It’s likely happened to you at least once if not many times before. It sometimes occurs in the middle of a peaceful night’s sleep, or midway through an awe-inspiring workout, or maybe while leisurely swimming in the beautiful summer waters. All of a sudden, BAM. You are jolted out of your blissful state of mind by a sudden, unexpected, and involuntary leg cramp.
Can vitamin D Deficiency Cause Leg Cramps?
Some people claim that muscle fatigue is the cause of cramps. Others say it’s dehydration or lack of potassium. More so lately, vitamin D has been called to question when exploring the etiology of leg cramps. Historically, vitamin D has been linked to its role in calcium absorption, skeletal health, and bone disorders, such as osteoporosis or rickets. While the association between vitamin D status and musculoskeletal health is not as thoroughly studied, vitamin D has been recognized to exert wide-ranging effects on the body, including a potentially important role in muscle health. So, is insufficient vitamin D the culprit of those rude awakenings?
What Does the Evidence Show about Vitamin D and Muscle Health?
There is little doubt that vitamin D plays a role in muscle health, and there is growing evidence tying vitamin D deficiency to chronic and nonspecific musculoskeletal pain. Chronic musculoskeletal pain has begun to pose significant social and economic burdens as it has become a widespread and costly disorder.
In 2003, a study of 150 patients with pain of uncertain etiology found that 93% of them had vitamin D deficiency, with mean levels of 10.5 ng/mL. Another study found similar observations, where 71% of people with chronic pain were vitamin D deficient. Furthermore, other studies have found that vitamin D deficiency was explicitly linked to low back pain, which affects 577 million people worldwide.
Vitamin D deficiency has also been linked to muscle weakness and sarcopenia in aging populations. Sarcopenia, or low muscle mass, is associated with increased morbidity and mortality, and several studies suggest an association between low vitamin D and falls in the elderly.
One large study out of the Netherlands found that serum vitamin D levels below 10 ng/mL were significantly associated with two or more falls in those aged 65-75. They noted that falls were mediated by poor physical performance and that poor muscle function in those with low vitamin D levels was likely a contributing risk factor.
Interestingly, other evidence suggests that the beneficial effects of vitamin D on fall risk can be explained more by its action on neuromuscular and cognitive function than by its direct effect on bone or muscle. Either way, the impact of vitamin D on falls is felt to be significant enough that consensus societies have made recommendations regarding the topic. The US Preventative Services Task Force and the American Society of Geriatrics recommend 600 IUs of vitamin D per day for adults and 800 IUs of vitamin D per day for adults over 70 to reduce the risk of falls.
Does Vitamin D Deficiency Cause Leg Cramps Specifically?
Fewer studies have observed the effects of vitamin D deficiency on muscle spasms or cramps. One small case series observed the association between vitamin D deficiency and concurrent episodes of pain and muscle spasms. Although the mechanisms are unclear, it’s been hypothesized that the imbalanced homeostasis of electrolytes, including calcium, magnesium, and phosphorus, resulting from vitamin D deficiency could lead to muscle dysfunction and potential cramping.
However, there is conflicting evidence that vitamin D plays a role. Another small study published in 2017 evaluated whether the correction of vitamin D insufficiency relieved muscle cramps in postmenopausal women. The researchers found that vitamin D did not affect the frequency or severity of muscle cramps despite vitamin D repletion. This same study also found no relationship between muscle cramps and dietary or serum magnesium or fluid intake.
They did, however, identify that serum albumin, higher potassium intake, and physical activity were inversely associated with the severity of cramps in the study subjects. Even though it is well established that vitamin D plays a role in maintaining blood levels of calcium and phosphate, there is not enough evidence to suggest that vitamin D deficiency causes leg cramps or that vitamin D deficiency correction will eliminate them.
So What Causes Leg Cramps?
Muscle cramps are thought to be caused by one (or more) of three underlying causes. First, inadequate blood supply by narrowing of the arteries (like with the buildup of arterial plaque) or temporary obstruction (like sitting cross-legged and cutting off blood supply to an extremity temporarily) can lead to muscle cramps.
Second, medical conditions including lower motor neuron disorders, cirrhosis, dialysis, or taking certain medications can cause muscle cramps.
Finally, mineral depletion and nutrient imbalances such as hypocalcemia (low calcium), hypoglycemia (low blood sugar), hyponatremia (low sodium), and hypokalemia (low potassium) may lead to muscle dysfunction and cramping. However, most muscle cramps are idiopathic, meaning the cause is unknown.
Aside from staying hydrated and eating various nutrient-dense foods to ensure adequate vitamin and mineral intake, some other suggested interventions for muscle cramps have been proposed (although benefits have yet to be confirmed).
These include stretching before bed, vitamin B complex, vitamin E, magnesium, and gabapentin. Muscle cramps usually disappear on their own and are not harmful. However, see your doctor if your muscle cramps are associated with leg swelling and changes to skin appearance, muscle weakness, occur often enough to affect your quality of life or are not resolved in a reasonable time. Also, speak with your doctor before adding new supplements or medications to your routine.
Vitamin D Deficiency is not Something to Sleep on
Regardless of vitamin D’s inability to resolve leg cramps, global health experts claim that vitamin D deficiency is a worldwide health epidemic, with 1 billion people considered to be vitamin D deficient or insufficient. In the United States alone, it’s estimated that up to 40% of adults are vitamin D deficient.
Vitamin D deficiency is associated with many health problems, including poor muscle and bone health, autoimmune diseases like multiple sclerosis and arthritis, cardiovascular disease, certain types of cancers, neurocognitive dysfunction, and mental illness. The Endocrine Society, the National and International Osteoporosis Foundation, and the American Geriatric Society define vitamin D deficiency as a level of 25-hydroxyvitamin (25 OH D) of less than 30 ng/mL.
Although the RDA for adults is 600 IUs, per day, the Endocrine Society recommends that most adults get 1,500-2,000 IUs of vitamin D daily. If you want to learn more about improving your vitamin D intake by adding the right foods to your diet, check out this link here.