CHROMIUM IN ADULT DIABETES AND CARDIOVASCULAR DISEASE
by John H Olwin, MD, Clinical Professor of Surgery, Emeritus, Rush Medical College and Abraham Lincoln School of Medicine, University of Illinois; Attending Surgeon, Emeritus, Rush-Presbyterian-St. Luke's Medical Center; member of NOHA's Professional Advisory Board
and Eugene L Kanabrocki, PhD*
Scientists for many years have recognized that very small concentrations of certain elements, such as zinc and iodine, are essential for the metabolic processes involved in life. Years ago these elements were identified as "trace" elements because their exact concentrations were unobtainable by the methods then available. Today we define a trace element as one that constitutes less than 0.01 per cent of an organism and we are able to measure concentrations in parts per million to parts per billion with great accuracy and precision.
At least fourteen different trace elements have been identified as probably essential to human metabolism and health, all but four of which are metals. The list includes chromium, cobalt, copper, fluorine, iodine, iron, manganese, molybdenum, nickel, selenium, silicon, tin, vanadium and zinc. Arsenic may also be essential. There is a voluminous literature for each of these elements, particularly as to how it relates to health and disease. This article is concerned primarily with chromium and its role in the prevention and control of latent diabetes and cardiovascular disease.
During the past several decades considerable attention has been focused on the biological form of chromium, most of the studies being concerned with the site and mode of its action. More recently, the micro-nutritional role of chromium in plants, animals and man, has been noted in relation to the ever-increasing consumption of highly refined and processed foods from which chromium has been either eliminated or greatly reduced. In the industrial countries of Western Europe and North America, where most of this processing has occurred, there has also been an increase in the incidence of adult-onset diabetes mellitus (Type II) and cardiovascular disease, both believed to be related to the increased consumption of refined sugar and refined flour products. Several independent observations indicate that chromium deficiency impairs glucose tolerance. There is recent medical evidence showing that a dietary supplement of chromium is of some value in the control of the early stages of adult-onset diabetes. This appears to depend on the presence of insulin production by special cells in the pancreas and diabetes cannot be controlled by supplements of chromium without an adequate supply of insulin. Chromium is apparently effective only in subjects who produce some endogenous insulin.
According to the latest estimates of the American Diabetic Association there are approximately 14 million Americans with diabetes, half of whom are undiagnosed. Approximately 90% have adult-onset diabetes, and the remaining 10%, the Juvenile type (Type I). The latter, the more severe type, is responsible for most of the severe complications notably early blindness, diabetic coma, insulin reaction, and severe atherosclerosis and its many complications. Diabetes costs the American economy more than $20 billion a year and is responsible for at least one in every ten hospital admissions.
Sugar supplies one quarter of the total calories consumed in the average American diet. From all sources this amounts to over 200 grams of sugar per day. Refined sugar contains little or no chromium. Other than sugar, the major source of carbohydrates in our diet is from refined white flour. Whole wheat contains about 175 micrograms of chromium per 100 grams while refined flour contains only 23. White flour may cause a depletion of body chromium just as does the refined sugar. An estimated 50 to 90 per cent of Americans fail to ingest the required daily allowance of 50-200 micrograms of chromium recommended by the National Research Council. Marginal dietary intake of chromium appears widespread in the United States and other developed countries. Frequently even supposedly well-balanced diets do not provide adequate chromium to meet the daily requirement. Aging, stress, and continuing the consumption of highly refined sugar and flour products further compromises the chromium status of most individuals. Chromium deficiency can take ten to forty years to manifest itself as glucose intolerance, resulting frequently in Type II diabetes and subsequent cardiovascular disorders.
Chromium, its properties and distribution
Chromium (Cr) atomic weight 51.996, has valences of 1 to 6. It is a steel-gray, lustrous metal with concentrations in the earth's crust of100 to 300 ppm. It is absorbed by the roots of plants, including grains, and finds its way into the food chain as a biologically active organic complex, known as Glucose-Tolerance-Factor (GTF), an as yet chemically unidentified chromium-containing compound, readily absorbed by animals, including man. GTF has been shown to act as a cofactor with zinc for insulin utilization in glucose metabolism. It is non-toxic, and is more readily metabolized than the inorganic salts of chromium, which are very poorly absorbed by the gastrointestinal tract and may cause some irritation when given in doses larger than 200 micrograms per day. As with any essential element too much can be toxic. Chronic exposure to chromate dust has been correlated with increased incidence of lung cancer.
