Sunshine May Be Key to Longer Life
Results from these studies have shown that death rates are higher for people with the lowest levels of vitamin D in their body.
Vitamin D is sometimes called the sunshine vitamin, as it can be made by the skin when exposed to ultra-violet rays from the sun.
It was previously thought that vitamin D was useful only to help the body absorb calcium, build bone density, and prevent osteoporosis and rickets.
But in one study, reported in the Archives of Internal Medicine in June 2008 by researchers from the Medical University of Graz in Austria, it was found that mortality rates from any cause were twice that for people with the lowest levels of vitamin D, compared to those with the highest levels.
The study involved 3,258 men and women in south-east Germany, with an average age of 62.
The participants, who had their vitamin D levels checked in weekly blood tests, were followed up over an eight-year period.
In the follow-up, researchers found that more patients with the lowest levels of vitamin D in their blood had died from a variety of causes, including heart disease and cancer.
In a second study, conducted by staff from the Albert Einstein College of Medicine in New York City, the correlation between vitamin D levels and risk of death was studied in over 13,000 adults who represented a cross-section of the American public.
Over a follow-up period of nine years, it was similarly found that people with the lowest levels of vitamin D were 26% more likely to die.
In a previous study at Harvard University, it had been noted that people with high levels of vitamin D were less likely to develop cancer, and 30% less likely to die from it.
They also had an almost 50% reduction in colorectal cancers.
These findings support other recent studies that show that vitamin D may help to regulate the body's immune system, extend the lives of patients with digestive tract cancer, and prevent health problems such as tuberculosis, type 2 diabetes, and cancer.
Low levels of blood vitamin D are also linked to signs of inflammation and auto-immune diseases such as rheumatoid arthritis and multiple sclerosis.
It also appears that people with low vitamin D levels face greater risk of Peripheral Artery Disease or PAD.
PAD happens when arteries in the legs are narrowed by fatty deposits, which causes pain and numbness, and adversely affects walking ability.
According to the American Heart Association, PAD affects about 8 million Americans and is linked to many cases of disease and death.
Vitamin D is present in a number of foods, including fish liver oils, salmon, sardine, animal liver, and dairy products fortified with vitamin D, but many people do not take enough of it.
It is estimated that more than half of older adults worldwide are low in vitamin D.
A large number of young adults are also deficient in it.
According to the authors of the studies, possible reasons for the deficiency include lack of outdoor activities, air pollution, and a decline in the skin's ability to produce vitamin D from sunlight as it ages.
So you might want to make sure you're getting at least 1000 IU (25 µg or micrograms) of vitamin D daily.
But this does not mean that you should go out and spend hours in the sun.
It is a well-known fact that too much sunshine increases skin cancer risks.
Nor should you pop mega doses of vitamin D pills, as excessive intake can be harmful.
Overdosing might cause nausea, vomiting, kidney damage, and over time, deposits of calcium in blood vessels and in the lungs.
Lack of vitamin D may also be a reflection of lack of exercise and other lifestyle factors that affect health.
Or it could be due to health problems such as intestinal or gallbladder disorders, or to intake of medication, that interfere with absorption of the nutrient from food.