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MAGNESIUM AND BORON

 

Biol Trace Elem Res 1988 Sep-Dec;17:91-107

Magnesium and methionine deprivation affect the response of rats to boron deprivation.

Nielsen FH, Shuler TR, Zimmerman TJ, Uthus EO

US Department of Agriculture, Grand Forks Human Nutrition Research Center, ND 58202.

A series of nine experiments were done to obtain further evidence that boron might be involved in major mineral metabolism (Ca, P, and Mg), thus indicating that boron is an essential nutrient for animals. Eight factorially arranged experiments of 6-10 wk durations were done with weanling Sprague-Dawley male rats. One factorially arranged experiment was done with weanling spontaneously hypertensive rats. The variables in each experiment were dietary boron supplements of 0 and 3 micrograms g, and dietary magnesium supplements of either 200 (Experiments 1-3) or 100 (Experiments 4-9) and 400 micrograms/g. In Experiments 7 and 9, a third variable was dietary manganese supplements of 25 and 50 micrograms/g. Methionine status was varied throughout the series of experiments by supplementing the casein-based diet with methionine and arginine. Findings were obtained indicating that the severity of magnesium deprivation and the methionine status of the rat strongly influence the extent and nature of the interaction between magnesium and boron, and the response to boron deprivation. When magnesium deprivation was severe enough to cause typical signs of deficiency, a significant interaction between boron and magnesium was found. Generally, the interaction was characterized by the deprivation of one of the elements making the deficiency signs of the other more marked. The interaction was most evident when the diet was not supplemented with methionine and especially when the diet contained luxuriant arginine. Signs of boron deprivation were also more marked and consistent when the diet contained marginal methionine and luxuriant arginine. Among the signs of boron deprivation exhibited by rats fed marginal methionine were depressed growth and bone magnesium concentration, and elevated spleen wt/body wt and kidney wt/body wt ratios. Because the boron supplement of 3 micrograms/g did not make the dietary intake of this element unusual, it seems likely that the response of the rats to dietary boron in the present study were manifestations of physiological, not pharmacological, actions, and support the hypothesis that boron is an essential nutrient for the rat.

 

Environ Health Perspect 1994 Nov;102 Suppl 7:79-82

Effects of boron supplementation on bone mineral density and dietary, blood, and urinary calcium, phosphorus, magnesium, and boron in female athletes.

Meacham SL, Taper LJ, Volpe SL

Department of Human Nutrition, Winthrop University, Rock Hill, South Carolina 29733.

The effects of boron supplementation on blood and urinary minerals were studied in female college students--17 athletes and 11 sedentary controls--over a one-year period. The athletes had lower percent body fat and higher aerobic capacities than sedentary controls. Athletic subjects consumed more boron in their normal diets than sedentary subjects; all other dietary measures were similar between the two groups. The athletes showed a slight increase in bone mineral density, whereas the sedentary group showed a slight decrease. Serum phosphorus concentrations were lower in boron-supplemented subjects than in subjects receiving placebos, and were lower at the end of the study period than during baseline analysis. Activity depressed changes in serum phosphorus in boron-supplemented subjects. Serum magnesium concentrations were greatest in the sedentary controls whose diets were supplemented with boron, and increased with time in all subjects. A group x supplement interaction was observed with serum magnesium; exercise in boron-supplemented subjects lowered serum magnesium. In all subjects, calcium excretion increased over time; in boron-supplemented subjects, boron excretion increased over time. In all subjects, boron supplementation affected serum phosphorus and magnesium, and the excretion of urinary boron.

 

Biol Trace Elem Res 1992 Dec;35(3):225-37

Studies of the interaction between boron and calcium, and its modification by magnesium and potassium, in rats. Effects on growth, blood variables, and bone mineral composition.

Nielsen FH, Shuler TR

United States Department of Agriculture, Grand Forks Human Nutrition Research Center, ND 58202-7166.

