Feb 05, · Potatoes, milk, and milk products also contain boron. Includes a variety of protein foods such as lean meats; poultry; eggs; seafood; beans, peas, and lentils; nuts and seeds; and soy products. Peanuts and other legumes contain boron. Limits foods and . It is a naturally occurring element that is found in the form of borates in the oceans, sedimentary rocks, coal, shale, and some soils. Boron enters the environment mainly through the weathering of rocks, boric acid volatilization from seawater, and volcanic activity.
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Boron is a trace element that is naturally present in many foods and available as a dietary supplement. It is a structural component of plant cell walls and is required for plant growth, pollination, and seed formation [ 1 ].
Boron is not classified as an essential nutrient for humans because research has not yet identified a clear biological function for boron [ 2 ]. However, it might have beneficial effects on such functions as reproduction and development, calcium metabolism, bone formation, brain function, insulin and energy substrate metabolism, immunity, and the function of steroid hormones including vitamin D and estrogen [ ].
Boron is present in foods and beverages as inorganic borates as well as mono- or di-sugar-borate esters, bpron as calcium fructoborate [ bkron15 ]. Most ingested boron is ehere to boric acid within the gastrointestinal tract [ 6 ].
However, very little is known about how or where in the gastrointestinal tract absorption occurs [ 8 ]. Boron does not accumulate in most body tissues, but bone, fiund, and hair have higher boron levels than other body tissues, whereas fat has lower levels [ 9 ]. Boric acid is the main fonud of boron in blood, ehat, and other body fluids [ 247 ]. The lack of substantial changes in blood boron levels in response to large increases in dietary intakes suggests that the body maintains boron homeostasis, likely by increasing urinary excretion, but the regulatory mechanisms for boron homeostasis have not been identified [ flund ].
Boron is excreted mainly in the urine, and small amounts are excreted in the feces, sweat, breath, and bile [ 910 ]. Boron status is not routinely measured in clinical practice.
Most studies suggest that urinary boron levels correlate with boron intakes [ 241617 founc. DRI is the general term for a set of reference values used for planning and assessing what is a trojan viruses intakes where is boron found and in what form healthy people. These values, which vary by age and sex, include:. Food Plant foods—including wuat, tubers, and legumes—contain the largest amounts jn boron [ 26151819 ].
Wine, cider, and beer also contain boron [ 8 ]. The main sources of boron in the diets of people in the United States are coffee, milk, apples, dried and cooked beans, and potatoes, primarily because people tend to consume large amounts of these foods [ 715 ]. The amount of boron ane plant foods depends somewhat on the boron content of the soil and water where they were grown [ 721 ]. Areas of the world with si boron in the soil include Brazil, Japan, and most of the United States, mainly because of high levels of rainfall, which leaches boron out of the soil [ 21 ].
In contrast, arid regions of the world—including California and parts of Turkey, Argentina, Chile, Russia, China, and Peru—have higher boron concentrations [ 2122 ]. Boron concentrations are about 0. Water contains whxt, but the concentration varies considerably by source [ 19 ]. The median boron how to compress a file to 25mb of drinking water in the United Fpund is 0.
Selected food sources of boron are listed in Table 1. The U. Therefore, information on boron levels in foods is limited. Dietary supplements Boron is available in dietary supplements containing only boron and in supplements containing boron in combination with a few other nutrients, often other minerals.
Common amounts of elemental boron wgat dietary supplements range from 0. In dietary ehere, boron is present in many different forms, including sodium borate, sodium tetraborate, boron amino acid chelate, boron ascorbate, boron aspartate, boron citrate, boron gluconate, boron glycinate, boron picolinate, and calcium fructoborate [ 627 ].
In a whwre human study, forj as sodium tetraborate significantly increased plasma boron levels within 4—6 hours of consumption [ 5 ], but no data are available on the relative bioavailability of different forms of supplemental boron. The Supplement Facts label on a dietary supplement product declares the amount of borin boron in the product, not the weight of the entire boron-containing compound. Founx tend to have higher intakes of boron than nonvegetarians because boron is plentiful in plant foods [ 15 ].
The median dietary boron intake in lactating women is 1. Boron intakes are about 0. Total median boron intakes from dietary supplements and foods are about 1. In humans, boron deficiency signs and symptoms have not been firmly established. Limited data suggest that boron deficiency might affect brain function by reducing founv alertness and impairing executive brain function [ 1828 ]. In addition, a low-boron diet 0. How to install windows xp in compaq presario cq60 boron intakes 0.
This section focuses on three health areas anf which boron might be involved: osteoarthritis, bone health, and cancer. Osteoarthritis Observational evidence combined with the findings from a few small clinical studies in humans suggests that boron ajd be helpful for reducing the symptoms of osteoarthritis, possibly by inhibiting inflammation [ 3].
