A previous study had shown a link between daily calcium supplementation and reduced colorectal adenoma risk, and the recent follow-up study showed that the supplements continue to offer protection after patients discontinue use.
Data from 587 patients who previously had at least one colonoscopy was analyzed for seven years after the conclusion of the previous study. At the five-year-mark, the former calcium users showed a 31.5 percent rate of adenoma formation, while the group who never used calcium supplements showed 43.2 percent growth, but no apparent effect on either group was noted after that time. The study also showed that the prior use of calcium supplements reduced advanced adenoma risk, but not in a way that was statistically significant.
In an interview with Reuters, study co-author Dr. John A. Baron of Dartmouth Medical School in Lebanon, New Hampshire, said he would like to see future researchers duplicate the results of his study, but noted it was too early to say calcium supplements were a viable way to prevent colorectal cancer. He added that the study turned up evidence that prostate cancer risk might be increased by calcium supplementation.
"I would urge consumers to supplement only with high-grade calcium sources, and avoid products like Tums which actually reduce stomach acid, interfering with the assimilation of minerals like calcium," said Mike Adams, author of "The 7 Laws of Nutrition" and a consumer health advocate. Adams said that calcium carbonate is a poor source of calcium, and that calcium citrate is better. The best sources, he said, include things like calcium malate, and he recommended consumers visit WellnessResources.com for "very high-grade calcium."
"The best way to take calcium is with acidic natural foods such as citrus or strawberries," he said. "A little vinegar, taken with calcium supplements, can also boost absorption and assimilation."