"The design and logic of the study were completely wrong. As a friend once said, "The well meaning are often ill doing."
Imagine a study that gave people a year's worth of vitamin A, or iron (both are nutrients that are stored in the body like vitamin D) in one dose. The vitamin A would cause immediate liver failure and death. In fact, the way the Inuit used to kill explorers in the Arctic was to feed them polar bear liver, which gave them toxic doses of vitamin A. A year's worth of iron in one dose would cause severe intestinal problems and iron poisoning.
Biologically we understand why a single high dose of vitamin D may cause problems. A single high dose induces protective mechanisms that reduce the available vitamin D by increasing the activity of enzymes that cause the vitamin D to be broken down by the body. (xi) The body requires a balance of the right nutrients at the right dose at the right time. No one would eat a year's worth of anything in one day and expect it to be healthy.
The question that remains is: How can you get the right amounts of vitamin D for you?
6 Tips for Getting the Right Amount of Vitamin D
Unless you're spending all your time at the beach, eating 30 ounces of wild salmon a day, or downing 10 tablespoons of cod liver oil a day, supplementing with vitamin D is essential. The exact amount needed to get your blood levels to the optimal range (100 to160 nmol/L) will vary depending on your age, how far north you live, how much time you spend in the sun and even the time of the year. But once you reach optimal levels, you'll be amazed at the results.
For example, one study found that vitamin D supplementation could reduce the risk of getting type 1 diabetes by 80 percent.(xii
) In the Nurses' Health Study (a study of more than 130,000 nurses over 3 decades), vitamin D supplementation reduced the risk of multiple sclerosis by 40 percent.(xiii
I've seen many patients with chronic muscle aches and pains and fibromyalgia who are vitamin D deficient--a phenomenon that's been documented in studies. Their symptoms improve when they are treated with vitamin D. A Danish study of Arabic women with fibromyalgia found significant vitamin D deficiency and recovery with replacement of vitamin D.(xv
Finally, vitamin D has been shown to help prevent and treat osteoporosis. In fact, it's even more important than calcium. That's because your body needs vitamin D to be able to properly absorb calcium. Without adequate levels of vitamin D, the intestine absorbs only 10 to 15 percent of dietary calcium. Research shows that the bone-protective benefits of vitamin D keep increasing with the dose.
So here is my advice for getting optimal levels of vitamin D:
1. Get tested for 25 OH vitamin D.
The current ranges for "normal" are 25 to 137 nmol/L or 10 to 55 ng/ml. These are fine if you want to prevent rickets -- but NOT for optimal health. In that case, the range should be 100 to 160 nmol/L or 40 to 65 ng/ml. In the future, we may raise this "optimal" level even higher.
2. Take the right type of vitamin D.
The only active form of vitamin D is vitamin D3 (cholecalciferol). Look for this type. Many vitamins and prescriptions of vitamin D have vitamin D2 -- which is not biologically active.
3. Take the right amount of vitamin D.
If you have a deficiency, you should correct it with 5,000 to 10,000 IU of vitamin D3 a day for three months--but only under a doctor's supervision. For maintenance, take 2,000 to 4,000 IU a day of vitamin D3. Some people may need higher doses over the long run to maintain optimal levels because of differences in vitamin D receptors, living in northern latitudes, indoor living, or skin color.
4. Monitor your vitamin D status until you are in the optimal range.
If you are taking high doses (10,000 IU a day) your doctor must also check your calcium, phosphorous and parathyroid hormone levels every three months.
5. Remember that it takes up to 6 to 10 months to "fill up the tank" for vitamin D
if you're deficient. Once this occurs, you can lower the dose to the maintenance dose of 2,000 to 4,000 Units a day.
6. Try to eat dietary sources of vitamin D.
• Fish liver oils, such as cod liver oil. 1 TBSP (15 ml) = 1,360 IU of vitamin D
• Cooked wild salmon. 3.5 oz = 360 IU of vitamin D
• Cooked mackerel. 3.5 oz = 345 IU of vitamin D
• Sardines, canned in oil, drained. 1.75 oz = 250 IU of vitamin D
• One whole egg = 20 IU of vitamin D
• Porcini mushrooms 4 ounces = 400 IU of vitamin D
You can see now why I feel so passionately about vitamin D. This vitamin is critical for good health
. So start aiming for optimal levels--and watch how your health improves.
