Vitamin D is an essential substance our bodies need to maintain strong bones and teeth. It’s something we can get from certain foods like egg yolks and fish, but we can also get Vitamin D from the sun when we’re exposed to sunlight. When we don’t get the proper amount of Vitamin D, a loss of bone density occurs and broken bones and osteoporosis can happen. Eat This, Not That! Health talked to experts who reveal the signs you’re lacking Vitamin D. Read the 6 tips below. Read on—and to ensure your health and the health of others, don’t miss these Sure Signs You’ve Already Had COVID.

“Vitamin D is obtained from sun exposure, a few foods and supplementation. It is a critical vitamin for bone health, nerve and muscle function,” explains Catherine Johnston, Registered Dietitian & Certified Personal Trainer. “Vitamin D supports immune system health as well. As little as 10-15 minutes of sunshine exposure a few times a week can provide a great dose of vitamin D— so try to be intentional about getting outside!” 

Sarah Bourdet RDN, a dietitian nutrition coach adds, “Vitamin D plays a role in protecting our body from not only osteoporosis (along with other factors), high blood pressure, diabetes, infection, and immune system disorders, as well as some cancers.”

Johnston says, “It is not always easy to know you have a Vitamin D deficiency until you already have significant damage to your bones or other related health issues. However — there are a few earlier signs of a potential Vitamin D deficiency that you can watch out for. Bone pain — especially in your back, frequently getting sick with colds and other bugs, and feeling tired after getting adequate sleep can all be indicators of a potential Vitamin D deficiency. There is still a lot of research being conducted on Vitamin D’s impact on overall health – but we do know that it is really important and that many people are deficient.”

Dr. Pana Ninan, PharmD, BS Functional Medicine Practitioner and Pharmacist adds, “While many people won’t even realize they have Vitamin D deficiency, there are some key indicators to look for such as decreased immune function, mood swings or depression, fatigue, and even bone pains and muscle weakness. It is important to get your Vitamin D levels checked annually through your physician. Over time, undiagnosed deficiency leads to loss of bone density or osteoporosis because Vitamin D is essential for our body’s to absorb calcium. Vitamin D plays a huge role in strengthening our immune function and regulating our sleep/wake cycles. Deficiencies will lead to a poorer quality of sleep and greater sickness. Seasonal Affective Disorder (a mood disorder) is also more prevalent in the winter months when the days are shorter and we spend less time outside helping our bodies produce natural Vitamin D.” 

According to Johnston, “Vitamin D deficiency can be diagnosed with a simple blood test. However – most physicians do not check Vitamin D routinely unless you have a risk factor, such as a digestive disorder. If you suspect you may have a Vitamin D deficiency, ask your doctor to check your labs at your next appointment. Keep in mind – many people are deficient mid-winter, so this can be the best time to get a true reading! 

Additionally — some groups of people are at higher risk of Vitamin D deficiency, including older adults, those taking certain medications, having a history of gastrointestinal surgery, people not exposed to sunlight regularly, people with darker skin and those living in an area with more air pollution.” 

In addition to an increased risk of physical health, our mood can change too if we don’t get enough Vitamin D, according to Dr. Taylor Graber, an MD Anesthesiologist and owner of ASAP IVs: “Mood changes (especially the development of depression) occurs with lack of vitamin D. Vitamin D plays a role in the development of seasonal affective disorder, or seasonal depression, which occurs during the winter months when there is a decreased exposure to sunlight (and thus decreased Vitamin D exposure/absorption). Vitamin D deficiency has been directly implicated with mood disorders, and supplementation has been shown to improve and reverse these as well.”

Graber explains, “The body needs Vitamin D to form 1,25(OH)2, which is the active form of Vitamin D. This active form has many important roles in the body. Once of which is helping to regulate the absorption of Calcium from the intestines. Calcium is integral in the contraction and function of most cells in the body, and especially those of the heart and muscle. Without the proper amount of calcium in the body, there is an inability to properly contract muscles. If a muscle lacks sufficient levels of calcium there will be a reduction of strength in response to a stimulus, resulting in a subjective feeling of fatigue or tiring of the muscle. Calcium is also needed for the muscle to relax, and lack of calcium can lead to cramping. Sunlight or direct vitamin D supplementation, whether orally or through high dose intramuscular injections, can help resolve these issues, especially when combined with recommended daily intake of calcium.”

If you have an autoimmune disease, it’s especially important to have the proper dose of Vitamin D. Julia Walker, a registered nurse with Paloma Health explains, “Certain diseases can also place you at greater risk for Vitamin D deficiency, including intestinal disorders like Crohn’s and Celiac Disease, as well as kidney and liver diseases. Obesity can also increase a person’s risk for Vitamin D deficiency, and that risk is heightened for people who undergo weight loss surgery. Importantly, people who have any health condition that limits their mobility should have their Vitamin D levels monitored regularly.” And to get through this pandemic at your healthiest, don’t miss these 35 Places You’re Most Likely to Catch COVID.