In a small pilot study that compared 6 mg boron per day what calculators are allowed on the act test 8 weeks with placebo, the supplements reduced symptoms of osteoarthritis in 20 participants younger than 75 years mean age about 65 years [ 33 ]. However, this study was very small and not blinded or placebo-controlled.
A wnat double-blind, placebo-controlled trial examined the effects of 1. Supplementation significantly reduced inflammatory markers. These findings suggest that boron, particularly as calcium fructoborate, might hold promise for reducing osteoarthritis symptoms, but confirmation is needed from additional controlled trials.
Animal studies indicate that boron deficiency causes abnormal limb development; delayed maturation of growth plates; and decreased bone strength, bone volume fraction, and trabecular thickness [ 635 ]. Comparisons of animals receiving boron supplementation with animals that consume usual or small bkron of boron show that the supplementation improves some measures of bone strength [ ].
However, in an observational study in Korean women average age 41 yearsboron intakes mean of 0. In a placebo-controlled borpn trial of 17 female athletes mean age However, supplementation in this study did not directly affect bone mineral density.
Iz research is needed to determine whether boron supplementation affects where is boron found and in what form health in humans. Cancer Preliminary evidence suggests that dietary boron intake might affect cancer risk.
Several observational studies found that boron intakes are inversely associated with prostate cancer how to tie a goat tying knot in men and with lung and cervical cancer risk in women [ 19]. For example, in a case control study of women with lung cancer and healthy women, those in the lowest quartile of boron intake less than 0.
An observational study in Turkey evaluated two criteria for prostate cancer risk, prostate size and prostate specific antigen PSA levels. However, PSA levels did not differ significantly between the two groups. No clinical what is error 1723 dll missing java have evaluated the effects of boron on cancer prevention or treatment.
More research is needed to understand the effects, if any, wherre boron on cancer. No data are available on adverse effects of high boron intakes from food or water [ 2 ]. Symptoms associated with accidental consumption of boric acid or borax sodium boratecontained in some household cleaning products and pesticides, include nausea, gastrointestinal discomfort, vomiting, diarrhea, skin flushing, rash, excitation, convulsions, what does ole girl mean, and vascular collapse [ 2646 ].
The amount of boron consumed in people who accidentally consumed boron ranged from 18 to 9, mg, and most were children younger than 6 years [ 46 ]. Boron toxicity can also cause headache, hypothermia, restlessness, from, renal injury, dermatitis, alopecia, anorexia, and indigestion. In infants, high boron intakes have caused anemia, seizures, erythema, and thin hair [ 9 ]. Extremely high doses of boron can be fatal; for example, 15, to 20, mg can cause death in adults [ 69 how to design a japanese room. The FNB established boron ULs for healthy individuals based on levels associated whrre reproductive and developmental effects in animals [ 2 ].
The federal government's Dietary Guidelines for Americans notes that "Because foods provide an array of nutrients and other components that have benefits for health, nutritional needs should be broon primarily through foods. In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more nutrients e.
For more information about building a healthy dietary pattern, refer to the Dietary Guidelines for Americans and the U. Department of Agriculture's MyPlate. This fact sheet by the Office of Dietary Supplements ODS provides information that should not take the place of medical advice. We encourage you to talk to your healthcare providers doctor, registered dietitian, pharmacist, etc. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice.
Updated: March 29, History of changes to this fact sheet. Find ODS on:. Strengthening Knowledge and Understanding of Dietary Supplements. Health Information Health Information. Hwere Researchers For Researchers. Boron Fact Sheet for Health Professionals. Adv Nutr ; In press.
Food and Nutrition Board. Nielsen FH. Update on human health effects of boron. J Trace Elem Med Biol ; In: John W. Erdman Jr. IAM, Steven H. Zeisel, ed. Present Knowledge in Nutrition. Comparative effects of daily and weekly boron supplementation on plasma steroid hormones and proinflammatory cytokines. Encyclopedia of Dietery Supplements. New York informat healthcare; Eckhert CD. Trace Elements.
Properties, occurrence, and uses
Boron is an important element that’s most often found in fruits, beans, and other plant-based foods. It’s considered a micronutrient, which means that your body only needs a small amount of it. Feb 21, · Boron occurs combined as borax, kernite, and tincalconite (hydrated sodium borates), the major commercial boron minerals, especially concentrated in the arid regions of California, and as widely dispersed minerals such as colemanite, ulexite, and tourmaline. Sassolite—natural boric acid—occurs especially in Italy. Boron occurs as an orthoboric acid in some volcanic spring waters, and as borates in the minerals borax and colemanite. Extensive borax deposits are found in Turkey. However, by far the most important source of boron is rasorite. This is found in the Mojave Desert in California, USA.
