You’ve heard about the wonderful vitamin D3 benefits, not just for bone health but for your immune system, cancer prevention, protection from depression, and more. But did you realize these benefits and many others don’t come unless there are adequate (or arguably, optimal) levels of vitamin D in your blood?

Who should have their vitamin D level checked?

Ideally, given all the known vitamin D3 benefits, everyone should have their vitamin D levels tested. The only way to know for sure how much vitamin D to take is to have the 25-hydroxyvitamin D blood test done regularly. Most docs are now clued in on Vitamin D and will run the test, but in most cases it still takes the initiative of the individual to ask his or her doctor to order the labwork. Your other option is to order it directly from places like Direct Labs for $59 or from Life Extension Foundation for $63. 

What’s the optimal vitamin D level?

That’s depends on which doctor you ask. No one knows for sure. Most vitamin D researchers, as well as organizations such as the US Endocrine Society and the International Osteoporosis Organization, say optimal levels are at least 30 ng/mL (75 nmol/L), although some, like Dr. Michael Holick of Boston University, say at least 40 ng/mL (100 nmol/L).[1,2] Most integrative doctors and naturopathic physicians shoot for higher optimal levels of at least 45 ng/mL (125 nmol/L), if not higher. While they may differ slightly on what constitutes optimal, they almost universally agree that most Americans’ levels are far too low for them to be receiving the full spectrum of vitamin D3 benefits. In their own words, here’s what some of the leading vitamin D researchers and integrative medicine experts have to say about optimum vitamin D levels:

 “I have all of my patients on enough vitamin D to maintain their blood levels between 40 and 100 ng/ml (100 to 250 nmol/L) which I believe to be both therapeutic and preventative for chronic diseases including common cancers.”  – Dr. Michael Holick, PhD, MD, Professor of Medicine, Physiology and Biophysics; Director of the General Clinical Research Unit; Director of the Bone Health Care Clinic at Boston University Medical Center.[3]

“The current ranges for “normal” are  10 to 55 ng/ml (25 to 137 nmol/L). These are fine if you want to prevent rickets — but NOT for optimal health. In that case, the range should be  40 to 65 ng/ml (100 to 160 nmol/L). In the future, we may raise this “optimal” level even higher.”  – Dr. Mark Hyman, MD, Chairman of the Institute for Functional Medicine.[4]

“My suggestion for the optimum level of vitamin D as measured by 25(OH)D3 is Caucasians, 50 to 70 ng/mL (125 to 175 nmol/L); Hispanics, 40 to 60 ng/mL (100 to 150 nmol/L); and African Americans, 32 to 48 ng/mL (80 to 120 nmol/L).”  – Dr. Joseph Pizzorno, ND, naturopathic physician and founding president of Bastyr University, editor-in-chief of Integrative Medicine: A Clinician’s Journal, Integrative Medicine and Wellness expert for WebMD.[5]

How much vitamin D do you need to take to maintain optimal blood levels?

It depends. The amount you would need to take in through food, sunlight, and supplements to get your blood levels optimal is highly variable. Everyone is different, but typically you will need to supplement at least 3,000 IU per day, and sometimes up to 5,000 IU per day to maintain blood levels around 50 ng/mL.[3] And yes, it is even better to get your Vitamin D from safe sun exposure. But that is exceedingly hard for most Americans to do on a regular basis. It requires 15 to 30 minutes each and every day of sun exposure with large portions of your body exposed. Going longer than that presents a skin cancer risk. So for most people with busy lives, that just is not practical.

If you are only supplementing smaller amounts (400-600 IU per day)  thinking you are fully protected, it is likely you are missing most of the amazing vitamin D3 benefits. You will likely be shocked when you get your labwork back showing you are Vitamin D deficient or borderline deficient.

A recommended supplement approach that will work for most people

Let’s not make this too complicated. For many people, an acceptable approach is to start supplementing with 2000 IU of Vitamin D3 each day and then run the 25-hydroxyvitamin D blood test two months later. Adjust your dosage based on your lab reading. If you are between 50 and 100 (ng/ml) you are at optimal levels according to most experts. You are getting the maximum benefit out of this super nutrient! If you are over 100, you will need to reduce your dosage some. Since there is quite a bit of individual variation between supplement dosage and blood levels, blood testing is essential. And if your labs show you are starting at a highly deficient state, work with your doctor who can help determine proper dosage to get those blood levels up more quickly than could be achieved on only 2000 IU per day.

Taking this one simple step – making sure your Vitamin D levels are optimal (around 50 ng/ml) could do more for your health than almost any other step. So don’t delay. For the full vitamin D3 benefits, find out your vitamin D level and start taking enough vitamin D to optimize yours!

[1] Vieth R. Why the minimum desirable serum 25-hydroxyvitamin D level should be 75 nmol/L (30 ng/ml). Best Pract Res Clin Endocrinol Metab. 2011 Aug;25(4):681-91.

[2] Holick MF. Vitamin D: extraskeletal health. Rheum Dis Clin North Am. 2012 Feb;38(1):141-60.

[3] Dr. Michael F. Holick on Vitamin D

[4] Vitamin D – Why You are Probably NOT Getting Enough by Dr. Mark Hyman

[5] Pizzorno J. The path ahead: what have we learned about vitamin D dosing? Int Med Clin J. 2010 Feb;9(1):8-12.