Vitamin D is regarded as one of the most important nutrients for our health. It regulates more than 2,000 of the 30,000 human genes and plays a significant role in immune function and physical performance. Vitamin D also helps the body absorb calcium, subsequently helping build bones and keep them strong and healthy.
Many people hear “vitamin D” and think of exposure to the sun. This is an accurate correlation, as vitamin D is produced in your skin in response to sunlight. However, if you live in non-equatorial latitudes, the sun may not be strong enough to produce vitamin D for about half of the year. In fact, as many as one billion people worldwide are estimated to be vitamin D-deficient. Sustained levels of vitamin D deficiency can result in brittle bones, bone pain, as well as muscle pain and weakness.
So, how does vitamin D impact normal body functioning? What’s the impact on those who rely on superior strength and muscle function, like professional athletes? What can be done to support healthy levels of vitamin D?
Impact on strength and muscle function
Vitamin D contributes to a variety of overall health functioning, including muscular strength and recovery, physical reaction time, as well as balance and coordination. A study conducted by the University of Southern California concluded that adequate vitamin D levels were important for promoting muscle and strength. Another study on adolescent females found a positive relationship between vitamin D levels and jump velocity, height, power, and force.
Conversely, deficient levels of vitamin D have an adverse effect on the human body. Vitamin D receptor expression within muscle tissue has been found to decrease with age, directly related to deteriorating muscle strength, mass, and function. In a study of 96 elderly women with post-stroke hemiplegic, half of the women were given 1,000 IU of vitamin D and the other half were given a placebo. The results? Those women treated with vitamin D saw a 59% reduction in the number of falls they experienced. Those subjects also saw an increase in the relative number and size of type-2 muscle fibers and presented with improved muscle strength.
Impact on athletic performance
Muscle strength is of course critical for every individual, but consistent, superior strength is especially essential for professional athletes. What’s one way for athletes to achieve and sustain optimum athletic performance? You guessed it—sufficient levels of vitamin D.
Vitamin D acts to maintain calcium and phosphate homeostasis within the body. Athletes deficient in vitamin D are at increased risk for potential problems, such as stress fractures, respiratory infections, and muscle injuries. A 2009 article in the Journal of Medicine Science in Sports concluded that “vitamin D may improve athletic performance in vitamin D deficient athletes.” The article further suggested that peak athletic performance may occur when vitamin D levels are at 50 mg. Another review in Molecular Aspects of Medicine showed that vitamin D increases the size of fast twitch muscles and muscular strength.
Impact on chronic pain
Research suggests that vitamin D may also serve as an effective treatment for chronic musculoskeletal pain. In one study, subjects weighing less than 50kg (110 lbs) were given 5,000 IU per day, while those over 50 kg were supplemented with 10,000 IU. After three months, the 299 subjects characterized as deficient in vitamin D reported a disappearance of their back pain. In total, 341 of the 360 subjects were relieved of their chronic low-back pain with this regimen of vitamin supplementation.
Impact on the immune system
Vitamin D was once thought to influence just four organs. With an influx of research studies conducted over the past two decades, research has revealed that vitamin D influences 36 target organs. Research also suggests that vitamin D may play a role in promoting neurological function, supporting heart health, and boosting immunity during cold and flu season.
Incorporating vitamin D into your diet
As I mentioned above, sun exposure alone isn’t enough to ensure sufficient levels of vitamin D. Some foods contain vitamin D naturally—think salmon, sardines, egg yolk, and shrimp—while others often have vitamin D added (and thus are considered fortified)—such as milk, yogurt, and orange juice. Even consuming foods containing vitamin D won’t ensure sufficient levels of the vitamin.
Incorporating vitamin D supplements into your regular diet is the best route for ensuring your body is getting enough vitamin D. However, I recommend taking a combination supplement of vitamin D plus vitamin K2. Together the two vitamins support calcium absorption and bone health. How? Vitamin D promotes calcium absorption from the GI tract into the bloodstream. Once calcium is absorbed, vitamin K helps transport it from the bloodstream and into the bone—supporting optimum bone density and normal bone growth.
Whether you’re a professional athlete at the top of your game or a retired athlete now enjoying the spoils of her hey-day (and aiming to avoid weakened bones in the process), vitamin D deficiency can affect us all. Adverse effects on our physical strength and immune system make incorporating vitamin D into a regular diet critical. Talk to your functional medicine practitioner today about a plan that works for you. Your performance—and pain-free lifestyle—could depend on it.
Robert G. Silverman, DC, MS, CNS, CCN, CSCS, CKTP, CES, CIISN, DACBN, DCBCN, HKC, FAKTR
Come See Dr. Silverman speak LIVE at one of these Biotics Research upcoming seminars:
EPIC Functional Medicine Conference - May 3-4 - J.W. Marriott Downtown Houston - Houston ,TX
The Gut-Brain Axis in Health and Disease - March 30 - Embassy Suites Hotel LAX North - Los Angeles, CA
The Gut-Brain Axis in Health and Disease - May 11- DoubleTree San Francisco Airport North - Brisbane , CA
Ward KA, Das G, Berry JL, et al. Vitamin D status and muscle function in post-menarchal adolescent girls. J Clin Endocrinol, Feb. 2009
Foo LH, Zhang Q, et al. Relationship between vitamin D status, body composition and physical exercise of adolescent girls in Beijing. Osteoporosis Int, March 2009; 20(3); p. 417-425
Soto Y, Iwamoto J, et al. Low-dose vitamin D prevents muscular atrophy and reduces falls and hip fractures in women after stroke. Cerebrovasc Ds, 2005. 20(3):187-192
Journal of Medicine Science in Sports, 2010. 20:182-190
American Journal of Sports Medicine, 2013, vol. 4(2)
University of Adelaide, School of Population Health
Faraj SA, Mutairi KA. Vitamin D deficiency and chronic low-back pain in Saudi Arabia. Spine 2003; 28:177-179