In an ideal world, everyone would obtain enough vitamin D from food sources and sunlight that the need for supplementation would be nonexistent. Unfortunately, as most people over two years of age are well aware, we do not live in an ideal world - at least not from the standpoint of health.

People are born and people die. People die as the result of violence, injury, drowning, murder and plenty of outer causes-of-death. However, by-far the leading cause-of-death in the world today is disease. This could entail such things as cancer, ALS, AIDS, pneumonia and a vast assortment of other illnesses and diseases.

There is a wealth of scientific data compiled from literally thousands of studies and experiments suggesting death from disease/illness can be postponed for a significant amount of time under the right circumstances. Since all people only get to live once, most people are willing to take steps they believe have the potential to extend the duration of their time on earth.

There are many different variables that factor in to whether or not a person becomes stricken with a potentially life-threatening illness/disease/condition, including some - like genetics - over which we as humans have very little control. However, there are a number of steps a person can take that science has demonstrated will vastly increase a person's odds of living a long and healthy life.

Among these are the obvious: Avoid smoking, excessive drinking and drug use, other risky behaviors and so on and so on and so forth. However, there are also a few proactive measures identified by science that are believed by an overwhelming majority of researchers who've studied the topics to hold the potential to strengthen the immune system, reduce one's likelihood of developing a debilitating illness or disease, and increase one's lifespan in general.

The most notable of these measures (besides the obvious - like seeing a doctor when sick) is having one's vitamin D levels tested, and then starting a supplementation regimen with the specific dose determined by the individual's specific need.

Enough studies have shown a majority of people in America and across the globe to have deficient levels of the nutrient in the blood that it can be accepted as scientific fact that a majority of people suffer from vitamin D deficiency. This dramatically increases a person's chances of developing a life-threatening condition, and also inhibits the body's immune system from effectively combating diseases and infections.

Other studies have shown that people with higher levels of vitamin D were less prone to be sickly. In addition, others still took the approach of monitoring individuals who were given supplements during the course of the study versus control groups who were issued placebo pills that looked identical to the supplements. These studies found that those given vitamin D3 supplements were far less likely to die during the course of the study of develop a serious illness.

Other research compared the two most common forms of vitamin D: D2 and D3, and found the latter to be so far superior many experts are now questioning the viability of D2 as a human nutritional supplement.

The bottom line is this: if you enjoy life and want to prolong it for as long as is possible, have your vitamin D levels tested and begin a vitamin D3 supplement regimen immediately thereafter. That is, assuming your doctor or healthcare provider instructs you to do so, which he or she almost certainly will if he or she cares about the health of the patient and is knowledgeable about the myriad diseases linked to vitamin D deficiency.