Choosing the numerous mineral waters available on the market is certainly not easy, not only for the aesthetic question or for the propensity or otherwise towards bubbles, but because the consumption of one mineral water rather than another can help to maintain health at various stages of the life cycle. In this regard, the labels placed on the containers represent a valid aid in choosing the most suitable mineral water for one’s needs. Indeed, the label uniquely identifies all the elements and characteristics of a mineral water .
However, it is not always easy to correctly interpret the information provided by this sort of “mini database”. There are in fact 48 parameters subjected to periodic analysis and many of these are shown on the packaging.
To help the consumer, we list below some of the most important characteristics to refer to.
The fixed residue
This data, reported on the label of mineral waters with the term “fixed residue at 180°C”, gives us an estimate of their mineral salt content .
The higher this value is, the more salts are dissolved in a litre. This figure is obtained by bringing the water to a temperature of 180°C; what remains after complete evaporation, i.e. the solid part of the water, represents the fixed residue.
This value is expressed in mg/L and allows mineral waters to be classified into four categories:
– minimally mineralized (fixed residue not exceeding 50 mg/L): it is a light water on the palate , with a delicate flavour. The lack of mineral salts and especially sodium stimulates diuresisand is particularly suitable for those suffering from hypertension and for feeding infants . It is useful for preventing kidney stones and represents about 9% of the Italian mineral waters on the market. – oligomineral or slightly mineralized (fixed residue less than 500 mg/L): promotes diuresis, contains little sodium and can therefore be indicated in cases of hypertension. The advertising enhances its characteristics, emphasizing its diuretic properties and its low sodium content. It is useful for preventing kidney stones.
– medium-mineral (although by law there is no definition for this category): (fixed residue between 500 and 1000 mg/L): the discrete mineral salt content makes it useful in sports nutrition, especially in the summer when it is necessary to replace the fluids and minerals lost through sweating
– rich in mineral salts: (fixed residue greater than 1,000 mg/L): it is a therapeutic water, very rich in salts. You buy it in pharmacies, but some are also found in supermarkets. To avoid overdose symptoms it is good to buy it only under average advice. It has a lower diuretic effect , and can promote the appearance of kidney stones .
TYPE OF MINERAL WATER |
FIXED RESIDUE |
| Minimally mineralized waters | < 50 mg/L |
| Oligomineral waters | >50 < 500 mg/L |
| Medium-mineral waters | > 500 < 1000 mg/L |
| Water rich in mineral salts | > 1000 mg/L |
Why is the mineral salt content so important?
Mineral salts are essential micronutrients for our body but if present in excess they can cause more or less serious problems. They are involved in the regulation of many bodily processes such as water and salt balance and the development and growth of organs and tissues.
The main minerals present in our body are: sodium, potassium , magnesium and calcium . Each of these elements, if taken in too little or too much, can be harmful.
Some waters are particularly rich in minerals. In these cases, a particular wording can be specified on the label to underline its characteristics:
containing bicarbonate HCO3 (the bicarbonate content is greater than 600 mg/L): it is indicated in gastric hypersecretion (stomach acid) and in kidney pathologies . The bicarbonate makes it particularly useful for those who play sports, as this substance is able to buffer lactic acid (see: Bicarbonate and sport ).
- sulphate water (the sulphate content is higher than 200 mg/L): it is slightly laxative, therefore indicated in case of digestive insufficiencies, spastic colitis and irritable bowel syndrome . Inadvisable during growth and in the postmenopausal period, because they can interfere with the absorption of calcium by increasing its excretion.
- chlorinated water (the chloride content is greater than 200 mg/L): it has a balancing action on the intestine , biliary tract and liver . It also has a laxative and purgative action typical of salty waters or sulphate salts.
- calcium water Ca++ (the calcium content is greater than 150 mg/L): it acts on the stomach and liver. It is indicated in growth, pregnancy, menopause and in the prevention of osteoporosis and hypertension . Calcium mineral waters are also indicated for those who are intolerant to milk and, despite the clichés, they do not increase the incidence of kidney stones.
- magnesium water Mg++ (if the magnesium content is higher than 50 mg/L): it mainly carries out a purgative action, but it also finds indications in the prevention of arteriosclerosis , since it favors the dilation of the arteries . It can also be useful in sports nutrition to prevent cramps .
- fluoridated or ” fluorine- containing” water (the fluorine content is greater than 1 mg/L): useful for strengthening the structure of the teeth and for the prevention of dental caries . It is indicated in the growth phase or for those suffering from osteoporosis , but the intake should not take place for prolonged periods (an excess of fluorine can be harmful to the health of the teeth and bones ) .
- ferruginous or ” iron -containing” water (the bivalent iron content is greater than 1 mg/L): indicated in iron-deficiency anemias . Also useful for vegetarians and for people with a high iron requirement: infants, adolescents, sportsmen and pregnant women.
| Salt composition of mineral waters | |
| Bicarbonate mineral water – Bicarbonate content: | > 600 mg/L |
| Calcium mineral water – Calcium content: | > 150mg/L |
| Chlorinated mineral water – Chlorine content : | > 200 mg/L |
| Ferruginous mineral water – Iron content: | > 1 mg/L |
| Fluorinated mineral water – Fluorine content: | > 1 mg/L |
| Magnesium mineral water – Magnesium content: | > 50mg/L |
| Sodium mineral water – Sodium content: | > 200 mg/L |
| Sulphated mineral water – Sulphate content | > 200 mg/L |
| Low sodium water – Sodium content | < 20 mg/L |
- acidic water (the content of free carbon dioxide is greater than 250 mg/L): it facilitates digestion . The carbon dioxide present in carbonated waters increases the acidity of the water. It should be emphasized, however, that our diets are already sufficiently rich in acidic substances and no integration is normally necessary.
