Humans are designed to require oxygen, water and sunshine. Of course, we need food, but few nutrients have as much impact on our health as does the vitamin D our skin makes when exposed to the sun. Studies continue to flood in and it is not surprising because every cell in the body has a receptor for vitamin D and it may control how as many as 100 of our genes behave. The evidence of the benefits from vitamin D is now overwhelming and it presents an exciting opportunity to improve our health with one easy step. If we aren’t getting sufficient sunshine, it seems we’d darned well better be supplementing vitamin D.
Another study proposes daily intake of 7,000 IU. Researchers believe early recommendations were flawed.
Please watch this short and very exciting Charles Gibson ABC News report about Vitamin D’s important role in reducing breast cancer, its spread and deaths from the disease. Click here.
Even mild insufficiency of vitamin D worsens surgical outcomes and pneumonia in children. LINK.
The media is quick to jump on recommendations to use sunscreen but they usually forget to mention vitamin D.
John Cannell, MD
Benefits. Inadequate Vitamin D levels are associated with arthritis, asthma, infections, depression, diabetes and dementia. Researchers also seem to agree that vitamin D helps prevent several cancers, heart disease, autoimmune conditions (e.g. multiple sclerosis), influenza, complications of the flu and in fact, death from all causes.1 It seems likely that in children, deficiency of Vitamin D may well be “THE [that emphasis was in the original quote] leading cause of cancer, type 1 diabetes, asthma, allergies, atopy [e.g. eczema], and possibly epidemic autism.2” The elderly should note that Vitamin D increases muscle strength and brain function while reducing chronic pain.
Two friends were surprised when horribly painful long standing breast lumps resolved after they got their Vitamin D levels into a healthier range. That’s an example of a benefit not yet specifically researched at length. (I did find one intervention study of almost 49,000 post-menopausal women.3 We shouldn’t be surprised at varied fringe benefits because most cells in the body have a receptor for Vitamin D and it appears to control 1,000 or more of our genes.4
Deficiency. Medical journals worldwide show that we’re not getting enough Vitamin D. Pregnant women and their breastfed babies are deficient.5,6 More than a third (36%) of healthy young adults are low.7 According to a German study of roughly 1,200 adults, 80% didn’t have blood levels supportive of bone health.8 A Stanford study says elderly folks aren’t getting enough and are therefore frailer.9 Perhaps as much as 80% of those with chronic illnesses are deficient. (Do you think there might be a connection?) Even people living in sunny US states can have low blood levels and those with dark skin are more at risk.
Certain mushrooms are one of the few foods that are a natural sources of vitamin D. Except for milk, very few food products are fortified with D and it uses vitamin D2 which is not as effective as natural vitamin D3.
Safety. Vitamin D toxicity is exceedingly rare because it is apparent that we were intended to spend some time daily in the sun without being coated in sunscreen. One reason for the relative safety is that over-the-counter Vitamin D supplements are in a storage form (Cholecalciferol). The body converts that form into the active form (Calcitriol) only as needed (unless there is a massive overload of the storage form or some disease process). French researchers gave adolescents single doses of 200,000 IU’s with no side effects observed.10 Dr. Cannell (founder of the non-profit Vitamin D Council) told me that Vitamin D at the first sign of an illness can scare it away but that most people don’t take enough. (He takes 200,000 IU for one day.)
Of course, you can overdo anything. Patients have become toxic from being prescribed overly aggressive treatments of the active form (not health food supplements). Accidental overdoses of the supplement form have been also been reported but mostly from errors in milk fortification or mislabeled supplements (choose brands carefully). Overdoses can result in too much calcium in the blood and in excess that causes mischief. A rare exception is that Sarcoidosis patients don’t tolerate vitamin D supplements very well.
The issue is more what you do consistently than individual doses and, as always in nutrition, balance is very important. Vitamin A and Vitamin K may compete a bit with D and they help protect us from overloading with D.11 Likewise vitamin D competes with them so it is important to be on vitamin K2 regularly (for that and other reasons) and a little vitamin A.
Testing. About the only way currently to know if we are getting enough D is to test blood levels. (The name of the specific blood test is with the 25-hydroxyvitamin D test —also called a 25(OH)D. The numbers are as ng/L, the most commonly reported. To convert to nmol/L, multiply by 2.5) Dr. Joseph Pizzorno, Editor in Chief of IMCJ (Integrative Medicine; A Clinician’s Journal) wrote 2 great articles reviewing of a number of studies and reported results of a corporate wellness program in which he participated. I’ve put his conclusions into the following chart of Vitamin D test result reference ranges:
32 (most experts believe this to still be dangerously low)
Outdoor workers average
Optimum (African American)
Safe upper limit
Lowest documented toxicity
Doctors and patients are often misled by the “normal ranges” printed on the report. Those standards are just too low (e.g. 35) according to most experts. (Labs don’t look for perfect bodies when establishing the norms—they average anyone well enough to be up walking around.)
