SECTION I Understanding Vitamins Notes
VITAMINS: A HISTORICAL PERSPECTIVE
Nutrition, or the lack of it, has shaped the world. The pages of history record human suffering, disease, and the disability occasioned by malnourishment through the millennia. From the first description of beriberi in ancient Chinese writings (2500 b.c.) to the blight of scurvy that crippled or destroyed armies and navies from the time of Hippocrates to the Crusades, nutritional deficiency played a role. And it didn't end then. Human suffering from malnutrition followed us straight into the early twentieth century, when physicians filled mental institutions of the post-Civil War American South to overflowing with the hopelessly insane and disabled, many of whom suffered only from lack of the B vitamin niacin. How different a history humankind might have recorded were it not for the diseases occasioned by epidemic vitamin and mineral malnourishment.
Although throughout history medical investigators struggled to discover the link between illness and certain food habits, the concept of dietary deficiency causing disease did not become widely accepted until the late nineteenth century. Prior to that time, the prevailing scientific wisdom held that the diseases called scurvy, beriberi, pellagra, and rickets--which modern nutritional and medical science now accept without question as being caused solely by vitamin deficiencies--were caused by an unknown infectious agent or a toxin or poison in the food. At the turn of the twentieth century, several researchers began to believe that perhaps certain foods contained an "accessory food factor" that prevented disease. Based on early investigations, researchers believed that the critical "accessory food factor" belonged to a group of organic nitrogen-containing compounds called amines. They named their discovery "vital amines" (from the Latin vita for life, and the chemical class of amines) or vitamines. Continued study would ultimately prove that the compounds were not amines at all, but the name for the food factors stuck. In deference to accuracy or to avoid confusion, the pioneers of nutritional research decided to drop the final "e," creating the name by which we call them today: vitamins.1
Each disorder and the vitamin deficiency that causes it has a unique and interesting place in medical history, replete with the missed clues, false trails, and serendipity with which the advancement of medical knowledge often stumbles and bumbles forward. I ask you to thumb through the pages of nutritional history with me now as we examine the Big Four dietary deficiency disorders in turn.
The Classic Vitamin Deficiency Diseases
Beriberi: Thiamine (Vitamin B1) Deficiency
Over 4000 years ago, the ancient Chinese first described the disorder we recognize today as thiamine deficiency. This disorder, with the unusual name beriberi, strikes a wide assortment of body systems. Impairment of the nervous system and muscles from insufficient thiamine in the diet causes symptoms ranging from pain and weakness to paralysis and wasting; in the gastrointestinal tract, lack of thiamine may cause nausea, vomiting, bowel sluggishness, and constipation; and mental aberrations from mild irritability to frank depression, dementia, and paranoia can occur as well. Carried to its extreme, thiamine deficiency proves fatal.
It is not surprising that the ancient Chinese, in their voluminous writings on medicine, would have identified and first recorded the symptoms of this vitamin deficiency disease, since thiamine is found in the husks or bran of rice, a main staple in the Orient. Once the rice has been milled to remove the bran, however, most of the thiamine is lost. And so, with the advent of milling processes, the incidence of beriberi among the Chinese increased. Modern food manufacturers add thiamine back into milled rice products--a process called enriching the rice. But even today, beriberi occurs in third world countries where populations rely on milled, unenriched, white rice as a main dietary staple.
In the nineteenth century, a Japanese naval scientist named Kanehiro Takaki observed that some crews on long voyages at sea fell victim to an alarming number of cases of a deadly form of nerve inflammation, while the crews of other ships did not. In examining the dietary differences between ships, Takaki noted that the crews that escaped serious health problems carried less polished rice and more meat, fish, vegetables, wheat, and milk than the stricken crews. The addition of these foods (which all are rich in thiamine) to the sailors' diets prevented nerve problems and deaths from beriberi, which prevailing medical wisdom of the day held to be infectious--an opinion mainstream medical scientists continued to hold even after Takaki published his observations in a prestigious medical journal. The idea that disease could be caused by lack of some substance in the diet simply hadn't taken root in medical thought at that time. It was not, in fact, until 1890 that a Dutch physician named Christiaan Eijkman observed the causative connection between beriberi and diets high in polished rice. Ten years later, his colleague, Gerrit Grijns, proved that the disease could be prevented by adding the polishings back into the diet. One small mental step for Drs. Eijkman and Grijns, one giant leap for the nutritional good of humankind.2, 3
Pellagra: Niacin (Vitamin B3) Deficiency
Medical historians credit an eighteenth-century Spaniard named Gaspar Casal for the first Western description (c. 1735) of pellagra, as well as for his observation of its frequent occurrence among people relying on maize (corn) as a staple. Although the disease did occur commonly in Spain, it also claimed victims in southern France, Italy (its name is, in fact, from the Italian pelle agra, meaning rough skin),4 and the Balkan states in Europe.
In the Americas, pellagra occurred widely in the midwestern and southeastern portions of the United States and swept with a vengeance through the rural South following the Civil War, where impoverished populations subsisted on milled cornmeal, white flour, sweet potatoes, rice, and sugar: all foods with little usable niacin (or other B vitamins, for that matter). Although whole corn does contain niacin, humans cannot absorb the vitamin from corn. It occurs in a "bound" form--called niacytin--in which the niacin is attached to another large fibrous substance that the human gastrointestinal tract cannot readily absorb. However, treatment of the cornmeal with an alkaline solution, such as lime--a culinary practice common for centuries in Mexico and the southwestern United States to make it suitable for tortilla preparation--releases the vitamin from its nyacytin bound form, freeing the niacin in the corn for absorption by the intestine. Reliance on the lowly tortilla spared the Mexican and southwestern Indian populations from the ravages of pellagra even though corn is a dietary staple in these areas, too.
Deficiency of niacin causes the development of not only an inflamed scaly skin eruption, swollen red tongue, and irritation of the intestinal lining with diarrhea, but severe mental disturbance, as well. In fact, as recently as the 1920s, medical specialists condemned huge numbers of unfortunate people to the grisly confines of mental institutions for intractable mental derangement that could have been cured by adequate niacin in their diets.
Niacin insufficiency still occurs in Asia and southern Africa, where maize constitutes a significant portion of the diet.
1. John Yudkin, The Penguin Encyclopedia of Nutrition (Middlesex, England: Penguin Books, Ltd., 1986), 374. 2. Eleanor R. Williams, Nutritional Principles, Issues, and Applications (New York: McGraw-Hill, Inc., 1984), 277-278. 3. Herbert L. Newbold, Meganutrients: A Prescription for Total Health (Los Angeles: The Body Press, 1987), 146-147. 4. Yudkin, 281.
Excerpted from The Doctor's Complete Guide to Vitamins and Minerals by Mary Dan Eades. . Excerpted by permission of Dell, a division of Random House LLC. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.