Now I'd like to hear from you ...
Have you experienced any symptoms of vitamin D deficiency?
Do you think you are not getting enough sun?
Have you experienced any health benefits from getting more sun or correcting a vitamin D deficiency you may have had?
Please let me know your thoughts by leaving a comment below.
To your good health,
Mark Hyman, M.D."
(i) Wilkins C.H., Sheline Y.I., Roe C.M., et al. (2006) Vitamin D deficiency is associated with low mood and worse cognitive performance in older adults. American Journal of Geriatric Psychiatry. 14(12):1032-1040.
(ii) Holick, M. (2004). Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers and cardiovascular disease [published online]. American Journal of Clinical Nutrition. (80)suppl:1678S-88S.
(iii) Kumar, J., Muntner, P., Kaskel, F., et al. (2009). Prevalence and associations of 25-hydroxyvitamin D deficiency in US children: NHANES 2001-2004. Pediatrics. 124(3):e362-e370.
(iv) Grant, W. (2009). In defense of the sun: An estimate of changes in mortality rates in the United States if mean serum 25-hydroxyvitamin D levels were raised to 45 ng/mL by solar ultraviolet-B irradiance. Dermato-Endocrinology. (1)4: 207-214.
(v) Laaksi I., Ruohola J.P., Tuohimaa P. et al. (2007). An association of serum vitamin D concentrations < 40 nmol/L with acute respiratory tract infection in young Finnish men. American Journal of Clinical Nutrition. 86(3):714-717.
(vi) Urashima, M., Segawa, T., Okazaki, M., et al. (2010). Randomized trial of vitamin D supplementation to prevent seasonal influenza A in schoolchildren. American Journal of Clinical Nutriton. 91(5)1255-1260.
(vii) Atherton, K., Berry, D.J., Parsons, T., et al. (2009). Vitamin D and chronic widespread pain in a white middle-aged British population: Evidence from a cross-sectional population survey. Annals of the Rheumatic Disease. 68(6):817¬-822.
(viii) Holick, M. (2006). Vitamin D deficiency. New England Journal of Medicine. 357(3):266.281. Review.
(ix) Heaney, R.P., Davies, K.M., Chen, T.C., et al. (2003). Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol. American Journal of Clinical Nutrition. 77(1):204-210.
(x) Sanders, K.M., Stuart, A.L., Williamson, E.J., et al. (2010) Annual high-dose oral vitamin D and falls and fractures in older women: A randomized controlled trial. Journal of the American Medical Association. 303(1
(xi) Dawson-Hughes, B., Harris, S.S. (2010) High-dose vitamin D supplementation: Too much of a good thing? Journal of the American Medical Association. 303(1
(xii) Hyppönen, E., Läärä, E., Reunanen, A., et al. (2001). Intake of vitamin D and risk of type 1 diabetes. A birth-cohort study. Lancet. 358(9292)1500-1503.
(xiii) Munger, K.L., Zhang, M., O'Reilly, E. (2004). Vitamin D intake and incidence of multiple sclerosis. Neurology. 62:60-65.
(xiv) Munger, K.L., Levin, L., Hollis, B., et al. (2006). Serum 25-hydroxyvitamin D levels and risk of multiple sclerosis. Journal of the American Medical Association. 296(23):2832-2838.
(xv) Glerup, H., Mikkelsen, K., Hass, E., et al. (2000). Commonly recommended daily intake of vitamin D is not sufficient if sunlight exposure is limited. Journal of Internal Medicine. 247(2):260-268.
Mark Hyman, M.D. practicing physician and founder of The UltraWellness Center is a pioneer in functional medicine. Dr. Hyman is now sharing the 7 ways to tap into your body's natural ability to heal itself. You can follow him on Twitter, connect with him on LinkedIn, watch his videos on Youtube and become a fan on Facebook.