino acids and is thus as complex as would be a word of thousands of letters (heaven forbid).
When proteins are eaten, the digestive processes of a healthy person break them down into amino acids which pass into the blood and are carried throughout the body. The cells select the amino acids they need and use them in constructing new body tissue and such vital substances as antibodies, hormones, enzymes, and blood cells.
Every instant of life, body proteins are being broken down by enzymes in your cells, and if your health is to be maintained, amino acids must be available for immediate replacement. Since the waste products are excreted by the kidneys, the urine can be analyzed for nitrogen which comes only from proteins; the quantity of nitrogen found in the urine shows the amount of body tissue being replaced at any given time. If your diet is adequate, the cells, by the help of enzymes, combine fresh amino acids into new proteins. Food proteins, therefore, are needed continuously from birth until death. If your diet is complete in other respects, you can maintain health whenever all the required amino acids are generously supplied.
When you eat more protein than your body can use immediately, your liver withdraws amino acids from your blood and changes them temporarily into storage protein. As your cells use amino acids, the supply is replenished from the breakdown of stored protein. As long as your diet is adequate, the amount of amino acids in your blood is thereby kept relatively constant. If you ignore your health to the extent of eating insufficient protein, the stored protein is quickly exhausted. From that time on, the less important body tissues are destroyed to free amino acids needed to rebuild more vital structures. Such a process may go on month after month or even year after year. Your body continues to function after a fashion. Unseen abnormalities set in because blood proteins, hormones, enzymes, and antibodies can no longer be formed in amounts needed. Muscles lose tone; wrinkles appear; aging creeps on; and you, my dear, are going to pot.
On the other hand, it is possible, although not probable, that you may eat more protein than your body needs. After the storage depots are filled, the leftover protein is changed by the liver into glucose and fat, the nitrogen portion being excreted in the urine; the sugar and fat may be used immediately to produce energy or may be stored as fat. Proteins are also used to produce energy whenever too few other foods are eaten to meet the calorie requirements, a situation which rarely occurs for the simple reason that protein foods are too expensive to be eaten exclusively.
Most of the 22 amino acids are needed in forming every tissue in the body. All but eight of these acids, however, can be made by the cells from fat or sugar combined with the nitrogen freed from the breakdown of used proteins. The eight which the body cannot make are spoken of as the essential amino acids, a misleading term because all amino acids are essential to health even though it is not essential that 14 of them be obtained from food. These so-called essential amino acids, however, must be supplied in the diet if health is to be maintained; each of them is as important as is any vitamin.
Physicians now use separate amino acids in the treatment of certain diseased conditions; since the names frequently appear in the lay press, you should be sufficiently familiar with them to recognize them as amino acids. The ones which cannot be made in the body are tryptophane, lysine, methionine, phenylalanine, threonine, valine, leucine, and isoleutine.1 Children usually cannot make enough histidine and arginine to support growth, especially during periods of stress; hence these two acids are at times essential to children. The amino acids which the body can make are glycine, alanine, glutamic acid, proline, hydroxproline, aspartic acid, serine, tyrosine, cystine, hydroxyglutamic acid, norleucine, and di-iodo-tyrosine.
The value of any protein depends on the number and amount of essential amino acids it contains. Proteins containing the eight essential amino acids in generous amounts are called complete or adequate. If enough of any complete protein, such as milk, is taken alone, it can support health. A protein lacking one or more essential amino acids or supplying too little of an essential amino acid to support health is spoken of as an incomplete or inadequate protein.
Since essential amino acids are supplied in greatest abundance in egg yolk, fresh milk, liver, and kidneys, these foods have the highest protein value. Proteins from muscle meats, used in roasts, steaks, and chops, are complete but contain fewer of some essential amino acids than do glandular meats and are therefore less valuable. On the whole, animal proteins, such as meat, fish, eggs, milk, and cheese, contain more essential amino acids in greater abundance than do vegetable proteins; hence they have superior value. Of the animal proteins egg white and gelatin alone lack essential amino acids.
Proteins from brewers' yeast, certain nuts, soybeans, cottonseed, and the germ of cereals are complete proteins. The proteins of peas, lentils, navy and lima beans, cereals and flour with the germ removed lack some of the essential amino acids; they are therefore incomplete and cannot support life alone. There are many proteins on the borderline between complete and incomplete. For example, the protein from peanuts can support growth and maintenance but not reproduction. Furthermore, the amino acid lysine is harmed when the nuts are roasted or milk is treated with heat during canning or drying, thus changing the protein from a complete to an incomplete form.
