Do you take vitamin D? It is one of the most potent health enhancing vitamins known, and I’ve written about it extensively. If you don’t, perhaps the findings of this study will persuade you to reconsider doing so. I am very happy to share this study with you, as it is very instructive as to how to prevent cancer with adequate vitamin D intake (and blood levels). It was published in the journal Anticancer Research shares the amazing power vitamin D has to prevent one of the most feared diseases-cancer. It found that adults needs to take 4,000 – 8,000 International Units (Ius) of vitamin D everyday to prevent cancer, and other chronic diseases.
According to the lead researcher, Dr. Cedric Garland, “We found that daily intakes of vitamin D by adults in the range of 4,000 to 8,000 IU [international units] are needed to maintain blood levels of vitamin D metabolites in the range needed to reduce by about half the risk of several diseases — breast cancer, colon cancer, multiple sclerosis and type 1 diabetes,” said Dr. Cedric Garland.
Dr. Garland is the professor of family and preventive medicine at the UC San Diego Moores Cancer Center. He went on to say: “I was surprised to find that the intakes required to maintain vitamin D status for disease prevention were so high — much higher than the minimal intake of vitamin D of 400 IU/day that was needed to defeat rickets in the 20th century.”
“This paper provides a long awaited insight into a dose-response relationship between orally administered vitamin D3 and the resulting levels of serum 25(OH)D in over 3600 citizens. The results will allow new definition of high vitamin D dose safety and reduce concerns about toxicity. This is a landmark contribution in the vitamin D nutrition field!” – Anthony Norman, Distinguished Professor of Biochemistry & Biomedical Sciences, Emeritus, University of California Riverside
Study Highlights
This particular study involved over 3,000 volunteers who were taking vitamin D supplements. Researchers drew blood samples from them in order to determine their levels of 25-vitamin D (the common form circulating in the blood).
The results were shocking even to the study authors, revealing that 90 percent of those studied were deficient in vitamin D, falling below the 40 – 60 ng/ml range now considered healthy. (Most nutritionally-aware experts in the natural health world recommend higher ranges of 60 – 70 ng/ml, actually.)
• The study examined 3,667 people and their vitamin D intake habits.
• Vitamin D intake of 10,000 IU / day had no toxicity.
• For those severely deficient in vitamin D, each 1,000 IU / day of increased supplementation resulted in an increase of 10 ng / ml in vitamin D blood levels.
• For those with existing blood levels above 30 ng / ml, each 1,000 IU / day of increased supplementation resulted in an increase of 8 ng / ml in vitamin D blood levels.
• For those with existing blood levels above 50 ng / ml, each 1,000 IU / day of increased supplementation resulted in an increase of 5 ng / ml in vitamin D blood levels.
• In other words, vitamin D supplementation has a curve of diminishing returns. Those with existing high levels of vitamin D do not experience as much benefit from vitamin D supplements as those with low levels (which is roughly 90% of the population).
• Vitamin D sales have increased 600% since 2001 (due largely to the efforts of those in both the natural health and honest science communities who are telling the truth about vitamin D).
• Vitamin D is remarkably safe! From the conclusion of the study:
“Universal intake of up to 40,000 IU vitamin D per day is unlikely to result in vitamin D toxicity.”
“Now that the results of this study are in, it will become common for almost every adult to take 4000 IU/day,” said Dr. Garland. “This is comfortably under the 10,000 IU/day that the IOM Committee Report considers as the lower limit of risk, and the benefits are substantial.”
“Now is the time for virtually everyone to take more vitamin D to help prevent some major types of cancer, several other serious illnesses, and fractures,” said Robert P. Heaney, MD, of Creighton University, an experienced biomedical scientist.
Here’s the title and abstract of the original study:
Vitamin D Supplement Doses and Serum 25-Hydroxyvitamin D in the Range Associated with Cancer Prevention
CEDRIC F. GARLAND, CHRISTINE B. FRENCH, , LEO L. BAGGERLY, and ROBERT P. HEANEY,
“This paper provides a long awaited insight into a dose-response relationship between orally administered vitamin D3 and the resulting levels of serum 25(OH)D in over 3600 citizens. The results will allow new definition of high vitamin D dose safety and reduce concerns about toxicity. This is a landmark contribution in the vitamin D nutrition field!” – Anthony Norman, Distinguished Professor of Biochemistry & Biomedical Sciences, Emeritus, University of California Riverside
Abstract. Background: Studies indicate that intake of vitamin D in the range from 1,100 to 4,000 IU/d and a serum 25- hydroxyvitamin D concentration [25(OH)D] from 60-80 ng/ml may be needed to reduce cancer risk. Few community-based studies allow estimation of the dose–response relationship between oral intake of vitamin D and corresponding serum 25(OH)D in the range above 1,000 IU/d. Materials and Methods: A descriptive study of serum 25(OH)D concentration and self-reported vitamin D intake in a community-based cohort (n=3,667, mean age 51.3±13.4 y). Results: Serum 25(OH)D rose as a function of self-reported vitamin D supplement ingestion in a curvilinear fashion, with no intakes of 10,000 IU/d or lower producing 25(OH)D values above the lower-bound of the zone of potential toxicity (200 ng/ml). Unsupplemented all-source input was estimated at 3,300 IU/d. The supplemental dose ensuring that 97.5% of this population achieved a serum 25(OH)D of at least 40 ng/ml was 9,600 IU/d. Conclusion: Universal intake of up to 40,000 IU vitamin D per day is unlikely to result in vitamin D toxicity.
The recent increase in interest in vitamin D by the general public has fueled a better than 200% increase in sales of over-the-counter vitamin D preparations from 2008 to 2009, and a more than 6-fold increase since 2001 (1). Additionally, products with progressively increasing content of vitamin D have been introduced with similar rapidity. There seems to have been little precedent for a change of this magnitude and duration for other nutrients (e.g., vitamins C and E) that have enjoyed brief periods of popularity among the general public. There is essentially no information on how the public uses these products or on their impact on the vitamin D status of consumers.
GrassrootsHealth (GRH), a non-profit community service organization dedicated to promoting public awareness about vitamin D, has assembled a database that includes information on supplemental vitamin D intake by a self-selected population cohort, and links these intakes to measured values for serum 25(OH)D, various demographic variables, and a variety of health status measures. GRH data include values from many individuals with daily supplemental intakes in and above the ranges often used today for cancer prevention and co-therapy (2, 3).
This study used the GRH database to describe the relationship of measured vitamin D status to vitamin D supplementation, both as practiced by health conscious individuals and as related to cancer prevention.
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