Boron is a trace mineral that has gained popularity in recent years due to claims that it can strengthen bones, build muscle mass, and boost brain activity. While such macrominerals as calcium, magnesium, and potassium have become household names because they make up over 98% of the body's mineral content, certain trace minerals are also considered essential in very tiny amounts to maintain health and ensure proper functioning of the body. They usually act as coenzymes, working as a team with proteins to facilitate important chemical reactions. While boron is considered essential for plants, it is not known if the mineral is necessary for humans.
Studies indicate that boron may contribute to the way that calcium, a vital building block of bone, and other minerals are processed by the body. Boron appears to increase the amount of calcium absorbed from food and lower the amount excreted by the body. These effects may help to keep bones strong. Boron may also improve mental functioning, strengthen the immune system, boost energy utilization, and affect cholesterol production. While the effects of a boron-free diet have not been observed in people, animal studies suggest that a lack of boron can be unhealthy. In one investigation, for example, a boron-deficient diet fed to animals seemed to increase the amount of calcium they lost. It also appeared to have a negative effect on bone development and energy utilization. It is not certain, however, that study results such as this confirm the nutritional importance of boron for human beings. As of 2000, research is still necessary to determine if boron can produce significant health benefits safely and effectively. The proper dosage of the mineral has not yet been established.
While not extensively studied, boron has been touted as having a number of beneficial effects. Some people take it to help treat osteoporosis or arthritis and to alleviate menopausal symptoms. It has been reported to enhance mental activity, memory, and hand-eye coordination. Some body builders and athletes take boron supplements as a muscle-enhancing agent despite the fact that there is no evidence to support this use. Overall, boron appears to have the most potential as a possible bonebuilder and brain booster.
The effects of boron on bone strength were investigated in a small study of 12 postmenopausal women between the ages of 48 and 82, published in the FASEB Journal in 1987. The women had received a low-boron diet (containing about 0.25 mg a day of the mineral) for several months before being given daily boron supplements of 3 mg. Once the women increased their intake of boron, they were able to retain more bone-building minerals such as calcium and magnesium. This effect was greater in women who started out with low levels of magnesium. Boron supplements also significantly increased levels of estrogen and testosterone, especially in the magnesium-deficient group. The results of this study suggest that getting an adequate amount of boron, whether through dietary intake or boron supplements, may help to maintain strong bones by allowing the body to use calcium and other important minerals more efficiently.
Most of the research suggesting that boron may be helpful for arthritis is indirect and circumstantial. Early studies in sheep and chickens indicated that boron may be useful in helping to treat the disease. There is also an interesting relationship between the incidence of arthritis and boron intake in certain geographical locations. In parts of the world where boron intake is high (intake can range anywhere from 3–10 mg), usually as a result of high boron levels in the soil and water, the number of people who develop arthritis tends to be lower than in areas where people consume less of the mineral. Boron levels in the water and soil are usually highest in arid climates, such as the desert regions of the United States and South America, the Red Sea region of the Middle East, and parts of Australia. There are few human studies of boron in relation to arthritis, although one small investigation in people has suggested that boron may help to relieve symptoms of the disease.
While there is some evidence that boron may be helpful in the treatment of postmenopausal osteoporosis, the mineral does not appear to ease the symptoms associated with menopause. In a five-week study involving 46 menopausal women, about 50% of those who received boron supplements experienced more frequent and severe hot flashes (as well as night sweats) and generally had an increase in menopausal symptoms. Over a third of the women who received boron reported that the mineral made no difference at all in their symptoms. Boron had a beneficial effect in only 15% of the women who took it. These findings suggest that boron may actually aggravate menopausal symptoms more often than it alleviates them.
Researchers from the Grand Forks Human Nutrition Research Center, which is affiliated with the United States Department of Agriculture (USDA), investigated the role of boron in brain and psychological function in several studies involving humans and animals. In one study, increasing boron intake in rats receiving a boron-deficient diet seemed to increase mental activity. Studies conducted in people suggested that a lack of boron can decrease mental activity and have a negative effect on hand-eye coordination, the ability to concentrate, and short-term memory. These findings seem to indicate an important role for boron in keeping the brain fit.
The use of boron by body builders stems from its apparent ability to increase testosterone levels. Because testosterone is known to play an important role in the development of muscles, some weight lifters have taken boron supplements because they believe it will increase levels of male hormone and make them stronger. There is no evidence, however, that boron can increase muscle mass or athletic performance. Boron supplements are generally not considered effective as a muscle-enhancing agent.
A recommended daily allowance (RDA) for boron has not been established. The estimated dosage of boron, which is available as an over-the-counter dietary supplement, is generally 3 mg a day. Even without taking supplements, most people get anywhere from 1–3 mg of boron through their diets. For this reason, some authorities suggest avoiding boron supplements altogether and eating foods known to contain the mineral. Good sources of boron include fruits, especially pears, apples, peaches, grapes, and raisins; leafy vegetables; peanuts and other nuts; and beans. Beer and wine also contain boron. Drinking water can be a good source of the mineral depending on geographical location. Getting too much of the mineral through food and drink is not considered a significant risk because boron is present only in very small amounts in plants and animals.
Boron is not known to be harmful when taken in recommended dosages, though there are some precautions to consider. Boron appears to increase estrogen levels, especially in women receiving estrogen therapy. For this reason, women receiving hormone therapy should talk to their doctors before taking boron supplements. Combining the mineral with estrogen drugs may result in elevated and potentially unhealthy levels of female hormone. However, it is considered safe for women on estrogen therapy to eat boron-containing foods. In fact, many of the fruits and vegetables containing the mineral are believed to contribute to good health.
The long-term health risks associated with taking boron supplements are unknown.
When taken in recommended dosages, boron has not been associated with any significant or bothersome side effects. At very high dosages, boron may cause nausea and vomiting, diarrhea, and headaches.
Combining boron and estrogen-containing drugs may cause an undesirable increase in estrogen levels.
Sifton, David W. PDR Family Guide to Natural Medicines and Healing Therapies. New York: Three Rivers Press, 1999.
Nielsen F.H., C.D. Hunt, and L.M. Mullen, et al. "Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women." FASEB Journal (1987): 394-7.
Grand Forks Human Nutrition Research Center. 2420 2nd Ave North. Grand Forks, ND 58202. <http://www.gfhnrc.ars.usda.gov.>
Discovery Health. <http://www.discoveryhealth.com>.