If two or more incomplete proteins are eaten at the same meal, one may supply the amino acids lacking in another, and together they may make a valuable contribution to health. For example, most grains lack the amino acids lysine and threonine, whereas beans supply these acids but lack methionine; the proteins of baked beans and brown bread together could supplement each other, and the body could form complete proteins by combining the amino acids of the two. Dr. Cannon2 has shown, however, that if half the essential amino acids are eaten at a certain time and the other half taken only one hour later, the body does not build protein from them. Formerly it was believed that if cereal and toast were eaten at breakfast, the amino acids from the digested protein would lounge about waiting for the missing amino acids to catch up, perhaps after the next meal. It appears now that the standards of the liver are so high that only complete proteins are held in storage. Since protein food is expensive, it becomes important to obtain all the amino acids at every meal to prevent their being wasted.
A tremendous amount of research is being done with both animals and humans to find the specific symptoms of ill health which occur when certain amino acids are lacking. For example, when the diet of animals or babies lacks tryptophane, methionine, or isoleucine,3 the liver cannot produce the blood proteins, albumin, and globulin (antibodies), and urine can no longer be collected normally; swelling, known as edema, and susceptibility to infections result. Methionine has been found to be particularly deficient in the diets of children with chronic rheumatic fever3 and of women suffering from the toxemia of pregnancy.4 In animals a lack of tryptophane or methionine causes the hair to fall out; a lack of histidine, phenylalanine, or any one of several other amino acids causes the eyes to become bloodshot and/or cataracts to form. An undersupply of arginine causes animals to become sterile and brings about a decrease in the formation and mobility of sperm in men,5 whereas too little tryptophane causes the animals' testicles to degenerate (atrophy) or females to lose their young. A deficiency of methionine allows fat to be retained in the liver of both animals and humans.
Only future research can give an understanding of the role each amino acid plays in building and maintaining the body. It is known, however, that all the amino acids are used together and that taking one or two alone can never build health.
Both the quality (or the number and abundance of amino acids supplied) and the quantity of proteins eaten, determined in grams per day per person, must be considered if health is to be maintained.
The greatest hindrance to good health in this respect is ignorance. Many surveys of thousands of persons having enough money to eat as they choose have shown that about 60 per cent get far less protein than is adequate. Since the complete proteins most enjoyed are expensive, persons with low incomes almost invariably suffer from protein deficiency. Yet adequate protein can be obtained even when the budget is extremely limited. It is my opinion that health cannot be built until persons learn the amount of protein they need and the grams supplied by ordinary foods. You should know these quantities so thoroughly that you can estimate in a second your protein intake for the day.
The Food and Nutrition Board of the National Research Council recommends the following amounts of protein, in grams, daily:
Children Adults
Under 12 Years Over 12 Years Men -- 70
1-3 -- 40 Girls 13-15 -- 80 Women -- 60
4-6 -- 50 Girls 16-20 -- 75 Pregnancy -- 85
7-9 -- 60 Boys 13-15 -- 85 Lactation -- 100
10-12 -- 70 Boys 16-20 -- 100
The National Research Council, however, has attempted to set up standards which they hope will be practical for our entire population, including millions of families whose income cannot buy foods necessary for optimum health. These figures, therefore, are generally considered to be too low. If you wish to maintain your attractiveness, vigor, and youthfulness as long as is humanly possible, it is probably wise to eat considerably more protein than the Board recommends and/or to count only the grams of adequate protein you eat. Whenever the diet has been deficient in protein for some time, an intake of 150 grams or more daily is probably advisable for a month or more. Such large amounts are also needed in the treatment of various disease conditions.
You should thoroughly familiarize yourself with the approximate quantities of protein in ordinary foods listed in the following table.