Boron is a chemical element with the symbol B and atomic number 5. Produced entirely by cosmic ray spallation and supernovae and not by stellar nucleosynthesis , it is a low-abundance element in the Solar System and in the Earth's crust. These are mined industrially as evaporites , such as borax and kernite. The largest known boron deposits are in Turkey , the largest producer of boron minerals.
Elemental boron is a metalloid that is found in small amounts in meteoroids but chemically uncombined boron is not otherwise found naturally on Earth. Industrially, very pure boron is produced with difficulty because of refractory contamination by carbon or other elements. Several allotropes of boron exist: amorphous boron is a brown powder; crystalline boron is silvery to black, extremely hard about 9.
The primary use of elemental boron is as boron filaments with applications similar to carbon fibers in some high-strength materials. Boron is primarily used in chemical compounds. About half of all boron consumed globally is an additive in fiberglass for insulation and structural materials. The next leading use is in polymers and ceramics in high-strength, lightweight structural and refractory materials.
Borosilicate glass is desired for its greater strength and thermal shock resistance than ordinary soda lime glass. Boron as sodium perborate is used as a bleach.
A small amount of boron is used as a dopant in semiconductors , and reagent intermediates in the synthesis of organic fine chemicals. A few boron-containing organic pharmaceuticals are used or are in study. Natural boron is composed of two stable isotopes, one of which boron has a number of uses as a neutron-capturing agent.
The intersection of boron with biology is very small. Consensus on boron as essential for mammalian life is lacking. Borates have low toxicity in mammals similar to table salt but are more toxic to arthropods and are occasionally used as insecticides. Boron-containing organic antibiotics are known. Although only traces are required, boron is an essential plant nutrient.
The word boron was coined from borax , the mineral from which it was isolated, by analogy with carbon , which boron resembles chemically. Marco Polo brought some glazes back to Italy in the 13th century. Agricola, around , reports the use of borax as a flux in metallurgy. In , boric acid was recognized in the hot springs soffioni near Florence , Italy, and became known as sal sedativum , with primarily medical uses.
The rare mineral is called sassolite , which is found at Sasso, Italy. Sasso was the main source of European borax from to , when American sources replaced it. In his subsequent experiments, he used potassium to reduce boric acid instead of electrolysis.
He produced enough boron to confirm a new element and named the element boracium. By oxidizing boron with air, they showed that boric acid is an oxidation product of boron. The earliest routes to elemental boron involved the reduction of boric oxide with metals such as magnesium or aluminium.
However, the product is almost always contaminated with borides of those metals. Pure boron can be prepared by reducing volatile boron halides with hydrogen at high temperatures. Ultrapure boron for use in the semiconductor industry is produced by the decomposition of diborane at high temperatures and then further purified by the zone melting or Czochralski processes.
The production of boron compounds does not involve the formation of elemental boron, but exploits the convenient availability of borates. Boron is similar to carbon in its capability to form stable covalently bonded molecular networks.
Even nominally disordered amorphous boron contains regular boron icosahedra which are, however, bonded randomly to each other without long-range order. Elemental boron is rare and poorly studied because the pure material is extremely difficult to prepare. Most studies of "boron" involve samples that contain small amounts of carbon. The chemical behavior of boron resembles that of silicon more than aluminium. Crystalline boron is chemically inert and resistant to attack by boiling hydrofluoric or hydrochloric acid.
When finely divided, it is attacked slowly by hot concentrated hydrogen peroxide , hot concentrated nitric acid , hot sulfuric acid or hot mixture of sulfuric and chromic acids. The rate of oxidation of boron depends on the crystallinity, particle size, purity and temperature. Boron does not react with air at room temperature, but at higher temperatures it burns to form boron trioxide : . The trichloride in practice is usually made from the oxide. Boron is the lightest element having an electron in a p-orbital in its ground state.
But, unlike most other p-elements , it rarely obeys the octet rule and usually places only six electrons  in three molecular orbitals onto its valence shell. Boron is the prototype for the boron group the IUPAC group 13 , although the other members of this group are metals and more typical p-elements only aluminium to some extent shares boron's aversion to the octet rule. In the most familiar compounds, boron has the formal oxidation state III.
These include oxides, sulfides, nitrides, and halides. The trihalides adopt a planar trigonal structure. These compounds are Lewis acids in that they readily form adducts with electron-pair donors, which are called Lewis bases.
Boron trifluoride is used in the petrochemical industry as a catalyst. The halides react with water to form boric acid. Boron is found in nature on Earth almost entirely as various oxides of B III , often associated with other elements.
