ADVANCES in science are helping researchers find new ways to identify diseases earlier, a new breakthrough indicates that free circulating vitamin D levels in the bloodstream may be a good predictor of future health and disease risk in aging men.
Vitamin D is important for maintaining healthy bones, as well as protecting against infections and diseases. Vitamin D deficiency is a major global health problem, with estimates suggesting that about 1 billion people have low levels of vitamin D in their blood.
Vitamin D deficiency is particularly common in older people. Also, studies are increasingly showing the importance of vitamin D in protecting against a range of health conditions associated with aging.
Researchers have linked low blood levels of vitamin D with major age-related health problems, including:
• osteoporosis
• increased risk of death from cardiovascular disease
• cancer
• type 2 diabetes
• cognitive decline
There are several forms, or metabolites, of vitamin D in the body. However, the medical community typically uses the total amount of these metabolites to determine people’s vitamin D status.
The body converts the prohormone form, 25-dihydroxyvitamin D, to 1,25-dihydroxyvitamin D, which scientists consider the active form of vitamin D in the body.
However, more than 99% of all metabolites of vitamin D in the blood are bound to proteins, so only a tiny portion of it can be biologically active. This explains why the free, active forms of the vitamin may be a better predictor of current and future health than the total levels.
To investigate whether the free metabolites of vitamin D can better forecast health concerns, the team compared the levels of free and total vitamin D in the men’s bodies with their current health status, considering their age, body mass index (BMI), and lifestyle.
The findings demonstrated that even though both free and bound vitamin D metabolites were linked to a higher risk of death, only free 25-hydroxyvitamin D was predictive of future health problems and not free 1,25-dihydroxyvitamin D.
These data further confirm that vitamin D deficiency is associated with a negative impact on general health and can be predictive of a higher risk of death.
While these findings are promising, the study was observational in nature, so the researchers could not determine the underlying mechanisms.
