Chromium and Carbohydrate Metabolism

Chromium supplementation in impaired glucose tolerance of elderly: effects on blood glucose, plasma insulin, C-peptide and lipid levels

Matti I. J. Uusitupa^a1, Leena Mykkänen^a2, Onni Siitonen^a2, Markku Laakso^a2, Helena Sarlund^a2, Päivi Kolehmainen^a2, Tiina Räsänen^a2, Jorma Kumpulainen^a3 and Kalevi Pyörälä^a2

^a1 Department of Clinical Nutrition University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland

^a2 Department of Medicine, University of Kuopio, P.O. Box 1627, 70211 Kuopio, Finland

^a3 Central Laboratory, Agricultural Research Centre of Finland, Jokioinen, Finland

Abstract

Altogether twenty-six elderly subjects (aged 65–74 years) with persistent impaired glucose tolerance (World Health Organization (1985) criteria) identified in a population-based study, were randomly treated either with chromium-rich yeast (160 μg Cr/d) or with placebo for 6 months. The 24 h urinary Cr increased from 0.13 (se 0.03) to 0.40 (se 0.06) μg/d in the Cr group (n 13) but no change was found in the placebo group (n 11) (0.13 (se 0.02) v. 0.11 (se 0.02) μg/d). No significant change was observed in the oral glucose tolerance test (glucose dose 75 g; 0, 1 and 2 h blood glucose respectively): 5.3 (se 0.1), 9.3 (se 0.3), 8.2 (se 0.3) mmol/l v. 5.0 (se 0.1), 8.5 (se 0.4), 7.3 (se 0.5) mmol/l in the Cr group; 4.9 (se 0.2), 9.2 (se 0.6), 8.1 (se 0.3) mmol/l v. 4.8 (se 0.2), 8.5 (se 0.5), 7.0 (se 0.6) mmol/l in the placebo group (baseline v. 6 months). Glycosylated haemoglobin, plasma insulin, C-peptide and apolipoprotein Al and B levels remained unchanged, and no improvement was seen in serum total cholesterol (6.2 (se 0.3) v. 6.4 (se 0.3) mmol/l for the Cr group, 6.2 (se 0.4) v. 6.5 (se 0.3) mmol/l for the placebo group), high-density-lipoprotein-cholesterol (1.1 (se 0.1) v. 1.2 (se 0.1) mmol/l for the Cr group, 1.0 (se 0.1) v. 1.1 (se 0.1) mmol/l for the placebo group) or triacylglycerols (2.5 (se 0.4) v. 2.0 (se 0.4) mmol/l for the Cr group, 2.4 (se 0.2) v. 2.5 (se 0.2) mmol/l for the placebo group). The present results indicate that Cr supplementation does not improve glucose tolerance or serum lipid levels in elderly subjects with stable impaired glucose tolerance.

(Received November 09 1990)

(Accepted August 01 1991)

Key Words:

• Chromium;
• Impaired glucose tolerance;
• Insulin;
• C-peptide;
• Serum peptide