The Story of Nutrition

ELIZABETH NEIGE TODHUNTER.

THIS is the story of man's long search for exact knowledge of the food his body needs. It is a story of laboratories, experiments, failures, successes, and discoveries. It is even more a story of men and women with curiosity, ideas, persistence, and a driving desire to help people live better.

It is a story of a fight against ignorance and superstitions and the strange ideas people always have had now, too! about the things they eat.

It is an old story that could begin with the first man and the little he knew beyond the fact that he liked to eat.

It is, though, primarily a story of accomplishments in this century indeed, in the last few years; a story so new that it is far from its end.

Although for centuries people tried to solve some of their problems of what to eat and how much and why, they Made little progress until chemistry was well developed and we could analyze foods and know what they are made of. We also had to wait until physiology became a science that could provide understanding of the human body and how it functions. We needed as well the contributions of physics, medicine, agriculture, and biology.

Because it is a "new" science, then, let us begin with the man who has been called "the father of American nutrition" and later go back to the men and ideas that preceded him for nutrition, like every science and almost every other great development, has been built on things that went before.

Wilbur Olin Atwater was born in 1844 in Johnstown, N.Y. He attended the University of Vermont and Wesleyan University in Middletown, Conn. For his thesis for his doctor's degree at Yale University in 1869 he for the first time in this country used modern methods to analyze corn fodder.

He went to Europe in 1869 to study agricultural and physiological chemistry at the Universities of Leipzig and Berlin. When the first experiment station in the United States was established at Middletown in 1875, he became its first director. He later became director of the Connecticut Agricultural Experiment Station at Storrs when it was organized in 1887.

His studies on the acquisition of atmospheric nitrogen by plants and on the composition of feeds, begun several years earlier, he continued as part of the work at Storrs during the 14 years he was director. These investigations led to his interest in the composition of man's food.

Dr. Atwater made a series of analyses of fish for the United States Fish Commission and of the flesh of domestic animals for the Smithsonian Institution between 1879 and 1883. He conducted studies of the dietaries of people in Massachusetts and Canada.

Dr. Atwater returned to Europe in 1887. He worked in the laboratory in Munich where Carl Voit was doing outstanding work in studies of respiration the exchange of gases between the blood and the tissues and calorimetry, the measurement of heat, the first steps toward quantitative knowledge of nutritional requirements.

Another American student who worked in Dr. Voit's laboratory was Graham Lusk, who brought back with him a small model of a calorimeter Voit had made and later built others at Cornell University Medical College in New York City for studies with dogs and children. We shall come back to Dr. Voit later.

Dr. Atwater also returned to this country inspired to do further calorimetry studies at Wesleyan University. With his coworkers be built a calorimeter for studies on man and designed a bomb calorimeter for measurement of caloric value of foods. He made adjustment for the indigestible fraction in food and the incomplete oxidation of protein in the body and gave the values, widely used ever since, of 4, 9, 4 Calories per gram of carbohydrate, fat, and protein in a mixed diet.

The Congress in 1894 appropriated to thousand dollars "to enable the Secretary of Agriculture to investigate and report upon the nutritive value of the various articles and commodities used for human food, with special suggestion of full, wholesome, and edible rations less wasteful and more economical than those in common use."

This work was assigned to the Office of Experiment Stations under Dr. Atwater, who was designated "chief of nutrition investigations."

From that time forward, biochemists, nutritionists, home economists, and investigators in animal and poultry husbandry at agricultural experiment stations throughout the country have steadily and continuously helped build the newer knowledge of nutrition.

Headquarters for the work were established at Middletown, and Dr. Atwater was made chief. He and his colleagues investigated the diets of hundreds of persons of different occupations and compared the results of similar studies in other countries. They made many experiments with men on digestion and carried on special studies of the nutritive value of cereals, meats, vegetables, fruit, and nuts and the effects of cooking and other forms of preparation on nutritive values.

He and his coworkers demonstrated that the amount of heat energy a person develops during a given period is the amount that can be derived from the energy liberated in the oxidation of food materials during the period.

