Boron is an ultratrace element that is present in the body in very low concentrations (approximately 0.3-0.7mg in the whole body of an adult) but that has a remarkably broad range of physiological functions. Boron is a regulator of the steroid hormone receptors — it binds to the oestrogen receptor alpha (ER-alpha) and enhances the transcriptional activity of the oestrogen-ER complex, amplifying the effects of oestrogen on gene expression in bone, brain, and other target tissues. Boron is also a regulator of the vitamin D receptor (VDR) — it enhances the transcriptional activity of the vitamin D-VDR complex and amplifies the effects of vitamin D on calcium absorption and on bone mineralisation. Boron is also an inhibitor of the enzymes that metabolise the steroid hormones — it inhibits the aromatase enzyme (which converts androgens to oestrogens) and the steroid dehydrogenase enzymes, thereby altering the balance of the steroid hormones in ways that are clinically significant, particularly in postmenopausal women and in men with low testosterone. This broad range of boron-dependent hormonal effects makes boron one of the most important and most overlooked regulators of hormone metabolism in the body.
Boron and Oestrogen in Postmenopausal Women
The effect of boron on oestrogen metabolism is most clearly demonstrated in postmenopausal women, where the decline in ovarian oestrogen production leads to the rapid bone loss, the hot flushes, the cognitive changes, and the other symptoms that characterise the menopause. Boron supplementation in postmenopausal women (at 3-25mg daily) has been shown to significantly increase the serum concentrations of the oestrogen metabolites (particularly oestradiol and oestrone) and to reduce the urinary excretion of calcium and magnesium (reflecting the reduced bone resorption that is associated with improved oestrogen status). A double-blind RCT in 43 postmenopausal women found that boron supplementation at 3mg daily for 8 weeks significantly increased the serum oestradiol concentration (by approximately 25%) and reduced the urinary calcium excretion (by approximately 30%), with benefits that were greater in women who had lower initial boron intake and who were not taking oestrogen replacement therapy. These findings suggest that boron supplementation may be a useful adjunct to the management of the symptoms of the menopause, particularly in women who cannot or will not take conventional hormone replacement therapy.
Boron also has important effects on testosterone metabolism in men — it inhibits the steroid dehydrogenase enzymes that convert testosterone to the less active dihydrotestosterone (DHT), thereby increasing the ratio of testosterone to DHT and improving the anabolic effects of testosterone on muscle, bone, and cognitive function. A double-blind RCT in 8 healthy men found that boron supplementation at 10mg daily for 8 weeks significantly increased the serum testosterone concentration (by approximately 30%) and reduced the serum DHT concentration (by approximately 25%), with corresponding improvements in the reaction time and the spatial ability that are regulated by testosterone. These findings suggest that boron supplementation may be a useful strategy for the support of testosterone levels in men with low testosterone, though the evidence is still preliminary and larger studies are needed to confirm these findings.
Boron and Bone Health
Boron is also important for bone health through its effects on the vitamin D receptor — it enhances the transcriptional activity of the vitamin D-VDR complex and thereby amplifies the effects of vitamin D on calcium absorption, on bone mineralisation, and on the regulation of the osteoblast and osteoclast activity that controls bone remodelling. This boron-vitamin D interaction is clinically important for the prevention of osteoporosis, particularly in postmenopausal women who have reduced oestrogen levels and who are at increased risk of osteoporosis due to the increased bone resorption that accompanies the menopause. Boron supplementation (at 3-10mg daily) in combination with calcium, vitamin D, and the other bone-support nutrients may be more effective for the prevention of osteoporosis than any of these nutrients alone, because boron amplifies the effects of vitamin D on calcium metabolism and thereby improves the efficiency of calcium utilisation.
Practical Application
For general boron supplementation, the evidence-based dose is 3-10mg of boron daily (as boron citrate, boron glycinate, or boron aspartate, the commonly used forms), taken with a meal for optimal absorption. The tolerable upper intake level (UL) for boron is 20mg daily for adults, and most people in the developed world achieve this from a varied diet that includes fruits (particularly apples, pears, grapes, and avocados), vegetables (particularly leafy green vegetables), nuts, and the small amounts of boron that are present in most foods. Boron is generally well-tolerated with no significant adverse adverse effects at therapeutic doses, though chronic supplementation above 20mg daily should be avoided because boron can accumulate to toxic levels in the body (producing the toxic effects that include skin rashes, GI upset, and in severe cases, neurological symptoms). For comprehensive hormone and bone support, boron pairs well with the vitamin D (which boron amplifies through the VDR interaction), with the calcium (which is the primary mineral component of bone), with the magnesium (which is required for the activity of the osteoblasts and for the bone mineralisation process), and with the phytoestrogens (including the isoflavones from soy and the lignans from flaxseed, which have weak oestrogenic effects that are amplified by the boron-oestrogen receptor interaction).
Leave a Reply