Fluoride

Why fluoride is good for you

Fluoride is a trace mineral, yet has a very important role in ensuring teeth and bones are healthy and it is especially implicated in preventing tooth decay.

When teeth and bone are formed calcium and phosphorus forms crystalline structures called hydroxyapatite. Fluoride then replaces a part of the hydroxyapatite crystal, creating fluorapatite, which makes the bones stronger and gives the teeth better resistance to decay.

Fluoride is involved in maintenance and regulation (activation and deactivation) of several important enzyme systems in the body.

Important fluoride facts

• Foods cooked in fluoridated water will get more of this nutrient
• Not every water system in every country is fluoridated, check with the local council to know for sure
• Fluoride is one of the trace minerals, which means only a small amount of it is required in the diet to ensure good health

Fluoride works best with

• Iron
• Magnesium
• Molybdenum

Fluoride and health

• Tooth decay
  Many studies have shown that fluoride prevents dental caries (cavities) so now most water supplies have fluoride added. There is some conflicting evidence about the safety of water fluoridation, which has not be absolutely proved to be safe or effective, but most literature shows it to be safe in the doses administered. It is only when fluoride concentration in water supplies reaches 150 parts per million that it can cause toxic symptoms (normal fluoridated water contains 1 part per million)
• Fluoride is needed for healthy bones and teeth
  Fluoride has a very important role in ensuring teeth and bones are healthy and it is especially implicated in preventing tooth decay.
• Fluoride helps to metabolise calcium, iron and magnesium
  Fluoride has an important role in helping the body metabolise and use the minerals calcium, iron and magnesium, two of which are important in mineralisation of bones and teeth to ensure they are healthy and strong. When teeth and bone are formed, calcium and phosphorus forms crystalline structures called hydroxyapatite. Fluoride then replaces a part of the hydroxyapatite crystal, creating fluorapatite, which makes the bones stronger and gives the teeth better resistance to decay.
• Fluoride is needed to activate many enzymes
  Fluoride is required to activate the activity of a number of important enzymes in the body

People who wish to take an fluoride supplement should talk to a medical professional before taking it.

Groups at risk of fluoride deficiency

Very few people are at risk of fluoride deficiency as most water supplies are fluoridated, but the following may be the only groups who are at risk:

• People who don’t drink much water
  May have less exposure to fluoride and may be at risk of deficiency
• People who live in areas with low water fluoride content
  Some studies show that people living in areas with water that has been fluoridated at low levels or not at all, may be at a higher risk for fluoride deficiency. Other studies show that if the diet is varied and includes plenty of whole foods, then risk of fluoride deficiency will be low.

Symptoms of fluoride deficiency

Symptoms of fluoride deficiency are:

• Increased dental cavities
• Weakened tooth enamel

While there is a lot of research indicating that fluoridating water supplies help to decrease dental cavities, there is also some conflicting research showing that fluoridating water supplies has proven to be neither safe nor effective. Diet (especially high sugar and processed food intake) plays a bigger role in the development of dental cavities than water fluoridation.

Fluoride in food

FOOD	AMOUNT	fluoride (mcg)
Black tea made with tap water	1 cup	884.0
Raisins, seedless	1 cup (165g)	386.0
Blue crab, canned	1 can (125g)	262.0
Coffee made with tap water	1 cup	215.0
Tap water	1 cup	169.0
Cranberry juice	1 cup	168.0
Instant oats cooked with water	1 cup	168.0
Spinach, cooked	1 cup (180g)	68.0
Tuna, canned in oil	1 can (125g)	53.0
Potato chips, plain	1 packet (50g)	53.0
Cheddar cheese	1 cup (132g)	46.1
Kellogg’s Raisin Bran cereal	1 bowl (30g)	39.7
Carrots, cooked no salt	1 cup (78g)	37.0
Red wine (table variety)	1 glass	30.6
General Mills Cheerios	1 bowl (30g)	20.3
Asparagus, cooked no salt	½ cup (90g)	19.7
Bread, Rye	1 slice	16.3
Bread, Wholewheat	1 slice	13.7
Bread, White	1 slice	12.3

 

Fluoride recommended daily intake (RDI)

RDA	lifestage	age	amount
	INFANTS	0-6mths 7-12mths	0.01mg 0.5mg
	CHILDREN	1-3yrs 4-8yrs	0.7mg 1.0mg
	CHILDREN	9-13yrs 14-18yrs	2.0mg 3.0mg
	ADULTS	male: 19-50yrs female: 19-50yrs	4.0mg 3.0mg
	SENIORS	male: 51+yrs female: 51+yrs	4.0mg 3.0mg
	PREGNANT	all ages	3.0mg
	LACTATING	all ages	3.0mg
TOLERABLE UPPER LIMIT	lifestage	age	amount
	INFANTS	0-6mths 7-12mths	0.7mg 0.9mg
	CHILDREN	1-3yrs 4-8yrs	1.3mg 2.2mg
	CHILDREN	9-18yrs	10mg
	ADULTS	19-50yrs	10mg
	SENIORS	51+yrs	10mg
	PREGNANT	all ages	10mg
	LACTATING	all ages	10mg
Toxic Levels	> 30mg

The tolerable upper limits should only be taken for short periods and only under medical supervision.

