Why not add some sparkle to your life?

Proper hydration is an important element in wellbeing, particularly in terms of mental functioning and even mood. I was recently driving and accompanied by a friend. As I drove, I was occasionally drinking from a water bottle, and my friend commented that she should really drink more. She said the problem for her was that she "hates plain water". I asked if she liked sparkling. She said she did, but imagined it was somehow unhealthy.

One common thought here is that the carbon dioxide in sparkling waters imparts some acidity, and this can cause erosion of tooth enamel. An analysis of more than 30 types of carbonated mineral waters found that pH ranged from 4.23 - 6.49 (anything less than 7 is acidic) [1]. It's perhaps worth bearing in mind that the pH of Coca Cola Classic is 2.37 (not far off lemon juice), which actually makes it about 100 times as acidic as the most acidic carbonated water tested in the analysis cited above.

Also, when people drink, fluid normally only momentarily touches the teeth during drinking, and is then generally quickly diluted with saliva. If you wanted to be on the safe side, you could always drink carbonated water through a straw, as this helps ensure it only has minimal contact with the teeth by depositing the water more to the back of the mouth.

The truth is, my preferred water is sparkling (I have a Sodastream at home - no affiliation). I told my friend the only reason I was drinking still water in the car is because that's what happened to be in the car at the time.

This exchange also reminded me of a study published not so long ago that examined the effect of drinking sparkling or still water in adults exposed to the ‘heat-stress’ of a room held at 37 C/99 F temperature and 50% humidity [2].

The study subjects were given either cold (4 C/39 F) carbonated or still water to drink, and subsequently, certain measurements and assessments were made. While not all things that were measured improved, several things did, including blood pressure (this increased, which is generally useful, as heat and sweating can lower blood pressure to suboptimal levels), blood flow to the brain, sleepiness and motivation. What was interesting about this study for me is that while both still and sparkling water brought benefits, the magnitude of improvement was actually greater for sparkling water.

While my personal preference is for sparkling water, my general advice is for people to drink the form they prefer, on the basis that this is the one they're likely to drink more of.

Conventional advice urges us to drink a specific amount of water each day, typically 2 litres or eight glasses. However, our actual individual needs depend on many factors, including body weight, ambient temperature and levels of activity. A decent guide to the state of our hydration is the colour of our urine. My broad advice here is to drink enough to ensure we keep our urine pale yellow throughout the day.

References:

Morgado M, et al. pH analysis of still and carbonated bottled water: Potential influence on dental erosion. Clin Exp Dent Res. 2022 Apr;8(2):552-560

Fujii N, et al. Ingestion of carbonated water increases middle cerebral artery blood velocity and improves mood states in resting humans exposed to ambient heat stress. Physiol Behav. 2022 Oct 15;255:11394

Note: This study was funded by the Japanese drinks company Asahi. Asahi makes a range of beverages, including sparkling and still waters.