ABSTRACT
We have undertaken studies in humans and animals that aimed to obtain further information about the intake and excretion of boron (B) as well as its effects on markers of coronary heart disease. In humans, we have shown that the intake of B is 2.2 mg/d; its urinary excretion is 1.9 mg/d, and there appears to be little intraindividual variation. Supplementation with 10 mg of B/d resulted in the recovery of 84% of the dose in the urine and a significant increase in plasma estradiol concentration, but no effect on plasma lipoproteins. In rats, increasing the intake of B through the drinking water is reflected in the tissue concentrations, results in an increase in plasma testosterone and vitamin D, and results in a decrease in HDL cholesterol. It is clear that B has the potential to impact significantly on a number of metabolic processes.
Subject(s)
Boron/administration & dosage , Diet , Animals , Boron/adverse effects , Boron/metabolism , Boron/urine , Drug Interactions , Humans , Randomized Controlled Trials as Topic , Risk Factors , Tissue DistributionABSTRACT
Twenty-four adult male volunteers were asked to ingest 50 or 100 mg elemental zinc (as zinc sulphate) for 7 days. The design was a randomized cross-over trial with a 3 week wash-out period. A significant increase in 24 h urinary zinc excretion occurred after supplementation with 100 mg with a change from 48.0 +/- 4.6 (mg Zn/mmol creatinine, mean +/- SE) at day 0 to 82.6 +/- 15.9 at day 7 (P < 0.05). No significant change was observed following supplementation with 50 mg zinc. Taken together with published data, this suggests urinary zinc excretion is sensitive only to extreme changes in dietary zinc intake.
