Written by Susan Sweeny Johnson, PhD, Biochem. Experimenters used a pre-diabetic mouse model to see if the onset of diabetes could be delayed by ingesting large doses of Vitamin A (250 IU/gm of food per day) or polyphenol-rich whole grape powder (1% of the food by weight).Type 1 diabetes mellitus, or juvenile diabetes, is an autoimmune inflammatory disease beginning early in life when T-cells attack the pancreas cells that produce insulin causing inflammation which progressively destroys them. Many treatments aimed at slowing the progression and onset of Type I diabetes focus on interference with the inflammation process. (1)   Vitamin A is known to reduce certain immune responses. (2)  Supplementation in patients with autoimmune encephalomyelitis showed significant reduction in inflammation. (3)  The antioxidants in grapes – stilbene, resveratrol, and the flavonoids: quercetin, catechins, and anthocyanins- are also known to have anti-inflammatory properties (4) and have been shown to protect insulin producing cells from damaging oxidation. (5)

In this new study, experimenters used a pre-diabetic mouse model to see if the onset of diabetes could be delayed by ingesting large doses of Vitamin A (250 IU/gm of food per day) or polyphenol-rich whole grape powder (1% of the food by weight).  By about 7 months of age, 71% of control mice progressed to diabetes. Incidence of diabetes was reduced to 33% (P < 0.05) and 25% (P <0.05) in mice receiving 1% dietary grape powder and Vitamin A, respectively.

When the spleens of the mice were examined after onset of diabetes, the insulin producing cells in both groups of supplemented mice showed much less damage from inflammation than the control mice. Also there was some evidence that inflammation was reduced in both supplemented groups of mice – levels of some cytokines in the blood were reduced.   Since Vitamin A and polyphenol-rich grape concentrate significantly delayed the onset of Type I diabetes in mice, further studies are warranted in human populations.

About 7% of the US population has some form of diabetes. Type I comprises 5-10% of all diagnosed cases. Direct medical costs from all types total $92 billion annually. Using natural products to delay onset of Type I diabetes would save significant governmental and private dollars.

Source: Zunino, Susan J., David H. Storms, and Charles B. Stephensen. “Diets rich in polyphenols and vitamin A inhibit the development of type I autoimmune diabetes in nonobese diabetic mice.” The Journal of nutrition 137, no. 5 (2007): 1216-1221.

© 2007 American Society for Nutrition.

Posted August 6, 2008.

References:

  1. Winter WE, Schatz D. Prevention strategies for type I diabetes mellitus: current status and future directions. BioDrugs. 2003;17:39–64
  2. Cui D, Moldoveanu Z, Stephensen CB. High-level dietary vitamin A enhances T-helper type 2 cytokine production and secretory immunoglobulin A response to influenza A virus infection in BALB/c mice. J Nutr. 2000;130:1132–9
  3. J NutrXu J, Storer PD, Chavis JA, Racke MK, Drew PD. Agonists for the peroxisome proliferator-activated receptor-alpha and the retinoid X receptor inhibit inflammatory responses of microglia. J Neurosci Res. 2005;81:403–11.
  4. Hou D-X, Fujii M, Terahara N, Yoshimoto M. Molecular mechanisms behind the chemopreventive effects of anthocyanidins. J Biomed Biotechnol. 2004;2004:321–5
  5. Lapidot T,Walker MD, Kanner J. Antioxidant and prooxidant effects of phenolics on pancreatic b-cells in vitro. J Agric Food Chem. 2002;50:7220–5