Recent research has shown that vitamin D, or lack of it, plays an extremely important role in chronic pain. Even more importantly at this moment of crisis, there is a huge body of evidence that vitamin D plays an important role in immune response.

Acute Respiratory Infection and the High Prevalence of Vitamin D Deficiency

 A 2017 review of 25 high quality, randomized, controlled studies that included over 11,000 patients found that vitamin D supplementation reduced the risk of acute respiratory tract infections among all participants. Patients who were very vitamin D deficient and those receiving daily dosages rather than sporadic megadoses received the most benefit.[1]

Extremely concerning is the fact that a significant proportion of people in the United States and globally are deficient in vitamin D. There is some disagreement in the medical community about what constitutes an adequate level of vitamin D. Levels of the vitamin can be measured with a simple blood test. Levels below 20 ng/mL (50 nmol/L) are generally considered deficient in conventional medicine. Others have defined deficiency as below 32 ng/mL, with the optimum range 50 to 70 ng/mL.

A study that looked at U.S. population data from 2011 to 2012 using the more conservative definition of deficiency found that 40% of Americans were vitamin D deficient, with higher rates of deficiency among African-Americans and Hispanics.[2] Other studies have shown decreasing vitamin D levels with age.[3]

A study at the University of Minnesota of people with nonspecific musculoskeletal pain (pain without evidence of injury, disease, or anatomical or neurological defect) found that 93% of participants were deficient in vitamin D.[4] Another study, this one including participants with nonspecific musculoskeletal pain from diverse age groups and ethnicities, found that 100% of African Americans, Hispanics, and Native Americans were vitamin D deficient. All subjects younger than 30 were also deficient, with 55% severely so and five patients so deficient that their vitamin D levels were undetectable.[5]

Could lower vitamin D levels be behind the higher rate of death from COVID-19 among African-Americans and the elderly and the unexplained deaths from COVID-19 amongst apparently otherwise healthy young people?

Vitamin D Deficiency and Pain

Studies in adults have shown that an inadequate level of vitamin D is associated with many types of pain and many other disorders including:[6],[7]  

• Cardiovascular disease
• High cholesterol levels
• Inflammation
• Diabetes
• Weight gain
• Infectious diseases
• Multiple sclerosis
• Declining cognitive function
• Physical functional impairment
• Nonspecific bone and joint pain
• Fatigue, including Chronic fatigue syndrome
• Muscle weakness
• Fibromyalgia
• Osteoarthritis
• Rheumatoid disorders
• Headaches
• Immune disorders
• Depression and other mood disorders
• Mortality from all causes

Many studies have documented a reduction in pain when vitamin D supplements have been given to people in chronic pain. An article published in Archives of Internal Medicine reported that five patients who had chronic pain and low vitamin D levels had resolution of their pain in five to seven days after they were given vitamin D2 supplements. These patients had been hypersensitive to pain stimuli, and the pain did not improve with the use of any pain medications, including narcotics and tricyclic antidepressants. One of the patients had a decline in vitamin D level and a return of pain after several months; the pain was again resolved with vitamin D supplementation.[8]

A randomized controlled trial in the Netherlands of vitamin D3 supplementation of nonspecific musculoskeletal pain in non-Western (Arab and African) immigrants found that patients receiving a single dose of 150,000 IU of vitamin D3 were more likely, after six weeks, to report pain relief and an improvement in ability to climb stairs than those in the placebo group. Those receiving a second dose of vitamin D3 at six weeks were more likely to report improvements than the group that didn’t receive a second dose.[9]

A randomized controlled study of patients with knee pain and vitamin D insufficiency, who received either vitamin D supplementation or a placebo for a year, found that the treatment group experienced significantly less pain and better knee function than the placebo group.[10] US veterans with multiple areas of chronic pain and low vitamin D levels who were given vitamin D supplementation had less pain, better sleep, and better quality of life.[11]

A small study of women with diabetes who had neuropathic pain, tingling, and numbness found that six months of weekly vitamin D2 supplementation reduced pain and depression.[12]

How to Get Adequate Amounts of Vitamin D

Vitamin D is produced naturally in the body when the skin is exposed to ultraviolet rays from sunlight. Using sunscreen blocks the body’s ability to produce vitamin D. People with dark skin synthesize 99% less vitamin D because melanin, the substance responsible for dark skin pigmentation, absorbs the UVB rays. Our bodies also become less able to synthesize vitamin D as we age. People living in the northern United States, where the sun is less direct and winters are longer, are also less likely to synthesize enough of the vitamin.[15] Many drugs also block the synthesis of vitamin D or reduce absorption, including some antacids, barbiturates, anticonvulsants, antirejection drugs, antiviral drugs, nicotine, blood thinners, cholesterol-lowering medication, and steroids.[16]

Food sources of this critical vitamin include fortified milk, egg yolk, cod liver oil, oysters, fatty fish, fortified soy milk, and fortified cereal.[17] These foods, however, are rarely consumed in sufficient quantities to maintain vitamin D at optimum levels. For instance, to obtain a target dose of 4000 to 8000 IU of vitamin D a day, a person would need to consume ¼ cup of cod-liver oil daily or 18 to 36 capsules.[18] Fortunately, vitamin D is inexpensive and readily available in supplement form. Vitamin D3, the natural form of vitamin D, is absorbed more readily than the synthetic form, vitamin D2.[19], [20] 

An article published earlier this month in the journal Nutrients recommended taking 10,000 IU daily for a month and then 5000 IU daily after that.[21] Another recent review suggested using vitamin D loading doses of 200,000–300,000 IU in 50,000-IU capsules to reduce the risk and severity of COVID-19.[22]

A 2011 editorial in the Scandinavian Journal of Primary Health Care stated that vitamin D supplementation in patients with chronic pain seems reasonable, as the treatment is cheap and relatively safe, and evidence indicates that vitamin D supplementation has overall positive effects on health. The editorial recommended a daily dose of 2000 IU for chronic pain patients.[23] Others have documented a vitamin D requirement of 4000 to 8000 IU daily, or 35 IU per pound of body weight.[24] A more individualized approach, based on testing of vitamin D levels along with follow-up testing to determine the level of supplementation needed to maintain adequate blood serum levels, would probably yield the most effective results.

