• Upper Safe Limit Of Vit D Supplementation Established

      From Science Daily

      Researchers claim to have calculated for the first time, the upper safe limit of vitamin D levels, above which the associated risk for cardiovascular events or death raises significantly, according to a recent study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM).

      There is increasing evidence that vitamin D plays a pivotal role in human physiology. Vitamin D deficiency has been linked to cardiovascular events and mortality, but previous studies have found supplementation fails to decrease mortality or cardiovascular events, while other studies found only minor positive effects.

      "The unpredictable results from previous studies may be due to the misconception that 'the higher the better,'" said Yosef Dror, PhD, of Hebrew University in Rehovot, Israel, and lead author of the study. "Although our study did not directly test the impact of vitamin D supplementation, we believe our results suggest it may be possible that only moderate supplementation within a narrow range of serum calcidiol (the main vitamin D fraction in the blood) will be associated with the most positive results."

      Researchers conducted a study of 422,000 people aged 45 years or older, who underwent vitamin D blood assays. They found for the first time that the safe range of vitamin D levels with respect to coronary morbidity lies between 20 to 36 ng/mL. Vitamin D levels below and above this range adjusted rates of increased mortality and morbidity significantly.

      More than 60 percent of the tested population had insufficient blood levels of vitamin D. Half of these subjects had severely low vitamin D levels which was associated with a 1.5 times increased risk of acute coronary morbidity or mortality. Three percent of those tested had elevated vitamin D levels above 36 ng/mL, which was associated with a 1.13 times elevated risk of coronary morbidity or death.

      "Supplementing the entire population may jeopardize those found within the upper-normal range, shifting them to levels that are beyond the range associated with the lowest morbidity rates," said Dror. "Although we could not assess the impact of Vitamin D supplementation, our results may suggest that such supplementation to increase vitamin D blood levels, with strict monitoring to avoid overload, may have a significant influence on public health. This hypothesis still needs to be assessed in intervention trials"

      Other researchers working on the study include: Shmuel Meir Giveon of Tel-Aviv University in Israel; and Moshe Hoshen, Ilan Feldhamer, Ran Balicer and Becca Feldman of the Clalit Research Institute, Clalit Health Services in Israel.

      Story Source:
      The above story is reprinted from materials provided by The Endocrine Society.
      Note: Materials may be edited for content and length. For further information, please contact the source cited above.

      Journal Reference:
      Y. Dror, S. Giveon, M. Hoshen, I. Feldhamer, R. Balicer, B. Feldman. Vitamin D Levels for Preventing Acute Coronary Syndrome and Mortality: Evidence of a Non-Linear Association. Journal of Clinical Endocrinology & Metabolism, 2013; DOI: 10.1210/jc.2013-1185

      Source: http://www.sciencedaily.com/releases...Supplements%29
      Comments 3 Comments
      1. ITW's Avatar
        ITW -

        1. Vitamin d supplementation is generally a good thing
        2. Preliminary results indicate risk/reward of vitamin d concentration levels in the blood
        3. Too little, bad. Too much, bad.

        ...how much vitamin d is needed to reach "desirable" levels, who knows? Will vary person to person for a whole host of reasons. Trial and error with some individual bloodwork could help...if you're that concerned...
      1. mcc23's Avatar
        mcc23 -
        Theres research indicating that there are benefits of higher Vit D serum levels (60-80 ng/ml). IIRC ~1000 IU's of D3 (the more bioavailable form) equates to maintaining about 10 ng/ml serum concentrations..I had vit d deficiency (16 ng/ml). I supp'd with ~8000 IU's of D3 and brought my levels up to 70 in about 8 weeks.
      1. tussmann's Avatar
        tussmann -
        Originally Posted by mcc23 View Post
        I had vit d deficiency (16 ng/ml). I supp'd with ~8000 IU's of D3 and brought my levels up to 70 in about 8 weeks.
        It may have helped you, but that's a costly and illogical amount to take. I take 5,000 iu every other day and feel great. Some weeks I skip it just to mix things up. In my experience, 5,000 just makes me feel less healthy in the scope of numerous health domains.
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