Use of calcium supplements has been already been associated with an increased risk of prostate cancer for men for many years in
a National Institute of Health (NIH) an Institute of Medicine (IOM)report, (see page 6 and see excerpt later in this post)(and prostate cancer is also mentioned in a 1997 report on page 144, and from page 142 a summary statement about some groups of people who may be more at risk from excessive calcium intake:
“Subpopulations known to be particularly susceptible to the toxic effects of calcium include individuals with renal failure, those using thiazide diuretics (Whiting and Wood, 1997), and those with low intakes of minerals that interact with calcium (for example, iron, magnesium, zinc).”)
from: Dietary Reference Intakes for Calcium, Phosphorus, Magnesium, Vitamin D, and Fluoride, Jan 1, 1997 [http://iom.nationalacademies.org/Reports/1997/Dietary-Reference-Intakes-for-Calcium-Phosphorus-Magnesium-Vitamin-D-and-Fluoride.aspx]
If you are a person who is already seeing health professionals about prostate cancer risks and you haven’t been told that excess calcium has been associated with an increased risk of prostate cancer then maybe it’s time to ask why not? The following webpage does suggest men may be better to use calcium rich foods instead of supplements, however prostate cancer risk is not mentioned: MayoClinic.
While I was looking for the Institute of Medicine report I found a more recent National Institute of Health update on vitamin D levels and prostate cancer which shows on an apparent U-shaped trend for risk of prostate cancer and vitamin D levels.
Having low levels of vitamin D and having elevated levels of vitamin D was associated with risk of prostate cancer in men, however the trend was only apparent when patient’s data was grouped by quartiles rather than by the three currently accepted categories of vitamin D sufficiency. Quartiles divide the data into five groups. If the U-shaped trend was more apparent for the 20% of patients with the lowest levels of vitamin D and for the 20% with the most elevated levels of vitamin D then the lab values of those groups of patients must not have overlapped very closely with the range of lab values that are included in any of the three established categories of vitamin D sufficiency: “(concentrations less than 50 nmol/L being considered deficient, 50–75 nmol/L insufficient, and 75–125 nmol/L considered sufficient).” — which suggests to me that those currently accepted ranges of vitamin D sufficiency do not actually provide any information that is useful for assessing or counseling men about their risk of prostate cancer.
We would need to go to the original research study and see what the lab values were for the patients who fell in the lowest and highest quartiles — the 20% with the lowest values and the 20% with the highest lab values for vitamin D — in order to have some idea of how low or how elevated the lab values were for the men who had an increased risk of prostate cancer. The lowest 20% might have had values that were lower than 50 nmol/L (below 20-30 nmol/L is considered deficient) and the most elevated 20% may or may not have had values below or above 75 nmol/L — but we have no idea without going back to the original research article.
Excerpt from Vitamin D and Calcium: A Systematic Review of Health Outcomes (Update).:
“In the current report, four new nested case-control studies (two rated A, two rated B) and one new prospective cohort study (rated B) found no association between baseline serum 25(OH)D concentrations and risk for prostate cancer. Two new nested case-control studies (both rated B) observed a trend between higher serum vitamin D concentrations and increasing risk for prostate cancer. In one study this increase was seen only among men whose sera were sampled in summer or autumn; in the other study, this trend was observed only when participants were divided by quartiles of 25(OH)D concentration, but not when they were divided by categories of vitamin D sufficiency (concentrations less than 50 nmol/L being considered deficient, 50–75 nmol/L insufficient, and 75–125 nmol/L considered sufficient).”
“In the original report, 12 nested case-control studies (3 rated B, 9 C) evaluated the association of baseline serum 25(OH)D concentrations and prostate cancer risk. No eligible RCTs were identified. Eight of the nested case-control studies found no statistically significant dose-response relationship between serum 25(OH)D concentrations and the risk of prostate cancer. One C-rated study found a significant association between lower baseline serum 25(OH)D concentrations (<30 compared with >55 nmol/L) and higher risk of prostate cancer. Another C-rated study suggested the possibility of a U-shaped association between baseline serum 25(OH)D concentrations and the risk of prostate cancer (i.e., lower and higher serum 25(OH)D concentrations were associated with an increased risk of prostate cancer compared with that of the in between reference level).”
Evidence Reports/Technology Assessments, No. 217.
Newberry SJ, Chung M, Shekelle PG, et al.
Dietary reference intakes for calcium and vitamin D / Committee to Review Dietary Reference Intakes for Vitamin D and Calcium, Food and Nutrition Board ; A. Catharine Ross … [et al.], editors. Copyright 2011 by the National Academy of Sciences — ISBN 978-0-309-16395-8 (pdf) [http://www.nap.edu/read/13050/chapter/2#5] Excerpt, Box S-3: Potential Indicators of Adverse Outcomes for Excess Intake of Calcium and Vitamin D (page 6):
BOX S-3: Potential Indicators of Adverse Outcomes for Excess Intake of Calcium and Vitamin D (page 6)
Intoxication and related hypercalcemia and hypercalciuria
Measures in infants: retarded growth, hypercalcemia
Emerging evidence for all-cause mortality, cancer, cardiovascular risk, falls and fractures
So excess calcium and excess vitamin D are both officially associated with increased risk of prostate cancer or with “emerging evidence for cancer” in general.
From some old notes, : 12. [ncbi.nlm.nih] Carcinogenesis. 2011 Jun;32(6):822-8. Epub 2011 Mar 10. Enhanced formation of 5-oxo-6,8,11,14-eicosatetraenoic acid by cancer cells in response to oxidative stress, docosahexaenoic acid and neutrophil-derived 5-hydroxy-6,8,11,14-eicosatetraenoic acid. Grant GE, Rubino S, Gravel S, Wang X, Patel P, Rokach J, Powell WS.
“Stimulation of neutrophils with arachidonic acid and calcium ionophore in the presence of PC3 cells led to a large and selective increase in 5-oxo-ETE synthesis compared with controls in which PC3 cell 5-oxo-ETE synthesis was selectively blocked by pretreatment with NEM. The ability of prostate tumor cells to synthesize 5-oxo-ETE may contribute to tumor cell proliferation as well as the influx of inflammatory cells, which may further induce cell proliferation through the release of cytokines. 5-Oxo-ETE may be an attractive target in cancer therapy.”
***Did anyone besides me notice that they stimulated those cancer cells with calcium? Might simply not over stimulating cancer with excess calcium be an attractive target for cancer therapy? and cheap? – less calcium intake – more health output? /speculation/
/Disclosure: This information is provided for educational purposes within the guidelines of fair use. Information is not a substitute for individual health guidance. Please see a health professional for individual health care purposes./