[it is a steroid hormone–a “seco-steroid”.]
 I assumed that adequate amounts are in the food and/or multivitamins. It is not. If it is a hormone that we manufacture, why should it be?
 I did not know how to interpret labs—vitamin D 25-OH vs vitamin D 1,25,dihydroxy.
 I thought Vitamin D was only important for bones.
 I thought that levels above 30 ng/ml were good enough.
 I thought I was dosing on the high end at 2000 I.U. /day. Nine months later, levels were often still below 30.
 For a while I used Vitamin D2 50,000 I.U. pills 1x/week (by Rx; Medicaid pays for it). It is from sea algae. It is too weak and does not stay in the body long. D3 is better. Virtually all OTC (over the counter) vitamin D is D3.

THE BOTTOM LINE:

There is no significant D in food or multivitamins.1
 It was mistakenly called a “vitamin” D in the 1920’s when it was found that 1 tsp of cod liver oil cured rickets in beagle dogs. But fish use the same hormone as we use to make bone and there is a small amount of it in the liver of fish—400 I.U. in a teaspoon of cod liver oil. (The biggest source is the skin of fish, where they store this hormone.) This is where the FDA got the idea that 400 I.U. /day is the right dose for adults—it IS the right dose for a 10 lb beagle or a 10 lb baby, but a 100 lb person needs about 10 times that much—about 4000 I.U. /day. A 200 lb person needs about 8000 I.U./day. [If adults take those doses, the level will usually be between 50 and 100 ng/ml after a few months.]

 It is a steroid hormone that we manufacture in about 5 steps.

 One step in the manufacture of D requires UVB light from the sun to hit the skin. (This is about the 3rd step of 5 steps). Because of school, office work, air conditioning and sun screen, NONE OF US MAKES ENOUGH D.

 The sun has to be above 45 degrees (i.e., your shadow has to be shorter than you) in order to make D. 99.5% of UVB light is blocked by the atmosphere, but if the sun is below 45 degrees, 100% is blocked.

 You can only make D for 20 to 30 minutes per day. To make a sufficient amount for the year, you need to be in a bathing suit in middle of the day a few times per week all summer.

 70 % of American children have a level below 30. [Pediatrics August, 2009] Even more adults are below that. Orthodox people and dark skinned people have particularly low levels.

 Low D is associated with a much higher risk of a number of cancers [including breast, ovarian, prostate and colon cancer] and autoimmune disorders [Type I Diabetes, Crohn’s Disease, ulcerative colitis, M.S., et al] [Journal Watch for General Medicine 12/31/09]

o The initiation of cancer may not be mutagenesis, but rather unregulated cell proliferation, which occurs when Vitamin D and calcium are in short supply. [Garland CF, Gorham ED, Mohr SB, Garland FC. Vitamin D for cancer prevention: globalperspective. Ann Epidemiol 2009. 19 (7):468-83.]

o One of the mechanisms by which Vitamin D is anti-proliferative is its involvement in the programmed cell death (apoptosis) of rapidly dividing cells. [Mathiasen, Ida Stenfeldt, Sergeev Igor N, et a, Calcium and Calpain as Key Mediators of Apoptosis-like DeathInduced by Vitamin D Compounds in Breast Cancer Cells, The Journal Of Biological Chemistry Vol. 277, No. 34, Issue of August 23, pp. 30738–30745, 2002]

o When cells divide too fast, which may mean they are an early cancer, there is a mechanism by which they commit suicide (apoptosis). Vitamin D is an essential part of that mechanism, which is part of the reason cancers are more common the farther one is from the equator. Women begin to have 50% less breast cancer below 35 degrees latitude (Atlanta). In Columbia, South America, there is 2/3 less breast cancer. Rural blacks in Africa have 80% less colon cancer than we do. However, blacks in the U.S. have more colon cancer, breast cancer and prostate cancer than whites because their Vitamin D levels are lower than that of whites–because of their dark skin.

 Many children are not growing to their full height because of low D.

 The only important level to measure is the storage form: vitamin D 25-OH (calcidiol).

 You can take your dose of D3 once a week or once a month, as D3 converts to calcidiol.

