Fluoride is a naturally occurring mineral found in water and some foods. The levels of fluoride found naturally in tap water vary across the country, and sometimes the organic level even exceeds the amount the water fluoridation scheme aims to achieve. The current scheme aims to increase fluoride levels to 1 milligram per litre of water, with a maximum permitted value of 1.5 mg/l litre. 

Fluoride helps to prevent tooth decay by strengthening your enamel and making it more resistant to acid attacks. It also helps to reverse the early signs of tooth decay, known as caries. Some areas in the UK have had a fluoridated water supply since the 1960s, and unsurprisingly, these areas have fewer cases of tooth decay than parts of the UK with no fluoride added to the water. In Scotland, for example, no public water supplies are currently fluoridated, and naturally occurring fluoride is generally around 0.1mg/l.

Fluoride occurs naturally in some of the foods we eat and things we drink. You’ll find fluoride in:

• Grapes and raisins

• Fruits, including apples, strawberries, cherries, bananas, peaches and watermelon

• Vegetables, including spinach and potatoes

• Seafood, like prawns and crab legs

• Black tea and coffee

Since tap water is often fluoridated, you may have wondered, does bottled water have fluoride? Bottled water may contain low levels of naturally occurring fluoride, but it rarely has fluoride added to it in quantities that provide any oral health benefits. If your bottled water does have fluoride added, it will state it on the label. Keep in mind, if you only drink bottled water, you could be missing out on the dental benefits a fluoridated water supply can provide.

If bottled water is your primary source of drinking water, you may not be getting enough fluoride. While fluoride is added to public water supplies to reduce tooth decay, the majority of bottled waters on the market do not contain optimal levels (0.7-1.2 parts per million) of fluoride.

Several factors affect whether or not you're getting enough fluoride, including:

• The fluoride level in your bottled water, which can vary greatly by brand, If the fluoride content does not appear on the label, contact the company and ask.

• The amount of bottled water you drink during the day

• Whether you use bottled water for drinking, cooking or reconstituting soups, juices and other drinks

• Whether you also drink fluoridated water at school, work or elsewhere

If you drink mostly bottled water, you should talk to your dentist about whether you or your children need supplemental fluoride treatments. Your dentist may recommend fluoride drops or tablets if he or she feels you or your child is not receiving adequate levels of fluoride.

So, what does fluoride do for your teeth? Fluoride strengthens your teeth and can reduce the risk of developing tooth decay by around 25%. If that’s not enough reason to want fluoride in drinking water, here are a few more fluoridation benefits:

• Fluoride helps to remineralise your tooth enamel

• It can reverse the early signs of tooth decay

• It slows down the demineralisation of tooth enamel

• It helps to prevent bacteria that cause cavities from growing 

• It’s a natural mineral

• It’s safe and effective 

• It can improve your overall dental health and save you money on expensive treatments

When it comes to fluoride in water, it’s safe to say the oral health benefits outweigh the risks. However, if used excessively or ingested in large quantities, fluoride can cause health problems. Like many substances, fluoride is helpful in small quantities but can be harmful in large quantities. Here are some of the health problems associated with excessive fluoride consumption:

•  Dental fluorosis – using high concentrations of fluoride during childhood when teeth are developing can result in white streaks or spots on the tooth enamel known as flurosis. This is why it’s important children use a toothpaste suitable for their age range and don’t use adult toothpaste or mouthwash until around the age of 6. Children must also be taught to spit out toothpaste residue and never swallow it. 

• Skeletal fluorosis – ingesting too much fluoride over many years can result in damage to your bones and joints, known as skeletal flurosis. Bones can become hardened and more at risk of fractures and joint mobility. 

• Neurological problems – a study in the US by the National Toxicology Program has linked high levels of fluoride to lower IQ levels in children. However, more research is needed, and more recent studies show there is no negative association between fluoride and cognitive development. 

• Fluoride poisoning – ingesting excessive quantities of fluoride can cause abdominal pain, excessive saliva, sickness and nausea, muscle spasms and even seizures. It’s important to note, this won’t result from drinking fluoride in water and is more likely when swallowing high levels of over-the-counter or prescription products that contain fluoride.

Here are the answers to some commonly asked questions about fluoride in water: