This isn’t an easy topic to write about nor is it an easy topic to find information about since it’s quite complex.
Abstract
Vitamin D is a hormone synthesized in the skin in the presence of sunlight. Here we review the possible role of vitamin D in nociceptive and inflammatory pain. Recent interventional studies have shown promising effects of vitamin D supplementation on cancer pain and muscular pain—but only in patients with insufficient levels of vitamin D when starting intervention.
Possible mechanisms for vitamin D in pain management are the anti-inflammatory effects mediated by reduced cytokine and prostaglandin release and effects on T-cell responses. Our conclusion is that vitamin D may constitute a safe, simple and potentially beneficial way to reduce pain among patients with vitamin D deficiency, but that more randomized and placebo-controlled studies are needed before any firm conclusions can be drawn.
Introduction
Chronic pain is a complex disease in its own right for which currently available analgesics have been deemed woefully inadequate since ~20% of the sufferers derive no benefit.
Vitamin D, commonly identified as a fat-soluble vitamin, is known for its role in calcium homeostasis and bone metabolism. Recent studies have linked vitamin D status and its receptor activity with several health conditions, including development of chronic pain, the leading cause of disability and disease burden globally (2). Studies on the association between vitamin D status and incidence of chronic pain have been contradictory (3, 4).
Indeed, several other studies have now reported a progressive exacerbation of pain with decreasing serum vitamin D levels and conversely, by increasing serum vitamin D levels through appropriate vitamin D supplementation, especially in vitamin D deficient patients, leads to an improvement in pain-relief (see Table 1). However, the potential underlying mechanisms by which vitamin D might exert its analgesic effects are poorly understood. In this review, we discuss pathways involved in pain sensing and processing primarily at the level of DRG neurons and the potential interplay between vitamin D/VDR and known specific pain signaling pathways including nerve growth factor (NGF), glial-derived neurotrophic factor (GDNF), epidermal growth factor receptor (EGFR), and opioid receptors.
We also discuss how vitamin D might influence immune cells and pain sensitization as well as include a section on the increasingly important topic of vitamin D toxicity. Examples of clinical studies showing benefit in pain-relief following vitamin D supplementation.
Boosting Vitamin D, Easing Pain
Greg Plotnikoff, MD, senior consultant with the Allina Center for Health Care Innovations in Minnesota, still remembers the woman in her 40s who told him that he was the 30th doctor she’d seen.
“Twelve of them had told her she was crazy,” says Plotnikoff, formerly an associate professor of internal medicine and pediatrics at the University of Minnesota Medical School. “She had weakness, achiness, fatigue — three pages worth of symptoms. That’s just one woman.
Her case doesn’t mean vitamin D will erase pain for everyone. However, Plotnikoff published a study in 2003 on 150 people in Minneapolis who came to a community health clinic complaining of chronic pain. Vitamin D blood levels of 30-40 ng/mL are considered ideal.
“The group with the lowest levels of vitamin D were white women of childbearing age,” Plotnikoff says. They attributed their pain to an inability to manage stress.
Why Do We Need Vitamin D?
This is called osteomalacia in adults and rickets in children. In addition, the vitamin may affect the immune system and could help to manage autoimmune conditions such as RA, Type 1 diabetes, and multiple sclerosis (MS). Typical symptoms include: fatigue
joint pain
muscle pain and weakness
bone pain
respiratory issues
neurological concerns including numbness
low mood, specifically seasonal affective disorder (SAD).