Boron is a chemical element with symbol B that is found in food and the environment and is taken as medicine. Greater fruit and vegetable consumption could significantly increase boron intakes, especially Avocado . Estimated daily intake of boron ranges from 0.3-41 mg per day . B may be involved in a number of clinical conditions such as arthritis, however, more research needs to be done before B is accepted as an essential nutrient for humans. Dietary boron influences the activity of many metabolic enzymes, as well as the metabolism of steroid hormones and several micronutrients, including calcium, magnesium, and vitamin D. In the bodybuilding world various forms of boron are emerging as testosterone boosters.
Foods Rich in Boron (mg/100 g) :
- Avocado 2.06
- Apricots (dried) 2.11
- Currants 1.74
- Grapes (red) 0.50
- Peach 0.52
- Prunes 1.88
- Raisins 4.51
- Red kidney beans 1.4
- Lentils 0.74
- Almonds 2.82
- Brazil nuts 1.72
- Cashew nuts 1.15
- Hazelnuts 2.77
- Peanut butter 1.92
- Pistachio nuts 1.20
- Walnuts 1.63
- Wine (Shiraz Cabernet) 0.86
Recommended daily allowance (RDA) for boron is not set since an essential biological role for it has not been identified . Diets considered to be high in boron provide approximately 3.25 mg of B per 2000 kcal per day. Diets considered to be low in B provide 0.25 mg of B per 2000 kcal per day . In clinical studies, it is administered in a wide range of doses (daily dosage of 2.5 to 6 mg). In supplements, typical dose ranges from 2 to 4 mg. In medicine, it is often most commonly found in the form of boric acid and sodium borate. It is well tolerated even in large amounts, because animals and humans excrete excess boron , while consistent signs of deficiency include depressed growth and a reduction in some blood indices, particularly steroid hormone concentrations . However, an adult dose of 18 to 20 mg of boron has been shown to be fatal .
The European Union established an upper intake level for total boron intake based on body weight that equals about 10 mg/d for adults, while The World Health Organization decided to set a tolerable upper intake level to 0.4 mg/kg body weight (28 mg/d for a 70 kg person) .
It is estimated that typical human adult dietary consumption (through food and personal care products) of B in the United States is in the range of 1-2 mg .
Boron as Testosterone Enhancer and Muscle Builder
A growing body of evidence indicates that boron interacts with other nutrients and plays a regulatory role in the metabolism of minerals, such as calcium, and subsequently bone metabolism [2,3]. Mechanisms remain unknown, however, it may be mediated by increasing the concentration of steroid hormones such as testosterone and beta-oestradiol .
Boron has been touted as an ergogenic aid capable of increasing testosterone. These claims are based exclusively on Forrest H. Nielsen et al.  study where increased testosterone levels were found in postmenopausal women. Therefore, Nancy and Ferrando  examined the effect of a supplemental boron (in a randomized, placebo-controlled, double-blind fashion) in healthy male bodybuilders on plasma free and total testosterone, plasma boron, lean body mass, and strength. Elevated testosterone and increased strength and lean body mass were noted in both groups (placebo and boron) and were not further increased by boron supplementation. This means that the increase in strength parameters was most likely the result of a concentrated bodybuilding training program. Taking it by mouth does not seem to improve body mass, muscle mass, or testosterone levels in male bodybuilders. There was also no clear relationship between dietary boron and testosterone production in in vitro by Naghii and Samman . On the other hand, here is one more recent very small experimental study which reported decreased SHBG (sex hormone binding globulin) with 10 mg/day of Boron supplementation leading to increased free testosterone in eight apparently healthy male volunteers .
In rats, increasing the intake of boron resulted in an increase in plasma testosterone and vitamin D, and a decrease in HDL cholesterol . It does seem to have an impact on various metabolic processes .
Bones and Joints
Since 1963, evidence has accumulated that suggests boron is a safe and effective treatment for some forms of arthritis. In vitro, animal, and human experiments have shown that B beneficially affects bone growth . It has been shown that boron and magnesium are apparently needed for optimal calcium metabolism and for prevention of excessive bone loss as their deficiency induces changes similar to those seen in women with post-menopausal osteoporosis . Boron deprivation was shown to cause harmful charges to bone formation; e.g., depress plasma ionized calcium and calcitonin, elevated plasma total calcium and urinary calcium excretion . The important finding of this study is that adequate dietary levels of boron decreased serum calcitonin which has been shown to increase calcium loss in humans, and serum calcitonin concentrations are higher in women with postmenopausal osteoporosis. In 1994 an experimental evidence from a double-blind placebo-boron supplementation trial with 20 subjects with osteoarthritis reported that 50% of subjects receiving the supplement improved compared to only 10% receiving the placebo . However, when boron’s effect on bone mineral density was examined in 28 female college athletes results indicated that dietary boron (as tri-boron supplement of 3 mg or a placebo for 10 months) had no effect on bone mineral density .
Calcium fructoborate (CFB), a natural plant mineral borate complex commonly found in plants, at a dose of 110 mg twice per day has repeatedly shown to improve knee pain during the 2 weeks of intake [15,16]. Six months of CFB supplementation (226 mg/day) has also been found to improve bone density in 66 of 100 patients with osteoporosis .
Even though there is convincing evidence in vitro and in animals, more studies are needed to determin the relationship between boron and bone health in humans.
It is noted in the literature that a relatively short restricted B intake results in significantly poorer performance on tasks emphasizing manual dexterity, eye-hand coordination, attention, perception, encoding and short-term memory, and long-term memory [22,23].
Accumulating evidence suggests that boron supplementation plays a determining role in the brain due to one or more of these biological activities because :
- it is related to metabolism of other mineral elements, including Ca, Cu, Mg, Mo, and P,
- affects energy metabolism, indicated by changes in glucose, triglycerides, and insulin production,
- selectively accumulates in certain areas of the brain and affects the concentration of other minerals in the brain,
- affects cell membrane function and hormone metabolism,
- may affect catecholamine and histamine metabolism
Metabolism of Boron
After administration B is swiftly absorbed from the gastrointestinal tract into the bloodstream and distributed throughout the body . Hunt et al.,  reported that humans and animals absorb nearly 100% of supplemental inorganic boron. It is not metabolized and is excreted from body primary from the kidneys through urine . However, it appears to accumulate in bones but not in soft tissue .
Possible Side Effects
Animal studies are indicating that dietary B affects several aspects of mineral metabolism. As mentioned before, boron supplements can lower the amount urinary calcium and magnesium excretion which leads to higher than usual blood levels of magnesium . However, a study by Curtiss D. Hunt and colleagues  reported that boron supplementation did not affect urinary magnesium excretion but it did induce a minor decrease in dietary calcium loss in urine. Supplemental boron might also reduce blood phosphorus levels in some people . Supplementing with boron by mouth in high doses is possibly unsafe for pregnant and breastfeeding women. Higher amounts may be harmful and should not be used by pregnant women because it has been linked to birth defects .
(Other common names: Boric acid, Sodium borate, Sodium tetraborate, Boric oxide, Decaborane, Tetraborate, Atomic number 5, B, Borate, Boron citrate/aspartate/glycinate, B supplements, Boron Supplement, Supplemental Boron, Calcium Borogluconate, Calcium fructopyranose borate, CFB, Calcium fructoborate, Boron amino acid complex)
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