It's becoming increasingly clear from all the new research is that vitamin D deficiency may be the root cause behind many degenerative diseases. Insufficient vitamin D is linked to virtually every age-related disorder including cancer, heart disease, diabetes, chronic inflammation, as well as depression and autoimmune diseases. High levels of vitamin D not only protect bone health, but they also strengthen the immune system and lead to substantially fewer colds, flu, and other viral infections.

Vitamin D, is a fat-soluble vitamin. It is found in some foods, and is also made in the body after exposure to ultraviolet rays from the sun. Vitamin D exists in several forms, each with a different activity. Some forms are relatively inactive in the body, and have limited ability to function as a vitamin. The liver and kidney help convert vitamin D to its active hormone form.

The major function of vitamin D is to maintain normal blood levels of calcium and phosphorus. Vitamin D aids in the absorption of calcium, helping to form and maintain strong bones, and promotes bone mineralization.

Without vitamin D, bones can become thin, brittle, soft, or misshapen. Vitamin D prevents rickets in children and osteomalacia in adults, which are skeletal diseases that result in defects that weaken bones.

Vitamin D Deficiency Causes flu and Other infections

Vitamin D is crucial to fending off infections. This super-vitamin plays a key role in boosting the immune system and scientists have identified reduced vitamin D levels in winter months as a key factor in the increase of infectious disease cases.

In particular, research has found that it triggers and arms the body's T cells, the cells in the body that seek out and destroy any invading bacteria and viruses. Vitamin D is crucial to activating the immune defences and without sufficient intake of the vitamin, the killer cells of the immune system - T cells - will not be able to react to and fight off serious infections in the body.

These T cells activate and multiply at an explosive rate and can create an inflammatory environment with serious consequences for the body. Therefore vitamin D is crucial not only in fighting disease but also in dealing with anti-immune reactions of the body, like arthritis.

Vitamin D Helps Prevent diabetes and Protects heart health

According to researchers, middle aged and elderly people with high levels of vitamin D could reduce their chances of developing heart disease or diabetes by 43 percent.

A review of 28 studies on the relationship between vitamin D and cardiometabolic disorders revealed a significant association between high levels of vitamin D and a decreased risk of developing cardiovascular disease, type 2 diabetes, and metabolic syndrome.

High-dose vitamin D supplements have been associated with helping to increase the body's sensitivity to the blood sugar-regulating hormone insulin, thus reducing the risk of diabetes.

Vitamin D Fights cancer

Vitamin D affects virtually every cell in the body and is one of most potent natural cancer fighters. Receptors that respond to vitamin D have been found in nearly every type of human cell, from the bones to the brain.

The body's organs convert vitamin D in the bloodstream into calcitriol, which is the hormonal or activated version of vitamin D. This is then used by the organs to repair damage, including that from cancer cells.

Numerous studies have confirmed that vitamin D is actually able to enter cancer cells and trigger apoptosis or cancer cell death.

One study found that vitamin D worked as well at killing cancer cells as the toxic breast cancer drug Tamoxifen, without any of the detrimental side effects and at a tiny fraction of the cost.

In mice, cancer tumors shrank by more than 50 percent, and some altogether disappeared, when vitamin D was injected.

Theories linking vitamin D to certain cancers have been tested and confirmed in more than 200 epidemiological studies, and more and more evidence is emerging hthat vitamin D plays a key role in the prevention of all types of cancer.

Vitamin D's protective effect against cancer works in multiple ways, including:

• Increasing the self-destruction of mutated cells (which, if allowed to replicate, could lead to cancer)
• Reducing the spread and reproduction of cancer cells
• Causing cells to become differentiated (cancer cells often lack differentiation)
• Reducing the growth of new blood vessels from pre-existing ones, which is one way that dormant tumors turn cancerous.

Optimize Your vitamin D Levels

Making sure that your vitamin D levels are optimized is one of the simplest, yet most health-beneficial things you can do to protect your health.

The few dietary sources of vitamin D are foods like fatty fish (salmon, mackerel, tuna, sardines) or fish livers (such as cod liver oil), milk and dairy products, egg yolks, and beef liver.

However the major source of vitamin D is sunlight, specifically ultraviolet B (UVB) radiation, which synthesizes vitamin D in the skin.

Another option is taking a vitamin D supplement. Make sure to supplement with natural vitamin D3 (cholecalciferol), which is the natural form of this vitamin, and not the synthetic and highly inferior vitamin D2.