Fluoride 101: Benefits, Deficiency & Food Sources

Growing up in Singapore, like many others, I drank tap water without thinking twice about what was in it. It wasn't until later, during my own journey navigating chronic health conditions, that I began questioning not just what I ate, but what I drank, breathed, and brushed with.

Fluoride became one of those topics I stumbled into—not because I feared it, but because I wanted to understand it better. I was surprised by how polarizing the conversation was: one side praised it as essential for dental health, while the other warned of toxicity and long-term harm.

In this article, I'll break down what fluoride actually is, how it works, and what the science says—so you can make your own informed decisions, just like I did.

• Fluoride helps prevent tooth decay by strengthening enamel and remineralizing early damage, especially when used topically in toothpaste or mouth rinses.
  
  

• Fluoridated water is widely considered safe at regulated levels (~0.7 mg/L), though excessive exposure—particularly in young children—can lead to fluorosis.
  
  

• Most people get enough fluoride through drinking water and dental products; supplements are only recommended in specific cases under professional guidance.
  
  

• Too much fluoride can cause harm, including dental staining, bone stiffness, and potential thyroid effects—especially when multiple sources are combined.
  
  

• Balance is key—fluoride can be beneficial when used wisely, but awareness of total intake from all sources is essential for long-term health.

Fluoride is a natural mineral—a negatively charged ion of the element fluorine—commonly found in soil, water, plants, and even the oceans. It occurs naturally in varying concentrations throughout our environment, but its most well-known role is in dental health.

Fluoride helps strengthen tooth enamel, the outer protective layer of your teeth, making it more resistant to acid attacks from plaque and sugars. It's used both topically (like in toothpaste and dental varnishes) and systemically (such as in fluoridated drinking water or supplements).

The idea behind fluoride is simple: small, controlled exposure helps prevent tooth decay. But like many things in health, the dose and context matter.

Before we understand dietary implications, let’s first understand sodium’s chemistry. As a free element, sodium is so reactive it can’t exist naturally in its metallic form. Instead, the sodium atom loses an electron to form a sodium anion and combines with other elements.

This reactivity is why sodium reacts violently with water, producing hydrogen gas and sodium hydroxide (also known as caustic soda). This property makes liquid sodium useful in certain industrial applications, including as a coolant in nuclear reactors.

Sodium forms alloys with other metals and is important in organic synthesis processes. Common sodium compounds we encounter include:

• Sodium carbonate (soda ash): Used in glass manufacturing and cleaning products

• Sodium peroxide: A powerful oxidizing agent

• Sodium nitrite: A food preservative

• Sodium benzoate: A common food preservative

• Sodium cyanide: Used in mining (but highly toxic)

• Sodium hydride: A powerful reducing agent

• Sodium saccharin: An artificial sweetener

Monosodium glutamate (MSG) is another sodium compound used as a flavor enhancer, though it contains much less sodium than table salt.

Fluoride is one of the most studied minerals in public health, and for good reason.

1. Strengthens Enamel

When applied topically, fluoride helps to remineralize weakened enamel, reversing early signs of tooth decay before cavities form. It also makes the tooth surface more resistant to future acid attacks, which is crucial for preventing cavities.

2. Reduces Dental Caries

Consistent fluoride exposure, especially in children, has been shown to lower the risk of cavities significantly.

Community water fluoridation is recognized by the Centers for Disease Control and Prevention as one of the top ten public health achievements of the 20th century due to its significant impact on reducing tooth decay.

Fluoride works best when combined with good oral hygiene and a low-sugar diet.

3. Benefits Growing Teeth

For children, fluoride supports proper tooth development and provides systemic protection while teeth are still forming under the gums. This protection continues as teeth erupt, giving them a stronger foundation from the start.

4. Supports Community Dental Health

Public health measures like water fluoridation have been linked to a reduction in dental decay across populations.

Water has been fluoridated in Singapore since 1958, and tooth decay rates in children have declined over the decades. The success of community water supplies with added fluoride has been replicated in many regions worldwide.

5. May Support Bone Health (in small doses)

Some early studies suggest fluoride may help strengthen bones, but too much can lead to skeletal fluorosis, so this area remains under careful evaluation. Scientific evidence continues to evolve regarding fluoride's role beyond oral health.

