1. Anderson RA, Cheng N, Bryden NA, Polansky MM, Cheng N, Chi J, et al. Elevated intakes of supplemental chromium improve glucose and insulin variables in individuals with type 2 diabetes. Diabetes 1997;46:1786–91.
2. Nestler JE, Beer NA, Jakubowicz DJ, Beer RM. Effects of a reduction in circulating insulin by metformin on serum dehydroepiandrosterone sulfate in nondiabetic men. J Clin Endocrinol Metab 1994;78:549–54.
3. Crave JC, Fimbel S, Lejeune H, et al. Effects of diet and metformin administration on sex hormone-binding globulin, androgens, and insulin in hirsute and obese women. J Clin Endocrinol Metab 1995;80:2057–62.
4. de Jager J, Kooy A, Lehert P, et al. Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B-12 deficiency: randomised placebo controlled trial. BMJ 2010;340:c2181.
5. Carpentier JL, Bury J, Luyckx A, Lefebvre P. Vitamin B 12 and folic acid serum levels in diabetics under various therapeutic regimens. Diabete Metab 1976;2:187–90.
6. Carlsen SM, Folling I, Grill V, et al. Metformin increases total serum homocysteine levels in non-diabetic male patients with coronary heart disease. Scand J Clin Lab Invest 1997;57:521–7.
7. Bauman WA, Shaw S, Jayatilleke E, et al. Increased intake of calcium reverses vitamin B12 malabsorption induced by metformin. Diabetes Care 2000;23:1227–9.
8. McBain AM, Brown IR, Menzies DG, Campbell IW. Effects of improved glycaemic control on calcium and magnesium homeostasis in type II diabetes. J Clin Pathol 1988;41:933–5.
9. Gin H, Orgerie MB, Aubertin J. The influence of Guar gum on absorption of metformin from the gut in healthy volunteers. Horm Metab Res 1989;21:81–3.
10. Kudolo GB. The effect of 3-month ingestion of Ginkgo biloba extract (EGb 761) on pancreatic beta-cell function in response to glucose loading in individuals with non-insulin-dependent diabetes mellitus. J Clin Pharmacol 2001;41:600–11.
11. Cardot JM, Saffar F, Aiache JM. Influence of food on glycemia, insulin, C-peptide and glucagon levels in diabetic patients treated with antidiabetic metformin at steady-state. Methods Find Exp Clin Pharmacol 1997;19:715–21.
12. Sambol NC, Brookes LG, Chiang J, et al. Food intake and dosage level, but not tablet vs solution dosage form, affect the absorption of metformin HCl in man. Br J Clin Pharmacol 1996;42:510–2.
13. Sifton DW, ed. Physicians Desk Reference, Montvale, NJ: Medical Economics Co., Inc., 2000, 831–5.
14. Threlkeld DS, ed. Hormones, Antidiabetic Agents, Biguanides, Metformin HCl. In Facts and Comparisons Drug Information. St. Louis, MO: Facts and Comparisons, May 1995, 130n–130u.
