Mineral water is part of our diet, but when we drink a mineral water we have some difficulty in finding our way around the label.

Few, essential words about sulphates (SO₄).

Sulphates and sulfuric acid products are used in the production of additives in the food industry, fertilizers, chemicals, dyes, glass, paper, soaps, textiles, fungicides, insecticides, astringents and emetics.

Sulphates are mineral salts containing sulphur and high sulphate content can confer a slightly bitter taste to mineral waters and an unpleasant smell (rotten eggs).

Sulphates in mineral water, if they exceed 200 milligrams per litre, have a slightly laxative effect, which could be considered an advantage for people suffering from constipation (1). Conversely, higher amounts of sulphates could lead to intestinal problems. diarrhoea and more (2).

Mineral waters containing sulphates in significant proportions, are used, in clinical therapy, as balneotherapy, hydropinotherapy, balneotherapy, mud therapy, mudbalneotherapy, inhalation crenotherapy or irrigation, through different methods of administration (3).

The results of this study on hydropinotherapy of sulphate-bicarbonate-calcium-magnesium mineral water show a significant improvement in symptoms in patients with biliary tract disorders (4).

When sulphates are present in large quantities in mineral waters, they give origin to (5):

• Sodium and magnesium sulphates.—Sodium and magnesium sulphates, or Glauber and Epsom salts, respectively, in small doses act as a laxative, in large doses as a cathartic. 
• Potassium sulphate.—Potassium sulphate is frequently present in mineral waters, but in smaller quantities than the magnesium and sodium salts. Its action is practically the same as that of the other two sulphates mentioned above.
• Calcium sulphate.—Calcium sulphate occurs in a great many mineral waters, and is the component that gives to them the property of permanent hardness.
• Iron and aluminum sulphates.—Iron and aluminum sulphates are usually found associated with each other in mineral waters. They are both powerful astringents. 

Contraindications are only high concentrations of this mineral salt. High doses can interfere with the absorption of calcium in the human body. Therefore, special care should be taken when administering water that is very rich in sulphates to children and those with bone disorders.

References_________________________________________________________________

(1) Bothe G, Coh A, Auinger A. Efficacy and safety of a natural mineral water rich in magnesium and sulphate for bowel function: a double-blind, randomized, placebo-controlled study. Eur J Nutr. 2017;56(2):491–499. doi:10.1007/s00394-015-1094-8

(2) http://www.saskh2o.ca/PDF-WaterCommittee/sulphate.pdf

(3) Costantino M, Conti V, Corbi G, Marongiu F, Marongiu MB, Filippelli A. Sulphurous mud-bath therapy for treatment of chronic low back pain caused by lumbar spine osteoarthritis. Intern Emerg Med. 2019;14(1):187–190. doi:10.1007/s11739-018-1967-y

(4) Mennuni G, Petraccia L, Fontana M, et al. The therapeutic activity of sulphate-bicarbonate-calcium-magnesiac mineral water in the functional disorders of the biliary tract. Clin Ter. 2014;165(5):e346–e352. doi:10.7417/CT.2014.1761

(5) THE CHEMICAL COMPOSITION OF THE WATERS OF THE HOT SPRINGS OF ARKANSAS. HOT SPRINGS  Analyses of the Waters of The Hot Springs of Arkansas  Geological Sketch of Hot Springs, Arkansas  https://www.nps.gov/parkhistory/online_books/hosp/haywood-weed/sec2.htm