|Seaborn, Carol - U OF WISC - MENOMONIE|
Submitted to: Biological Trace Element Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 21, 2002
Publication Date: December 1, 2002
Citation: Seaborn, C.D., Nielsen, F.H. 2002. Dietary silicon and arginine affect mineral element composition of rat femur and vertebra. Biological Trace Element Research. 89(3):239-250. Interpretive Summary: There is evidence that both the mineral element silicon, and the amino acid arginine, can affect the formation of collagen upon which bone mineralization occurs, and thus both affect bone mineral composition which influences bone structure and strength. However, there has been no examination of whether bone composition is affected by an interaction between arginine and silicon. Therefore, an experiment was conducted with the objective of determining whether a high or a supra nutritional intake compared to a normal intake of arginine would alter the effect of silicon deficiency on bone composition in rats. In both vertebrae and long bone (femur) of rats, silicon deficiency decreased calcium the main component of bone mineral, and zinc and copper which are important for a normal organic matrix containing collagen upon which calcification occurs; these decreases were more marked when dietary arginine was normal than when it was high. The findings indicate that silicon is of nutritional or physiological importance because of beneficial effects on bone formation or mineralization. Because high dietary arginine alleviated some of the changes caused by silicon deprivation and arginine promotes collagen formation, and because silicon deficiency induces changes in mineral elements involved in bone collagen formation and breakdown, silicon apparently has an important role in the formation of the organic matrix, which includes collagen, upon which bone calcification occurs.
Technical Abstract: An experiment was designed to determine if dietary arginine would alter the effect of dietary silicon (Si) on bone mineralization and vice versa. Male weanling Sprague-Dawley rats were assigned to groups of 12 in a 2 x 2 factorially arranged experiment. Supplemented to a ground corn/casein basal diet containing 2.3 ug Si/g and adequate arginine were silicon as sodium meta-silicate at 0 or 35 ug/g and arginine at 0 or 5 mg/g diet. The rats were fed ad libitum deionized water and their respective diets for eight weeks. Body weight, liver weight/body weight ratio and plasma Si were decreased, and plasma alkaline phosphatase activity was increased by Si deprivation. Silicon deprivation also decreased femoral calcium, copper, potassium and zinc concentrations, but increased the femoral manganese concentration. Arginine supplementation decreased femoral molybdenum concentration but increased the femoral manganese concentration. Vertebral lconcentrations of phosphorus, sodium, potassium, copper, manganese, and zinc were decreased by Si deprivation. Arginine supplementation increased vertebral concentrations of sodium, potassium, manganese, zinc and iron. The arginine effects were more marked in the Si-deprived animals, especially in the vertebra. Germanium concentrations of the femur and vertebra were affected by an interaction between silicon and arginine; the concentrations were decreased by Si deprivation in those animals not fed supplemental arginine. The change in germanium is consistent with a previous finding by us suggesting this element may be physiologically important, especially as related to bone DNA concentrations. The findings support the contention that Si has a physiological role in bone formation and that arginine intake can affect that role.