Today's simple food charts aim to help everyone eat well.
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Biological aide Ellie Giron (left) and ARS chemist Phyllis Johnson prepare a sample for analysis at the ARS Grand Forks Human Nutrition Research Center in Grand Forks, North Dakota.
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History of Research at the U.S. Department of Agriculture and Agricultural Research Service
Founding American Nutrition Science
In early 1893, the odds that Wilbur Olin Atwater would get public support for his grand plan for food investigations were slim to none. In fact, the future of the Office of Experiment Stations, which he had worked so hard to establish, was in doubt. But as often happens to people of vision, an "angel" interceded—in the form of a close personal friend of the Secretary of Agriculture who knew and admired Atwater.
On May 23, the Secretary wrote: "Mr. Edward Atkinson of Boston suggests the expediency of establishing food laboratories ...."
With those simple words, the door was pried open for the first federal funding of human nutrition research in the United States. Although it took another year of intensive skirmishing and skillful diplomacy, Atwater's efforts paid off. In May 1894, the agricultural appropriations bill included $10,000 for food investigations.
Today, we take for granted federal funding of nutrition research. In fact, in FY 1992, federal support of all U.S. Department of Agriculture activities in human nutrition research was about $82 million; nearly $200 million was spent on nutrition education and information programs.
And these figures do not include nutrition programs in other federal departments such as Health and Human Services. But in the 1890's, nutrition studies were quite new in the United States, and most of them were being done by Atwater himself.
"It is scarcely 50 years since the classical researches of Liebig [the renowned German chemist] began to pave the way for finding practically everything we know today of the ingredients of our food materials, the way in which they are used in the body, and the kinds and combinations which are best adapted to health and purse. Nearly all of the best experimental inquiry in these lines has been carried on in Europe," wrote A.C. True in introducing the first of Atwater's landmark publications, Bulletin No. 21, shortly after the new funding was granted.
Knowledge of the nutrients and their functions was very limited. Carbohydrates and fat provided energy to maintain body temperature and do muscular work. Protein had the added duty of building and repairing tissues. Vitamins were unknown. And only a few major minerals, such as calcium and phosphorus, were recognized as somehow essential, but their role in the body was unclear.
Atwater's quest for a scientific understanding of nutrition was coupled with the social consciousness of the day. In a 1894 letter, he wrote: "The individual man is coming to realize that he is his brother's keeper, and that his brother is not only of his household but may live on the other side of the world. With all these thoughtful people the conviction is growing that there is one fundamental condition of the intellectual and moral elevation of the poor, the ignorant, the weak, the destitute, namely the improvement of their physical condition."
Atwater joined the thinkers of the day in the conviction ". . .that the intellectual and moral condition and progress of men and women is largely regulated by their plane of living; that the plane of their intellectual and moral life depends upon how they are housed and clothed and fed."
A Man of Action
The son of a Methodist minister, Atwater was born in Upstate New York on May 3, 1844, but was reared in Vermont. He attended the University of Vermont for 2 years and graduated from Wesleyan University in Middletown, Connecticut.
After a short period as a schoolteacher and principal, he entered Yale University's Sheffield Scientific School, where his interest in agricultural chemistry was kindled. For his doctoral thesis, Atwater made the first modern analysis of a food—in this case, feed corn—in the United States.
With the ink still fresh on his doctorate, he set out for Leipzig and Berlin to study physiological chemistry with the masters. During his 2 years abroad, he became familiar with European agricultural experiment stations. This spurred him to campaign actively for a similar scientific program in the United States.
Two years after returning home, he found his way back to his alma mater and remained at Wesleyan University until his death in 1907. But he didn't teach much at Wesleyan; research was his love. Atwater's son recalled that his father was threatened with having his salary cut in half "if he persisted in outside experiments...." However, he was given the alternative of hiring a teaching assistant at his own expense—which he did.
One experiment Atwater did not plan occurred accidentally while he was in Parisin early 1893, and it illustrates his equanimity. He related the episode to his close friend and colleague C.D. Woods back in Middletown:
"You know I have long wanted to know the action of ptomaines from the flesh of fish. In accordance with my usual theory that the best way to learn is by practical experiment, I have been eating fish with the ptomaines—at least that is what the doctor says.
"Literally from the crown of my head to the sole of my feet I have been covered with swelling and blotches, feel as big as an ox, have a color approaching that of beefsteak, and a variety of aches and bruises which have left me with no lack of entertainment.... I think this one experiment will suffice of the demonstration."
Even under duress, Atwater showed good humor, though quite dismayed that the illness "took ten precious days out of my working time." He was a man of action.