Sources of proteins, Amounts, Completeness (com=complete, inc=incomplete), Grams of Proteins
soybean flour, low fat 1 cup com. 60
cottonseed flour 1 cup com. 60
white flour 1 cup inc. 8 to 12
wheat germ 1/2 cup com 24
brewers' yeast, powdered 1/2 cup com 50
powdered skim milk 1 cup inc 60 to 70
egg 1 com 6
milk, whole or skim,
buttermilk 1 qt. com 32 to 35
cottage cheese 1/2 cup com 20
American or Swiss cheese 2 slices com 10 to 12
soybeans, cooked 1/2 cup com 20
peanut butter 2 tbsp inc 9
cooked cereals 3/4 cup inc 10 to 18
prepared cereals 1 cup inc 1 to 3
navy or lima beans 1 cup inc 6 to 8
macaroni, noodles, rice 3/4 cup inc 3 to 4
bread or bacon 1 slice inc 2
nuts* 1/2 cup 14 to 22
Meat, fish, fowl boned or with little bone or fat** 1/4 pound 1 serving com 18 to 22
meat, fish, fowl with moderate bone and/or fat *** 1/4 pound 15 to 18
meat, fish, fowl with much bone and/or fat **** 1/4 pound 10 to 15
* The protein in certain nuts is complete; in others incomplete
**Such as liver, tongue, rump roast, round steak, or soup meat;
roast leg of lamp; veal chops, cutlets, or stew; boned rabbit or
rabbit thigh or breast of chicken or turkey; halibut and other fresh
fish, fresh corned beef, canned chicken, tuna, sardines salmon or mackerel.
***Such as hamburger, rib roasts or steaks, loin steaks or stew meat;
lamb chops or shoulder roast; ham or pork chops, one frankfurter;
heart or kidney; canned corned beef of shrimps; live sausage and
other luncheon meats; less bony pieces of rabbit, chicken, or other
fowl; cod, haddock, lobster, crab, or fresh shrimps.
****Picnic ham, link sausages, or spareribs; brains or sweetbreads;
corned-beef hash, bony parts of chicken or other fowl; herring, clams,
oysters, and scallops.
There are, of course, many foods not listed in the foregoing table which supply protein but which, in my opinion, are not worth bothering with. Gelatin, for example, lacks two essential amino acids and is almost entirely lacking in three others; hence its protein value approaches nil. Similarly, many vegetable proteins are so incomplete that it is misleading to emphasize their protein content. Most cereals aside from pure germ are not only deficient in lysine and threonine but often contain almost no protein. For example, rice flakes and puffed wheat supply only one gram of poor-quality protein per cup. Prepared cereals are largely pure starch which is changed into sugar; allowing a child to eat them is like passing him the sugar bowl and saying, "Help yourself." The latter would be less troublesome and expensive.
Until a person knows enough about nutrition to estimate his daily intake by counting protein grams easily and to distinguish between complete and incomplete proteins, he almost invariably believes he consumes a far better diet than he does. Thousands of persons think they get adequate protein from one egg at breakfast and meat for dinner; their actual intake may be 26 grams or less, although their requirement is perhaps many times that amount. Since a quart of milk supplies 32 to 35 grams of protein, one usually finds that the person who drinks a quart daily has a fairly adequate protein intake, whereas the person who avoids milk is almost invariably deficient.
If milk, cheese, or eggs are disliked or unobtainable, getting adequate protein becomes a serious matter indeed. When the complete proteins of wheat germ, soybeans, brewers' yeast, and nuts are eaten, it is possible to obtain sufficient amounts of essential amino acids, provided the diet is planned with utmost care. Some of the world's leading athletes and scholars have been vegetarians. Unless a vegetarian is trained in nutrition, however, he usually becomes an unhealthy vegetarian.
Of all proteins available, the most concentrated and least expensive are brewers' yeast,6 powdered skim milk, wheat germ, soy flour, and cottonseed flour.7 The use of these foods makes it possible to obtain protein on an extremely limited budget and can change a diet low in protein to one high in protein with little thought or effort.
To obtain too little protein is a mark of carelessness or ignorance; to obtain too much is foolish and probably impossible; to obtain an adequate amount is to stay young for your years.
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Footnotes
1 W. C. Rose, "Amino Acid Requirements of Man," Federation Proceedings, VIII (1949 ), Return
2 Paul R. Cannon, Recent Advances in Nutrition (Lawrence: University of Kansas Press, 1950). Return
3 Anthony A. Albanese, "The Effects of Amino Acid Deficiencies in Man," Journal of Clinical Nutrition, XLIV (1952), 1. Return
4 N. W. Philpot, M. Hendelman, and T. Primrose, "The Use of Methionine in Obstetrics," American Journal of Obstetrics and Gynecology, LVII (1949 ), 125 Return
5 L. l;. Holt, Jr., and A. A. Albanese, "Observations on Amino Acid Deficiencies in Man," Transactions of the Association of American Physicians, 'LVI11 (1944), 143. Return
6 See tiger's milk recipe, p. 114. Return
7 Hundreds of recipes using these foods are to be found in the writer's Let's Cook It Right (Harcourt, Brace and Company, 1947 ). Return
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