Toxic levels of fluoride

Fluoride is toxic at doses greater than 20mg per day.

Acute fluoride toxicity

Acute toxicity from taking too much in fluoride supplements – over 50mg can cause the following symptoms:

• Severe fluorosis*
• Skin rash, especially if it has a rapid onset

Chronic fluoride toxicity

Chronic toxicity of fluoride from taking higher than the therapeutic dose of supplements for a long time can cause the following symptoms:

• Abdominal pain
• Constipation
• Fluorosis*
• Loss of appetite
• Mottling and discolouration of teeth
• Mild skin rash
• Nausea
• Pain or tingling in arms, face and legs
• Vomiting

People who experience any of the above toxicity symptoms should discontinue their fluoride supplements and see their doctor for advice. Overdosage and toxicity is more likely to occur from taking too many supplements, whereas dietary intake of fluoride is highly unlikely to cause overdosage.

Fluorosis

Fluorosis is a condition which occurs when there has been a high intake of fluoride (either over a long time or in a short duration) and affects the teeth by giving them a mottled an discoloured appearance. Fluorosis only occurs during tooth development (in young children and teenagers) and cannot be reversed.

Fluorosis

Overdosage of fluoride is called fluorosis and it affects the teeth by giving them a mottled appearance. Fluorosis only occurs during tooth development (in young children and teenagers) and cannot be reversed.

Mild cases of fluorosis causes

• the teeth have white spots and some mottling in their appearance

Severe cases of fluorosis causes

• the enamel becomes pitted and very badly stained.

Other signs of toxicity/overdosage of fluoride

• abdominal pain
• diarrhoea
• nausea
• vomiting
• pain or tingling in arms, face and legs

Synergistic nutrients that reduce fluoride toxicity

The following nutrients reduce toxicity of excessive fluoride intake:

• Vitamin C
• Glutathione
• Calcium

Precautions

Certain people should not take fluoride supplements at all:

• People who live in an area that water is highly fluoridated

The local council or local government need to be contacted in order to determine if a water supply has high levels of fluoridation. If this is the case, then extra fluoride supplements may produce toxic effects, such as fluorosis, a condition which affects the teeth mainly by causing a mottling of the colour.

Certain people should not take fluoride supplements without first consulting their doctor for advice:

• People who have an underactive thyroid (hypothyroidism)
  People with an underactive thyroid may experience an increase in the symptoms of their condition if they take high levels of fluoride supplements
• People who have osteoporosis
  People with osteoporosis may experience an increase in the symptoms of their condition if they take high levels of fluoride supplements
• Women who are pregnant
  There is conflicting research about the benefits of fluoride supplementation on the unborn foetus, so further advice is needed before taking fluoride supplements.

Interactions with medications and supplements

The following are the medications and supplements that are more likely to cause a reaction with fluoride supplements:

• Aluminium hydroxide
  Aluminium hydroxide (an antacid) decreases absorption of fluoride, so this medication should be taken at least 2 hours before or after taking fluoride supplements.
• Calcium supplements
  Calcium supplements decrease absorption of fluoride, so should be taken several hours apart or not at all.
• Milk and other dairy products
  Milk, just like calcium supplements causes fluoride to be less absorbed, so take fluoride supplements at least 2 hours before or after drinking milk (or larger amounts of other dairy products such as cheese, yoghurt or cream).
• Vitamin C and glutathione
  Vitamin C and glutathione both detoxify the body of excess levels of fluoride, by reducing absorption of fluoride.

Other interactions with fluoride

There are none reported.

Fluoride’s effect on lab tests

Fluoride has the following effects on lab tests:

• Serum calcium
• Serum phosphatase
• Protein-bound iodine
• Serum aspartate aminotransferase (SGOT)

Fluoride supplements can cause falsely decreased levels of serum calcium, phosphatase and protein-bound iodine as well as falsely increased levels of SGOT.

References

• Bratthall D, Hansel-Petersson G, Sundberg H. Reasons for the caries decline: what do the experts believe? European Journal of Oral Science. 1996 104:416-22
• Burt BA, et al. The effects of a break in water fluoridation on the development of dental caries and fluorosis. Journal of Dental Research, 2000. 79(2):761-9
• Neurath C. Tooth decay trends for 12 year olds in nonfluoridated and fluoridated countries. Fluoride 2005. 38:324-325
• Osiecki, H. The Nutrient Bible. Bio-Concepts Publishing QLD, 2002
• Whitney EN, Cataldo DB, Rolfes SR. Understanding Normal and Clinical Nutrition, 6th Edition. Wadsworth/Thomson Learning, 2002

Last updated: 6 May 2024