Vitamin D is well-known for its vital role in healthy immune function, promoting calcium absorption, normal bone mineralization, cellular differentiation and growth, and proper glucose metabolism. Serum vitamin D deficiency (<12 ng/mL) or insufficiency (12 ng/mL to 20 ng/mL) increases the risk of osteoporosis, rickets (in children), muscle pain and weakness, muscle cramps and spasms, impaired immune integrity, hyperparathyroidism, and adverse effects on glucose tolerance and insulin secretion in patients who have type 2 diabetes.

Results from the 2018 National Survey on Drug Use and Health found that approximately 2 million people 12 years of age and older have opioid use disorder (OUD), and roughly 10.3 million people have misused opioids within the past year. OUD has become an ever-increasing medical concern in the U.S. In 2019, nearly 50,000 people overdosed on drugs containing opioids. The number of deaths in the U.S. from overdoses involving prescription medications and illicit opioid drugs was staggering at 500,000 between 1999 and 2019, according to the Centers for Disease Control and Prevention (CDC). 

Could Vitamin D Status Play a Role?

According to a recent study published in Science Advances that was led by researchers at the Massachusetts General Hospital, vitamin D deficiency may increase the risk of addiction to opioids and other endorphin-seeking behavior. 

Moreover, human studies showed that addiction to ultraviolet (UV) rays (e.g., tanning) exhibits similar characteristics to that of opioid addiction; an endogenous opioid-mediated addiction-like pathway has been identified to be triggered by UV-induced synthesis of beta-endorphin in the skin. It is well-known that serum vitamin D synthesis is UV-dependent, leading researchers to hypothesize that serum vitamin D deficiency drives UV-seeking behavior and may also contribute to OUD through enhanced sensitization of exogenous opioids (i.e., endorphin-seeking behavior). 

Using data from the 2003-2004 National Health and Nutrition Examination Survey (NHANES), the researchers analyzed if a relationship existed between serum vitamin D status and opioid use in humans, independent of pain. The results demonstrated that people with vitamin D deficiency or insufficiency were significantly more likely to use opioid painkillers compared with those with normal or sufficient vitamin D levels. They went on to compare patients at Massachusetts General Hospital who were diagnosed with OUD to those without OUD (by matching age, sex, race, and provider), and it was discovered that more OUD patients were vitamin D-deficient compared with the controls. 

Furthermore, mice fed a vitamin D-deficient diet for 8 weeks with a mouse model of vitamin D receptor signaling deficiency had an increased sensitivity to morphine reward compared with mice fed a vitamin D-containing diet. Fortunately, when the vitamin D-deficient mice were given oral vitamin D supplementation, the morphine preference pattern was restored back to that of vitamin D-replete mice, and restoration of vitamin D signaling normalized the opioid response. Additional findings show a feedback loop exists where improper vitamin D signaling increases nociceptive thresholds and opioid analgesia that were normalized upon restoration of vitamin D signaling and cutaneous vitamin D synthesis.

These findings suggest that restoring vitamin D levels by supplementation may help support the treatment of opioid use disorder and reduce UV- and endorphin-seeking behavior. Vitamin D supplements are relatively inexpensive and available in various doses depending on the level of insufficiency or deficiency. It is important to find a supplement that includes vitamins K1 and K2 with vitamin D3 to support optimal bone health and cardiovascular health. 

By Caitlin Higgins, MS, CNS