|Calcium & Cancer|
Note: The following abstracts are written in extremely technical language and include technical research and case studies. References are provided. For 'user-friendly' informative reading, check out the health topics presented by Dr. Martin and Dr. Davenport. Feel free to contact us for more information or if you have any questions.
Relationship between vitamin and calcium supplement use and colon cancer
The relationship between vitamin supplement use and colon cancer was assessed in a population-based case-control study among men and women aged 30-62 years. Cases were 251 men and 193 women diagnosed with colon cancer in 1985-1989 in three counties in the Seattle metropolitan area who were identified from the Surveillance, Epidemiology, and End Results cancer registry. Controls were 233 men and 194 women identified by random digit dialing. Supplement use was assessed by questions on frequency, duration, and dose per day (for individual supplements) or type (for multivitamins) during the 10-year period ending 2 years before diagnosis. All results were adjusted for age and sex and were not confounded by other measured behaviors. The average daily intake of supplemental vitamins A, C, E, folic acid, calcium, and multivitamins during the reference period were each associated with reduced risk of colon cancer (all P for trend < 0.03). The strongest associations were for use of vitamin E (odds ratio, 0.43; 95% confidence interval, 0.26-0.71 for > or = 200 IU/day versus none) and multivitamins (odds ratio, 0.49; 95% confidence interval, 0.35-0.69 for daily use versus no use; both P for trend < 0.001). These two associations were also significant using a stricter test of trend limited to supplement users, which reduces the effect of colinearity among these exposures. Because almost all vitamin D supplementation comes from multivitamin pills, the association of vitamin D use with colon cancer could not be distinguished from that of multivitamin use. Clinical trials or cohort studies with long-term assessment would be needed before public health recommendations could be made about supplement use.
White-E; Shannon-JS; Patterson-RE
Cancer-Epidemiol-Biomarkers-Prev. 1997 Oct; 6(10): 769-74
Pharmacologic prevention of colonic neoplasms. Effects of calcium, vitamins, omega fatty acids, and nonsteroidal anti-inflammatory drugs
Dietary supplements of calcium, vitamins A, C, and E, carotenoids, and omega-3 fatty acids can reduce the yield of experimental cancers in animals and reverse the pattern of abnormal epithelial proliferation in animals and humans. Epidemiological studies indicate that diets containing high amounts of these agents convey a protective effect against the development of colon cancer. Moreover, regular aspirin use in humans appears to reduce the risk of colon cancer and sulindac causes regression of polyps in patients with familial polyposis. These agents are promising for the prevention of human colorectal cancer, but their efficacy has not yet been shown in prospective, controlled trials. Thus, although it is tempting to speculate that in the future we may treat our patients who have a predisposition to colon polyps and cancer, or even healthy people at average risk, with such ordinary supplements as calcium, vitamins, fish oil, or aspirin, such advice at this time is premature.
Dig-Dis. 1996 Mar-Apr; 14(2): 119-28
Calcium supplementation modifies the relative amounts of bile acids in bile and affects key aspects of human colon physiology
Use of calcium supplements has increased dramatically in recent years yet little is known about the effect of calcium supplementation on colon physiology. We supplemented 22 individuals with a history of resected adenocarcinoma of the colon, but currently free of cancer, with 2000 or 3000 mg calcium for 16 wk. The effects of supplementation on duodenal bile acids and important fecal characteristics including total fecal output, wet and dry weight, pH, bile acids (in solids and in fecal water), and concentrations and total excretion of calcium, magnesium, phosphates (organic and inorganic), unesterified fatty acids and total fat were determined. Calcium supplementation significantly decreased the proportion of water in the stool (P = 0.03), doubled fecal excretion of calcium (P = 0.006), and increased excretion of organic phosphate (P = 0.035) but not magnesium. Calcium supplementation significantly decreased the proportion of chenodeoxycholic acid in bile (P = 0.007) and decreased the ratio of lithocholate to deoxycholate in feces (P = 0.06). The concentration of primary bile acids in fecal water decreased after 16 wk Ca supplementation. Together with other reports of a "healthier" bile acid profile with respect to colon cancer when changes such as those observed in this study were achieved, these results suggest a protective effect of calcium supplementation against this disease.
