Author
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Hunt, Curtiss |
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Submitted to: Book Chapter
Publication Type: Book / Chapter Publication Acceptance Date: 6/13/2000 Publication Date: 6/1/2003 Citation: Hunt, C.D. Boron. 2003. In: Caballero, B., Trugo, L., and Finglas, P., editors. Encyclopedia of Food Sciences and Nutrition. London, UK:Academic Press. p.566-574. Interpretive Summary: Technical Abstract: Vascular plants, diatoms, and some species of fungi have acquired an absolute requirement for boron although the primary role remains unknown. Discovery of two classes of naturally occurring organoboron compounds provides insight into the biomolecular role of boron. Recent findings indicate that boron is important for embryological development of lower vertebrates. Dietary boron alleviates signs of vitamin D deficiency but does not replace vitamin D. Also, boron supplementation increases circulating estradiol concentrations in postmenopausal women on estrogen therapy and in perimenopausal women. Boron influences the activities of at least 26 enzymes examined, always in a reversible manner and most often as an inhibitor. There is evidence to support the hypothesis that boron helps to control the normal inflammatory process by serving as a suppressive signal that down-regulates specific enzymatic activities that are typically elevated during inflammation at the inflammation site. At physiological concentrations and pH, boron may react with one nitrogen group or one to four hydroxyl groups on specific biological ligands with suitable configuration and charge to form dissociable organoboron compounds or complexes. Suitable ligands include serine protease enzymes and pyridine [e.g., NAD**+ or NADP] or flavin [e.g., FAD] nucleotide enzyme cofactors. There are indications that boron is important for membrane function in both plant and animal species but through unknown mechanisms. Boron produces toxicity in all tested biological organisms when excessive amounts are absorbed. The minimum lethal dose of boron for humans has not been established although single doses of 18 to 20 grams in adults have been fatal. |