The estimated total chromium in an average adult is less than 6 milligrams. It is widely distributed in human tissues in extremely low concentrations, 0.02 to 0.04 ppm, on a dry-weight basis. Prolonged consumption of insufficient amounts of dietary chromium leads to symptoms similar to those observed for diabetes mellitus and cardiovascular disease. Studies in mice and rats reveal that chromium is essential for growth, and increases the animals' longevity. The concentration of chromium in the human pancreas (obtained at autopsies of subjects with a variety of diseases) range between 0.10 to 0.85 ppm. The chromium concentration in organs from diabetic subjects is significantly lower than that obtained from non-diabetics. Here in the United States tissue levels of chromium are known to decline with age, a trend the authors have observed in their own pilot-study of chromium concentration in finger-nails.
Adult-onset diabetes and cardiovascular disease
Tissue levels of chromium in populations with a high incidence of adult-onset diabetes and cardiovascular diseases, such as Western Europeans and North Americans, decrease markedly with age, whereas in populations with a lower incidence of these diseases, such as Africans and Orientals, these levels remain high. The chromium content in the hearts of these subjects is 4 times higher than in North Americans, and in the kidneys and aortas it is 7 times higher.
Schwartz and Mertz (some NOHA members will remember Dr. Walter Mertz who spoke before its membership in May, 1983) have shown that the trivalent form of chromium increases glucose tolerance in rats. Later work established chromium as a cofactor with insulin at the cellular level forming a complex at pancreatic membrane sites. These same investigators have demonstrated that impaired glucose tolerance was due to a deficiency of the "new" dietary agent designated as GTF in which the active component was shown to be trivalent chromium. Significant improvement in glucose tolerance in people with chromium deficiency has been demonstrated during oral supplementation with trivalent inorganic chromium. Glucose intolerant subjects are known to be at high risk for Type II diabetes and subsequent cardiovascular disease. Such intolerance is diminished following chromium supplementation.
Although chromium deficiency can take 10 to 40 years to manifest itself as glucose intolerance, the condition can be reversed very quickly when adequate chromium is added to the diet. It should be emphasized again that to be able to reverse the glucose intolerance, the subject must produce endogenous insulin. Subjects who do not show evidence of endogenous insulin, such as those with Juvenile (Type I) diabetes, appear not to benefit from exogenous chromium. Marginal chromium deficiency states, confirmed by improvement in glucose tolerance testing following chromium supplementation have been described in malnourished children, diabetics, the elderly, and in apparently healthy individuals.
Experiments in rats show that chromium deficiency is associated with higher prevalence of aortic plaques, whereas a life-time administration of this metal in trace amounts prevents the formation of atheromatous lesions, decreases the serum cholesterol level, and prolongs the life-span of these animals. A significant decline in serum cholesterol has also been reported in patients receiving 2 milligrams of chromium, in acetate form, daily for a period of five months. More recently in a large study involving 63 human adult subjects, each receiving 600 micrograms of biologically active chromium (GTF) daily over a period of 3 months, their high-density-lipoprotein cholesterol (the protective portion of total cholesterol) increased – a much desired and otherwise very difficult-to-achieve effect in subjects with coronary artery disease.
Dietary sources of chromium
Brewers yeast appears to be the richest source of GTF-chromium, followed closely by black pepper, wheat germ, rye bread, mushrooms, prunes, wine, and beer. Most meats, fresh fruits, and cheeses are fair sources of chromium. Cereals are poorer sources, their chromium decreasing with refining and processing. A good reference on "Chromium in Foods in Relation to Biological Activity" by Toepfer, Mertz, Rodinsky and Polansky, was published in 1973 in Agricultural and Food Chemistry, Volume 21, pages 69-73. Most reference materials available to dietitians today provide very inadequate trace element information, particularly on chromium.
