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Boron

Medically reviewed on Jun 7, 2018

Common Name(s)

Boron, boric acid, boric anhydride, boric tartrate, borax sodium, borate.

What is Boron?

The element boron (B, atomic number 5) is found in deposits in the earth's crust at a concentration of about 0.001%. It is obtained in the form of its compounds and never in its elemental state.

Since 1857, it has been known that environmental boron is taken up by plants in trace amounts, and in 1923 boron was recognized as an essential nutrient for plants. Accordingly, plants contribute to our dietary boron intake, with primary sources being fruits, nuts, and vegetables. Good sources of boron include peanuts, peanut butter, almonds, hazelnuts, seaweed, soybeans, parsley, cocoa, wine, raisins, prunes, apples, and peaches.

Boron was originally obtained in 1895 from the reduction of boric anhydride, which remains a commercially important way to produce impure boron today. Pure boron takes the form of clear red or black crystals, depending on its crystalline shape. The crystals can be as hard as diamonds. The chemistry of boron is extremely complex.

What is it used for?

Traditional/Ethnobotanical uses

Reports suggest the Babylonians used borax as a flux for working gold 4,000 years ago. It was also used in the Saudi Arabian area of Mecca and Medina in the 8th century and by European goldsmiths in the 12th century. Borates were used as a food preservative between 1870 and 1920 and during World War I and II.

Borate-mineral concentrates, borax, boric acid, and other refined products have been used in glass, fiberglass, and washing products, and in combination with other metals to make harder alloys, fertilizers, wood treatments, insecticide and rodent repellant, and microbicides. As an insect and rodent repellent, boric acid was sprinkled in corners and along floor boards; however, this practice should be avoided because of the serious toxicity that can occur if ingested by small children or pets.

In medicine, boron has usually been found in the form of boric acid, which has been used on the skin as an astringent, anti-infective, and as an eyewash. Sodium borate slows bacterial growth and has been added to cold creams, eye washes, and mouth rinses. Boric acid solutions for external use are generally diluted. A 2.2% solution of boric acid is safe to use in the eyes. Because boric acid has weak antifungal and antibacterial activity, it has been used as a mild disinfectant in concentrations ranging from 2% to 10%. Boric acid/borax powder has been applied to the ear canal for mild infections.

Boron is used in nuclear medicine and chemistry to absorb neutrons.

General uses

Boron has been included in nutritional supplements or natural remedies designed to improve bone and joint health. Boron deficiency has been shown to impair brain function, inflammatory regulation, and immune response, and to increase the risk of some cancers. However, there is no evidence that boron supplementation above the levels found in a normal diet is beneficial. Therefore, supplementation is likely to only be useful if there isn't enough boron in the diet. Boric acid, not to be confused with elemental boron, has been used traditionally on the skin as an astringent, a mild anti-infective, as an eyewash, rodent repellent, and insecticide. It has also been used for recurring vaginal yeast infections.

What is the recommended dosage?

An acceptable safe oral boron intake for adults could be between 1 and 20 mg/day. Upper limits for boron are: adults 19 years and older, 20 mg/day; adolescents 14 to 18 years of age, 17 mg/day; children 9 to 13 years of age, 11 mg/day; children 4 to 8 years of age, 6 mg/day; children 1 to 3 years of age, 3 mg/day. For the treatment of vaginal yeast infections, a boric acid douche using 600 mg once or twice daily for 2 weeks has been used; for the prevention of recurring vaginal yeast infections the same amount twice weekly has been used.

Contraindications

Contraindications have not yet been identified.

Pregnancy/Lactation

Information regarding safety and efficacy in pregnancy and lactation is lacking, but when boron is used orally at doses below upper intake levels, it is likely to be safe. Boric acid should not be used during pregnancy. Intravaginal boric acid has been associated with birth defects in the first 4 months of pregnancy.

Interactions

None well documented.

Side Effects

There is little clinical data concerning adverse effects of boron when used at doses less than upper intake levels.

Toxicology

While boric acid, borates, and other compounds containing boron are used medicinally, they are potentially toxic if ingested or absorbed through broken skin.

References

1. Boron. Review of Natural Products. Facts & Comparisons [database online]. St. Louis, MO: Wolters Kluwer Health Inc; July 2012.

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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