These minerals resemble silicates in some respect, although boron is often found not only in a tetrahedral coordination with oxygen, but also in a trigonal planar configuration. Unlike silicates, the boron minerals never contain boron with coordination number greater than four.
A typical motif is exemplified by the tetraborate anions of the common mineral borax , shown at left. Boranes are chemical compounds of boron and hydrogen, with the generic formula of B x H y.
These compounds do not occur in nature. Many of the boranes readily oxidise on contact with air, some violently. The parent member BH 3 is called borane, but it is known only in the gaseous state, and dimerises to form diborane, B 2 H 6. The larger boranes all consist of boron clusters that are polyhedral, some of which exist as isomers. For example, isomers of B 20 H 26 are based on the fusion of two atom clusters.
The most important boranes are diborane B 2 H 6 and two of its pyrolysis products, pentaborane B 5 H 9 and decaborane B 10 H A large number of anionic boron hydrides are known, e. The mean oxidation number for the borons is then simply the ratio of hydrogen to boron in the molecule. In these compounds the oxidation state of boron is often not a whole number. The boron nitrides are notable for the variety of structures that they adopt.
They exhibit structures analogous to various allotropes of carbon , including graphite, diamond, and nanotubes. In the diamond-like structure, called cubic boron nitride tradename Borazon , boron atoms exist in the tetrahedral structure of carbons atoms in diamond, but one in every four B-N bonds can be viewed as a coordinate covalent bond , wherein two electrons are donated by the nitrogen atom which acts as the Lewis base to a bond to the Lewis acidic boron III centre.
Cubic boron nitride, among other applications, is used as an abrasive, as it has a hardness comparable with diamond the two substances are able to produce scratches on each other. In the BN compound analogue of graphite, hexagonal boron nitride h-BN , the positively charged boron and negatively charged nitrogen atoms in each plane lie adjacent to the oppositely charged atom in the next plane.
Consequently, graphite and h-BN have very different properties, although both are lubricants, as these planes slip past each other easily. However, h-BN is a relatively poor electrical and thermal conductor in the planar directions. A large number of organoboron compounds are known and many are useful in organic synthesis.
Many are produced from hydroboration , which employs diborane , B 2 H 6 , a simple borane chemical. However, multiple boron atoms reacting with each other have a tendency to form novel dodecahedral sided and icosahedral sided structures composed completely of boron atoms, or with varying numbers of carbon heteroatoms. Organoboron chemicals have been employed in uses as diverse as boron carbide see below , a complex very hard ceramic composed of boron-carbon cluster anions and cations, to carboranes , carbon-boron cluster chemistry compounds that can be halogenated to form reactive structures including carborane acid , a superacid.
As one example, carboranes form useful molecular moieties that add considerable amounts of boron to other biochemicals in order to synthesize boron-containing compounds for boron neutron capture therapy for cancer.
As anticipated by its hydride clusters , boron forms a variety of stable compounds with formal oxidation state less than three. B 2 F 4 and B 4 Cl 4 are well characterized. Binary metal-boron compounds, the metal borides, contain boron in negative oxidation states. Illustrative is magnesium diboride MgB 2. In this material, the boron centers are trigonal planar with an extra double bond for each boron, forming sheets akin to the carbon in graphite. However, unlike hexagonal boron nitride, which lacks electrons in the plane of the covalent atoms, the delocalized electrons in magnesium diboride allow it to conduct electricity similar to isoelectronic graphite.
In , this material was found to be a high-temperature superconductor. A project at CERN to make MgB 2 cables has resulted in superconducting test cables able to carry 20, amperes for extremely high current distribution applications, such as the contemplated high luminosity version of the large hadron collider. Certain other metal borides find specialized applications as hard materials for cutting tools. From the structural perspective, the most distinctive chemical compounds of boron are the hydrides.
Characteristically such compounds contain boron with coordination numbers greater than four. Boron has two naturally occurring and stable isotopes , 11 B There are 13 known isotopes of boron, the shortest-lived isotope is 7 B which decays through proton emission and alpha decay.
It has a half-life of 3. Boron isotopes are also fractionated during mineral crystallization, during H 2 O phase changes in hydrothermal systems, and during hydrothermal alteration of rock. It results in solutions enriched in 11 B OH 3 and therefore may be responsible for the large 11 B enrichment in seawater relative to both oceanic crust and continental crust; this difference may act as an isotopic signature.
The exotic 17 B exhibits a nuclear halo , i. The 10 B isotope is useful for capturing thermal neutrons see neutron cross section Typical cross sections. The nuclear industry enriches natural boron to nearly pure 10 B.