This is where it gets complicated. Community water fluoridation is the practice of adding fluoride to municipal water supplies to improve dental health.

Many health authorities, including the World Health Organization, the American Dental Association, and the American Medical Association, consider it safe and effective.

But not everyone agrees.

The Support:

• Reduces cavities, especially in underserved populations

• Cost-effective for large-scale public health

• Safe at recommended levels (typically 0.7 mg/L in many countries)

The Concerns:

• Overexposure in children can lead to dental fluorosis—white or brown stains on the teeth

• Some researchers worry about possible links to thyroid issues, lower IQ in children, or neurotoxicity, though most of these findings are inconclusive or based on very high levels not used in public water systems

• Some feel mass fluoridation removes individual choice

In Singapore, water fluoridation continues as a public health measure. In contrast, some European countries have moved away from fluoridating water, opting instead to encourage topical fluoride use, like fluoridated toothpaste or fluoride mouth rinse.

So is fluoride harmful? At regulated levels, it's widely considered safe. Problems tend to arise with excessive intake—especially from multiple sources that people aren't aware of.

Most people associate fluoride with excess, but not getting enough fluoride can also have consequences.

Signs of Deficiency:

• Increased risk of dental cavities

• Weakened tooth enamel in children

• Faster breakdown of existing dental work

• Potentially higher susceptibility to gum disease

Signs of Excess:

• Dental fluorosis (mild to severe discoloration or pitting of the teeth)

• Skeletal fluorosis (in very high chronic doses – stiffness, joint pain)

• Stomach upset or nausea with acute overexposure

• Possible thyroid suppression or hormonal changes (still under debate)

Children under 8 are especially sensitive, as their teeth are still developing and more susceptible to fluorosis.

For infants, overexposure can occur when formula is mixed with fluoridated water. Breast milk naturally contains very low fluoride levels, even when mothers drink fluoridated water.

Here's a breakdown of where fluoride comes from in everyday life:

⚠️ Tip: Young children who swallow toothpaste instead of spitting it out can unintentionally consume too much fluoride. Use a pea-sized amount on your child's toothbrush and supervise children's brushing, especially for children younger than six years.

Beyond water and toothpaste, fluoride comes in various forms for both in-office and at-home use:

Professional Fluoride Treatments

At your dentist's office, you might receive:

• Fluoride varnish: A highly concentrated form painted directly onto teeth

• Fluoride gel: Applied using trays that fit over your teeth

• Fluoride foam: Similar to gel but in a lighter form

These professional fluoride treatments typically contain a much higher amount of fluoride than what's found in consumer products and are particularly beneficial for those at high risk for cavities.

At-Home Fluoride Products

For daily or weekly use:

• Fluoridated toothpaste: The cornerstone of most oral hygiene routines

• Fluoride mouth rinse: Useful for additional protection, especially for both children and adults with cavity-prone teeth

• Dietary supplements: Available for those who don't drink fluoridated water

Dietary fluoride supplements are usually recommended only in areas where water isn't fluoridated and the risk of cavities is high. They're available as:

• Drops (for infants)

• Chewable tablets (for children)

• Rinses (for older kids or adults with high cavity risk)

Your dentist or pediatrician can help determine whether additional fluoride is necessary based on your water source, age, and oral health status.

Disease control and prevention experts at organizations like the Centers for Disease Control recommend careful assessment before prescribing fluoride supplements for a child's teeth.

Here's a look at daily recommended fluoride intake vs. the tolerable upper limit to avoid toxicity:

Source: Institute of Medicine, National Academies of Sciences

Monitoring fluoride levels from all sources is important, especially for young children. The fluoride levels in your water, combined with oral hygiene products and dietary sources, should be considered when evaluating total exposure.

Fluoride used to be something I never questioned. Then it became something I feared. Now, it's something I understand in a more balanced, evidence-based way.

For me, the key has been focusing on moderation and informed choice. I still use fluoride toothpaste and drink water, but I also make sure I'm not doubling up unnecessarily through supplements or food. When it comes to our health, context and awareness matter more than fear.

So if you're wondering whether fluoride is good or bad, the truth is, it's both. It all depends on how much, from where, and for whom.