Authors
Urberg M. Zemel MB.
Title
Evidence for synergism between chromium and nicotinic acid
in the control of glucose tolerance in elderly humans.
Source
Metabolism: Clinical & Experimental. 36(9):896-9, 1987 Sep.
Abstract
Impaired glucose tolerance results from Cr restriction in animals, and Cr
supplementation improves glucose tolerance in diabetic animals. These effects
are presumably due to the role of Cr in glucose tolerance factor (GTF), a
complex of Cr and nicotinic acid believed to facilitate insulin binding.
Humans, however, do not uniformly respond to Cr supplementation. The present
study was designed to evaluate the possibility that the failure results from
inadequate levels of dietary nicotinic acid to serve as substrate for GTF
synthesis. Sixteen healthy elderly volunteers were divided into three groups
and given either 200 micrograms Cr, 100 mg nicotinic acid, or 200 micrograms
Cr + 100 mg nicotinic acid daily for 28 days and evaluated on days 0 and 28.
Fasting glucose and glucose tolerance were unaffected by either
chromium or nicotinic acid alone. In contrast, the combined
chromium-nicotinic acid supplement caused a 15% decrease in
a glucose area integrated total (p less than .025) and a 7% decrease in
fasting glucose. None of the treatments exerted any effect on fasting or
one-hour insulin levels. Thus, these data suggest that the inability to
respond to chromium supplementation may result from
suboptimal levels of dietary nicotinic acid.