Monday NOv 23, 2015 (foodconsumer.org) -- Harvard University researchers published a study suggesting that high intake of phosphorus may increase the risk of all sorts of prostate cancer including advanced and high grade prostate cancer.
Early studies have found high calcium intake associated with increased risk of advanced and high grade prostate cancer and high phosphorus intake was linked to prostate cancer risk.
For the current study, researchers analyzed data from the Health Professionals Follow-Up Study which involved 47,885 men. During up to 24 years of follow-up, 5861 cases of prostate cancer including 789 cases of lethal cancers were recorded.
The researchers found daily intakes of more than 2000 mg of calcium were associated with greater risk of total prostate cancer and lethal/high-grade prostate cancers. The associations after adjustment for phosphorus intake became no longer significant.
The effects of calcium and phosphorus exposure had different latencies. Calcium intake was correlated with increased risk of advanced and high grade prostate cancer 12 to 16 years after exposure while phosphorus intake was linked to increased risk for advanced-stage and high grade prostate cancer 0 to 8 year after exposure. These findings suggest that it may take longer time for calcium to have an effect on the prostate cancer risk.
The researchers concluded "Phosphorus is independently associated with risk of lethal and high-grade prostate cancer. Calcium may not have a strong independent effect on prostate cancer risk except with long latency periods."
The study suggests that it may not be a good idea for prostate cancer patients to take calcium supplements and have a high intake of phosphorus. Phosphate in large quantity can be found in bakery products. High calcium is found in dairy products, which have been associated with elevated risk for prostate cancer.
Edward Giovannucci at Harvard University and colleagues published a study in 1998 in Cancer Causes & Control that shows men with daily intake of calcium greater than 1183 mg were twice as likely as those with daily intake of lower than 825 mg. For metastatic prostate cancer, the risk was 164% higher among those with such high calcium intake.
The researchers also found eating dairy foods was associated with 50% increased risk for prostate cancer.
Cancer Causes & Control, December 1998, Volume 9, Issue 6, pp 559-566
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