Signs of vitamin D3 deficiency include bone pain and muscle weakness, according to MedicineNet. However, mild vitamin D deficiency does not always cause symptoms. Severe deficiency of vitamin D can lead to rickets, a condition in which the bones soften and deform.
The symptoms of Vitamin D deficiency are usually subtle, as stated by WebMD, and may include bone pain and muscle weakness. However, low levels of vitamin D in the blood can pose serious risks, including an increased risk of cardiovascular disease, asthma in children, cognitive impairment in adults and an increased risk of cancer. These risks are present even when the deficiency does not cause noticeable symptoms. When rickets occurs in adults, it is usually called osteomalacia, according to MedicineNet.
Vitamin D3, also known as cholecalciferol, is one of two forms of Vitamin D. The body naturally produces vitamin D3 when sunlight shines on the skin. The other form of vitamin D, which is known as ergocalciferol or vitamin D2, is found in many foods. Most experts recommend that people who need to take vitamin D supplements take vitamin D3, as the body absorbs it more readily than vitamin D2 and it does not accumulate in the blood, according to EverydayHealth.