Dr. Atwater studied digestibility of food, made numerous dietary studies, and analyzed many foods. He prepared in 1896 the famous Bulletin 28 of the United States Department of Agriculture. It was the first extensive table of food values ever prepared in this country.

Atwater sought to find what was the best and most economical diet for man. At that time only protein and Calories, as supplied by fat and carbohydrate, were considered of importance, and such foods as green, leafy vegetables and fruit were regarded as expensive purchases or luxuries.

A chapter Dr. Atwater wrote for the 1894 Yearbook of Agriculture has meaning for us today. I quote a few sentences from it:

"Materials for the food of man make up the larger part of our agricultural production and the largest item of our export abroad. Our food production is one-sided. It includes a relative excess of the fat of meat, of starch, and of sugar, the substances that serve the body for fuel to yield heat and muscular power, while the nitrogenous substances, those which make blood and muscle, bone and brain, are relatively deficient. . . . What is needed is more nitrogen in the soil for plant food, more nitrogen in plants to make better food for animals and man, and more nitrogen in the food of man. Better culture of the soil and better manuring will bring not only larger crops, but crops richer in nitrogen.

"The power of a man to do work depends upon his nutrition. A well-fed horse can draw a heavy load. With less food he does less work. A well-fed man has strength of muscle and of brain, while a poorly nourished man has not."

He defined food as "that which, when taken into the body, builds up its tissues and keeps them in repair, or which is consumed in the body to yield energy in the form of heat to keep it warm and create strength for its work. . . ."

"The most healthful food is that which is best fitted to the wants of the user.

"The cheapest food is that which furnishes the most nutriment at the least cost.

"The most economical food is that which is both most healthful and cheapest.

"To make the most out of a man, to bring him up to the desirable level of productive capacity, to enable him to live as a man ought to live, he must be well fed.

"One of the ways in which the worst economy is practiced is in the buying of high-priced foods. For this error, prejudice, the palate, and poor cooking are mainly responsible. There is a Prevalent but unfounded idea that Costly foods, such as the tenderest Meats, the finest fish, the highest Priced butter, the choicest flour, and the most delicate vegetables possess Some peculiar virtue which is lacking in the less expensive materials. . . . The maxim that 'the best is the cheapest' does not apply to food."

LET US GO BACK now for a glimpse at the beliefs and knowledge on which Atwater and other scientists of the loth century built. Such a quick survey will help us to understand better the growth of the science of nutrition and the speed with which it has grown.

Back in the days of the Greeks, before the birth of Christ, man's inquiring mind was asking questions about the world in which he lived. The "science" of that day believed that there were four elements earth, air, fire, and water; four qualities dry, cold, hot, and wet; and four humors, or liquids, that comprised the body blood, phlegm, black bile, and yellow bile.

Hippocrates, the father of medicine, taught the value of diet, but he believed in one universal aliment, an idea that prevailed until the early part of the 19th century.

Galen, a Greek physician who settled in Rome in A.D. 164, wrote many books about anatomy, diet, and health. His word was accepted without question through the centuries that saw the decline of Rome, the Dark Ages, and the first light of the Renaissance, until Andreas Vesalius (1514 1564), a Flemish student of anatomy, overthrew some of Galen's ideas and dared to investigate for himself, rather than follow blindly the master's dicta.

One original thinker in Italy tried to study nutrition. He asked the right questions, but he could not get the answers because he had neither a knowledge of chemistry nor the necessary tools. Santorio Sanctorius 1561-1636) day after day sat on his big balance and weighed himself and the food he ate, but could not find the answer to the difference in weight after he had eaten. He has truly been called the father of experiments in metabolism, but it was some 300 years later before investigators could explain the nutrition problem he had posed.

In the 17th century, "the Golden Age of Science," the experimental method began to take hold. The British William Harvey revolutionized our concept of the human body by demonstrating that blood circulates from the heart throughout the body. The Dutch Anton van Leeuwenhoek developed the microscope and studied the red cells or corpuscles of the blood stream. At meetings of the Royal Society, which received its charter in 1662, scientists discussed their experiments and the curiosities of nature they had found.