University of Illinois Extension

What About Fluoride and Magnesium?

Most of the body’s fluoride is found in the teeth and bones. Fluoride is often added to municipal water sources to aid in cavity reduction. Fluoride also helps maintain bone structure.

Children who drink well water may need fluoride supplementation to help prevent cavities. The Food and Nutrition Center of the Institute of Medicine's recommendations for fluoride are for children 1 to 3 years of age 0.7 mg per day; 4 to 8 years 1 mg/day; 9 to 13 years 2 mg/day; and 14-18 years 3 mg/day.

For adults, males age 19 and older need 4 mg/day; females 3 mg/day.

Magnesium is another mineral that is abundant in the body. About half of the magnesium in the human body can be found in bone; the remaining half is found in cells of body tissues and organs.

Magnesium is used by the body to maintain the muscle and nerve function including a steady heart rhythm, maintaining a healthy immune system, and keeping bones strong. According to the National Institutes of Health Office of Dietary Supplements, magnesium also helps regulate blood glucose levels, promotes normal blood pressure, and aids in energy metabolism and protein synthesis.

Adult men (age 31 and over) need 420 milligrams of magnesium per day; women 320 milligrams per day. Amounts vary slightly with age, pregnancy, and lactation.

Magnesium is found in a wide variety of foods including green vegetables, some legumes, nuts, seeds, and whole, unrefined grains. Information about food sources and needs for magnesium can be found at:

Recommended Intake of Nutrients Associated with Bone Health for Adults over Age 50

Nutrient Adequate Intake (AI) or
Recommended Dietary Allowance (RDA)
Upper Limit of Safety
Calcium 1200 mg 2500 mg
Vitamin D 10 µg or 400 IU, 51-70 years; 15 µg or 600 IU, > 70 years 50 µg or 2000 IU
Protein 0.8 gm/kg body weight None set
Sodium 1.3 grams, 51-70 years; 1.2 grams if >70 years 2.3 grams
Vitamin A 700 µg retinal activity equivalents (RAE), females 900 µg RAE, males 3000 µg preformed vitamin A
Vitamin K 90 µg, females; 120 µg, males None set
Magnesium 320 mg, females; 420 mg, males 350 mg of supplemental magnesium
Fluoride 3 mg, females; 4 mg, males 10 mg