Calcium dietary

One method of treatment is to inject calcitonin, which decreases blood Ca " concentration and increases bone calcification (33). Another is to increase the release of calcitonin into the blood by increasing the blood level of Ca " ( 4). This latter treatment is accompHshed by increasing Ca " absorption from the intestine requiring dietary calcium supplements and avoidance of high phosphate diets. The latter decrease Ca " absorption by precipitation of the insoluble calcium phosphate. 

Vitamin D withdrawal is an obvious treatment for D toxicity (219). However, because of the 5—7 d half-life of plasma vitamin D and 20—30 d half-life of 25-hydroxy vitamin D, it may not be immediately successful. A prompt reduction in dietary calcium is also indicated to reduce hypercalcemia. Sodium phytate can aid in reducing intestinal calcium transport. Calcitonin glucagon and glucocorticoid therapy have also been reported to reduce semm calcium resulting from D intoxication (210). 

Wasserman, R., Comar, C.L. and Papadopoulou, D. 1957 Dietary calcium levels and retention of radiostrontium in the growing rat. Science 126 1180-1182. 

WEAVER c M, PROULX w R and HEANEY R (1999) Choices for achieving adequate dietary calcium with a vegetarian diet. Am J Clin Nutr. 70 (3 Suppl) 543S-548S. 

Wise, K., Bergmann, E., Sherrard, D. and Massey, L., Interactions between dietary calcium and caffeine consumption on caffeine in hypertensive humans. Am JHypertens 9(3), 223-229, 1996. 

Hasling, C., Sondergaard, K., Charles, P., Mosekilde, L., Calcium metabolism in postmenopausal osteoporotic women is determined by dietary calcium and coffee intake, Journal of Nutrition, 122, 1119, 1992. 

Massey, L. K., Sherrard, D. J., Bergman, E. A., Dietary caffeine lower ultrafiltrable calcium levels in women consuming low dietary calcium, Journal of Bone and Mineral Research, 4(Sup 1), 249(Abstract), 1989. 

Holbrook, T. L., Barrett-Connor, E., Wingard, D. L., Dietary calcium and risk of hip fracture 14 year prospective population study, Lancet, 2, 1046, 1988. 

Dietary calcium intake appears to affect lead absorption. An inverse relationship has been observed between dietary calcium intake and blood lead concentration in children, suggesting that children who are calcium deficient may absorb more lead than calcium replete children (Mahaffey et al. 1986 Ziegler et al. 1978). An effect of calcium on lead absorption is also evident in adults. In experimental studies of adults, absorption of a single dose of lead (100-300 ig lead chloride) was lower when the lead was... 

Calcium Rat Lead in tissues and severity of effect at low levels of dietary calcium Low dietary calcium (0.1 %) increase lead absorption and severity of effects Six and Goyer 1970 Mahaffey et al. 1973... 

Calcium Rat Lead in tissues at high levels of dietary calcium during pregnancy Reduced release of lead from bone Bogden et al. 1995... 

Calcium Pig Lead in tissues at low levels of dietary calcium Increased absorption of lead with low dietary calcium Hsu et al. 1975... 

Anonymous. 1985. Blood lead levels, dietary calcium, and hypertension. Annals of Internal Medicine 103 403-404. 

Bogden JD, Kemp FW, Han S, et al. 1995. Dietary calcium and lead interact to modify maternal blood pressure, erythropoiesis, and fetal and neonatal growth in rats during pregnancy and lactation. J Nutr 125 990-1002. 

Bourgoin BP, Evans DR, Cornett JR, et al. 1993. Lead content in 70 brands of dietary calcium supplements. Am J Pub Health 83(8) 1155-1160. 

Fullmer CS, Rosen JF. 1990. Effect of dietary calcium and lead status on intestinal calcium absorption. Environ Res 51 91-99. 

Hsu FS, Krook L, Pond WG, et al. 1975. Interactions of dietary calcium with toxic levels of lead and zinc in pigs. J Nutr 105 112-118. 

