GetSmart Series: Managing Insulin Resistance

Does your horse have a cresty neck? Does he gain weight on air? Does he develop laminitis at the mere sight of spring grass? If so, your horse could have insulin resistance. Lydia F. Gray, DVM, MA, medical director/staff veterinarian for SmartPa


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Does your horse have a cresty neck? Does he gain weight on air? Does he develop laminitis at the mere sight of spring grass? If so, your horse could have insulin resistance. Lydia F. Gray, DVM, MA, medical director/staff veterinarian for SmartPak presented a lecture on managing this condition at the SmartPak retail store in Natick, Mass., on March 19.

The following is a summary of her presentation.

The triad of insulin resistance, laminitis, and obesity make up what is now being referred to as equine metabolic syndrome. Reducing the obesity is paramount to success in managing this condition, and requires a three-pronged approach.

First, reduce the sugars/starches in the horse’s diet by replacing grain with a vitamin/mineral supplement, ration balancer, or low-starch grain. Owners often must also remove the horse from pasture and make sure the hay offered is less than about 10 to 15% sugar/starch.

Second, provide exercise! While turnout is nice, usually these “easy keepers” will not exercise themselves so you have to hand-walk, longe, ride, drive, pony, etc. Daily exercise is good, twice-daily is even better. Start any exercise program slowly, and consult your veterinarian before exercising a laminitic horse.

Step three is supplementation. Philip Johnson, BVSc(Hons), MS, Dipl. ACVIM, Dipl. ECEIM, MRCVS, of the University of Missouri, suggested that enhancing the whole-body antioxidant status might be beneficial in managing metabolic syndrome1. Dietary supplementation with high levels of vitamin E has been associated with clinical improvement in horses with motor neuron disease, another condition associated with depleted whole-body antioxidants, and might be logically and safely used in the management of obese horses. A growing body of research supports the use of antioxidants such as vitamin E, grape seed extract, alpha lipoic acid, and other compounds in the management of equine metabolic syndrome.

Several products have been formulated in the spirit of supporting and maintaining healthy metabolic function. These products generally contain antioxidants, herbs, amino acids, vitamins, and minerals that are believed to support proper blood glucose and insulin levels. Below is a list of some of these active ingredients, along with their understood impact on the healthy structure and function of metabolic pathways:

  • Banaba Leaf Extract–might increase insulin sensitivity and improve hyperglycemia2
  • Biotin–might enhance insulin sensitivity and glucokinase activity in the liver3
  • Bitter melon–might help stimulate insulin release and possibly glycogen synthesis in the liver4
  • Chromium–a component of glucose tolerance factor (GTF) which may potentiate the action of insulin5,6
  • Cinnamon–might increase glucose disposal by enhancing translocation of glucose transporter-4 (GLUT-4)7
  • Fenugreek–might have hypoglycemic properties8
  • Magnesium–cofactor of many enzymes involved in glucose metabolism, required for both proper glucose utilization and insulin signaling9
  • Taurine–amino acid that may act as a minor insulin mimetic10

The next GetSmart lecture “Laminitis and Founder: What do fructans have to do with it?” will be held at the SmartPak store April 16, 2008. For more information and a complete presentation schedule visit

1. Johnson PJ. Peripheral Cushingoid Syndrome (Equine Metabolic Syndrome). In: Robinson NE, editor. Current therapy in equine medicine, 5th edition. St. Louis (MO). Elsevier Science; 2003. pp812-816.

2. Park MY, Lee KS, Sung MK. Effects of dietary mulberry, Korean red ginseng, and banaba on glucose homeostasis in relation to PPAR-alpha, PPAR-gamma, and LPL mRNA expressions. Life Sci. 2005 Nov 12;77(26):3344-54.

3. McCarty MF. High-dose biotin, an inducer of glucokinase expression, may synergize with chromium picolinate to enable a definitie nutritional therapy for type II diabetes. Med Hypotheses. 1999 May;52(5):401-6.

4. Krawinkel MB, Keding GB, Bitter gourd (Momordica Charantis): A dietary approach to hyperglycemia. Nutr Rev. 2006 Jul;64(7 Pt 1):331-7.

5. Ott EA, Kivipelto J. Influence of chromium tripicolinate on growth and glucose metabolism in yearling horses. J Anim Sci. 1999 Nov;77(11):3022-30.

6. Pagan JD, Jackson SG, Duren SE. The effect of chromium supplementation on metabolic response to exercise in thoroughbred horses. In: Proceedings of the 14th Equine Nutrition and Physiology Society, Ontario, CA: pp96-101.

7. Kim W, Khil LY, Clark R, et al. Naphthalenemethyl ester derivative of dihydroxyhydrocinnamic acid, a component of cinnamon, increases glucose disposal by enhancing translocation of glucose transporter 4. Diabetologia. 2006 Oct;49(10):2437-48.

8. Basch E, Ulbricht C, Kuo G, et al. Therapeutic applications of fenugreek. Altern Med Rev. 2003 Feb;8(1):20-7.

9. Takaya J, Higashino H, Kobayashi Y. Intracellular magnesium and insulin resistance. Magnes Res. 2004 Jun;17(2):126-36.

10. Franconi F, Di Leo MA, Bennardini F, Ghirland G. Is taurine beneficial in reduce risk factors for diabetes mellitus? Neurochem Res. 2004 Jan;29(1):143-50

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Written by:

Lydia Gray, DVM, is Medical Director and Staff Veterinarian for SmartPak Equine. She was previously the executive director of the Hooved Animal Humane Society in Woodstock, IL, and an Owner Education Director for the American Association of Equine Practitioners.

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