As a special agent for USDA, he scouted top European laboratories and solicited articles and abstracts from the foremost researchers in agricultural and human nutrition studies. These would be translated and printed in the Experiment Station Record, one of three periodicals Atwater began as director of USDA's Office of Experiment Stations.
With utmost courtesy, Atwater badgered the European heavyweights for articles, abstracts, and answers. He wanted "to lift the Record and Bulletins to a higher scientific level," he wrote to a USDA contact. These publications were intended to inform researchers in the fledgling stations about the state of physiological research and guide them in designing their own studies.
But Atwater was aiming even higher. "My opinion," he noted, "is that we are in a fair way to make the Record and Bulletins the best publications of their kind in any language, and that if we keep on improving they will come to be recognized as such."
His leadership had been a major factor in getting Congress to provide $15,000 annually to each state and territory for the support of agricultural experiment stations. In fact, Atwater served as the first director of the new Office of Experiment Stations, on the condition that he could continue his research as professor at Wesleyan and director of the state station at Storrs, Connecticut.
When the workload grew to require full-time management in 1891, Atwater resigned his position—but not his mission. In fact, his life's calling was just beginning to crystallize. He began formulating plans for comprehensive studies of the chemical composition of foods, the effects of cooking and processing on nutrient content, the amount and types of food consumed by different groups of Americans, and the amount of energy (calories) people burned each day and thus needed to replace. He focused on soliciting funds to support this research. After all, these were uncharted waters, and there was no guarantee that USDA would come through.
So Atwater "talked nutrition to church groups, businessmen's clubs, wealthy potential patrons, and government officials," notes Ross A. Gortner, Jr., a successor of Atwater's at Wesleyan University. "On many occasions, he financed the purchase of new equipment out of his own pocket. His staff, too, shared his enthusiasm and at times carried on their share of the work knowing that there might not be funds to cover their salaries."
Atwater even succumbed to showmanship. In October 1893, at the Chicago World Fair, he assembled l6 chemists who prepared and analyzed food before wide-eyed onlookers. The demonstrations stirred public interest and no doubt gave nutrition research a big push.
Atwater's most persistent trait was persistence itself. He did not become the father of American nutrition on intellect, charm, and vision alone. He simply never gave up.
In the 10 years that Atwater headed the federal nutrition program, he conducted or coordinated research in four areas:
1.Types and amounts of foods consumed by different groups.
2.Chemical composition of foods.
3.Effects of cooking and food processing on nutritional quality.
4.Amounts and types of nutrients people need to function at their best; this entailed studies of human metabolism and respiration.
The fact that these four research areas are still pursued actively today is testimony to Atwater's vision. He could not have imagined the scale or scope of today's research, but he would have applauded the emphasis on maintaining health through a good diet. The following sampling of today's research at the five human nutrition research centers under USDA's Agricultural Research Service attempts to bridge the gap between then and now.
Atwater oversaw more than 300 food consumption studies of families and institutions in 17 states, involving more than 10,000 men, women, and children. These included students, college athletes, the families of professional men, mechanics, farmers, and laborers, in widely separated states and of diverse ethnic groups.
Concerned about the nutrition of the poor and disadvantaged, Atwater supervised intake studies of black sharecroppers, Mexican families, poor whites, and inmates in state mental institutions. His observations ring true even today: "The differences in diet. . . are influenced, to some extent, by race habits, and to a still larger extent, by the material conditions of the consumer. . .especially the income."
Then and Now
Atwater left no stone unturned in gathering data on the eating habits of people worldwide. He scoured the European literature, wrote to missionaries in India, and cited studies of Chinese living on the U.S. Pacific coast, among others.
But the data he collated would pale beside the hundreds of intake studies done today, ranging from surveys of small population subgroups to those of national scope. Unlike the earlier surveys, today's studies are based on scientific samplings that accurately reflect the populations under scrutiny.
USDA's Human Nutrition Information Service (HNIS) and the Department of Health and Human Service's National Center for Health Statistics are the two federal agencies responsible for conducting the major national surveys. Happily, the two agencies are located side-by-side in Hyattsville, Maryland.
ARS, while rarely involved in population surveys, develops or improves tools used in collecting and analyzing such data. For example, researchers at the Western Human Nutrition Research Center in San Francisco have automated the recordkeeping for smaller surveys.
Volunteers need only enter bar codes of the food they eat and weigh the portions. A laptop computer connected to the scale computes and stores the data for later evaluation.
Studies done with NESSY—the Nutrition Evaluation Scale System—show it doesn't cause people to eat less than they normally would. That's been a problem before, when people are asked to write down everything that passes through their lips.
