I have a friend who drinks a lot of seltzer water and I worry this is adding acidity to his body. What’s your opinion about this?

A: “Seltzer water” is made by dissolving carbon dioxide under pressure into water. This process causes the water to become effervescent. It was first designed as a low-cost alternative to naturally carbonated European mineral waters, which can be relatively expensive. In the carbonation process, carbon dioxide dissolves in the water creating carbonic acid, which gives the water a slightly sour taste and a pH between 3 and 4. Plain seltzer water is acid-forming and adds to one’s acid load as you suspected.

Be aware that “soda water" is slightly different. In soda water, generally, an alkalizing agent such as sodium bicarbonate, or a potassium-based alkaline compound, is added to the artificially carbonated water. This reduces the acidity of the water to some degree and can add a slight salty taste.