Chapter 12. Micronutrients for Bones

Fluoride

Role of Fluoride

Fluoride is known mostly as the mineral that combats tooth decay. It assists in tooth and bone development and maintenance. Fluoride combats tooth decay via three mechanisms:

  1. Blocking acid formation by bacteria
  2. Preventing demineralization of teeth
  3. Enhancing remineralization of destroyed enamel

Fluoride is added to drinking water in 45% of communities in Canada. In British Columbia, only 3.7% of the population has access to fluoridated water. Fluoridated water, on average, prevents 27 percent of cavities in children and between 20 and 40 percent of cavities in adults, however, it can be expensive.

The optimal fluoride concentration in water to prevent tooth decay ranges between 0.7–1.2 milligrams per liter. Exposure to fluoride at three to five times this concentration before the growth of permanent teeth can cause fluorosis, which is the mottling and discoloring of the teeth.

 

Fluorosis
Figure 12.7 A severe case of fluorosis.

A severe case of fluorosis caused by excessive fluoride exposure. Figure 12.7 portrays discolored teeth with brown, yellow, or black stains and visible enamel damage.

Fluoride’s benefits to mineralized tissues of the teeth are well substantiated, but the effects of fluoride on bone are not as well known. Fluoride is currently being researched as a potential treatment for osteoporosis. The data are inconsistent on whether consuming fluoridated water reduces the incidence of osteoporosis and fracture risk. Fluoride does stimulate osteoblast bone-building activity, and fluoride therapy in patients with osteoporosis has been shown to increase bone mineral density. In general, it appears that at low doses, fluoride treatment increases bone mineral density in people with osteoporosis and is more effective in increasing bone quality when the intake of calcium and vitamin D is adequate.

Dietary Reference Intake for Fluoride

The Adequate Intakes (AI) for fluoride are available, but RDAs have not yet been developed. The AIs are based on the doses of fluoride shown to reduce the incidence of cavities, but not cause dental fluorosis. From infancy to adolescence, the AIs for fluoride increase from 0.01 milligrams per day for ages less than six months to 2 milligrams per day for those between the ages of fourteen and eighteen. In adulthood, the AI for males is 4 milligrams per day and 3 milligrams per day for females. The UL for young children is 1.3 and 2.2 milligrams per day for girls and boys, respectively. For adults, the UL is set at 10 milligrams per day.

Table 12.11: Dietary reference intakes for fluoride
Age Group AI (mg/day) UL (mg/day)
Infants (0–6 months) 0.01 0.7
Infants (6–12 months) 0.50 0.9
Children (1–3 years) 0.70 1.3
Children (4–8 years) 1.00 2.2
Children (9–13 years) 2.00 10.0
Adolescents (14–18 years) 3.00 10.0
Adult Females (> 19 years) 3.00 10.0
Adult Males (> 19 years) 4.00 10.0
Data Source: (“Dietary Reference Intakes,” 1997)[1]

 

Dietary Sources of Fluoride

Greater than 70 percent of a person’s fluoride intake comes from drinking fluoridated water when they live in a community that fluoridates the drinking water. Other beverages with a high amount of fluoride include teas and grape juice. Solid foods do not contain a large amount of fluoride. Fluoride content in foods depends on whether it was grown in soils and water that contained fluoride or cooked with fluoridated water. Canned meats and fish that contain bones do contain some fluoride.
Table 12.12: Fluoride content of various foods
Food Serving Fluoride (mg) Percent Daily Value*
Fruit Juice 3.5 fl oz. 0.02-2.1 0.7-70
Crab, canned 3.5 oz. 0.21 7
Rice, cooked 3.5 oz. 0.04 1.3
Fish, cooked 3.5 oz. 0.02 0.7
Chicken 3.5 oz. 0.015 0.5
* Current AI used to determine Percent Daily Value
Data Source: (“Fluoride,” 2015)[2]

Consuming Too Little Fluoride

Insufficient fluoride intake can play a role in dental cavities.

Consuming Too Much Fluoride

Exposure to high fluoride concentrations before the growth of permanent teeth can cause fluorosis, which is the mottling and discoloring of the teeth.


  1. Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. January 1, 1997. http://www.iom.edu/Reports/1997/Dietary-Reference-Intakes-for-Calcium-Phosphorus-Magnesium-Vitamin-D-and-Fluoride.aspx..
  2. Micronutrient Information Center: Fluoride. Oregon State University, Linus Pauling Institute. lpi.oregonstate.edu/mic/minerals/fluoride . Updated in April 29, 2015. Accessed October 22, 2017.

License

Icon for the Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License

Fluoride Copyright © 2022 by Luisa Giles and Komal Dhaliwal is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

Share This Book