Sports Drinks, Gels and the Slow Erosion Nobody Warns You About

My dentist turned the little mirror round and told me to look at the biting edges of my top front teeth. They were faintly see-through, like the edge of a sheet of frosted glass held up to a window. I was thirty-four and I had never noticed. She asked what I drank while training. I said the obvious things and did the arithmetic out loud, and the number came out somewhere north of four litres of sports drink a week, for about a decade.

Nothing had ever hurt. That is the whole problem with erosion. It is not decay, there is no hole, no ache, no moment where you catch it happening. It is the outer surface dissolving slowly, and by the time you can see it in a mirror it has been running for years. I should say plainly that I am not a dentist. This is what I understood after asking a lot of questions and then reading for a year.

The acid does the damage, not the sugar

Sugar feeds bacteria that produce acid, and that is the cavity story everybody already knows. Erosion is more direct than that. The drink itself is acidic and it dissolves mineral straight out of the enamel surface on contact. Most sports drinks land somewhere around pH 3, which puts them in the same neighbourhood as orange juice. Gels are often worse, partly because they are more acidic and partly because they stick around. Enamel starts losing mineral below roughly pH 5.5, so essentially everything we swallow during endurance work sits under the line. The American Dental Association write-up on erosive tooth wear is a good sober summary if you want it from people who actually know.

Saliva repairs this, slowly. It buffers the acid back up and puts minerals back, and given half an hour of peace it does a decent job. The trouble is that we never give it half an hour.

Sipping is the real crime

Two hundred millilitres drunk in one go is one acid event. The same bottle sipped every four minutes across an hour is fifteen acid events, and your mouth never climbs back above the line in between. I did the second thing for a decade, because that is how you are taught to hydrate, and it genuinely is better for performance. It is also close to the worst possible pattern for your teeth.

Dry mouth multiplies all of it

Here is the part nobody mentioned to me. Under hard effort you stop breathing through your nose. High-volume mouth breathing dries everything out fast, and dehydration cuts saliva production at the same time. So at the exact moment you are pouring acid over your teeth, you have the least amount of the fluid that neutralises it. Anyone who has finished a long session with that thick, sticky, gluey mouth has been riding with almost no protection at all.

There is a related trap for anyone who trains in a guard. Put a mouthguard in over a mouthful of sports drink and you have just sealed acid against the enamel for the next two hours. Rinsing with plain water first takes four seconds. I treat it as part of putting the guard in now, the same way you would not pull a wetsuit on over a layer of sand.

What I actually changed

• Plain water for anything under ninety minutes. Most of my sessions never needed fuel, I was drinking sugar out of habit.
• On long days the drink goes in a bottle I take proper swigs from, not a soft flask I nurse for two hours.
• Rinse with water straight after a gel. That one is not optional for me any more.
• No brushing for at least half an hour after anything acidic. Softened enamel plus bristles is abrasion, and you scrub away the surface you are trying to protect.
• Fluoride toothpaste last thing at night, spit, do not rinse. Easiest change on the list by a distance.
• Nothing acidic in the two hours before bed, because saliva flow drops right off overnight.

None of that is heroic and none of it cost me anything in performance. Two years on, the see-through edges have not moved, which is the best result available, because enamel does not grow back. What is gone is gone. All you are ever doing is stopping the clock where it stands.

The trade-off I will not pretend away

I am not going to tell an endurance athlete to skip fuelling. Running out of energy two kilometres offshore is a safety problem, and a considerably bigger one than a thinning enamel edge. The honest position is that carbohydrate during long efforts is useful and the delivery method is negotiable. Real food, a less acidic drink, bigger swallows rather than a constant trickle, water in between. The World Health Organization fact sheet on oral health makes the general point that diet is the largest lever most people have, and it is one of the few parts of this that sits entirely under your own control.

Two other things are worth checking while you are at it. Erosion and clenching stack in a nasty way. Acid-softened enamel wears much faster under load, and a lot of us clench without ever noticing, particularly after an injury. I ended up going down that road myself and wrote it up in my notes on jaw pain after a hit.

And if you already have restoration work, the rules shift again. Composite fillings and crown margins do not respond to acid the way enamel does. Some of it holds up better, some of it worse, and where the material meets the tooth is its own conversation. That is a question for the person who did the work rather than for a blog, but it is worth actually asking instead of assuming it is fine. I listed what I asked mine in going back to training after dental work.

The thing I keep coming back to is how avoidable this was. Not the falls, not the handle to the face, none of that. Just a bottle I sipped from every four minutes for ten years because nobody ever told me it mattered.