FOR MANY people protein has taken on special, almost magic qualities. They have been told it can be counted on as a body builder and also a body slimmer! Because of some popular reducing diets, the notion seems to be widespread that protein either does not contain any calories or it "burns up fat" in some marvelous way!
Many individuals who claim to be especially careful about their diet will tell you they eat "very few starches—they are fattening, you know. And fats, well, what about cholesterol and heart disease? But protein—oh yes, it represents the best!" Today, with the world facing a food crisis, especially a shortage of proteins, it is important to separate fallacy from fact.
Although many people talk about them, relatively few know what proteins are and what they really do. And never before has the Seventh-day Adventist home-maker had such a golden opportunity to share her knowledge. Many are searching for ways to lower their food costs and some how stretch the ever-shrinking food dollar and still be assured they are feeding their families nutritious meals.
In a very real sense people are what they eat. The substances in foods are continually being rearranged into the living persons they are. Food becomes muscles, bones, nerves, blood, heart. And proteins are vital ingredients of every living cell. No one will argue this point.
However, the functioning of the nutrients in the body should be thought of as a team effort. Each nutrient in the amount needed by the body is essential and no one of them can be considered the most important. The nutrient needed in the least amount is as essential as the one needed in the largest quantity.
When the chemist analyzes proteins, he finds that they are really packages of basic units called amino acids. Proteins, which can be likened to words and sentences, are made up of twenty amino acids, comparable to the twenty-six letters in the alphabet. Even as almost a countless number of words can be made from just twenty-six letters, so thousands of different proteins can be made from only twenty amino acids. The body hooks them together by chemical bonds into long chains of hundreds and sometimes thou sands of amino acids to form a protein molecule. Each amino acid has a precise place in the chain and proteins are among the most complex substances known to man. The laws governing the continual, rapid, and orderly formation of the hundreds of complex proteins in the body are indeed outstanding evidences of God's sustaining control in our life processes.
Since protein is present in every cell, its major function is to build new tissue. For this reason the need for adequate protein is especially important during the growing years of childhood and adolescence, as well as during pregnancy and lactation.
Adults, however, never outgrow their need for protein. There is a constant breaking down and building up of body tissues from the beginning to the end of life. In this intricate exchange plan, there is some loss, some destruction which makes necessary a continual replacement.
Besides being necessary for growth and replacement, proteins are involved in hundreds of biological processes. In this way, they serve as body regulators.
Certain vitamins and minerals combine with proteins to form enzyme systems, which promote and coordinate activities occurring throughout the body. Many of the hormones that regulate vital processes are protein in nature. Hereditary traits and characteristics are determined by the genes, which also are made from proteins. We marvel at the Creator's handiwork when we realize that from such a limited assortment of amino acids, substances are made with such a multiplicity and diversity of functions!
Proteins contain calories and— like starches, sugar, and fats— supply energy. One gram of protein will yield four calories when it is burned in the body. This is about the same amount of energy provided by starches and sugars.
In order for the body to function at all, fuel is a basic necessity. When one is running or climbing stairs, he is aware that he is using energy. And when one stops to think about it, he realizes that it takes energy for the heart to move blood through miles of arteries, veins, and capillaries!
But there are hundreds of unseen and unthought-of chores that the body constantly does to keep us alive. It takes energy, for example, to split the large molecules of food proteins into the amino acids and then join them together again to build the large variety of proteins found in the body.
Carbohydrates and fats are the main suppliers of fuel and energy, although protein may also be used for this purpose if there are not enough fuel foods in the diet. As we have just seen, however, protein has many specific functions that only it can perform. When it is called on to meet fuel needs, it cannot perform these truly protein functions.
Food proteins are broken up by stomach acids and enzymes into fragments, and in the intestine they are broken down further into single amino acids. After absorption they enter the cells and are reassembled into human proteins.
The body can even make some of its own amino acids out of other ones. These are called "nonessential" amino acids—not because they are not essential to life, but because it is not essential to eat food proteins to get them. In other words, the body has the ability to make them and does not depend upon a food source for them. Eight of the twenty amino acids, however, are called "essential"—they must come from the food because the body cannot make them from other substances it has available.
Early in nutrition research it be came apparent that the proteins found in various foods differed from each other. This difference was due to the proportion of the amino acids they contained. Each food has a certain pattern and if there is not quite enough of one essential amino acid, it must be supplied by another food source. For this reason it is wise to eat a variety of foods so that the assortment of amino acids coming from these various sources will meet ail the needs of the body. Nutritionists speak of this improved value when amino acids from several foods are combined as "supplementation."
It is a well-known fact that animal foods adequately supplement plant proteins. Thus the practice of adding milk to breakfast cereal is an example of an excellent combination. What is not so generally known, however, is the excellent supplementation that occurs among the various kinds of plant proteins.
In general, legumes and vegetables are low in sulfur amino acids, and cereals are low in lysine. Since legumes and vegetables are generally good sources of lysine, they will nicely supplement cereal proteins. Some good combinations are peas and wheat, whole wheat bread and peanuts, or whole-wheat bread and beans. Scientific studies have substantiated an observation that Dr. Henry C. Sherman, of Columbia University, made years ago when he said: "The customary combination of baked beans and brown bread makes a 'main dish' that ranks with meat as a source of nutritionally good proteins and vitamins of the B group."—H. C. Sherman, Chemistry of Food and Nutrition (New York: The Macmillan Co., 1952), p. 602.
Refining food often removes not only valuable vitamins and minerals but excellent protein portions, too. White flour, for example, is lower in both quantity and quality of protein than whole wheat. Some of the richest part of the protein content is found in the embryo or germ portion. Another good reason for using whole grains.
Since many Americans equate the word "protein" with meat and in its absence or insufficiency they feel health and vigor cannot be maintained, Seventh-day Adventist homemakers can share with their neighbors the advantages of a meatless diet. They can assure them of the complete adequacy of such a diet. After all, Seventh-day Adventists have more than a hundred years of experience with the meatless diet! Specific details as to recent information that can be shared will be presented in next month's article.
(To be continued)
