Plants need boron for proper health, but it's not known whether humans do. However, boron does seem to assist in the proper absorption of calcium, magnesium, and phosphorus from foods, and slows the loss of these minerals through urination. Very preliminary evidence suggests that boron supplements may be helpful for osteoarthritis and osteoporosis .
No dietary or nutritional requirement for boron has been established, and boron deficiency is not known to cause any disease. Good sources include leafy vegetables, raisins, prunes, nuts, non-citrus fruits, and grains. A typical American daily diet provides 1.5 to 3 mg of boron.
When used as a treatment for osteoarthritis or osteoporosis, boron is often recommended at a dosage of 3 mg per day, an amount similar to the average daily intake from food. However, food sources may be safer (see Safety Issues ).
Boron aids in the proper metabolism of vitamins and minerals involved with bone development, such as calcium , copper , magnesium , and vitamin D . 4,10,14-18 In addition, boron appears to affect estrogen and possibly testosterone as well, hormones that affect bone health. 4,10,19 On this basis, boron has been suggested for preventing or treating osteoporosis . However, there have been no clinical studies to evaluate the potential benefits of boron supplements for any bone-related conditions.
On the basis of similarly weak evidence, 2,6 boron is often added to supplements intended for the treatment of osteoarthritis.
Boron has also been proposed as a sports supplement , based on its effects on hormones. 20 However, studies have, as yet, failed to find evidence that it helps increase muscle mass or enhances performance. 21,22
One large observational study suggests that higher intake of boron may reduce risk of prostate cancer . 5
Finally, boron is sometimes recommended as a treatment for rheumatoid arthritis , but there is no evidence to support this use.
In areas of the world where people eat relatively high amounts of boron—between 3 and 10 mg per day—the incidence of osteoarthritis is below 10%. 6 However, in regions where there is less boron in the diet—1 mg or less per day—the incidence of arthritis is much higher. In addition, the joints of people with osteoarthritis have been found to contain less boron than people without the condition. These observations have given rise to the hypothesis that boron supplements might be helpful for people who already have arthritis symptoms.
However, the only direct evidence that it works comes from one highly preliminary study reported in 1990. 7
In one small study, 13 postmenopausal women were first fed a diet that provided 0.25 mg of boron for 119 days; then they were fed the same diet with a boron supplement of 3 mg daily for 48 days. 9 The results revealed that boron supplementation reduced the amount of calcium lost in the urine. This suggests (but certainly doesn't prove) that boron can help prevent osteoporosis.
However, in a similar study, boron administration did not affect urine calcium loss. 10 Another study found that boron fails to affect calcium loss among people who receive enough magnesium. 23
Since the therapeutic dosage of boron is about the same as the amount you can get from food, it is probably fairly safe. Unpleasant side effects, including nausea and vomiting, are only reported at about 50 times the highest recommended dose.
One potential concern with boron regards its effect on hormones. In at least two small studies, boron was found to increase the body's own estrogen levels, especially in women on estrogen-replacement therapy. 11,12 Because elevated estrogen increases the risk of breast and uterine cancer in women past menopause, this may be a matter of concern for those who wish to take supplemental boron. Further research is necessary to discover whether boron's apparent effect on estrogen is a real problem or not. At the present time, we would recommend getting your boron from fruits and vegetables: a large study found that high intake of boron from these sources did not affect breast cancer rates. 13
If you are taking:
References
1. de Fabio A. Treatment and prevention of osteoarthritis. Townsend Letter for Doctors. 1990:143-148.
2. Travers RL, Rennie GC, Newnham RE. Boron and arthritis: the results of a double-blind pilot study. J Nutr Med . 1990;1:127-132.
3. Travers RL, Rennie GC. Clinical trial—boron and arthritis. The results of a double blind pilot study. Townsend Letter for Doctors . June 1990:360-362.
4. Nielsen FH, Hunt CD, Mullen LM, et al. Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. FASEB. 1987;1:394-397.
5. Zhang ZF, Winton MI, Rainey C, et al. Boron is associated with decreased risk of human prostate cancer. Presented at: Experimental Biology 2001; March 31-April 4, 2001; Orlando, FL.
6. Newnham RE. Essentiality of boron for healthy bones and joints. Environ Health Perspect . 1994;102:83-85
7. Travers RL, Rennie GC, Newnham RE. Boron and arthritis: the results of a double-blind pilot study. J Nutr Med . 1990;1:127-132.
8. Travers RL, Rennie GC. Clinical trial—boron and arthritis. The results of a double blind pilot study. Townsend Letter for Doctors . 1990:360-362.
9. Nielsen FH, Hunt CD, Mullen LM, et al. Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. FASEB. 1987;1:394-397.
10. Beattie JH, Peace HS. The influence of a low boron-diet and boron supplementation on bone, major mineral and sex steroid metabolism in postmenopausal women. Br J Nutr . 1993;69:871-884.
11. Nielsen FH, Hunt CD, Mullen LM, et al. Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women. FASEB. 1987;1:394-397.
12. Naghii MR, Samman S. The effect of boron supplementation on its urinary excretion and selected cardiovascular risk factors in healthy male subjects. Biol Trace Elem Res . 1997;56:273-286.
13. Zhang ZF, Winton MI, Rainey C, et al. Boron is associated with decreased risk of human prostate cancer. Presented at: Experimental Biology 2001; March 31-April 4, 2001; Orlando, FL.
14. Benderdour M, Bui-Van T, Dicko A, et al. In vivo and in vitro effects of boron and boronated compounds. J Trace Elem Med Biol. 1998;12:2-7.
15. Groff, J. Advanced Nutrition and Human Metabolism . 2nd ed. St. Paul, MN: West Publishing Company; 1995.
16. Hunt CD, Herbel JL, Nielsen FH. Metabolic responses of postmenopausal women to supplemental dietary boron and aluminum during usual and low magnesium intake: boron, calcium, and magnesium absorption and retention and blood mineral concentrations. Am J Clin Nutr . 1997;65:803-813.
17. Nielsen FH. Studies on the relationship between boron and magnesium which possibly affects the formation and maintenance of bones. Magnes Trace Elem . 1990;9:61-69.
18. Volpe SL, Taper LJ, Meacham S. The relationship between boron and magnesium status and bone mineral density in the human: a review. Magnes Res. 1993;6:291-296.
19. Samman S, Naghii MR, Lyons Wall PM, et al. The nutritional and metabolic effects of boron in humans and animals. Biol Trace Elem Res. 1998;66:227-235.
20. Naghii MR. The significance of dietary boron, with particular reference to athletes. Nutr Health. 1999;13:31-37.
21. Kreider RB. Dietary supplements and the promotion of muscle growth with resistance exercise. Sports Med . 1999;27:97-110.
22. Ferrando AA, Green NR. The effect of boron supplementation on lean body mass, plasma testosterone levels, and strength in male bodybuilders. Int J Sport Nutr. 1993;3:140-149.
23. Hunt CD, Herbel JL, Nielsen FH. Metabolic responses of postmenopausal women to supplemental dietary boron and aluminum during usual and low magnesium intake: boron, calcium, and magnesium absorption and retention and blood mineral concentrations. Am J Clin Nutr. 1997;65:803-813.
Last reviewed April 2009 by EBSCO CAM Review Board
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