High CA²⁺ intake controls cardiovascular & metabolic abnormalities of diet-induced diabetes in C57BL/6J mice

Several studies in animals have shown that high Ca²⁺ intake lowers blood pressure. However, this effect of Ca²⁺ supplementation has not been established in non-insulin dependent (type II) diabetes, in which obesity, dyslipidemia and poor glucose/insulin control are associated with hypertension. We therefore determined the cardiovascular and metabolic consequences of increased Ca²⁺ intake in type II diabetes. Genetically susceptible diabetic mice (BL/6) were fed for 18 weeks either a high-fat, high-carbohydrate (HFC) or a normal (NFC) diet, and had free access to tap water (both diets contained 0.5% Ca). Another group was fed the HFC diet and drank water + 1% CaCl₂ (HFC+Ca). Body weight (BW), tail-cuff systolic BP (SBP), as well as plasma cholesterol (Chol), glucose and insulin levels were determined. The results (meantSEM) were as follows: n = 9-12/group NFC HFC HFC+Ca BW, g 33.6±0.6 48.8±0.6 a 36.0±1.0 b SBP, mmHg 133±3 149±2 a 130±3 b Chol, mg/dl 82.8±8.6 173.8±15.1 a 121.1±2.6 a,b Glucose, mg/dl 137.9±12.3 247.7±21.9 a 197.2±19.5 Insulin, ng/ml 0.51±0.29 3.73±1.36 a 0.50±0.12 b a, p < 0.05 vs NFC: b, p< 0.05 vs HFC (ANOVA) We conclude that Ca²⁺ supplementation significantly reduces risks factors in experimental diabetes and that increasing Ca²⁺ intake in patients with type II diabetes may have a protective cardiovascular effect.