The Discovery of Vitamins and Their Relationship to Good Health

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The Discovery of Vitamins and Their Relationship to Good Health

Overview

Vitamins are organic substances found mainly in foods that are essential in minute quantities for growth and health. Vitamins aid in regulating the body's metabolism and serve as catalysts for important chemical processes throughout the body. Some vitamins are necessary to aid in the release of energy from digested food. Others assist in the formation of hormones, blood, bones, skin, glands, and nerves. Only vitamin D can be manufactured by the body; all others must be introduced through the diet. Lack of sufficient vitamin intake has contributed to disease and dysfunction throughout the history of the world. During the early twentieth century, the important role of diet in the prevention of disease and maintenance of health was confirmed with the discovery of vitamins. Recent advances in chemistry, physiology, and biochemistry paved the way for scientists to isolate the "accessory food factors" (vitamins) necessary for health.

Background

Since ancient times, man suspected that diet and disease shared some relationship. The Greek physician Hippocrates (c. 460-377 b.c.) encouraged those who had trouble seeing the stars at night to eat beef liver. It is now known that liver contains vitamin A, a necessary vitamin for retinal health and vision. In the early eighteenth century Native Americans realized the benefit of consuming extracts made from pine needles when afflicted with scurvy, a disease causing bleeding gums, bruising, and severe weakness. The same symptoms were observed among British sailors later in the century, and the disease was remedied by including citrus fruit at intervals in the rations of the sailors (hence the nickname "limey"). Both pine needles and citrus fruit contain vitamin C, and scurvy is caused by the lack of vitamin C in the diet.

In the nineteenth century the relationship between disease and diet diminished in prominence, as French bacteriologist Louis Pasteur (1822-1895) and German physician Robert Koch (1843-1910) established the germ theory of disease. Between 1879 and 1900 the microorganisms responsible for many of the world's dangerous diseases were being discovered at a rate of over one per year. Infectious diseases were the leading cause of death, and the prevailing assumption was that diseases such as pellagra and beriberi, later known to be caused by vitamin deficiencies, were probably the result of infectious agents.

The study of beriberi by Dutch bacteriologist Christiaan Eijkman (1858-1930) paved the way for the discovery of vitamins. Eijkman was sent to the Dutch East Indies (present-day Indonesia) in 1886 to identify the microorganism presumed responsible for beriberi, a disease common to the rice-growing cultures of Asia. Symptoms of beriberi include severe muscle weakness and, eventually, cardiac failure. As director of the medical school and research laboratory in Batavia (now Jakarta), Eijkman probed the cause of beriberi by studying the diet of the hospital chickens. Eijkman found that the chickens developed an avian (bird) form of beriberi when they were fed the polished white rice given to patients. When given their normal diet of brown rice, the chickens recovered. Eijkman and his colleagues suggested that beriberi was due to the absence of some factor in the polished rice that the brown rice hulls contained. Next, Eijkman surveyed prisoners on the Indonesian island of Java, documenting the prisoners' environment, diet, and the incidence of beriberi. Eijkman found no correlation between environment and beriberi, but he did discover that two thirds of the prisoners who were fed polished white rice had the disease, compared with only a few who were fed brown rice. Eijkman later produced an extract from the rice hulls that he was convinced contained the "antidote" for beriberi.

British biologist Frederick Gowland Hopkins (1861-1947) shared the view that certain disease states could be explained by dietary deficiencies. At Cambridge University in 1906, he conducted a series of experiments manipulating the diet of young rats. In feeding the rats starch, sugar, salt, casein, and lard, Hopkins gave the rats all the nutrients that were, at that time, presumed necessary for life. Hopkins supplemented the diet of some of the rats with milk. The rats without milk failed to thrive, while the rats given milk grew normally. Hopkins concluded that small amounts of "accessory food factors" are necessary for growth, and without them diseases of deficiency occur.

At the Lister Institute in London, Polish-born biochemist Casimir Funk (1884-1967) in 1912 isolated the "accessory food factor" in rice hulls that prevented beriberi. His name for the substance was "vitamine"—vital for life and containing nitrogen (amine). With the deficiency process shown in the laboratory, the search began to isolate and define vitamins. Later, the final "e" was dropped when it was learned that all vitamins did not contain amines.

