THE EFFECT OF CALCIUM SUPPLEMENTATION ON BLOOD PRESSURE OF HEALTHY ADULT BLACK MALES AND WHITE MALES (PARATHYROID HORMONE, URINE BIOCHEMICALS)
Abstract
A relatively new and promising area of research points to a key role for dietary calcium in the regulation of blood pressure (BP). The purpose of this research was to examine the effect of a 1500 mg/day calcium supplementation, given in a divided dose three times/day for 12 weeks following a four week baseline period, on BP and specific biochemical variables in normotensive black (n = 21) and white (n = 54) males, aged 19-52 years. Assignment to a treatment (TX) or placebo (P) group was random and double-blind. During the experimental period, multiple BP measurements were taken every two weeks in both the seated and supine positions using a random "O" sphygmomanometer. A repeated measures analysis of covariance yielded a modest but significantly lower (p = .004) seated mean arterial pressure (MAP) in the treatment group compared to the control group, but no difference between the races. Results were similar for supine BP. Calcium supplementation in comparison to a placebo resulted in lower MAP in normotensive black and white males during a 12 week period. The effects of the calcium supplement on serum ionized calcium (SIC), total calcium (STC), total phosphorus (STP), parathyroid hormone (PTH); and urinary calcium (UC), phosphorus (UP), sodium (UNA), and potassium (UK) were determined at baseline, six and twelve weeks. At the end of the supplement period, blacks had a lower STC than the whites (p = .009), UK was greater in the blacks than the whites (p = .04), and UC was greater in the TX group than in the P group (p = .003). The overall hypotensive effect of the calcium supplement could not be explained by the response of these selected biochemicals during the twelve week study. Within the treatment group only, responders (RES) ((GREATERTHEQ)5 mmHg decrease in pre to post MAP, n = 14) were compared to nonresponders (NR) (<5 mmHg decrease in pre to post>MAP, n = 23) RES were older (p = .002), exhibited higher baseline MAP (p = .001), higher baseline PTH (p = .01), and lower baseline STC (p = .001). Discriminant function analysis revealed that MAP and STC correctly classified 78.8% of RES and NR. Thus age, baseline BP, PTH, and STC may influence BP response to supplemental calcium.
Degree
Ph.D.
Subject Area
Physical education|Nutrition
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