All five ARS centers develop or improve methods to assess people's nutritional status, particularly by noninvasive means. But it is a major emphasis at the Western center. Scientists there focus on marginal vitamin and mineral deficiencies—which are much more common than severe malnutrition in this country—and also on the consequences of excess intakes.
More than a decade ago, the Human Nutrition Research Center on Aging at Tufts in Boston was launched to study the role of nutrition in keeping people healthy well into old age. One of the first orders of business was to get a nutritional profile of the over-60 population.
Center scientists gathered data on the diets and nutritional status of nearly 700 people living on their own in the Boston area and of some 350 living in nursing homes. The eldest was 102. The survey provided much data on this rapidly growing segment of the U.S. population and has served to guide researchers to problem areas or unanswered questions.
In 1896, Atwater and Wesleyan graduate student A.P. Bryant published The Chemical Composition of American Food Materials, or simply, Bulletin No. 28. This bulletin would become the forerunner of USDA's Agriculture Handbook 8—the dietitian's bible. It listed the minimum, maximum, and average values of the known nutrients in all American foods analyzed by July 1895.
"Within 4 years, so many new analyses had appeared that a revised edition of the bulletin was issued," wrote Ross A. Gortner, Jr., who followed Atwater at Wesleyan University. "More than a third of all these analyses were performed by Atwater and his associates in the chemical laboratory at Wesleyan."
A 1906 reprinting of the bulletin, with only minor changes, stood until June of 1940 when USDA Circular No. 549 was published. Gortner noted, "I'm sure that [Atwater] could not have anticipated that it would not be superseded until some 40 years later...."
The responsibility for maintaining and updating data on the composition of American foods now lies with the HNIS. Chemists at ARS' Human Nutrition Research Center in Beltsville, Maryland, work hand in hand with HNIS to develop faster, simpler, or more accurate analytical methods and to ensure quality control in the testing laboratories.
For example, they have streamlined the official analytical methods for assessing dietary fiber as well as for cholesterol in mixed foods. And they have developed several food standards that testing laboratories use to check their procedures for accuracy.
Research is also being conducted on vitamins and other food constituents that appear to prevent heart disease or cancer, such as carotenoids and flavonoids. These two classes of compounds are abundant in many fruits and vegetables and give these foods their distinctive colors and flavors.
"The analytical sensitivity of many of the methods that are being used could not have been imagined by scientists during the time of Atwater, says Joseph T. Spence, director of the Beltsville center.
What Do Fresh Foods Lose?
Atwater also wanted to know how cooking and processing affected the nutritional quality of foods. He launched studies on nutrient losses during the boiling of vegetables, digestibility of breakfast cereals, changes incurred in the cooking of meats, and effects of milling and baking bread.
Because he was concerned only with fats, carbohydrates, and proteins, some of Atwater's conclusions are faulty today. For instance, he found that people absorbed more of these nutrients from bread when the flour was finely ground. So he concluded that milling wheat to retain a large proportion of the bran and germ decreased its nutritional value.
Today, we know that whole wheat flour contains vitamins, minerals, and fiber not found in white flour.
This line of research is now largely in the hands of state universities, although a good deal is conducted by the food industry for its own use. ARS, on the other hand, is heavily involved in breeding crops having better balance and availability of nutrients, such as beta carotene or beta glucans, and meat animals with less fat or less saturated fat.
One ARS study, however, captured the news in 1992. It looked at the effects of trans fatty acids on blood cholesterol. These fats are formed when vegetable oils are hydrogenated to make margarine and many other products. The study showed that they have the potential to raise cholesterol and their place in the diet has become a matter of controversy. Now Beltsville researchers are working to define the circumstances under which this might occur.
Just the Right Amount?
Most of the research done by ARS nutrition centers is about nutrient requirements. Knowledge of the types and amounts of nutrients we need to consume each day has grown exponentially since the days of Atwater. All of the vitamins and most of the minerals and trace elements known to date were discovered after his death in 1907. And other food constituents are proving their value against cancer, diabetes, or heart disease.
What's more, the emphasis is no longer on increasing human physical output or preventing deficiency diseases. Research today aims at enabling everyone to reach their optimum health, given the genes they are dealt at conception, and to maintain it as long as they live.
The best way to maintain good health throughout life is to get off to a good start. That's why the Children's Nutrition Research Center was begun in 1978 as a cooperative venture with Baylor College of Medicine and Texas Children's Hospital in Houston.
Most of the studies have dealt with infants, including the tiniest preemies, pregnant women, and nursing mothers. But research here is expanding to address energy and other nutrient requirements of children and the special needs of pregnant and nursing teenagers.
