Vitamin D information - dosage, safety with long term use

A low vitamin D intake of about 200 to 400 international units (IU) -- the recommended daily dosage in the United States and Canada is about 200 IU for adults - is enough to help prevent some symptoms of deficiency, such as bone-related problems. But higher vitamin D levels may provide benefits for the prevention of cancer and other diseases. The ideal amount of this hormone vitamin to take on a daily is currently disputed, but it appears that a minimum of 400 units is helpful. We suggest avoiding tablets or capsules that are more than 1000 units until long term studies are published regarding the safety of this vitamin.
   Vitamin D deficiency may be a common but unrecognized problem among U.S. adolescents. Researchers found that among 11- to 18-year-olds living in Boston, nearly one-quarter were deficient in vitamin D, a nutrient that aids in calcium absorption and is vital for healthy bone development. If you wish to buy
Vitamin D discount or if you would like to buy a
Calcium supplement.

The problem is preventable with an adequate diet and time outdoors. The body naturally synthesizes vitamin D when the skin is exposed to the sun, and milk and certain other foods, including many breakfast cereals, are fortified with the vitamin. But U.S. children increasingly fill up on soft drinks at the expense of milk, and spend more time in front of the TV or computer than outdoors.

Vitamin D information regarding recommended daily dosage
The recommended daily intake of vitamin D is 200 iu for adults younger than 50 years and 600 iu for those older than 70 years. Vitamin D supplementation is especially important in elderly persons because skin synthesis and absorption of vitamin D may be impaired.

Sources of vitamin D
Vitamin D also is found in fortified milk and oily fish, but it’s hard to get enough just from diet. Sunlight is the biggest source of vitamin D, which is needed for strong bones. Studies have linked high levels of vitamin D in the blood to lower risks of a variety of cancers.

Which form of vitamin D to use
Vitamin D2 or vitamin D3?
Rev Med Interne. 2008 April. Mistretta VI, Delanaye P, Chapelle JP, Souberbielle JC, Cavalier E. Service de chimie médicale, CHU de Liège, université de Liège, domaine du Sart-Tilman, 4000 Liège, Belgique.
Nearly one billion people around the world are deficient in vitamin D and need to be supplemented. Vitamin D is available in medicines and fortified foods. It is available in two forms: vitamin D2 ( ergocalciferol ) and vitamin D3 ( cholecalciferol ). Several studies have showed that serum level of 25(OH)D is increased more effectively with vitamin D3 than vitamin D2. Vitamin D2 has shorter plasma half-life and a lower affinity for the vitamin D binding protein, the hepatic vitamin D hydroxylase and the vitamin D receptor. Vitamin D2 should not be regarded anymore as suitable for supplementation or fortification. Currently though, it is still the most used in some countries such as Portugal and Australia.

Pancreatic cancer benefit
Taking a Vitamin D supplement may reduce the risk of fatal pancreatic cancer. Vitamin D has shown benefit in preventing and treating several types of cancer. Regions with greater sunlight exposure have lower incidence and mortality for prostate, breast, and colon cancers. Harvard University researchers reviewed data and found that people who took Vitamin D, 400 IU a day had a lower risk of pancreatic cancer. Those who took doses of less than 150 IU per day had a 22 percent reduced risk of cancer. Taking more than 400 IU a day did not reduce the risk any further.

Vitamin D and telomere length
Vitamin D is a potent inhibitor of inflammation and reduces turnover rate of leukocytes (white blood cells). Leukocyte telomere length is a predictor of aging-related disease and decreases with each cell cycle and increased inflammation. Higher body vitamin D concentrations, which can be achieved through sunlight exposure, diet, and vitamin D supplements, are associated with longer leukocyte telomere length, which indicates vitamin D has an influence on aging and age-related diseases.

Vitamin D deficiency
Vitamin D deficiency is widespread in many locations in the USA. Vitamin D deficiency is particularly prevalent in the elderly and may cause osteoporosis, increased risk of cancer, and altered glucose and lipid metabolism. Increasing evidence strongly supports the benefits of vitamin D supplementation and also reveals that present recommendations are inadequate, especially for older individuals. Physicians should consider prescribing vitamin D supplements at least 400 to 600 international units (IU) per day - to all elderly patients. Oral vitamin D supplements at that level is inexpensive, safe, and effective, and has great potential to improve the quality of life of the elderly.

Vitamin D and atorvastatin statin drug
It appears that taking a vitamin D supplement reduces atorvastatin levels but also reduces cholesterol levels, which is a good thing. The effects of long term use of vitamin D supplements along with statin drugs is not clear.

Effects of Vitamin D Supplementation in Atorvastatin-Treated Patients: A New Drug Interaction With an Unexpected Consequence.
Clin Pharmacol Ther. 2008 August. Schwartz J. [1] 1The Jewish Home of San Francisco, Department of Research, San Francisco, California, USA [2] 2Division of Clinical Pharmacology, Department of Medicine, University of California, San Francisco, California, USA.
The objective of this study was to determine vitamin D supplementation effects on concentrations of atorvastatin and cholesterol in patients. Sixteen patients (8 men, 8 women; 10 Caucasians, 4 African Americans, 1 Hispanic, 1 Asian), aged 63 +/- 11 years on atorvastatin (45 +/- 33 mg/day) were studied with and without supplemental vitamin D (800 IU/day for 6 weeks). Levels of vitamin D (1,25-dihydroxy(OH) and 25 OH-metabolites), atorvastatin (parent, OH-acid metabolites, lactone, and lactone metabolites), and cholesterol (total, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol) were determined at 0.5, 3, and 10 h after dosing. Vitamin D supplementation increased vitamin D-25-OH metabolites without increased 1,25-dihydroxy vitamin D. Atorvastatin and active metabolite concentrations as well as LDL-cholesterol and total-cholesterol levels were lower during vitamin D supplementation. The conclusion of the study is that vitamin D supplementation lowers atorvastatin and active metabolite concentrations yet has synergistic effects on cholesterol concentrations.