At the time of Funk's discovery in England, the United States was plagued with pellagra, a disease whose symptoms include skin eruptions, diarrhea, dementia, and death. Pellagra was mostly confined to the southern states, with South Carolina alone reporting over 30,000 cases with a 40% mortality rate. Hungarian-American physician Joseph Goldberger (1874-1929), a surgeon with the United States Marine Hospital Service (later named the United States Public Health Service), was sent to the South in 1914 to find a cure for pellagra. During his travels throughout the southern states, Goldberger noticed that pellagra did not occur in those who consumed a well-balanced diet. Neither Goldberger nor his colleagues contracted the disease although they spent considerable time among those affected. Goldberger, convinced that the solution to pellagra lay with chemistry and nutrition, abandoned the search for an infectious agent. In a series of controlled dietary experiments, Goldberger fed children in two Mississippi orphanages and inmates at the Georgia State Asylum a diet rich in fresh meats, milk, and vegetables, instead of their usual corn-based diet. The results were dramatic. Those at the institutions recovered from pellagra. Newcomers who were fed the new diet did not develop the disease. In a repeat study, eleven Mississippi prisoners (volunteers offered pardons for their participation) were fed only a corn-based diet. Goldberger noticed pellagra rash in six of the prisoners within six months. In a final dramatic experiment to convince critics that pellagra was not an infectious disease, Goldberger and his assistant injected themselves with blood from a person suffering from pellagra. Neither developed the disease. Although Goldberger never determined the vitamin deficiency responsible for pellagra (niacin, one of the B-complex vitamins), his epidemiological studies confirmed that balanced nutritional components are necessary for healthy life and disease prevention.

Impact

Goldberger brought the politics of nutrition under scrutiny with lectures condemning the relationship between wealthy landowners of the South and the poor sharecroppers who worked the land. Goldberger believed that the poor tenant farmers and millworkers were too destitute to eat a healthy diet and that the only permanent cure was social reform. In 1920, when a drop in cotton prices resulted in decreased income for many southerners, Goldberger predicted a rise in the number of pellagra cases to follow. Federal aid and appeals to southerners to provide local relief to the poor were inadequate, as many feared that investment and tourism would suffer if the southern states carried out a noisy public campaign against pellagra. By the end of 1922, pellagra cases had risen as Goldberger predicted. Land reform was occurring, not as a result of Goldberger's reasoning but due to the boll weevils' invasion of the cotton crop. Forced to diversify their plantings to eliminate the boll weevil, southerners also diversified their diets, and the number of pellagra cases declined.

The 1920s and 1930s brought a surge of discovery in the role of vitamins and nutrition. The anti-pellagra factor was shown to be a member of the B-group of vitamins in 1926. Eijkman won the Nobel Prize for his pioneering work in the discovery of vitamins in 1929. Thiamine, the vitamin whose deficiency causes beriberi, was finally crystallized from rice bran in 1926. In 1922 vitamin D was isolated and shown to be effective against rickets, a bone-weakening disease that was estimated to affect 80% of the poor children of Boston in 1900. Nobel prize winning scientist Albert Szent-Györgyi (1893-1986), discoverer of vitamin C in 1933, frequently lectured about the importance of vitamins in an attempt to raise the nutrition consciousness of his colleagues. American biochemist Edward A. Doisy (1893-1986) and Danish biochemist Henrick Dam (1895-1976) were jointly awarded the Nobel Prize for their work in the discovery of vitamin K and its importance in metabolic processes. In 1948 the complex relationship between vitamin B₁₂ stomach secretions, and pernicious anemia was unfolding. Usually considered fatal, pernicious anemia was effectively controlled with injections of vitamin B₁₂ isolated from beef liver.

World awareness of hunger and nutritional deficiency was made apparent by the economic depression of the West in the 1930s, famine in the developing world, and pockets of famine in countries devastated by World War II. In 1948 the League of Nations established the United Nations Food and Agriculture Organization, based on the belief that adequate food supply was essential to peace as well as the reduction of disease.

By 1950 vitamins became commercially available and specially formulated for the individual needs of babies, pregnant women, and adults. Fortification of foods, especially breads, cereals, flour, and other grains, with certain vitamins became standard practice. The National Academy of Sciences established recommended daily intakes for vitamins and minerals essential to health. Vitamin deficiency diseases such as pellagra and beriberi thereafter became almost non-existent in the United States and other industrial countries but remained a problem in the developing world.

BRENDA WILMOTH LERNER