Almost everyone is deficient in vitamin D3, and large percentages of the population are extremely deficient, so a daily supplement is a good way to protect against deficiency. Sunscreen blocks the beneficial rays which turn cholesterol in the skin into valuable vitamin D3. The darker your skin, the more your natural SPF – and usually the more deficient you are.
Possible benefits: may reduce cancer risk; improves immunity; safeguards against frequent infections; cardiovascular health; improves lung function; helps prevent heart disease; prevents bone & muscle pain; excellent for Rheumatoid Arthritis improves bone health and density; improves depression/anxiety; improves focus and concentration; prevents fatigue; prevents excess sweating; quickens wound healing; prevents hair loss; helps with weight loss.
The Longer Story: It must be D3 Not D2 because Vitamin D3 is actually a hormone-regulating gene expression in the nucleus of a cell, i.e. regulating our biochemistry (same family of steroid hormones as estrogen, progesterone, testosterone, cortisol).
Receptors that respond to vitamin D have been found in almost every human cell and researchers are finding health benefits of vitamin D in every area they look – there are so many benefits.
However, not many foods contain vitamin D. Some fish (salmon, tuna, mackerel), as well as fish liver oils, are very good sources, but vitamin D is also present in beef liver, cheese, and egg yolks. Vitamin D is perhaps best taken in a variety of these foods, limited sunlight, and wise supplementation.
The National Health and Nutrition Examination Survey III conducted by the Centre for Disease Control shows a relationship between vitamin D deficiency and obesity, hypertension, and diabetes in adults. There is evidence that atrial fibrillation is linked to low vitamin D levels. Vitamin D is important for calcium absorption and strong bones and teeth. It also slows cell growth (in malignant tumours), and is used in cancer treatment in many centres around the world.