Vitamin D summary
During the past few decades, major advances have reported the importance of vitamin D on the bone metabolism and other health benefits. Adequate vitamin D reduces the risk of non vertebral fractures, improves neuromuscular function. A possible role of vitamin D has been implicated in the reduction of mortality, of non-skin cancers, of the risk of infections, of inflammatory diseases, of cardiovascular diseases and maybe osteoarthritis. Serum vitamin D level is influenced by several factors (skin vitamin D production, fat mass, dietary sources, UV-B exposure, latitude).

Scientific Experts Call For Increased Vitamin D UL
2007-01-22 - Council for Responsible Nutrition
Newly-Published Risk Assessment Supports Safety of Higher Intakes Needed to Reap Additional Health Benefits—
WASHINGTON, D.C., January 22, 2007 — Four nutrition experts, including two Council for Responsible Nutrition scientists and two of the world’s pre-eminent vitamin D researchers, are urging the Food and Nutrition Board (FNB) to raise the vitamin D Tolerable Upper Intake Level (UL) five-fold, based on a safety evaluation of the latest scientific research that shows this vitamin to be safe at intake levels much higher than its current UL. John Hathcock, Ph.D., and Andrew Shao, Ph.D., both of CRN, and Reinhold Vieth, Ph.D., of Mount Sinai Hospital, Toronto, and Robert Heaney, M.D., of Creighton University, have co-authored a vitamin D risk assessment using the FNB method and published in the American Journal of Clinical Nutrition (AJCN) this month (Jan 2007; 85: 6-18). The paper concludes the safety profile of vitamin D should safely permit raising the UL for vitamin D to 250 µg (10,000 IU) per day from the current UL of 50 µg (2,000 IU) per day. “The UL established by the FNB in 1997 for vitamin D is outdated. It is not based on current evidence and is viewed by many in the scientific community as being too restrictive—limiting research, commercial development, and optimization of nutritional policy,” noted Dr. Vieth. “An ample collection of human clinical trial data published since the 1997 recommendation was made supports a significantly higher UL.” Although many experts have been calling for a revision of the vitamin D UL in recent years, the AJCN risk assessment review article is the first to provide a quantitative basis and recommendation for an actual revised UL value. For the vitamin D risk assessment, Drs. Hathcock, Shao, Vieth and Heaney considered 21 relevant, well-designed human clinical trials using a vitamin D dose substantially above the current range of adequate intake (AI) levels of between 5 µg (200 IU) and 15 ?g (600 IU) per day for different populations. Collectively, the absence of toxicity in these trials conducted in healthy adults that used a vitamin D dose 250 µg (10,000 IU vitamin D3) per day supports the confident selection of this value as the UL. Dr. Hathcock noted that the term UL does not suggest that nutrient intakes above the level identified are unsafe, nor does it constitute a recommended intake. The UL simply identifies a level of daily intake at which there is no known toxicity and at which there is sufficient evidence of safety for the nutrient.
   The Council for Responsible Nutrition (CRN), founded in 1973, is a Washington, D.C.-based trade association representing dietary supplement industry ingredient suppliers and manufacturers. CRN members voluntarily adhere to a strong code of ethics, comply with dosage limits and manufacture dietary supplements to high quality standards under good manufacturing practices.

Q. I heard a program that said there's a "handshake" between vitamins A and D; I'm not clear on what was meant but I took the meaning to be that more vitamin A should be taken if one takes more vitamin D. Does this make any sense, and if so, can you clarify what might be meant?
   A. It is not clear to us what a "handshake" between vitamins A and D means. These two vitamins are not too closely related and it is best not to take too high a dosage of each for prolonged periods.

Q. I've spent too much time searching the web with no results on how long after taking a vitamin D supplement should someone wait in order for it to be in the blood in ample supply before sunning for maximum benefit. Is there an average time period? Say an hour... 3 hours, etc?
   A. We are not aware of any need to sun after taking a vitamin D supplement. The vitamin D supplement already provides the final molecule needed for its effects, there is no need to expose oneself to sunlight for this purpose. Sun exposure would help the body form more vitamin D, but we don't see how it would influence the vitamin D supplement already ingested.

Q. I am taking an erectile dysfunction herbal formula, would a vitamin D supplement product interfere with sexual herbs?
   A. We don't see any reason why vitamin E supplements would interfere with the use of herbs.

Q. I take a
yohimbe bark supplement twice a week, will this influence a vitamin D dosage of 400 units a day, any information would be helpful.
   A. We don't think there would be any interaction.

I have been tested as very low in vitamin D, but whenever I take it I get extremely depressed, even with small doses. I wondered if there is an explanation for this, or a way I can take it without this effect.
    We have not had this side effect reported to us before on low dosages.

There is some debate about the most constantly absorbed form to take - powdered or gel cap and it appears that the gel caps do make a difference according to Dr. William Davis.
    We have not seen any comparison studies as of August 2009.