Everyone knows that vitamin D is needed for strong bones, but what most don’t know is that it’s one of those amazing substances that changes how our genes operate in all of our tissues and organs… even the brain. In the case of bone, vitamin D causes the genes in intestinal cells to produce more of a calcium binding protein that helps pull more calcium into the body. Hence, people with adequate vitamin D levels, for example, will absorb 30-80% of dietary calcium, while people that are deficient will only absorb 10-15% of their calcium.
But that’s just the tip of the iceberg when it comes to its benefits. Adequate vitamin D levels are also associated with proper metabolism, healing the intestinal track, balancing microbes in the gut, reducing inflammation, reducing cancer and cardiovascular disease risk…even reducing pain. In fact, there have been some interesting studies involving adults with non-specific musculoskeletal pain who presented with abnormally low vitamin D levels (e.g., 9-12ng/ml). Not only did those particular individuals require 1.9x the dose of opiods for pain relief for 1.6x longer than their counterparts with healthy vitamin D levels, but after supplementation of 5,000-10,000IU of vitamin D3 a day for 3 months, 95% of patients resolved their pain. Hence, the authors concluded “…vitamin D inadequacy may represent an under-recognized source of nociception and impaired neuromuscular functioning among patients with chronic pain.”
Healthy Vitamin D Levels
With so many good things that come from vitamin D, you’d think there’d be a standard for what’s considered a healthy blood level, but there’s not. Here’s guidance from three reputable sources:
Optimal Blood Level of Vitamin D Source
40-80 ng/ml Vitamin D Council 
30-50 ng/ml Endocrine Society 
50-100 ng/ml Dr. Mercola 
It’s a pretty big range…right? According to most physicians, 20-50 ng/ml is considered adequate for healthy people, whereas <12 ng/ml indicates a deficiency. However, the Vitamin D Council has recently come out saying that levels of 60-80 ng/ml reduces the risks of cancer and many diseases including cognitive impairment. They also say individuals with greater than 70 ng/ml have increased energy production, improved metabolic rate and tissue repair and recover faster from strenuous exercise! Only levels >100 are considered an excess.
Factors That Make It Difficult to Raise Vitamin D Levels
So, you might be thinking…I get it. Vitamin D is critical for good health, so I’ll take a supplement and be done with it. Well, there’s another nuisance to this and that’s dosage versus absorption. Nowadays, many doctors tell adults they can raise levels by spending more time outdoors, eating more foods with vitamin d (e.g., salmon, sardines, eggs, and shitake mushrooms) or taking 5000 IUs a day until they reach a blood level of 40 ng/ml (the bare minimum). But for many this isn’t enough, and here’s why.
Bottom line, some people will need much higher (e.g., 8000-10,000 IUs) of vitamin D to achieve optimum levels.
Importance of Regular Testing
How do you figure out what’s the right dose for you? You really can’t without testing. In fact, experts like Dr. Alan Christianson and advanced functional medicine practitioner Tom Malterre recommend testing 2-3x a year…at the peak of summer (for your max level), middle of winter (for your storage ability) and end of spring (for your low point.) (Note: The preferred test is called “25-hydroxy vitamin D” or “25 OH-Vitamin D”.) That’s the best way to get a complete picture of how well your body is managing its vitamin D levels. Then, depending on your age, weight and lifestyle, you can discuss with your doctor what the optimal level is for you.
Interestingly, when I had my levels checked last summer, they were close to 90 ng/ml, but I was also taking a vitamin d supplement at the time. Now, my levels are at 78 ng/ml (without supplementation). After talking with my doctor, she and I agreed that 70-80 ng/ml range is good for me as it’s probably aiding with immunity and exercise recovery. The fact that they’ve gone down suggests that my body produces less vitamin D during the winter which is common for many adults. So, next year she suggested I re-start my regimen of 5,000 IUs during the winter months and then re-test again in summer.
What Type of Vitamin D Works Best
Vitamin D3 is the preferred form, and it’s best absorbed when taken with food. Likewise, if you’re already supplementing, make sure you’re also getting enough vitamin K2 as the combination of vitamin D3 and K2 work together to strengthen your bones and improve overall cardiovascular function. Just think of vitamins D3/K2 as the driver and calcium as the bus. With adequate levels of vitamin D3/K2, they’ll help drive calcium to the bones and in parallel remove calcium from your arteries. It’s a win-win.
Anyway, I hope this information helps you figure out the right amount of vitamin D that your body needs. As always, seek strength!
 Prevalance and Clinical Correlates of Vitamin D Inadequacy Among Patients with Chronic Pain, Pain Medicine. Nov, 2008. Michael K. Turner, MD,W. Michael Hooten, MD, John E. Schmidt, PhD, Jennifer L. Kerkvliet, MA, Cynthia O. Townsend, PhD and Barbara K Bruce. Pain Medicine, November, 2008.
 Vitamin D Council, “I Tested My Vitamin D Level. What Do My Results Mean?,” July 30, 2010, http://www.vitamindcouncil.org/further-topics/i-tested-my-vitamin-d-level-what-do-my-results-mean/.
 Holick MF, et al., “Evaluation, Treatment, and Prevention of Vitamin D Deficiency: An Endocrine Society Clinical Practice Guideline,” Journal of Clinical Endocrinology & Metabolism, July 2011.
 Mercola, J, “New Analysis Claims Vitamin D Supplements Are Useless - Here’s Why It’s Wrong,” February 17, 2014, http://articles.mercola.com/sites/articles/archive/2014/02/17/vitamin-d-supplements.aspx.