Two experiments were performed to confirm that boron interacts with calcium, and that this interaction can be modified by dietary magnesium and potassium in the rat. Upon manipulating the dietary variables listed above, it was found that under certain conditions, boron and calcium deprivation similarly affected several variables; for example, they both could be made to elevate plasma alkaline phosphatase activity and to depress femur calcium concentration. Under some dietary conditions, both boron and calcium deprivation affected some variables related to blood or iron metabolism. However, the effects of dietary boron and calcium on spleen weight/body weight ratio, hematocrit, and femur iron concentration generally were not similar. Femur copper, magnesium, phosphorus, and zinc also were affected by an interaction between boron and calcium under some dietary conditions. The findings show that there is a relationship between boron and calcium, but they do not clearly indicate the nature of the relationship. However, the data suggest that boron and calcium act on similar systems in the rat.

 

Biol Trace Elem Res 1989 Nov;22(2):201-20

Dietary boron modified the effects of magnesium and molybdenum on mineral metabolism in the cholecalciferol-deficient chick.

Hunt CD

US Department of Agriculture, Grand Forks Human Nutrition Research Center, ND 58202.

The metabolic effects of dietary boron, magnesium, and molybdenum on mineral metabolism in the cholecalciferol-deficient chick, with emphasis on growth cartilage histology, were studied. One-day-old cockerel chicks were assigned to groups in a fully-crossed, three factor, 2 x 2 x 2 design. The basal diet was based on ground corn, high-protein casein, and corn oil and contained 125 IU cholecalciferol (inadequate), 0.465 mg B, 2.500 mg Mg, and 0.420 mg Mo/kg. The treatments were the supplementation of the basal diet with B at O or 3; Mg at 300 (inadequate) or 500 (adequate); and Mo at 0 or 20 mg/kg. At d 25, B depressed mortality, alleviated the cholecalciferol-deficiency induced distortion of the marrow sprouts (MS) of the proximal tibial epiphysial plate, and elevated the numbers of osteoclasts within the MS. Adequate Mg exacerbated the cholecalciferol-deficiency induced bone lesions. Mo widened the MS markedly. In Mg-deficient chicks, B elevated plasma Ca and Mg concentrations and growth, but inhibited initiation of cartilage calcification; B had the opposite effect in Mg-adequate chicks. An interaction among B, Mg, and Mo affected plasma uric acid and glucose concentrations. B may function to modify mineral metabolism in cholecalciferol deficiency, suppressing bone anabolism in concurrent Mg deficiency and bone catabolism in concurrent Mg adequacy.

 

FASEB J 1987 Nov;1(5):394-7

Effect of dietary boron on mineral, estrogen, and testosterone metabolism in postmenopausal women.

Nielsen FH, Hunt CD, Mullen LM, Hunt JR

United States Department of Agriculture, Grand Forks Human Nutrition Research Center, North Dakota 58202.

A study was done to examine the effects of aluminum, magnesium, and boron on major mineral metabolism in postmenopausal women. This communication describes some of the effects of dietary boron on 12 women between the ages of 48 and 82 housed in a metabolic unit. A boron supplement of 3 mg/day markedly affected several indices of mineral metabolism of seven women consuming a low-magnesium diet and five women consuming a diet adequate in magnesium; the women had consumed a conventional diet supplying about 0.25 mg boron/day for 119 days. Boron supplementation markedly reduced the urinary excretion of calcium and magnesium; the depression seemed more marked when dietary magnesium was low. Boron supplementation depressed the urinary excretion of phosphorus by the low-magnesium, but not by the adequate-magnesium, women. Boron supplementation markedly elevated the serum concentrations of 17 beta-estradiol and testosterone; the elevation seemed more marked when dietary magnesium was low. Neither high dietary aluminum (1000 mg/day) nor an interaction between boron and aluminum affected the variables presented. The findings suggest that supplementation of a low-boron diet with an amount of boron commonly found in diets high in fruits and vegetables induces changes in postmenopausal women consistent with the prevention of calcium loss and bone demineralization.