In case there's still any doubt in anyone's mind about the effects of vitamin D on intestinal and health benefits, please check out a recent study discussed in a Medscape article.
Higher levels of vitamin D were associated with markedly improved progression-free survival and overall survival in patients receiving treatment for metastatic colorectal cancer, according to an analysis of more than 1,000 patients. The findings were presented at the recent Gastrointestinal Cancers Symposium (abstract 507).
Study Bolsters Link Between Vitamin D Levels and CRCThe investigators organized patient data from lowest to highest levels of vitamin D, and then divided patients into five groups. They discovered that both progression-free survival and overall survival were significantly improved in patients with higher vitamin D levels (Table). The association persisted across all patient subgroups and after adjusting for multiple prognostic factors. “Patients who had levels in the highest quintile had a median survival of 32.6 months compared with 24.5 months for patients with levels in the lowest quintile,” Dr. Ng said.
But when we look at the results table in the article, we see that the patients in the highest quintile had a median vitamin D blood level of only 27.5 ng/mL.
That's still insufficient! Those in the lowest quintile had a median vitamin D level of only 8.0 nt/mL. Holy cow! All of that appears to be pretty clear evidence that vitamin D deficiency is strongly associated with advanced (metastatic) colon cancer.And as we can see by the table in the article, if we combine the 2 groups between 15.5 and 24.0 ng/mL, and consider their average combined value, and then plot those values, the improvement in survival time appears to be a an exponential function of vitamin D level. IOW, the higher the vitamin D level, the faster the corresponding rate of improvement (of overall survival) grows. Since the vitamin D median of even the highest group was below the sufficiency level, that suggests that patients who actually have a decent vitamin D level most likely have a much better success rate.
For example, if we were to project the rate of improvement based on a linear function of vitamin D level, it appears that a vitamin D level of approximately 47 would almost double the median survival time of the highest group in the table (to approximately 60 months). But the data show an exponential improvement (rather than just linear), so the actually benefit to overall survival would be much higher (assuming that the same rate of improvement holds true for higher vitamin D levels). That suggests that an average vitamin D blood level of somewhere in the neighborhood of 50–60 ng/mL might possibly be associated with a far higher overall survival rate than the study indicates.
That's pure speculation, of course, but it makes a very strong case for at least considering much higher vitamin D supplemental rates when treating colon cancer patients (and of course, much higher rates for preventing colon cancer in the first place). My question is, "Why on earth don't researchers do similar studies using respectable rates of vitamin D supplementation, in order to develop some truly useful and compelling data?"
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