7 Signs You Are Vitamin D Deficient
Vitamin D is a vital nutrient for promoting optimal health. It performs a number of functions in the human body: helping build strong muscles, supports healthy bones, prevents the body from forming cancer cells, and protects against the development of type II diabetes. Additionally, young children can avoid developing rickets by getting sufficient levels of Vitamin D. 
Sources of Vitamin D
Not many people know this but there are actually two types of vitamin D known to man; D2 and D3. And as studies have found, one is better than the other.  Very few foods in nature contain the right type of vitamin D. Fatty fish and fish oils are two of the best sources of Vitamin D3, though it can also be found in trace amounts in enriched whole milk, cheese, and in the yolks of eggs. Plant sources like mushrooms, especially those grown under UV lights provide you with the less potent type, D2. Learn about the difference between Vitamin D2 and Vitamin D3 Vitamin D can be found in dietary form and from supplementation, but 90 percent of the Vitamin D we get is from exposure to the sun. Studies show that between 5 and 30 minutes of exposure to direct sunlight between the hours of 10AM and 3PM without sunscreen twice weekly is enough sunlight to keep Vitamin D levels high enough for optimal health. 
What are the Symptoms of Vitamin D Deficiency?
A Vitamin D deficiency can have many effects, some of which include:
1. Depression and Mood Swings Vitamin D deficiency can contribute to depression and mood swings. Supplementation and lifestyle changes to bring levels up may help ease depression and improve your mood because Vitamin D plays an important roll in the areas of the brain linked the mental health. Though more study is needed, if you’re short on Vitamin D, go get more sunshine. You may be pleasantly surprised at how quickly it can help. 
2. Cancer Some studies suggest that sufficient Vitamin D intake may help reduce the risk of certain cancers, such as colorectal, prostate, pancreatic and breast cancers. Though studies are far from conclusive, getting enough Vitamin D while young just might save your life later on down the road. 
3. Inflammation Vitamin D has recently proven to not only prevent inflammation, but to help reduce it. In studies, low levels of Vitamin D in the blood failed to “inhibit the inflammatory cascade, while levels considered adequate did inhibit inflammatory signaling.” 
4. Allergies Allergies affect those living in the Western World more than in the Developing World, possibly because developed nations are located where there is less sunshine during the winter. Skin allergies or atopic dermatitis is reported more often in those with a Vitamin D deficiency. Additionally, deficiencies may affect the body’s susceptibility to certain types of infections which trigger or worsen allergic reactions. 
5. Cardiovascular health Continuous studies show that Vitamin D is essential to cardiovascular health. A deficiency is a strong risk factor for having a heart attack or developing heart diseases like, congestive heart failure, peripheral arterial disease, and strokes. Precursors to heart conditions like diabetes and high blood pressure are also affected by low Vitamin D levels. [7,8]
6. Bone and Joint Health Young people need sufficient levels of Vitamin D to help build and support healthy bones. A deficiency can lead to slowly weakening bones. By middle age, those with a Vitamin D deficiency often develop brittle bones, and bones will become malformed, or thin and weak. When paired with calcium, Vitamin D protects the elderly from osteoporosis. Begin supplementing and making lifestyle changes early if you are Vitamin D deficient. 
7. Type II Diabetes Studies show that Vitamin D may help your body process sugars and regulate calcium levels. While Vitamin D is never a replacement for diabetes medications, it may be an excellent booster for the medications you’re using now to control your condition. Young people with sufficient levels of Vitamin D are at a lower risk of developing Type II Diabetes compared with those who are deficient. Those with pre-diabetic conditions or with full-blown Type II Diabetes should discuss supplementation with their physicians.