Orienting oneself in the choice of the numerous mineral waters available on the market is certainly not a walk, not only for the aesthetic question or for the propensity or less towards bubbles, but because the consumption of a mineral water rather than another can help to maintain health at various stages of the life cycle.
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 reported on the packaging.
To help the consumer, here are some of the most important features to refer to.
The fixed residue
This data, reported on the mineral water label 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 liter. This data is obtained by bringing the water to a temperature of 180 ° C; what remains after complete evaporation, ie the solid part of the water, represents the fixed residue.
This value is expressed in mg / L and allows to classify mineral waters into four categories:
- minimally mineralized (fixed residue not exceeding 50 mg / L): it is a light water on the palate, with a delicate taste. The lack of mineral salts and especially of sodium, stimulates diuresis and is particularly indicated for those suffering from hypertension and in the feeding of newborns. It is useful to prevent kidney stones and represents about 9% of Italian mineral waters on the market.
- low mineral content or slightly mineralized (fixed residue less than 500 mg / L): promotes diuresis, contains little sodium and can therefore be indicated in cases of hypertension. Advertising enhances its characteristics, emphasizing its diuretic properties and its low sodium content. It is useful for preventing kidney stones.
- mediomineral (even if by law there is no provision for this category): (fixed residue between 500 and 1000 mg / L): the moderate content of mineral salts makes it useful in the nutrition of athletes, especially in the summer period when it is necessary to replenish liquids 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 can buy it at the pharmacy, but some can also be found in supermarkets. To avoid overdose symptoms it is good to buy it only under medium advice. It has a lower diuretic effect, and can favor the appearance of kidney stones.
TYPE OF MINERAL WATER
Mimimely mineralized waters
<50 mg / L
> 50 <500 mg / L
Middle mineral water
> 500 <1000 mg / L
Water rich in mineral salts
> 1000 mg / L
Why is the mineral salt content so important?
Minerals are essential micronutrients for our body but if present in excess they can cause more or less serious problems. They intervene in the regulation of numerous body processes such as salt and water 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 insufficient or excessive doses, can be harmful.
Some waters are particularly rich in minerals. In these cases, on the label, a particular wording can be specified to emphasize its characteristics:
containing HCO3 bicarbonate (bicarbonate content is higher than 600 mg / L): it is indicated in gastric hypersecretion (stomach acid) and in renal pathologies. Baking soda makes it particularly useful for those who practice sport, 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 insufficiency, spastic colitis and irritable bowel syndrome. Unadvisable during growth and in the postmenopausal period, because they can interfere with calcium absorption, increasing excretion.
- chlorinated water (the chloride content is greater than 200 mg / L): it has a balancing action on the intestine, bile ducts and liver. It also has a laxative and purgative action typical of salted or salted sulphate waters.
- Ca ++ calcium water (the calcium content is greater than 150 mg / L): acts on the stomach and liver. It is indicated in growth, in pregnancy, in menopause and in the prevention of osteoporosis and hypertension. The calcic 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 greater than 50 mg / L): it plays mainly 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 sportsmen's nutrition to prevent cramps.
- Fluorinated water or "fluorine-containing" (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 it should not be taken for prolonged periods (an excess of fluoride can be harmful to the health of 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 those with a high need for iron: infants, adolescents, sportsmen and pregnant women.
|Saline composition of mineral waters|
Bicarbonate mineral water - bicarbonate content:
> 600 mg / L
Calcium mineral water - Calcium content:
> 150 mg / 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:
> 50 mg / L
Sodium mineral water - Sodium content:
> 200 mg / L
Sulphate mineral water - Sulphate content
> 200 mg / L
Low sodium water - Sodium content
<20 mg / L
- acidulous water (free carbon dioxide content is greater than 250 mg / L): facilitates digestion. The carbon dioxide present in carbonated water increases the acidity of the water. It should be emphasized, however, that our diets are already sufficiently rich in acid substances and no integration is normally necessary.
- sodium water (the sodium content is higher than 200 mg / L): it positively influences the neuro-muscular excitability and is therefore suitable for athletes, especially during the summer months when large quantities of liquids are lost with 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.
- water with low sodium content ( sodium content is less than 20 mg / L): indicated for diets low in sodium and to combat hypertension and water retention.
Oligomineral waters with a particularly low or even zero nitrate content (no more than 10 mg / l due to the known risk of causing fetal methemoglobinemia). To increase the intake of mineral salts, given the increased needs of the pregnant woman, it is advisable to alternate mineral waters with medium mineral waters, preferring calcium ones.
The advice is similar to that given for pregnancy, with the foresight to drink more water to help restore the amount of fluid lost through breastfeeding. It may be useful to take ferrous water alternating with calcium water and low mineral water (iron is the only nutrient deficient in breast milk, however it is compensated by the stocks that the baby has already accumulated at birth).
|Dilution of baby milk powder|
Minimally mineralized water, practically free of mineral salts to avoid altering the carefully calibrated nutritional formula of the food. Once again, caution is advised in the amount of nitrates in mineral water, which must be zero or extremely low
Oligomineral, to purify the body by promoting the elimination of toxins
Oligomineral or minimally mineralized, to stimulate diuresis and prevent the formation of stones or facilitate their elimination (water stroke)
|Gout and hyperuricemia|
Oligomineral or minimally mineralized with a low sodium content (2/3 liters per day) → uric acid hemodilution → stimulation on diuresis → increased urinary excretion of uric acid
Mediominerale, with a good stock of calcium, iron, sodium, chlorine and bicarbonate. Taking mineral water and then integrating the same trace elements with salt and water supplements is like buying a dress without pockets and then having them added by a tailor: they throw away money!
Oligomineral with a low sodium content, associated with a diet as low in sodium, useful in the initial stages and as a prevention in those predisposed
Mineralized water rich in "bioavailable calcium" (check for this label)
Calcium bicarbonate mineral water
Ferruginous mineral water
Fluorinated mineral water
Salt-sulphate waters (increase excretion of bile acids with faeces)
It is important to emphasize that the therapeutic virtues of mineral waters are very mild and valid only for particular categories.
These properties must not in any way induce the consumer to think of healing or preventing some important diseases 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.
It is a wise behavior rule, consult a doctor's advice before buying water with special characteristics.
This data, 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 the 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).
This data is reported on the mineral water label with the term "specific electrical conductivity at 20 ° C".
This value increases with the increase of dissolved mineral substances. Therefore, the greater the electrical conductivity and the greater the mineral content.
It is easy to check the proportionality between the fixed residue and conductivity since both data depend on the mineral content.
Most of the marketed mineral waters have electrical conductivity between 100 and 700 µS / cm.
The hardness of a 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 water is considered limestone. It is in fact formed by calcareous and marly subsoils.
There is no limit value for mineral water hardness.
The nitrate content is a very important parameter to consider, especially with regard to feeding babies and children.
Nitrates are substances normally present in minimum and non-hazardous concentrations.
However, the massive use of fertilizers in agriculture can cause the penetration of these and other nitrogen compounds into the soil, with consequent pollution of the aquifers.
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 childhood.
In any case, for children, it is recommended not to exceed 25 mg of nitrates per liter.
Nitrates also have the possibility of combining with proteins, forming nitrosamines, substances considered carcinogenic to our body.