Sulphate-bicarbonate-calcium Water, Body Weight and Gut Microbiota

Effect of Sulphate-bicarbonate-calcium Water Consumption on the Body Weight and Gut Microbiota Composition in Overweight and Obese Patients Under Low-calorie Diet

Overweight and obese patients will be recruited and randomly assigned to two groups of intervention. To the first group [sulphate-bicarbonate-calcium water and low-calorie diet (SW-D)] will be administered "Acqua Santa di Chianciano"®, associated to a personalized low calorie diet, while the second group [tap water and low-calorie diet (TW-D)] will follow the personalized low calorie diet but will be asked to drink the same quantity of tap water, over a 4 week period. Stool samples will be collected and analyzed for changes in gut microbiota composition. Patients' body weight will be recorded at the beginning and at the end of the study.

Overweight (BMI>25) and obesity in adults is a global public health concern because weight excess increases the relative risk of disease and mortality 1-4. A range of diseases, notably cardiovascular disease, diabetes and a number of cancers, are related to excess weight 5. Traditional low-calorie diets are frequently ineffective 6. Although a number of pharmacological approaches for treatment of obesity have been investigated, only few are safe and most of them have adverse effects 7,8. Thus, further studies are necessary in order to find natural antiobesity remedies. Gut microbiota composition is thought to influence body weight 9. As recently demonstrated in our previous study 10, "Acqua Santa di Chianciano"® helps to maintain the body weight and the values of serum lipids stable in subjects under a relatively high-calorie diet. Possible mechanisms may be a) changing the gut microbiota composition and/or b) increasing the concentration and/or the qualitative pattern of serum bile acids with a subsequent increase of the energy expenditure 11. This study wants to assess the effectiveness in losing weight of "Acqua Santa di Chianciano"® in addition to a low-calorie diet and its effects on gut microbiota composition.

Experimental arm: Those patients assigned to this interventional arm of the study will be asked to follow a low-calorie diet. For the first 12 weeks, the diet will cover only basal metabolism expenditure ± 10%. At the end of this 12 weeks, for the following 12 weeks, patients will follow a maintenance diet which will cover both basal metabolism and physical activity expenditure. Patients will be invited to maintain the same level of physical activity preceding enrollment throughout the entire study period. During the first 4 weeks these patients will be asked to drink every morning, before breakfast, within 30 minutes, 500 mL of "Acqua Santa di Chianciano"® at room temperature.

Active comparator: Those patients assigned to this interventional arm of the study will be asked to follow the same low-calorie diet of the experimental arm. During the first 4 weeks these patients will be asked to drink every morning, before breakfast, within 30 minutes, 500 mL of Rome tap water at room temperature.

During the first 4 weeks the SW-D patients will be asked to drink every morning, before breakfast, within 30 minutes, 500 mL of "Acqua Santa di Chianciano"® at room temperature.

During the first 4 weeks the TW-D patients will be asked to drink every morning, before breakfast, within 30 minutes, 500 mL of tap water at room temperature.

The primary end-point of the present study is to assess the effect on body weight of the association between sulphate-bicarbonate-calcium water consumption and low-calorie diet (SW-D) compared to tap water and the low-calorie diet (TW-D). The expected result is to obtain a 50% greater mean weight loss in the SW-D than in the TW-D group.

One of the secondary end-points is the evaluation of the effects of the association between low-calorie diet and sulphate-bicarbonate-calcium water consumption on gut microbiota.

One of the secondary end-points is the evaluation of the effects of the association between low-calorie diet and sulphate-bicarbonate-calcium water consumption on body composition (lean body mass/fat body mass) assessed by BIA.

One of the secondary end-points is the evaluation of the effects of the association between low-calorie diet and sulphate-bicarbonate-calcium water consumption on the bile acids pool.

One of the secondary end-points is the evaluation of the effects of the association between low-calorie diet and sulphate-bicarbonate-calcium water consumption on energy expenditure

One of the secondary end-points is the evaluation of the effects of the association between low-calorie diet and sulphate-bicarbonate-calcium water consumption on thyroid function

Inclusion Criteria: Women with BMI between 29 and 35 kg/m2 Age between 18 and 65 years Exclusion Criteria: Therapy with antibiotics, bile salts, cholestyramine, laxatives, pre- or probiotics during the last 3 months before enrollment Helycobacter Pylori positivity Previous cholecystectomy Gallbladder disease Cholestasis Consumption of more than 20 g of alcohol/day Inflammatory bowel diseases Previous gastrointestinal surgery modifying the anatomy Pregnancy or lactating state Prescribed hypocaloric diet in the three previous months

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