Free vitamin D levels in the blood would be a good indicator of health risks, especially in older men. This is suggested by a study presented at the European Society of Endocrinology’s e-ECE 2020 conference.
- There are several forms of vitamin D and most often there are several forms of vitamin D in the body, but it is the total amount of vitamin D in the body that is measured to assess whether or not there is a lack.
- However, it is its free form in the blood, called free 25-hydroxyvitamin D, which would be the best indicator of health and the risk of disease.
Essential for healthy bones and teeth, vitamin D plays an essential role in the metabolism of calcium and phosphorus in the body: it regulates the level of calcium in the blood by improving its intestinal absorption, while minimizing its elimination through urine. It also participates in the deposition and removal of calcium from bones, in the proper functioning of muscles and the immune system and has a protective effect on neurons.
Adults suffering from vitamin D deficiency are particularly predisposed to a drop in muscle tone, bone demineralization, cardiovascular disease, a decline in intellectual faculties and have a general susceptibility to infections.
According to a new study by Louvain University Hospitals (Belgium) presented to the European Society of Endocrinology e-ECE 2020 conferencemeasuring circulating vitamin D levels in the blood would be a better indicator of health than measuring total vitamin D levels in the body, more accurately predicting future risk of disease and death.
Free metabolites, more reliable indicators of health
Indeed, there are several forms of vitamin D in the body, but it is the total amount of these metabolites that is most often used to assess people’s vitamin D levels. Over 99% of all vitamin D metabolites in our blood are protein bound, so only a very small fraction is free to be biologically active. Therefore, free and active forms may be a better indicator of current and future health. Among them, 25-dihydroxyvitamin D, which is converted into 1,25-dihydroxyvitamin D, is considered to be the active form of vitamin D in our body.
Researchers at Leuven University Hospitals investigated whether free vitamin D metabolites were better predictors of health than other forms of vitamin D. For this, they used data from a European study on aging male, which was collected from 1,970 community-dwelling men, aged 40 to 79, between 2003 and 2005.
Levels of total and free vitamin D metabolites were compared to their current state of health, taking into account factors such as age, body mass index (BMI), smoking, and state of health declared. Total levels of free and bound vitamin D metabolites have been associated with a higher risk of death. It turned out that only free 25-hydroxyvitamin D was predictive of future health problems and not free 1,25-dihydroxyvitamin D.
“Most studies focus on the association between total 25-hydroxyvitamin D levels and age-related disease and mortality. 1,25-dihydroxyvitamin D being the active form of vitamin D in our bodies , it is possible that it may have been a stronger predictor of disease and mortality. It has also been debated whether to measure total or free vitamin D levels. Our data now suggest that levels of Total and free 25-hydroxyvitamin D are the best measure of future health risk for men.”explains Dr. Leen Antonio, lead author of the work.
According to him, these data also confirm that “Vitamin D deficiency is associated with a negative impact on general health and may be predictive of a higher risk of death”.
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