Houston researchers are finding that the proteins and fats in mother's milk do more than nourish the infant. Some of them signal the infant's immune and digestive systems to mature, as well as affect the infant's overall health.
This could explain why breast-fed infants took in one-fourth fewer calories and one-half less protein than formula-fed infants, yet gained and developed with greater efficiency, says center director Buford Nichols. He believes that "the search for these and other 'molecular messages in the diet of infants and adults will continue to dominate nutrition research into the next century."
A substantial amount of the center's work goes into developing safe and noninvasive studies that can be done on infants, even those born before term. Researchers have perfected the use of stable isotopes—those nonradioactive variants of nature's elements. They can determine which amino acids an infant is synthesizing at a given time or how fast it is making its own cholesterol. These data will help nutritionists establish optimum diets for infants.
At the Western center, scientists are learning how adults can get a proper balance of nutrients when faced with the vast selection of foods in the marketplace—especially when health organizations and the federal government are recommending major changes in our diets. With only slight changes in food items, researchers were able to select diets containing 25 to 30 percent of calories from fat, much less cholesterol, and a higher ratio of polyunsaturated to saturated fat than in average contemporary diets.
The diets not only reduced serum cholesterol, says acting center director Judith R. Turnlund, they also had a dramatically higher vitamin and mineral content because of extra carbohydrates.
Studies at the Grand Forks [North Dakota] Human Nutrition Research Center over the past 20 years have resulted in the discovery of new trace elements—such as boron—as wel1 as new functions for known ones. That's the main mission of the Grand Forks center, although the Western and Beltsville centers are also involved in trace element research.
But discovery is just the beginning. Researchers need to determine how much is essential, what foods supply the element, what factors interfere with or enhance the body's absorption or use of it, and more. What's more, they also study established trace elements that are consumed in only thousandths or millionths of a gram, to learn the consequences of marginal intakes.
For example, in studies at Grand Forks, boron is proving to play a role in maintaining healthy bones and optimal brain and motor function. And adequate intakes of two well-known trace elements—iron and zinc—have been found necessary for people to maintain body temperature in the cold, in addition to their established functions. [See Agricultural Research, October 1992, pp. 4-11.]
Researchers at all five centers are developing or improving methods for measuring body fat and lean tissue. Many Americans are overfed: A high fat-to-lean ratio is our biggest health hazard. It's especially serious in the elderly, because they lose lean tissue at a much faster rate than younger people.
The Boston center, established in 1980, operates under a contract between ARS and Tufts University. Researchers there are breaking new ground in learning the special needs of older people.
Recommended Dietary Allowances have been estimated largely from studies of younger adults because of the paucity of data on the aging population. In fact, the RDA's currently put all people over 50 into a single category. But an 80-year-old is no more like a 50-year old than the latter is like a 20-year-old.
Center studies have shown that the loss of acid-secreting cells in the stomach—a common problem with aging—can interfere with absorption of vitamin B-12 from food but not from supplements. It also appears that senior citizens need to consume more vitamin B6 than currently recommended for their age group. And women past menopause need more vitamin D, as well as adequate calcium, to prevent osteoporosis.
A good deal of research at the Boston center deals with antioxidants, such as vitamins C and E and beta carotene. If the process of aging that we once took for granted is due to cumulative damage by oxygen free radicals, then increasing antioxidants may help prevent it, theory holds. And studies suggest that antioxidant vitamins may delay cataracts or boost a flagging immune system.
The most promising news out of the center shows that declines in cardiovascular fitness and muscle strength are due to inactivity rather than aging. Elderly people can vastly improve both functions with the right exercises. There truly is no age limit on getting fit.
Atwater recognized his limited knowledge when he wrote in the 1894 USDA Yearbook of Agriculture: "Some foods have at times a great value outside of their use for nourishment. Fruits and garden vegetables often benefit people greatly not as mere nutriment...." His words were prophetic: These foods provide a wealth of vitamins, minerals, and compounds like carotenoids; they also provide a lot of fiber.
And the concept of nutriment continues to grow.
Who knows how many food constituents—unknown or ignored—future research will show to have unsuspected effects on our metabolic processes? That's why it is so important to get our nutrients from a variety of fresh foods instead of relying on vitamin supplements to substitute for a poor diet. Look what we might be missing.—By Judy McBride, ARS, with contributions from nutrition research center directors Buford Nichols,Forrest Nielsen, Joseph Spence, and Judith Turnlund.
This article appeared as "W.O. Atwater - Father of American Nutrition Science", published in the June 1993 issue of Agricultural Research magazine.