ARS | Publication request: DIETARY BORON REDUCES SERUM INSULIN CONCENTRATIONS REGARDLESS OF VITAMIN D STATUS IN RATS

Submitted to: International Society For Trace Elements Research In Humans
Publication Type: Abstract Only
Publication Acceptance Date: June 11, 2004
Publication Date: December 1, 2004
Citation: Rhee, Y., Hunt, C., Idso, J.P. 2004. Dietary boron reduces serum insulin concentrations regardless of vitamin d status in rats [abstract]. The Journal of Trace Elements in Experimental Medicine. 17(4):208.

Technical Abstract: Our previous research indicated that dietary boron (B) decreased plasma insulin levels and increased insulin sensitivity independent of other marginal nutritional stressors. To investigate the effects of dietary boron on serum glucose (SG) and insulin (SI) levels during severe vitamin D (VD) deficiency, 60 male weanling Sprague Dawley rats were fed with diets depleted of VD and/or boron (0 IU VD/kg diet and/or 0 mg B/kg diet) or diets adequate in VD and/or boron (1000 IU VD/kg diet and/or 2.5 mg B/kg diet) for 12 wks. The rats were challenged with a glucose tolerance test (GTT, 0.133% glucose of body weight) at 6 wks. During the GTT, SI concentrations decreased and SG concentrations increased in VD depleted rats compared to those with adequate VD (SI: 0.285 vs. 0.561 ng/ml, p=0.0175, SG: 174 vs. 165 mg/dl, p=0.0224). During the GTT, dietary boron did not affect either SG or SI levels. At 12 wks, dietary boron significantly decreased SI levels (0.0886 vs. 0.1226 ng/ml, p=0.0041), but not SG nor body weight. As expected, severe VD deficiency lowered SI concentrations below the normal range (0.0628 vs. 0.148 ng/ml, p<0.0001) at 12 wks. The results suggest that dietary boron affects insulin concentrations independent of VD status. Because dietary boron reduces circulating insulin concentrations while maintaining serum glucose concentrations within the normal range, dietary boron might help prevent pancreatic exhaustion caused by chronic hyperinsulinemia.