Dosage. Studies show that doses of Vitamin D up to 10,000 IU per day are safe for extended periods. Some doctors use single boosts of 50,000 IU to play catch up with very low levels but, that is not a maintenance plan. But, until you know your blood levels the following generalizations are popular levels:
Kids – The government says 200 IU. Many docs recommend 400 IU, but Dr. Pizzorno points to a study showing that, after 2 years on that dose, most children were still not into an optimum range. A Japanese study had good results with flu prevention and asthma at 1,200 IU per day.12 Some children may need more especially if the only light their skin gets is from the glow of the video game display. Watch out for the liquid vitamin D drops because it’s easy to measure incorrectly.
Adolescents – A daily maintenance dose of 2,000 IU seems prudent.13
Adults – 5,000 IU daily seems safe and may be a good level for the average adult who doesn’t spend time a lot of time in the sun. More recent studies lean toward the 8,000 level and up.
Upper limits of daily dose – A routine dose of 10,000 IU/day seems to cause no harm.14 (During the summer in the midday sun in a bathing suit, you’d make 10,000 IU in a few minutes.) If a person’s blood levels are very low and especially if they live in a northern climate, they may benefit from a “loading dose” of up to 20,000 IU per day for a short time.
I’m quite encouraged that so many doctors now routinely test their patients’ vitamin D levels. However, many are still afraid of some theoretical toxicity and don’t give doses adequate to bring the blood levels into a healthy range where the patient is better protected. The odds of risk are really much more from being too low than being too high. It’s your health and the doc works for you, so push a little if you need to.
African-American Healthy: What You Need to Know to Protect Your Health by Richard W. Walker, MD
Athlete’s Edge: Faster, Quicker, Stronger with Vitamin D by John Cannell, MD
Copyright 2010-2016 by Martie Whittekin, CCN
1 Melamed ML, Michos ED, Post W, Astor B. “25-hydroxyvitamin D levels and the risk of mortality in the general population.” Arch Intern Med. 2008 Aug 11;168(15):1629-37.
2 J. Pizzorno. “Vitamin D: Still Learning About Dosing”, IMCJ, Vol. 9, No 3, June/July 2010.
3 Rohan TE, Negassa A, Caan B, Chlebowski RT, Curb JD, Ginsberg M, Lane DS, Neuhouser ML, Shikany JM, Wassertheil-Smoller S, Page DL. “Low-fat dietary pattern and risk of benign proliferative breast disease: a randomized, controlled dietary modification trial.” Cancer Prev Res (Phila Pa). 2008 Sep;1(4):275-84.
4 VitaminDCouncil.org April 2010 Newsletter
5 Yu CK, Sykes L, Sethi M, Teoh TG, Robinson S. “Vitamin D deficiency and supplementation during pregnancy.” Clin Endocrinol (Oxf). 2009 May;70(5):685-90. Epub 2008 Sep 2.
6 Balasubramanian S, Ganesh R. “Vitamin D deficiency in exclusively breast-fed infants.”
Indian J Med Res. 2008 Mar;127(3):250-5.
7 J. Pizzorno. “What have we learned about Vitamin D dosing”, IMCJ, Vol. 9, No 1, Feb/Mar 2010.
8 Leidig-Bruckner G, Roth HJ, Bruckner T, Lorenz A, Raue F, Frank-Raue K. “Are commonly recommended dosages for vitamin D supplementation too low? Vitamin D status and effects of supplementation on serum 25-hydroxyvitamin D levels-an observational study during clinical practice conditions.” Osteoporos Int. 2010 Jun 17. [Epub ahead of print]
9 Wilhelm-Leen ER, Hall YN, Deboer IH, Chertow GM. “Vitamin D deficiency and frailty in older Americans.” J Intern Med. 2010 Apr 28. [Epub ahead of print].
10 Mallet E, Philippe F, Castanet M, Basuyau JP. [“Administration of a single winter oral dose of 200,000 IU of vitamin D(3) in adolescents in Normandy: Evaluation of the safety and vitamin D status obtained.”] Arch Pediatr. 2010 Jun 7. [Epub ahead of print] [Article in French] Abstract in English.
11 J. Pizzorno. “Vitamin D: Still Learning About Dosing”, IMCJ, Vol. 9, No 3, June/July 2010.
12 Urashima M, Segawa T, Okazaki M, Kurihara M, Wada Y, Ida H. “Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren.” Am J Clin Nutr. 2010 May;91(5):1255-60.
13 Maalouf J, Nabulsi M, Vieth R, Kimball S, El-Rassi R, Mahfoud Z, El-Hajj Fuleihan G. “Short- and long-term safety of weekly high-dose vitamin D3 supplementation in school children.” J Clin Endocrinol Metab. 2008 Jul;93(7):2693-701.
14 Vieth R. “Vitamin D toxicity, policy, and science.” J Bone Miner Res. 2007 Dec;22 Suppl 2:V64-8.