Mahaffey KR, Gartside PS, Glueck CJ. 1986. Blood lead levels and dietary calcium intake in 1- to 11-year old children The Second National Health and Nutrition Examination Survey, 1976 to 1980. Pediatrics 78 257-262. 

Mahaffey KR, Goyer R, Haseman JK. 1973. Dose-response to lead ingestion in rats fed low dietary calcium. J Lab Clin Med 82 92-100. 

Morrison JN, Quarterman H, Humphries WR. 1977. The effect of dietary calcium and phosphate on lead poisoning in lambs. J Comp Pathol 87 417-429. 

Proctor SP, Rotnitzky A, Sparrow D, et al. 1996. The relationship of blood lead and dietary calcium to blood pressure in the normative aging study. Int J Epidemiol 25(3) 528-536. 

Quarterman J, Morrison JN. 1975. The effects of dietary calcium and phosphorus on the retention and excretion of lead in rats. Br J Nutr 34 351-362. 

Six KM, Goyer RA. 1970. Experimental enhancement of lead toxicity by low dietary calcium. JLab Clin Med 76 933-942. 

Thawley DG, Willoughby RA, McSherry BJ. et al. 1977. Toxic interaction among lead, zinc, and cadmium with varying levels of dietary calcium and vitamin D. Environ Res 14 463-475. 

Calcium oxalate (723) occurs as the monohydrate (whewellite, the thermodynamically stable form under ambient conditions (724)), the dihydrate (weddellite) in plant calcium stores and in sap, or the trihydrate (725). Calcium oxalate also plays a structural role in plants. Oxalate, for example from excessive amounts of rhubarb or spinach, inhibits absorption of Ca2+ from the GIT precipitation of calcium oxalate is the reason for the toxicity of oxalates. Calcium oxalate may also occur in man, where it can appear as minute star-shaped crystals in the urine. It is the main constituent of the majority of urinary calculi in man (726,727). The relationships between dietary calcium... 

Lead is toxic to all phyla of aquatic biota, but its toxic action is modified by species and physiological state, and by physical and chemical variables. Wong et al. (1978) stated that only soluble waterborne lead is toxic to aquatic biota, and that free cationic forms are more toxic than complexed forms. The biocidal properties of soluble lead are also modified significantly by water hardness as hardness increases, lead becomes less bioavailable because of precipitation increases (NRCC 1973). In salmonids, for example, the toxicity and fate of lead are influenced by the calcium status of the organism, and this relationship may account for the reduced effects of lead in hard or estuarine waters. In coho salmon (Oncorhynchus kisutch), an increase in waterborne or dietary calcium reduced uptake and retention of lead in skin and skeleton (Varanasi and Gmur 1978). 

The effect of diet on vulnerability to lead makes interpretation of published information on experimental lead poisoning in waterfowl extremely difficult (Chasko et al. 1984). For example, many mallards on a diet of com die within 10 to 14 days after ingesting a single lead shot, whereas similar birds on a balanced commercial duck ration appear outwardly normal after ingesting as many as 32 pellets of the same size (Wobeser 1981). Also, multiple nutritional deficiencies may have additional effects in potentiating the toxicity of lead in mallards (Carlson and Nielsen 1985). Under conditions of reduced dietary calcium availability, such as can occur in acid-impacted environments, birds risk increased uptake of lead (and other metals) and may accumulate toxic concentrations more rapidly (Scheuhammer 1996). Enhanced accumulation of lead was accompanied by an increased synthesis of metallothioneins and a greater inhibition of ALAD activity (Scheuhammer 1996). 

Carlson, B.L. and S.W. Nielsen. 1985. Influence of dietary calcium on lead poisoning in mallard ducks (Anas platyrhynchos). Amer. Jour. Vet. Res. 46 276-282. 

Scheuhammer, A.M. 1996. Influence of reduced dietary calcium on the accumulation and effects of lead, cadmium, and aluminum in birds. Environ. Pollut. 94 337-343. 

Varanasi, U. and D.J. Gmur. 1978. Influence of water-borne and dietary calcium on uptake and retention of lead by coho salmon (Oncorhynchus kisutch). Toxicol. Appl. Pharmacol. 46 65-75. 

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