The importance in human health and nutrition of deficient chromium intake from diets high in refined carbohydrates has been a topic of numerous reports. The general population, as well as the medical profession, appear to be poorly informed about the potential effects of dietary deficiencies. It has been estimated that at least 35 percent of all diseases in man can be traced to some dietary deficiency. In the case of cancer it is 30 to 65 per cent. The overall reduction in the consumption of saturated fats for the correction of lipid abnormalities and consequent heart disease, as well as increases in fiber consumption for the reduction of colon cancer, are but two examples where the public is getting the message. Similar dietary awareness with regard to the effect of insufficient dietary chromium is bound to affect beneficially the growing number of individuals with Type II diabetes and coronary artery disease. Avoidance or at least a reduction in consumption of highly refined carbohydrate products should be a high priority item in advice given by educators and the medical profession.
ACKNOWLEDGEMENT: We are indebted to Miss Eileen S Connor, RN, Dietary Service, Veterans Administration Hospital, Hines, Illinois 60141, for her assistance in the preparation of parts of this report.
Members of NOHA desiring further information on the role of metals in health and disease may wish to read my article, "Metals in the Life of Man" from volume one of the Journal of Analytical Toxicology. Reprints are available without cost by writing to NOHA, P.O. Box 380, Winnetka, Illinois 60093. Please enclose a self addressed, stamped, business-size envelope.
*The above article provides an introduction to NOHA members of Eugene L. Kanabrocki, PhD. He is a biochemist and he and I have been associated in various research projects over a period of years. He is particularly involved in the science of Chronobiology–the study of the relation of time to and its influence on biologic phenomena and functions in both health and disease. He received his BS in chemistry from DePaul University in Chicago, MS in biochemistry from Loyola University in Chicago, and his PhD from the Jagiellonian University in Krakow, Poland, in the same great hall of the university where Copernicus received his degree some four hundred years earlier. As many of you know, Copernicus first told the scientific world that the planets revolve around the sun and the earth's turning on its axis accounts for the apparent rising and setting of the sun and the stars.
Dr. Kanabrocki is presumably retired but to observe him at work and in the laboratory one would never suspect such.
For the convenience of those who may wish to learn more about the role of chromium in cellular metabolism and how chromium may be related in diabetes and cardiovascular disease, the following partial list of references is provided:
Anderson, R.A., N.A. Bryden, and M.M. Polansky, "Serum Chromium of Human Subjects: Effects of Chromium Supplementation and Glucose," The American Journal of Clinical Nutrition , 41: 571-7,1985.
Masironi, R., "Trace Elements and Cardiovascular Diseases," Bulletin,World Health Organization, 40: 305-12, 1969.
Masironi, R., W. Wolf, and W. Mertz, "Chromium In Refined and Unrefined Sugars –Possible Nutritional Implications In the Etiology of Cardiovascular Diseases," Bulletin,World Health Organization, 49: 322-4, 1973. Mertz, W. and E.E. Roginski in Newer Trace Elements In Nutrition, Mertz, W. and W.E. Cornatzer, Eds., Mercel-Dekker, New York, NY, pp. 123-53,1971.
Mertz, W., "Effects and Metabolism of Glucose Tolerance Factor," Nutrition Reviews, 33: 129-35, 1975.
Morris, B.W., A. Blumsohn, S. MacNeal, T.A. Gray, "The Trace Element Chromium – A Role In Glucose Homeostasis," American Journal of Clinical Nutrition, 55(5): 989-91, 1992.
Mossop, R.T., "Trivalent Chromium, In Atherosclerosis and Diabetes," Central African Journal of Medicine, 37(11): 369-74, 1991.
Naess, K., "The Significance of Chromium In Metabolic Cardiovascular Disease," Tidsskrift For Den Norske Laegeforening, 112(8): 1056-7, 1992.
Schroeder, H.A., "The Role of Chromium In Mammalian Nutrition," American Journal of Clinical Nutrition, 21: 230, 1968.
Underwood, E.J., Trace Elements In Human and Animal Nutrition, 3rd ed., Academic Press, New York, NY, pp. 253-64, 1971.Article from NOHA NEWS, Vol. XVII, No. 4, Fall 1992, pages 2-4