11.13 – Fluoride

learning Objective

  • Examine the role of Fluoride in the body.

 

Fluoride’s Functional Role

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:

  • Blocking acid formation by bacteria
  • Preventing demineralization of teeth
  • Enhancing remineralization of destroyed enamel

Fluoride was first added to drinking water in 1945 in Grand Rapids, Michigan; now over 60 percent of the US population consumes fluoridated drinking water. The Centers for Disease Control and Prevention (CDC) has reported that fluoridation of water prevents, on average, 27 percent of cavities in children and between 20 and 40 percent of cavities in adults. The CDC considers water fluoridation one of the ten great public health achievements in the twentieth century 1.

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.

 

Figure 11.13.1: A Severe Case of Fluorosis. Bellingham fluorosis by Editmore / Public Domain.

110 Great Public Health Achievements in the 20th Century. Centers for Disease Control, Morbidity, and Mortality Weekly Report. 1999; 48(12), 241–43 Accessed June 30, 2019.

 

 

Dietary Reference Intake

The IOM has given Adequate Intakes (AI) for fluoride but has not yet developed RDAs. 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 for females is 3 milligrams per day. The UL for young children is set at 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 11.9.1: Dietary Reference Intakes for Fluoride.
A table showing reference intakes of fluoride for all age groups
Age Group Adequate Intake U.L.
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 Males (> 19 years) 4.00 10.0
Adult Females (> 19 years) 3.00 10.0

Source: Institute of Medicine. Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride. January 1, 1997

Dietary Sources of Fluoride

Greater than 70 percent of a person’s fluoride 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 11.9.2: Fluoride Content of Various Foods
A table showing fluoride content in several food items
Food Serving Fluoride (milligrams) U.L. (milligrams per day)
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 .5

Current AI used to determine Percent Daily Value Micronutrient Information Center: Fluoride. Oregon State University, Linus Pauling Institute.
 
 

Contributors


University of Hawai’i at Mānoa Food Science and Human Nutrition Program: Allison Calabrese, Cheryl Gibby, Billy Meinke, Marie Kainoa Fialkowski Revilla, and Alan Titchenal