Can a Deficiency in Vitamin D Make a Person Tired?

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Vitamin D deficiency is becoming a common problem and may affect many Americans without their knowledge. According to a 2009 report in the “Archives of Internal Medicine,” as many as 77 percent of Americans are vitamin D-deficient. Vitamin D deficiency can lead to a variety of symptoms including bone softening and a higher risk of bone fractures, unexplained musculoskeletal pain, bone pain and fatigue. If you are constantly tired or battle with chronic fatigue, you should consult with your physician and have your vitamin D levels tested.

Vitamin D

Vitamin D is a fat-soluble nutrient. It can be found in limited dietary products such as vitamin D-fortified milk and oily fish like salmon. Vitamin D is also made by your body when you are exposed to the ultraviolet B rays of the sun. With the recent push for sunscreen use and the prevention of skin cancer, you may not be getting enough sun exposure to make the vitamin D your body needs. The National Institutes of Health’s Food and Nutrition Board recommends that adults between the ages of 19 and 70 receive at least 600 International Units, or IUs, of vitamin D a day, and adults over the age of 71 should receive 800. If your blood levels fall below 30 nanomoles per liter, you are considered vitamin D-deficient.

Fatigue and Chronic Fatigue Syndrome

Fatigue is more than just simply being tired. If you have missed out on sleep, you may find yourself feeling tired, but it is usually resolved by taking a nap. Fatigue is that tired feeling that is not relieved by getting sleep. Fatigue can be a symptom of an underlying condition, such as a vitamin D deficiency. Chronic Fatigue Syndrome occurs when severe fatigue symptoms last for more than six months and cannot be contributed to any other medical condition.

Medical Research

Medical research studies have linked vitamin D deficiency with fatigue and chronic fatigue. A 2010 report presented at the European Congress of Endocrinology found a link between vitamin D deficiency and chronic fatigue in patients with traumatic brain injury, with 65 percent of the patients studied showing significant vitamin D deficiency. A 2010 study published in the “Scandinavian Journal of Primary Health Care” looked at the possible connection between vitamin D deficiency and patients with nonspecific musculoskeletal pain, headache and fatigue. Looking at 572 patients, 58 percent of the participants were vitamin D-deficient. They determined that there was a connection and recommended that physicians test the vitamin D levels in patients presenting with these unexplained symptoms.


If you are suffering with fatigue or chronic fatigue that is not explained by any other condition, consult with your physician regarding a possible vitamin D deficiency. Your physician will run a blood test to evaluate your vitamin D level; if the results show you are deficient, he will begin a treatment plan to bring your levels within an optimal range. Treatment consists of high-dose vitamin D supplements for an average of eight weeks. Your levels will again be tested, and if you are still not within optimal range, the treatment will continue. If your level is within optimal range after treatment, your physician may advise you to take daily vitamin D supplements to avoid becoming deficient again. If your fatigue is vitamin D-related, your symptoms should improve once your vitamin D levels are regulated.