Vitamin D helps your body absorbcalcium. Calcium is one of the main building blocks of bone. Vitamin D also has a role in your nervous, muscle, and immune systems. You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms vitamin D naturally after exposure to sunlight. But too muchsun exposurecan lead to skin aging and skin cancer, so many people try to get their vitamin D from other sources. Here are signs and symptoms of vitamin D deficiency. Getting Sick or Infected Often. Share on Pinterest. ... Fatigue and Tiredness. Feeling tired can have many causes, and vitamin D deficiency may be one of them. ... Bone and Back Pain. ... Depression. ... Impaired Wound Healing. ... Bone Loss. ... Hair Loss. ... Muscle Pain. Being elderly. Being overweight or obese. Not eating much fish or dairy. Living far from the equator where there is little sun year-round. Always using sunscreen when going out. Staying indoors. People who live near the equator and get frequent sun exposure are less likely to be deficient, as their skin produces enough vitamin D to satisfy their bodies' needs. Most people don't realize that they’re deficient, as symptoms are generally subtle. You may not recognize them easily, even if they’re having a significant negative effect on your quality of life. Vitamin D plays important roles in immune function. One of the most common symptoms of deficiency is an increased risk of illness or infections. Excessive fatigue and tiredness may be a sign of vitamin D deficiency. Taking supplements may help improve energy levels. Some people are at higher risk of vitamin D deficiency: Breastfed infants, because human milk is a poor source of vitamin D. If you arebreastfeeding, give your infant a supplement of 400 IU of vitamin D every day. Older adults, because your skin doesn't make vitamin D when exposed to sunlight as efficiently as when you were young, and your kidneys are less able to convert vitamin D to its active form. People with dark skin, which has less ability to produce vitamin D from the sun. People with disorders such asCrohn's diseaseorceliac diseasewho don't handle fat properly, because vitamin D needs fat to be absorbed. People who haveobesity, because their body fat binds to some vitamin D and prevents it from getting into the blood. People who have hadgastric bypass surgery People with osteoporosis People withchronic kidneyorliver disease. People withhyperparathyroidism(too much of a hormone that controls the body's calcium level) People withsarcoidosis,tuberculosis,histoplasmosis, or other granulomatous disease (disease with granulomas, collections of cells caused by chronic inflammation) People with somelymphomas, a type of cancer. People who take medicines that affect vitamin D metabolism, such as cholestyramine (a cholesterol drug), anti-seizure drugs,glucocorticoids, antifungal drugs, andHIV/AIDS medicines. You can get vitamin D in three ways: through your skin, from your diet, and from supplements. Your body forms vitamin D naturally after exposure to sunlight. But too muchsun exposurecan lead to skin aging and skin cancer, so many people try to get their vitamin D from other sources.