X-Message-Number: 10772
Date: Fri, 13 Nov 1998 12:08:59 -0800 (PST)
From: Doug Skrecky <>
Subject: niacin deficiency blocks hypoglycemic effect of chromium

  Urberg M.  Zemel MB.
  Evidence for synergism between chromium and nicotinic acid
  in the control of glucose tolerance in elderly humans.
  Metabolism: Clinical & Experimental.  36(9):896-9, 1987 Sep.
  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.

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