Vitamin D is an essential nutrient for our overall health, but many people rely on vitamin D supplements due to the risk of vitamin D deficiency.
Vitamin D Supplement
A vitamin D supplement is an artificial source of vitamin D, an important pro-hormone in the body that can be generated by the skin when exposed to sunlight. Even mild or occasional exposure to the sun is enough for the body to store an adequate amount of vitamin D. However, in cases of vitamin D deficiency—if a person doesn’t have enough sun exposure, or the body is unable to utilize the stored vitamin D for any reason—a supplement may be recommended. Calcium and vitamin D work in tandem to prevent the bone mineral loss, thus preventing fractures and the negative symptoms of osteoporosis as we age. 
Are Vitamin D Supplements Good for Health?
Vitamin D supplements are very good for health in a number of ways.
Research conducted by Dr. Cynthia Aranow, published in the Journal of Investigative Medicine, has linked vitamin D deficiency to a greater susceptibility to infection, as well as a greater risk of autoimmune activity within the body. 
One of the major benefits of vitamin D in the body is that it increases calcium uptake in the gut, which is essential for protecting bone density as we age. In order to protect against osteoporosis and maintain a healthy intake of calcium, we also need adequate amounts of vitamin D in our system.
Research published in The American Journal of Clinical Nutrition revealed that vitamin D deficiency is an unrecognized epidemic in the US, and it is now the most common vitamin deficiency on the planet. Supplements of this vital substance can help those people in parts of the world that go without sunlight for weeks or months at a time, and protect them against the unpleasant side effects of this deficiency. 
Due to the nature of pregnancy and breastfeeding, many women in these situations experience vitamin D deficiency simply because their nutrients are being shared with their child. Research has suggested that supplementation is wise in such cases, for the health of both the baby and the mother. 
In a recent review of different studies, collected by the American Journal of Public Health , it was found that sufficient vitamin D levels had a protective effect against a higher risk of various types of cancer. While the link between vitamin D and chronic disease has yet to be firmly established, the evidence and data back up the claim.
High Blood Pressure
Studies have found correlations between decreased levels of hypertension in certain demographics and adequate levels of vitamin D intake, either through supplementation or natural exposure to sunlight. 
Side Effects of Vitamin D Supplements Overdose
There are some potential side effects that have been reported when people take supplements for vitamin D, in addition to sun exposure and vitamin D in their diet. Taking too much has a formal name—hypervitaminosis D. Some of the symptoms of consuming too much vitamin D include the following: 
- Calcification of bones and blood vessels 
- Loss of appetite
- Dry Mouth
Most experts agree that a daily intake of 10-20 micrograms of vitamin D is sufficient for the vast majority of the population. While some of the specific populations mentioned in the health benefits section of this article may do well with higher intake for short periods of time, a daily supplement range between 25-100 micrograms would be sufficient for nearly any patient. It is always wise to speak with your doctor before adding any new supplements to your daily diet, particularly if you are on other medications.