Dr. Joseph Mercola, a well-known holistic physician, recommends also supplementing with vitamin K2 if you are taking vitamin D supplements. Vitamin K2 helps keep calcium where it belongs in the body. The only known toxicity from excessive vitamin D intake is related to excessive calcium in the bloodstream.[25]

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References

[1] Martineuau A et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. British Medical Journal, 2017, 356:i6583 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5310969/

[2] Parva N et al. Prevalence of Vitamin D Deficiency and Associated Risk Factors in the US Population (2011-2012). Cureus, 2018 June 10(6) e2741 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6075634/ 

[3] Vasarhelyi, B.; Satori, A.; Olajos, F.; Szabo, A.; Beko, G. Low vitamin D levels among patients at Semmelweis University: Retrospective analysis during a one-year period. Orv. Hetil. 2011, 152, 1272–1277.

[4] People with undetermined muscle/bone pain tend to be severely vitamin D deficient. Public release: December 9, 2003, Minneapolis, St. Paul. Contact: ashleyb@umn.edu, University of Minnesota.

[5] Plotnikoff, G. A. & Quigley, J. M. (2003). Prevalence of severe hypovitaminosis D in patients with persistent, nonspecific musculoskeletal pain. Mayo Clin Proc, 78, 1463-1470.

[6] Birkner. (2010). Chronic Pain and Vitamin D.

[7] Autler, P., Boniol, M., Pizot, C., & Mullie, P. (2014). Vitamin D status and ill health: a systematic review. The Lancet Diabetes & Endocrinology, 2(1):76-89.

[8] Gloth, F. M. 3rd, Lindsay, J. M., Zelesnick, L. B., & Greenough, W. B. 3rd. (1991) Can vitamin D deficiency produce an unusual pain syndrome? Archives of Internal Medicine, 151(8), 1662-4.

[9] Schreuder, F., Bernsen, R. M., vn der Wouden, J. C. (2012). Vitamin D supplementation for nonspecific musculoskeletal pain in non-Western immigrants: a randomized controlled trial. Annals of Family Medicine, 10(6):547-55.

[10] Sanghi, D., Mishra, A., Sharma, A. C., Singh, A., Natu, S. M., Agarwal, S., & Srivastava, R. N. (2013). Does Vitamin D improve osteoarthritis of the knee: a randomized controlled pilot trial. Clinical Orthopedics and Related Research, (11), 3556-62.

[11] Huaang, W., Shah, S., Long, Q., Crankshaw, A. K., & Tangpricha, V. (2013). The Clinical Journal of Pain, (4), 341-7.

[12] Jancin, B. (2013). Vitamin D promising in women with diabetic pain. Internal Medicine News, 46(13), 35.

[13] Kragstrup, T. W. (2011). Vitamin D supplementation for patients with chronic pain. Scandinavian Journal of Primary Health Care, (29), 4-5.

[14] http://articles.mercola.com/sites/articles/archive/2014/02/17/vitamin-d-supplements.aspx accessed on 5/31/14.

[15] Birkner, K. (2010). Chronic Pain and Vitamin D. HER-92. Pain and Stress Publications.

[16] Birkner. (2010). Chronic Pain and Vitamin D.

[17] Sulindo-Ma & Isenhart. (2008). Nutrition and Supplements for Pain Management, 421.

[18] Vasquez, A. (2004). Vitamin D supplementation in the treatment of musculoskeletal pain. The Original Internist, 07.

[19] Trang, H. M, Cole, D. E, Rubin, L. A, Pierratos, A., Siu, S., Vieth, R. (1998). Evidence that vitamin D3 increases serum 25-hydroxyvitamin D more efficiently than does vitamin D2. American Journal of Clinical Nutrition, 68, 854-8.

[20] Amas, L. A., Hollis, B. W., & Heaney, R. P. (2004). Vitamin D2 is much less effective than Vitamin D3 in humans. Journal of Clinical Endocrimology Metabolism, 89, 5387-91.

[21]  Grant W et al. Evidence that Vitamin D Supplementation Could Reduce Risk of Influenza and COVID-19 Infections and Deaths. Nutrients, 2020, 12(4), 988. https://www.mdpi.com/2072-6643/12/4/988/htm 

[22]  Wimalawansa, S.J. Global epidemic of coronavirus--COVID-19: What we can do to minimze risksl. Eur. J. Biomed. Pharm. Sci. 2020, 7, 432–438

[23] Kragstrup, T. W. (2011). Vitamin D supplementation for patients with chronic pain. Scandinavian Journal of Primary Health Care, (29), 4-5.

[24] http://articles.mercola.com/sites/articles/archive/2014/02/17/vitamin-d-supplements.aspx accessed on 5/31/14.

[25] http://articles.mercola.com/sites/articles/archive/2014/02/17/vitamin-d-supplements.aspx