Increasing Calcium Dietary Intake Helps to Control Blood Presure and Body Weight

The DASH Study showed that the antihypertensive effects of a low-salt, low-lipid diet were significantly potentiated when the diet was enriched in calcium. This target may be reached either increasing the daily consumption of low-lipid milk and dairy products or increasing the daily consumption of calcium-rich vegetables. In the Italian population the mean daily consumption of calcium is rather low, not exceeding 700 mg/daily whilst it would be desirable a daily consumption of 1200 mg/daily. Unfortunately there are in Italy very few dairy products (particularly low-lipid cheese) that would ensure a variable and palatable calcium-rich diet. Aims of the present study are: 1. to prepare a low-sodium (about 3 g/daily) diet enrich in calcium (about 1200 mg/daily) and to compare the effects on blood pressure with those of a low-sodium diet similar to it in macronutrients but with a calcium content typical of the Mediterranean diet (no more than 700 mg/daily) (see Table 1); 2. to verify if this diet is able to improve the control of body weight and of the main parameters of the glucose and lipid metabolisms; 3. to evaluate if this diet is palatable enough to be prescribed in a long term study. Patients: At least 150 patients with arterial hypertension and/or overweight /obesity (IMC \> 28 kg/m2) will be enrolled. Methods: 1. evaluation of nutritional habits by an adequate frequency questionnaire at baseline, after a 3-month low-lipid low-sodium diet; 2. anthropometric measures (body weight, height, waist circumference); 3. measurements of blood pressure and heart rate; 4. measurements of serum total and HDL cholesterol serum triglycerides, fasting blood glucose, serum sodium potassium calcium and phosphorus. Design of the study: This is a randomized parallel-group study performed in the Outpatient Clinic. Patients enrolled in the study will be prescribed a low-sodium low-lipid diet for 3 months. At the end of the first phase they will be randomly divided in two groups: 1. Group A: patients will change their diet in a diet similar for total daily calories, sodium and macronutrients but enriched in calcium (1200 mg/daily) and will be followed up to 1 year with an intermediate control after the first 3 months; 2. Group B: patients will continue the low-lipid, low-sodium diet up to 1 year with an intermediate control after the first 3 months. At baseline, after 3, 6 and 12 months of observation, patients will repeat the measurements 1-4 described in the Methods. Composition in macro and micronutrients of the two diets NUTRIENTS LOW-SODIUM DIET LOW-SODIUN CALCIUM- ENRICHED DIET PROTEINS (%) 17 17 LIPIDS (%) 27 28 SATURATED FATTY ACIDS (%) 7 7 MONOUNSATURATED (%) 16 17 POLTYUNSATURATED (%) 4 4 CHOLESTEROL ( mg) 132 140 CARBOHYDRATES (%) 56 54 SOLUBLE CHO (%) 18 17 FIBRE (g) 39 42 Na (mg) 1397 1377 K (mg) 3973 4067 Fe (mg) 16 21 Ca (mg) 650 1211 P (mg) 1285 1501