B vitamins and Cancer



B vitamins and Cancer

Introduction

Vitamins, taken in the proper amounts, are essential for health maintenance the prevention of certain diseases such as cancer, scurvy, rickets and pellagra. They are generally considered healthy harmless, even in doses far exceeding the recommended daily allowance (RDA) are touted to enhance athletic performance prevent the common cold, facilitate weight loss, treat a multitude of medical ailments. However, taken in excess either chronically or acutely, many vitamins can cause significant toxicity.

B vitamin Nomenclature

The confusing nomenclature of the B vitamins can only be understood historically. In 1915 E. V. McCollum and M. Davis concluded that young rats needed two unknown “growth factors,” one fat-soluble and the other water-soluble, and for convenience they called them “factors A and B,” respectively. Casimir Funk had already coined the term “vitamine” in the belief that any unknown factors would prove to have the chemical structure of “amines.” J. C. Drummond then suggested that the term be modified to “vitamin,” which had no chemical significance, and he called the antiscurvy factor “vitamin C.”

Further research showed that “factor B” was made up of at least two components, one heat-labile and the other more stable; these were termed vitamins B1 and B2 respectively. Vitamin B1 was later shown to be the anti-beriberi vitamin, known as thiamine. The B2 factor was again found to be complex. Among other things, it included riboflavin, which was first named “vitamin G” in honor of Joseph Goldberger, who had made classical studies of pellagra in the United States. The designation vitamin B3 was given to a compound that seems to have been pantothenic acid but was sometimes incorrectly used to mean niacin. Biotin was first called “vitamin H” by workers in Germany who had shown that its deficiency in rats resulted in abnormalities of the skin (in German Haut), and folic acid, at one time, was termed “vitamin M” because it was first shown to be needed by monkeys. Today, however, these three letters, namely, G, H, and M, are no longer used, and the vitamins are known by the names riboflavin, biotin, and folic acid and classified as parts of the vitamin B complex.

In recent years, some entrepreneurs engaged in selling materials that have been claimed to cure cancer and other diseases have named their products as vitamins in attempts to portray them as essentially natural materials, and so to escape the strict regulations applying to drugs. An example is B17, or “laetrile,” which is not recognized by orthodox nutritionists.

Thiamine

Use of polished rice as a dietary staple has long been known to lead to the development of a disease known as beriberi, which was first described as affecting Japanese sailors as well as prisoners in the Dutch East Indies. Signs of beriberi include paralysis due to polyneuritis and congestive heart failure. Christian Eijkman, a medical officer in Java, was the first to show (1890) that a paralytic illness resembling beriberi could be produced in chickens by feeding them polished rice (Jansen ...