- sodium water (the sodium content is greater than 200 mg/L): it positively influences neuro-muscular excitability and is therefore recommended for sportsmen, especially during the summer months when considerable quantities of liquid are lost through sweating (remember that an excessive drop in sodium values in the blood has caused the death of some sportsmen). Sodium mineral waters are contraindicated for those suffering from hypertension.
- low sodium content water (the sodium content is less than 20 mg/L): indicated for low sodium diets and to combat hypertension and water retention .
CATEGORY |
MINERAL WATER |
| Pregnancy | Oligomineral waters with a particularly low or even zero nitrate content (not exceeding 10 mg/l due to the known risk of causing fetal methemoglobinemia). To increase the intake of mineral salts, considering the increased needs of the pregnant woman, it is advisable to alternate low-mineral waters with medium-mineral waters, preferring the calcium ones |
| Feeding time | The advice is similar to that given for pregnancy, with the foresight to drink larger quantities of water to help restore the amount of fluid lost through breastfeeding. The intake of ferrous water alternating with calcium water and oligomineral water may be useful (iron is the only nutrient deficient in mother’s milk , however compensated by the stocks that the newborn has already accumulated at the time of birth). |
| Dilution of powdered milk for babies | Minimally mineralized waters, practically free of mineral salts so as not to alter the carefully calibrated nutritional formula of the food. Once again, we recommend paying attention to the amount of nitrates in mineral water, which must be zero or extremely low |
| Slimming | Oligomineral, to purify the body by promoting the elimination of toxins |
| Kidney stones | Oligomineral or minimally mineralized, to stimulate diuresis and prevent the formation of stones or facilitate their elimination ( flush ) |
| Gout and hyperuricemia | Oligomineral or minimally mineralized with low sodium content (2/3 liters per day) → haemodilution of uric acid → stimulation of diuresis → increased urinary excretion of uric acid |
| Sport | Medium-mineral, with a good amount of calcium, iron, sodium, chlorine and bicarbonate. Taking oligomineral waters and then going to integrate the same trace elements with hydrosaline supplements is like buying a dress without pockets and then having them added by a tailor: money is thrown away! |
| Hypertension | Low sodium oligomineral, associated with an equally low sodium diet , useful in the initial stages and as prevention in predisposed subjects |
| Osteoporosis | Mineralized water rich in “bioavailable calcium” (check the presence of this wording on the label) |
| Gastric acidity | Calcium bicarbonate type mineral water |
| Anemia | Ferruginous type mineral water |
| Caries | Fluorinated mineral water |
| Hypercholesterolemia | Salty-sulfated waters (increase the excretion of bile acids with the feces) |
| Constipation | Sulphated water |
It is important to underline that the therapeutic virtues of mineral waters are very mild and valid only for particular categories.
These properties must in no way lead the consumer to think of curing or preventing some important pathologies SIMPLY by drinking one or two liters of “magic water” every day. If anything, water can become a valid support if combined with a correct diet and healthy lifestyle habits.
It is a wise rule of conduct to consult the opinion of a doctor before buying water with particular characteristics.
THE pH
This datum, reported on the label of mineral waters with the term “pH at the temperature of the spring water”, gives us an estimate of their acidity.
The pH is a scale that goes from 0 (maximum acidity) to 14 (maximum basicity); the intermediate point, 7, defines the condition of neutrality and is given by distilled water at a temperature of 25°C.
The pH of natural mineral waters is generally between 6.5 and 8.0.
The higher the carbon dioxide and sulphate content, the lower the pH (higher acidity).
Electric conducibility
This data is reported on the label of mineral waters with the term “specific electrical conductivity at 20°C”.
This value increases as the dissolved mineral substances increase. Therefore, the higher the electrical conductivity, the higher the mineral content.
It is easy to verify the proportionality between fixed residue and conductivity since both data depend on the mineral content.
Most of the commercially available mineral waters have an electrical conductivity between 100 and 700 µS/cm.
Hardness
The hardness of mineral water is expressed in French degrees (°F) and gives us an estimate of the presence of calcium and magnesium. The higher this value is, the more calcareous the water is. It is in fact formed from calcareous and marly subsoils.
There is no limit value for the hardness of mineral waters.
Nitrates
The nitrate content is a very important parameter to consider, especially as regards the nutrition of infants and children.
Nitrates are substances normally present in minimal and non-dangerous concentrations.
However, the massive use of fertilizers in agriculture can cause these and other nitrogenous compounds to penetrate the soil, with consequent pollution of the groundwater.
If taken in excess, nitrates can seriously hinder the transport of oxygen in the blood , with dangerous consequences especially for newborns.
For this reason, there are two different dosage limits in mineral waters:
- 45 mg/L in ordinary mineral waters
- 10 mg/L in those intended for children.
In any case, for children, it is recommended not to exceed the value of 25 mg of nitrates per litre.
Nitrates also have the ability to combine with proteins forming nitrosamines, substances considered carcinogenic to our body.