 The blood level for healthy bones is ≥ 32 ng/ml—The kidneys tightly regulate the production of the final, activated Vitamin D (Vitamin D 1,25,dihydroxy, or calcitriol) which is found in the blood—and which is necessary for maximum absorption of calcium, etc.

 The level of vitamin D 25-OH should actually be between 70ng/ml and 100 ng/ml. Vitamin D functions in two quite different areas. #1: What the kidneys produce is carried in the blood and regulates calcium. #2: The cells of the body themselves convert vitamin D 25-OH to the activated form, which stays in the cell, where it activates VDR’s [vitamin D receptors] on the nucleus. Another way of putting it: “Vitamin D functions in the body through both an endocrine mechanism (regulation of calcium absorption) and an autocrine mechanism (facilitation of gene expression). The former acts through circulating calcitriol, whereas the latter, which accounts for more than 80% of the metabolic utilization of the vitamin each day, produces, uses, and degrades calcitriol exclusively intracellularly.” [Heaney, Vitamin D in Health and Disease, Clin J Am Soc Nephrol 3: 1535-1541, 2008] There is a linear relationship between a higher vitamin D 25-OH level and decreasing morbidity of many illnesses – “at least up to serum levels of around 70 ng/mL.” [Journal Watch for General Medicine 12/31/09] The level of vitamin D 25-OH must be much higher than 32 ng/ml to allow a sufficient amount to enter the cells to be utilized.
 It is hard to overdose on D. When one takes a dose of D3, it is converted to the storage form (vitamin D 25-OH / calcidiol), which is inactive. There is about a thousand times more of the storage form of D in the blood than the activated form. Toxicity occurs if taking 50,000 I.U. per day for over 3-4 months. On lab slips 100 ng/ml is designated as the maximum largely because we cannot achieve a level above 100 ng/ml no matter how much sun exposure we have. Levels up to 200 ng/ml are actually safe [Heaney, Vitamin D in Health and Disease, Clin J Am Soc Nephrol 3: 1535-1541, 2008], so having occasional levels above 100 is not cause for alarm. The NIH website also states that levels up to 200 ng/ml are safe.

 For most adults the dose should take between 5000 and 10,000 I.U. /day. This usually puts their level somewhere between 50 and 100 ng/ml. The upper limit of tolerable safety is 10,000 I.U. /day. [Vitamin D supplementation, 25-hydroxyvitamin D concentrations, and safety, Reinhold Vieth, American Journal of Clinical Nutrition, Vol. 69, No. 5, 842-856, May 1999]

 I find it convenient to give 50,000 I.U. once a week—or 200,000 I.U. once a month. This gives an average of ~7000 I.U./day. In Canada there is a D3 shot available of 600,000 I.U. [15mg]. Thus the Canadian PMD does not have to convince every patient that this is a hormone, not a vitamin, and that they need to take another pill the rest of their life. With one shot there is a very good level for 3 months. In one study, even 12 months after that single shot, the patients’ levels were still above 20. [Medical Journal of Australia, July, 2005.]

 Prenatal vitamins are inadequate to maintain normal D levels in the mother. 10 to 56% of breastfed infants are deficient in D. [Megan, Implications of vitamin D deficiency in pregnancy and lactation, American J of Obstetrics and Gynecology, Volume 202, Issue 5, May 2010, Pages 429.e1-429.e9]

 Pregnant women should probably take 5000 to 6000 I.U. /day. In one study, only women taking 4000 I.U./day produced enough D in the breast milk for the baby. But it took 3 months for the infants’ levels to normalize! –because 4000 I.U./day is not a large dose and they started out low. [Assessment of dietary vitamin D requirements during pregnancy and lactation. Bruce W Hollis and Carol L Wagner. American Journal of Clinical Nutrition, Vol. 79, No. 5, 717-726]

 Obese people may need higher doses than other adults–in part, because D is stored in fat (as well as on carrier proteins, especially vitamin D-binding protein).

