Hoe vaak en hoeveel vitamine D?*
Zestien gerenommeerde deskundigen uit Amerika en Canada hebben in een gezamelijke verklaring de huidige aanbevolen dagelijkse hoeveelheden voor
vitamine D als wetenschappelijk niet langer verdedigbaar bestempeld. Kinderen zouden bijv. dagelijks 2 mcg vitamine D per kilo lichaamsgewicht moeten nemen en bij ziekte
zelfs nog duidelijk meer.
Uit een kleine studie blijkt dat het mogelijk is vitamine D niet dagelijks maar per week of per maand te nemen. 48 vrouwen van gemiddeld 80 jaar kregen of dagelijks 37,5 mcg of wekelijks 262,5 mcg of maandelijks 1.125 mcg. Na twee maanden bleken de bloedwaarden vitamine D vergelijkbare waarden te hebben van gemiddeld 33 ng/ml.
Vitamin D
Using the strongest language published to date, sixteen well-known experts, including professors Walter Willett and Ed Giovannucci of Harvard, Dr. John Hathcock of the Council for Responsible Nutrition, and Professor Reinhold Vieth of the University of Toronto condemned the current (1997) Food and Nutrition Board (FNB) recommendations for vitamin D, stating "The 1997 FNB recommendations offend the most basic principles of pharmacology and toxicology, leading us to conclude that the current official guidelines and limitations for vitamin D intakes are scientifically
indefensible."
The above experts recommended healthy children take 1,000 IU/day of vitamin D for every 25 pounds of body weight. In some cases this is more than ten times current recommendations for children by the government and professional organizations.
Finally, the group recommended that "children with chronic illness such as autism, diabetes, and/or frequent infections" may need to take even more vitamin D, "doses adequate to maintain their 25-hydroxy vitamin D in the mid normal of the reference range (65 ng/ml) - and should be so supplemented year around." Less than one percent of American children currently have such levels.
John J. Cannell, MD; Reinhold Vieth, MS, PhD; Walter Willett, MD, DrPH; Michael Zasloff, MD, PhD; John N. Hathcock, MSc, PhD; John H. White, PhD; Sherry A. Tanumihardjo, MSc, PhD; D. Enette Larson-Meyer, PhD; Heike A. Bischoff-Ferrari, MD, MPH; Christel J. Lamberg-Allardt, PhD; Joan M. Lappe, PhD, RN; Anthony W. Norman, PhD; Armin Zittermann, PhD; Susan J. Whiting, MSc, PhD; William B. Grant, PhD; Bruce W. Hollis, PhD; Edward Giovannucci, MD
Annals of Otology, Rhinology & Laryngology - 2008;117:864-870
Source
John Cannell, MD
http://www.vitamindcouncil.org/
Monthly vitamin D supplement safe and effective
A single high dose of vitamin D given every four weeks is as safe as smaller daily or weekly doses, and is as effective in achieving adequate circulating levels of the vitamin, according to a study conducted in Israel.
To prevent fractures in older patients, the level of the active metabolite of vitamin D -- that is, 25-hydroxyvitamin D -- should be higher than 30 nanograms per milliliter, Dr. Sophia Ish-Shalom and colleagues explain in the Journal of Clinical Endocrinology and Metabolism.
While monthly dosing could make it easier for people to stick to regular vitamin D supplementation, the researchers were concerned that a large dose might lead to a spike in calcium levels in the blood -- which could cause problems.
To check, the team conducted a clinical trial with 48 women, 81 years of age on average, who had undergone surgery to repair a hip fracture, to compare three dosing regimens of vitamin D supplementation: 1,500 International Units once daily, 10,500 IU once weekly, or 45,000 IU every 28 days.
After two months, blood levels of 25-hydroxyvitamin D were similar at 33.2, 29.2, and 37.1 nanograms per milliliter, respectively.
A single instance of excessive blood levels of calcium occurred, in a patient assigned to the daily supplement.
Ish-Shalom, at Rambam Medical Center in Haifa, Israel, and associates conclude that "the choice of dose frequency can be based on whichever approach will optimize an individual's adherence" to regular vitamin D supplementation.
SOURCE: Journal of Clinical Endocrinology and Metabolism (Januari
2009)
