The Mineral Water of Vichy and the Urinary Alkalization: A Study of the Dose - Effect of Bicarbonate Salt Water on the Urinary pH in Healthy Volunteers
Condition: Healthy
Study type: Interventional

Summary: 
      Vichy water is a type of spring water which traditionally comes from the famous spa town of
      Vichy, France. The springs which feed Vichy carry a high amount of dissolved minerals.
      Alkaline salts such as sodium bicarbonate are a primary ingredient in Vichy water, along with
      calcium and magnesium carbonates.

      Bicarbonates alkalinize urine, which is fundamental in preventing and/or diluting uric acid
      crystals. These are the main component of the uric acid stones or even oxalate stones, which
      generally " use " a crystal of uric acid as nucleus for stone formation. Cystine stones can
      also be treated by alkalinizing urine.

      Any disorder leading to a low urinary pH ( < 5.5 ) may predispose to stone formation. In this
      context , the solution of uric acid and the prevention and treatment of uric acid stones can
      be obtained by alkalization of the urine . The ideal alkalization is achieved when a urinary
      pH of 6-6.5 can be reached.

      The aim of this study is to evaluate the quantity of daily intake of the Vichy water
      necessary to obtain this alkalization of the urine. There are no data available in the
      literature about the relationship between the absolute quantity of Vichy water taken and the
      urinary pH ; nor about the possible influence of the Body Mass Index on this relationship.
    

Detailed description: 
      Vichy water is a type of spring water which traditionally comes from the famous spa town of
      Vichy, France. The springs which feed Vichy carry a high amount of dissolved minerals, and
      they create a distinctive naturally effervescent bubbling water. Alkaline salts such as
      sodium bicarbonate are a primary ingredient in Vichy water, along with calcium and magnesium
      carbonates. The water is sometimes slightly odorous, with substances like sulfur naturally
      bubbling up with the water. The water also has a distinct taste, due to the dissolved
      minerals.

      Bicarbonates alkalinize urine, which is fundamental in preventing and/or diluting uric acid
      crystals. These are the main component of the uric acid stones or even oxalate stones , which
      generally " use " a crystal of uric acid as nucleus for stone formation. Cystine stones can
      also be treated by alkalinizing urine.

      Three conditions influence the potential for uric acid stone formation : the quantitative
      excretion of uric acid , the volume of urine as it affects the urinary concentration of uric
      acid, and the urinary pH which seems to be the most important pathogenic factor . Uric acid
      is a weak acid with a pKa of 5.35 at 37° C . At that pH , half of the uric acid is present as
      the urate salt and half as free uric acid . Because sodium urate is approximately 20 times
      more soluble than the free acid, the relative proportion present as free uric acid strongly
      determinates the risk of stone formation . Low urinary pH increases concentrations of
      sparingly soluble undissociated uric acid, which leads to direct precipitation of uric acid .

      Any disorder leading to a low urinary pH ( < 5.5 ) may predispose to stone formation. For
      example a chronic metabolic acidosis can lead to a low urinary pH, a hypercalciuria and a
      hypocitraturia . "Gouty diathesis " refers to a stone - forming propensity characterized by
      low urinary pH of unknown etiology with or without associated gouty arthritis.

      In this context , the solution of uric acid and the prevention and treatment of uric acid
      stones can be obtained by alkalization of the urine. The ideal alkalization is achieved when
      a urinary pH of 6-6.5 can be reached.

      The aim of this study is to evaluate the quantity of daily intake of the Vichy water
      necessary to obtain this alkalization of the urine. There are no data available in the
      literature about the relationship between the absolute quantity of Vichy water taken and the
      urinary pH ; nor about the possible influence of the Body Mass Index on this relationship.
    

Intervention name(s): Vichy
Intervention type(s): Other
Intervention description(s): Volunteers will be asked during 3 days to take their usual intake of fluids. For the following 7 days, they will take the usual intake of fluids plus 250 ml of Vichy water at 1 pm. For the following 7 days, they will take the usual intake of fluids plus 250 ml of Vichy water at 7 am and 7 pm. Ph and density measurement of urine will be made three times a day, at 7 am, 2 pm and 8 pm.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Vichy; urine alkalization