 For children the dose should be 1000 I.U. /day for every 25 lbs. [Cannell, Vieth et al, Epidemic influenza and vitamin D, Epidemiology and Infection (2006), 134:6:1129-1140] Chewable pills or liquid are available. I prefer liquid—usually at a concentration of 5000 I.U. per drop [e.g., Zahler’s 5000] or 2000 I.U. (Nature’s Answer “4000”). Zahler’s tastes like lime. Nature’s Answer has D in olive oil, & is especially easy to put on children’s food—e.g.,, potatoes.

 Elderly people do not make D3 efficiently as there is little DHC (pre-D3) in their skin.

FOR ADULTS weighing 150 lbs or more I like to use a 50,000 I.U. pill: one per week [or 4 pills once a month] (average of ~7000 I.U. /day)—I myself take 4 of these pills once a month. If someone weighs 100 to 125 lbs, they need just 3 pills per month. Zahler’s has 50,000 I.U. pills: $25 for #120 pills (it lasts one person 2.4 years—i.e., ~$10/year).

DOSES using “Nature’s Answer 4000”— called “4000” as company suggests daily dose is 2 drops = 4000 I.U.; this is right dose for someone weighing 100 lbs; someone weighing 200 lbs would need 4 drops per day. Each tiny drop of olive oil [not a dropper full!] contains 2000 I.U. A child needs 1000 I.U. /day for every 25 lbs. (This is approximately what an adult needs as well.) Thus a child needs 2000 I.U./day for every 50 lbs. Since each drop has 2000 I.U., then the dose would be 7 drops per week (or 30 drops once a month) for every 50 lbs.
10 lbs: 400 I.U./day; there are liquids for babies, but if you use the liquid for adults [2000 I.U. /drop] then give the baby 7×400 = 2800 = 1-2 drops per week—or 3 drops every other week.
15 lbs → needs 600 I.U./day = 4200 I.U. /week = 2 drops per week or 8 drops per month.
20 lbs → needs 800 I.U. /day = 5600 I.U. /wk = 3 drops once a week, or 12 drops once a month
25 lbs → 1000 I.U. x 30days = 30,000 I.U. once a month = ~ 15 drops once a month; or 3-4 drops per week.
50 lbs → 2000 x 30 days =60,000 I.U. /month =1 pill/ month of 50K —30 drops 1x/month or 7 drops per week
75 lbs   90,000 I.U./mo  45 drops per month, or ~10 drops/week [or 2 pills of 50,000 I.U. once a month]
100 lbs  120,000 I.U./mo  or 60 drops 1x/month— or 15 drops per week [or 3 pills of 50K I.U. once a month]

An easy way to remember for kids is one drop per day for every 50 lbs, so for A 50 LB CHILD THE DOSE IS 30 DROPS ONCE A MONTH
For 25 lbs it is half that: 15 drops/mo; for 75 lbs it is 45 drops and for 100 lbs it is 60 drops/mo.
For a 10 lb baby it is 6 drops per month.

LOW D IS ASSOCIATED WITH MORE RISK OF:
• Rickets in children [Rare now b/o fortification of milk with Vitamin D.]
• Cancer: especially colon, breast, ovarian, prostate, & non-Hodgkins lymphoma
• Hypertension Diabetes Fibromyalgia
• Heart disease – including congestive heart failure Osteoporosis osteomalacia
• Tuberculosis Periodontal disease Bacterial vaginosis (noted 2009)
• Autoimmune disorders [MS, rheumatoid arthritis, inflammatory bowel disease, et al]
• Cognitive impairment including memory loss and “foggy brain”
• Parkinson’s Disease Depression, especially in the winter preeclampsia
LOW D RAISES RISK OF THIS PROBLEM:

short stature. (Compliance is a big problem in medicine everywhere but here. I get very good compliance from children and adolescents by telling them that they will grow taller if they take it.)
WHAT D IS PROVEN TO PREVENT:

D supplements are PROVEN to decrease risk of:
• Type I diabetes in children Fractures in the elderly
• Multiple Sclerosis and Rheumatoid Arthritis High blood sugar
• Seasonal affective disorder Hypertension
• schizophrenia in men [Vitamin D supplementation during the first year of life and risk of schizophrenia: a Finnish birth cohort study, Schizophrenia Research, Volume 67, Issue 3, Pages 237-245]

GOOD WEBSITE FOR INFORMATION IS www.VitaminDcouncil.org