Cycling and sugar (glucose)consumption go hand in hand. On rides of one to two-and-a-half hours, the latest nutritional guidelines suggest you need 30g to 60g of carbohydrates (ie sugar molecules) per hour to maintain performance, while this ramps up to 60g to 90g for anything longer.
Forgoing this advice can end a ride early when your body’s glycogen (the stored form of glucose found in the muscles and liver) reserves run dry, so it turns to fats and proteins for its source of energy, leading to the dreaded bonk. But all of that sweet stuff can’t be good for your teeth, right?
“Sugars are the main cause of tooth decay,” explains Professor Ian Needleman, who heads the Centre for Oral Health and Performance – a world-leading research group at UCL (University College London).
“The issue is the frequency, not the amount, and every time you have sugar – even a small amount – there’s enough in your mouth for the bacteria around the teeth to produce acid for about 20 to 30 minutes.”
This acid attacks the teeth’s enamel surface, which over time can lead to small holes known as cavities. While one gel here or there isn’t going to lead to gaping holes in your smile, if you use energy gels or sports drinks frequently, Needleman says you’re at increased risk.
“The advice for everyone – not just athletes – is that sugars at meal times aren’t an issue. If you’re having sugars three times a day, it’s very unlikely to cause tooth decay. It’s the additional times outside of that.”
He adds that there’s a big misunderstanding and mythology about natural sugars – for instance, honey. “Bacteria don’t care what type of sugar it is – sugar is sugar, so the risk will still be there.”
The problem is particularly relevant in cycling or any endurance sport, because it’s recommended you drip feed those carbohydrates across the duration of your ride to get the full benefit, turning your mouth into a petri dish of bacteria, sugar and their acid waste product.
“Throughout a ride, the mouth will be in a state where the balance has tipped from being stable to acidic.”
Over time, this can lead to tooth decay. Some of the early signs will be: teeth becoming more sensitive to hot and cold temperatures; small white, yellow or brown flecks on the enamel; and decay around existing fillings, which can start to loosen and fall out.
“The obvious symptom is pain,” adds Needleman. “It doesn’t tend to be an early symptom, but massive toothache can be very severe. The issue is that athletes will have a lifelong burden of treatment. Fillings only last a certain period of time, and every time they’re replaced, they’ll get larger.
"There’s only a certain number of times that can happen before the tooth can’t be refilled and is lost. If that’s happening on multiple teeth, not only is it very unpleasant having lots of dentistry, but it’s costly and will impact on your smile, confidence, ability to eat and so quality of life.”
Youth isn’t a barrier to issues either. Needleman has seen professional athletes in their 20s and 30s with many teeth that are either very difficult to repair or require multiple extractions.
“Our research suggests that if you’re an elite athlete and using energy supplements frequently, your oral health – in particular tooth decay – is worse than the normal population,” Needleman says, before adding that some athletes have been unable to compete or lost medals due to pain from decay or resulting root canal infections.
What can you do?
“The first step is to own the risk,” says Needleman. “It’s to recognise that, because of the love of cycling, you’re at that risk, similar to how you may be at increased risk of developing an overuse injury because of other elements of your training.”
In terms of mitigating it, there are several steps, starting with a trip to the dentist.
“It’s important to tell your dentist what you do and your frequency of sugar intake so that they can carry out a screening and give you a baseline of your decay risk.
"If you’re using energy gels frequently, you should see your dentist twice a year. If it’s the occasional thing and you don’t have recent tooth decay, then your dentist may say you only need to come once a year or once every two years.”
If you’re high-risk, Needleman advises using a high-fluoride toothpaste, only available from dentists or on prescription, which will strengthen the teeth and reduce the tendency for the acids to dissolve the enamel.
“Brush for at least two minutes twice a day, then spit but don’t rinse afterwards – fluoride protects as a surface effect on the enamel, so if you leave it in place for a few minutes or few hours, you’ll get the benefit. If you rinse out afterwards, you won’t,” he explains.
You don’t need to add teeth cleaning to your mid- or post-ride checklist though.
“Twice a day is good. But if your dentist assesses that you’re high risk, you can also use a fluoride-containing mouthwash, which increases the contact of fluoride on your teeth and protects them.”
In terms of mid-ride sustenance, Needleman says there isn’t anything on the market that has evidence it doesn’t cause the bacterial reaction in your mouth, but he does suggest one way of diluting the acidic reaction.
“It’s harder for other athletes, such as endurance runners, but on a bike, it’s possible to use a two-bottle strategy. If you’re using an energy drink, have a second bottle with water, and after taking in the gel or the energy drink, rinse with water.”
“Try to view the dentist as an oral health coach, as opposed to the person you’re scared of or who’s going to cost you lots of money," adds Needleman.
"Recognise you’re doing the sport because you love it, and here’s somebody who can help you.”
Top tip
Even if you aren’t at high risk, Needleman’s ‘spit don’t rinse’ mantra is important to follow when brushing your teeth or using mouthwash. The University of San Francisco found that this technique can reduce tooth decay by 25%.
