Colorectal Cancer Don't look for the scoop on colorectal cancer from PETA or PCRM. That's because studies suggest milk helps.
Not that it's a uniquely milk thing. Research suggests calcium from any source acts as a neutralizer of carcinogenic substances passing through the colon. Other studies that suggest sunlight reduces colon cancer implicate milk's vitamin D. And while milk has a few relatively proprietary substances that may be cancer-fighters, like conjugated linoleic acid (CLA) and whey protein, it also appears to raise blood levels of a growth hormone called IGF-1, which can promote cancer.
Most studies suggest high milk intakes reduce colorectal cancer risk by about 20 to 30 percent. But a recent study of men found a subgroup who may benefit much more. In that Harvard study, men with a high ratio of IGF-I to IGF-binding protein-3 (IGFBP-3) who drank lots of low-fat milk had just one third the risk of colorectal cancer compared to those who drank little or none.
VERDICT: Especially for people with a high IGF-I to IGFBP-3 ratio, low-fat milk appears to be protective against colorectal cancer. Research suggests sunshine and nondairy sources of calcium should work too, without raising IGF-1.
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