Plain seltzer or sparkling water’s lack of sugar, calories, added colors or artificial flavors and its relatively low acidity makes it a generally healthy choice compared to most beverage options on the market, including most sodas, juices and sports drinks. But check the product label to avoid added sweeteners or sodium or other additives.
Seltzer is water that has had pressurized carbon dioxide added to give it bubbles. Sparkling water is the umbrella term for carbonated water, including naturally carbonated sparkling mineral water and artificially carbonated seltzer and club soda. Studies have not shown ill health effects from drinking seltzer or other plain sparkling waters.
A 2006 study found an association between drinking colas and low bone mineral density. But the association was not seen in those who drank other carbonated beverages.
Colas, with their low pH (a measure of acidity), also have the potential to erode tooth enamel. But a study published earlier this year in the Journal of the American Dental Association found that the pH of plain sparkling water, about 5, is not low enough to erode enamel.
Carbonation does not in itself lead to dental erosion, said Dr. John Ruby, an adjunct professor of pediatric dentistry at The University of Alabama at Birmingham, who co-authored the paper. “It’s when they add citric acid or phosphoric acid that’s in your classic soft drinks that the pH can drop below the critical pH of 4, where you then can have dental erosion as an outcome. For example, Coca-Cola has a pH of about 2.4,” making it potentially over 100 times more erosive than sparkling water (because pH is on a logarithmic scale).
Bottled seltzers that have been flavored with citric acid, the acid found naturally in citrus fruits like lemons and limes, may be acidic enough to damage enamel. But you can get flavor in a less acidic form by adding a slice of lemon or lime (or other fruits, vegetables or herbs, such as cucumber, mint or basil) to plain sparkling water.
According to a spokesman from the American Dental Association, the greatest potential health drawback of consuming bottled sparkling water is missing out on the benefit of fluoride when you drink it instead of fluoridated tap water. In-home sparkling water makers, such as SodaStream, have gained popularity in recent years because they save money and have environmental benefits, but an additional advantage of making your own sparkling water from the tap may be the fluoride, which the ADA emphasizes is essential for maintaining long-term oral health.
An additional health note: Club soda, which contains added sodium to mimic the taste of mineral water, is not the same as seltzer. The amount of sodium can be small and varies by brand, but it can add up if consuming many servings. Too much sodium can increase blood pressure, and current sodium levels among most Americans are already considered too high.