Lupton-JR; Steinbach-G; Chang-WC; O'Brien-BC; Wiese-S; Stoltzfus-CL; Glober-GA; Wargovich-MJ; McPherson-RS; Winn-RJ
J-Nutr. 1996 May; 126(5): 1421-8
Randomized, double-blinded, placebo-controlled study of effect of wheat bran fiber and calcium on fecal bile acids in patients with resected adenomatous colon polyps
BACKGROUND: Ongoing epidemiologic and nutritional studies suggest that colorectal carcinogenesis is consistent with complex interactions between genetic susceptibility and environmental and dietary factors. Among the dietary components found to reduce colon cancer risk are high intakes of dietary fiber and calcium. PURPOSE: We designed and conducted a randomized, double-blinded, placebo-controlled trial involving supplementation of the customary dietary intake with fiber and calcium and measurements of fecal bile acids to examine the potential mechanisms by which added dietary interventions might reduce colorectal cancer risk. METHODS: In a randomized, double-blinded, phase II study, we used a factorial design to measure the effects of dietary wheat bran fiber (2.0 or 13.5 g/day) in the form of cereal and supplemental calcium carbonate (250 or 1500 mg/day elemental calcium) taken as a tablet on fecal bile acid concentrations and excretion rates. Measurements were made at base-line randomization (i.e., after a 3-month placebo run-in period using 2.0 g wheat bran fiber plus 250 mg calcium carbonate) and after 3 and 9 months on treatment in a randomly selected 52-patient subsample of the 95 fully assessable study participants who had a history of colon adenoma resection. Concentrations of fecal bile acids, total, primary (i.e., chenodeoxycholic and cholic), and secondary (i.e., deoxycholic, lithocholic, and ursodeoxycholic), were measured in 72-hour stool samples by gas-liquid chromatography. All P values resulted from two-sided tests. RESULTS: All geometric mean fecal bile acid concentrations and excretion rates were lower at 9 months than at 0 months or 3 months on treatment in the high-dose fiber, high-dose calcium, and high-dose fiber/high-dose calcium treatment groups. The high-dose fiber effect at 9 months of supplementation was statistically significant with respect to virtually all geometric mean fecal bile acid concentrations and excretion rates. For example at 9 months versus 0 months, high-dose fiber supplementation caused a reduction in fecal concentrations of total bile acids (52% reduction; P = .001) and deoxycholic acid (48% reduction; P = .003). High-dose calcium supplementation also had a significant, but lower, effect at 9 months versus 0 months on the geometric mean total bile acid (35% reduction; P = .044) and deoxycholic fecal bile acid (36% reduction; P = .052) concentrations. CONCLUSIONS: High-dose wheat bran fiber and calcium carbonate supplements given for 9 months are associated with statistically significant reductions in both total and secondary fecal bile acid concentrations and excretion rates in patients with resected colon adenomas. This study supports the hypothesis that one of the important ways in which a high intake of wheat bran fiber and calcium may reduce the risk of colorectal neoplasia and cancer is by reduction of the concentrations of fecal bile acids. IMPLICATION: Phase III studies of these agents in the prevention of adenoma recurrence are necessary to confirm this hypothesis and have now been initiated at multiple institutions.
Alberts-DS; Ritenbaugh-C; Story-JA; Aickin-M; Rees-McGee-S; Buller-MK; Atwood-J; Phelps-J; Ramanujam-PS; Bellapravalu-S; Patel-J; Bextinger-L; Clark-L
J-Natl-Cancer-Inst. 1996 Jan 17; 88(2): 81-92
Calcium is necessary for the prevention and treatment of diseases such as osteoporosis, hypertension, and, possibly, colon cancer. Supplementation is useful when dietary calcium intake is low, as is the current situation in North America. There are many factors to consider before recommending any one form of supplement. A consideration for calcium carbonate tablets is whether the tablet disintegrates and whether or not a lack of food or acid in the stomach will hinder utilization. Other forms of calcium, particularly the chelated calcium salts, are better absorbed in fasting achlorhydric subjects but have less calcium per gram of supplement. Interaction of calcium with other mineral nutrients and the presence of contaminating metals has focused attention on safety. Based on present evidence, chelated calcium and refined calcium carbonate tablets (including those labeled as antacids) may be safely and effectively ingested by most people at doses generally recommended for treatment or prevention of osteoporosis. One should not exceed 2,000 mg of calcium, except at the advice of their health care provider, as inadvertent mineral deficiencies may arise. Persons at risk for developing milk-alkali syndrome, such as thiazide users and persons with renal failure, should be identified and monitored for alkalosis and hypercalcemia when using calcium supplements.
Whiting-SJ; Wood-R; Kim-K
J-Am-Acad-Nurse-Pract. 1997 Apr; 9(4): 187-92
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