Q. Soda water and mineral water: what's the difference?

Soda Water

Soda water, also known as carbonated water, sparkling water or seltzer water, is plain water into which carbon dioxide gas has been dissolved. It usually contains low levels of a number of salts (ranging from added table salt, sodium citrate to sodium bicarbonate, potassium bicarbonate, potassium sulphate or disodium phosphate).

These additives are included to emulate the slightly salty taste of homemade soda water, which in the past was made by "charging" a refillable seltzer bottle by filling it with water and then adding carbon dioxide.

Mineral Water

Mineral water is water containing minerals or other dissolved substances that alter its taste or give it supposed therapeutic value. Salts, sulphur compounds and gases are among the substances that can be dissolved in the water. Mineral water can often be effervescent. It can be manufactured OR can occur naturally from springs.

Traditionally, mineral waters would be consumed at their source, often referred to as "taking the waters" or "taking the cure" and such sites were referred to as spas, baths or wells. Well-known brands include Perrier, Vichy and Evian. In modern times, it is far more common for mineral waters to be bottled at their source and then distributed for consumption.

In many places, "mineral water" is often colloquially used to mean any sort of carbonated drink.

How much sodium (salt)?

Contrary to popular opinion, today both soda and mineral water are NOT high in sodium.  The vast majority of mineral waters have less than 10mg per 100ml of sodium and are suitable for a low-salt diet.

A few mineral waters may have higher concentrations due to the natural salts in the particular spring where they are bottled but these are a minority.

From the table, you’ll see that Vichy is a lot higher than the others at 107mg per 100mL. While this higher sodium may be marketed as a health benefit, it’s not! It only adds to our already high sodium intake. The other minerals, however, such as magnesium, potassium, calcium as well as bicarbonates and sulphites are valuable and important to take in for good health.

If you're on a salt-free diet, always check the label to be sure - the cut-off for low salt foods is 120mg sodium per 100ml (equal to 1.2g per litre).

Source: Calorie King OR company website (where specified). Note: these figures only apply to Australia.