Wednesday, August 19, 2009

Vanadium

Overview

Vanadium is an essential trace mineral that has only recently been identified as being truly essential in humans. A normal diet typically provides about 10-30 micrograms (mcg) of vanadium per day. Although there is currently no RDA established, this amount appears to be adequate for most healthy adults. An Upper Limit dosage of 1.8mg/day has been established by the Food and Nutrition Board of the National Academies of Sciences.


Vanadium is thought to play a role in metabolism of carbohydrates and may have functions in cholesterol and blood lipid metabolism. Food sources of vanadium include seafood, mushrooms, some cereals and soybeans. In diabetics, vanadium supplements may have a positive effect in regulating blood glucose levels. Supplemental forms of vanadium are usually vanadyl or vanadate forms and are generally marketed with claims to mimic insulin action, reduce blood sugar levels, improve glycogen synthesis, and increase muscle size and vascularity.


Comments

Vanadium is an essential trace mineral that is not contained in many multi-vitamin/mineral supplements. It is thought, however, that we obtain enough vanadium from our diets. For those individuals concerned with maintaining blood glucose levels – such as diabetics or people with hypoglycemia, a vanadium supplement may be beneficial. Some bodybuilding and diabetic dietary supplements contain vanadium at milligram levels - when dietary needs are likely to be only in microgram amounts (1000 times lower). Prolonged consumption of high dose vanadium supplements is not recommended and may pose serious kidney and liver toxicity.


Scientific Support

Vanadium or the most common supplemental form, vanadyl sulfate, is thought to mimic the physiological effects of insulin by a mechanism which remains unclear (Cam et al. 2000). Through this insulin-mimetic effect, vanadium is thought to promote glycogen synthesis, maintain blood glucose levels and stimulate protein synthesis for muscle growth (Goldfine et al. 2000).


Vanadyl sulfate supplements have been shown to normalize blood glucose levels and reduce glycosylated hemoglobin levels (Boden et al. 1996) in patients with non-insulin dependent diabetes mellitus (NIDDM). Also in NIDDM patients, vanadium sulfate (100mg per day – a huge dose that is not suggested for long-term use) can reduce fasting glucose levels by about 20% and decrease hepatic insulin resistance (Cohen et al. 1995, Cusi et al. 2001). Normal (nondiabetic) subjects typically do not exhibit a significant change in glucose uptake or lipolysis, but vanadyl sulfate may acutely stimulate amino acid transport into skeletal muscle (Jandhyala and Hom, 1983). Studies of vanadyl sulfate for weight loss and exercise performance have been variable, with most showing only modest (if any) effects on body composition (Badmaev et al. 1999). Although vanadium has become a popular dietary supplement among bodybuilders, there is limited data to support claims of increased muscle mass and strength.


Safety/Dosage

Limited information is available about vanadium toxicity. Traditionally, vanadium is considered quite safe in humans (because of its poor absorption) – and an Upper Limit (UL) dosage of 1.8mg/day has been established by the Food and Nutrition Board of the National Academies of Sciences. In one safety study, 100mg of vanadyl sulfate (close to 10,000 times higher than dietary needs) was given to NIDDM subjects for 4 weeks (50mg twice per day). Gastrointestinal side effects were experienced by 75% of the subjects during the first week, but the supplements were well tolerated after that. The authors of the study concluded that vanadyl sulfate resulted in modest reductions of fasting plasma glucose – but they cautioned that the safety of large doses of vanadium supplements for long periods remained uncertain. It is thought that prolonged exposure to excessive vanadium could cause muscle cramps, emotional depression, and damage to the nervous system and other organs. Some animal studies have suggested the possibility of hematological and biochemical changes, reproductive and developmental toxicity, and pro-oxidative effects on glutathione, ascorbic acid, and lipids following prolonged vanadium feeding. Vanadium is now considered to be an essential trace mineral and 10mcg (micrograms) per day is thought to satisfy the body’s basic needs (our diets probably contain about 10-30mcg of vanadium per day).


References

1.Aharon Y, Mevorach M, Shamoon H. Vanadyl sulfate does not enhance insulin action in patients with type 1 diabetes. Diabetes Care. 1998 Dec;21(12):2194-5.

2.Badmaev V, Prakash S, Majeed M. Vanadium: a review of its potential role in the fight against diabetes. J Altern Complement Med. 1999 Jun;5(3):273-91.

3.Balasubramanyam M, Mohan V. Orally active insulin mimics: where do we stand now? J Biosci. 2001 Sep;26(3):383-90.

4.Boden G, Chen X, Ruiz J, van Rossum GD, Turco S. Effects of vanadyl sulfate on carbohydrate and lipid metabolism in patients with non-insulin-dependent diabetes mellitus. Metabolism. 1996 Sep;45(9):1130-5.

5.Brichard SM, Henquin JC. The role of vanadium in the management of diabetes. Trends Pharmacol Sci. 1995 Aug;16(8):265-70.

6.Cam MC, Brownsey RW, McNeill JH. Mechanisms of vanadium action: insulin-mimetic or insulin-enhancing agent? Can J Physiol Pharmacol. 2000 Oct;78(10):829-47.

7.Cohen N, Halberstam M, Shlimovich P, Chang CJ, Shamoon H, Rossetti L. Oral vanadyl sulfate improves hepatic and peripheral insulin sensitivity in patients with non-insulin-dependent diabetes mellitus. J Clin Invest. 1995 Jun;95(6):2501-9.

8.Cunningham JJ. Micronutrients as nutriceutical interventions in diabetes mellitus. J Am Coll Nutr. 1998 Feb;17(1):7-10.

9.Cusi K, Cukier S, DeFronzo RA, Torres M, Puchulu FM, Redondo JC. Vanadyl sulfate improves hepatic and muscle insulin sensitivity in type 2 diabetes. J Clin Endocrinol Metab. 2001 Mar;86(3):1410-7.

10.Goldfine AB, Patti ME, Zuberi L, Goldstein BJ, LeBlanc R, Landaker EJ, Jiang ZY, Willsky GR, Kahn CR. Metabolic effects of vanadyl sulfate in humans with non-insulin-dependent diabetes mellitus: in vivo and in vitro studies. Metabolism. 2000 Mar;49(3):400-10.

11.Goldwaser I, Gefel D, Gershonov E, Fridkin M, Shechter Y. Insulin-like effects of vanadium: basic and clinical implications. J Inorg Biochem. 2000 May 30;80(1-2):21-5.

12.Halberstam M, Cohen N, Shlimovich P, Rossetti L, Shamoon H. Oral vanadyl sulfate improves insulin sensitivity in NIDDM but not in obese nondiabetic subjects. Diabetes. 1996 May;45(5):659-66.

13.Jandhyala BS, Hom GJ. Minireview: physiological and pharmacological properties of vanadium. Life Sci. 1983 Oct 3;33(14):1325-40.

14.Poucheret P, Verma S, Grynpas MD, McNeill JH. Vanadium and diabetes. Mol Cell Biochem. 1998 Nov;188(1-2):73-80.

15.Sakurai H, Yasui H, Adachi Y. The therapeutic potential of insulin-mimetic vanadium complexes. Expert Opin Investig Drugs. 2003 Jul;12(7):1189-203.

16.Sakurai H. A new concept: the use of vanadium complexes in the treatment of diabetes mellitus. Chem Rec. 2002;2(4):237-48.

17.Srivastava AK. Anti-diabetic and toxic effects of vanadium compounds. Mol Cell Biochem. 2000 Mar;206(1-2):177-82.


EDITOR'S NOTE: This monograph can be found in The Health Professional's Guide to Dietary Supplements (Lippincott, Williams & Wilkins) by Shawn M. Talbott, PhD and Kerry Hughes, MS.

No comments: