Is it useful to use vitamin D supplements? And who can really benefit from it? Questions that seem innocuous, but which are at the center of one of the most bitter debates in the medical field: the scientific community is in fact divided between those who consider supplementation crucial for the prevention of a myriad of serious chronic diseases, and those who consider it useless.
One of the areas in which there was less controversy concerns bone disorders and the prevention of fractures, since the primary role of this hormone is to ensure the correct absorption of calcium by the body. A new, large, study, just published in the New England Journal of Medicine it is certainly destined, however, to warm the minds of the experts again: in the elderly and healthy adults, the intake of vitamin D does not seem to reduce the risk of fractures in any way, even in the presence of plasma levels of this hormone traditionally used to diagnose its shortage.
Vitamin D: what it is, what it is for, who needs it (all)
by Cinzia Lucchelli
The Vitamin D Effectiveness Debate
The debate comes from afar. There was a time, in fact, when vitamin D seemed to cure all ailments. Osteoporosis and other metabolic problems of the bones, of course, but not only: heart disease, neoplasms, degenerative, metabolic, respiratory diseases seemed to worsen in case of vitamin D deficiency. And consequently, the consumption of supplements over the last decade has skyrocketed skyrocketing worldwide: in 2017 our National Health Service spent more than 260 million euros to reimburse the supplements prescribed to millions of Italians.
The benefits are not so clear
Really a lot, indeed too much since in many cases the benefits are not so clear. For this reason, Aifa intervened in 2019 with a document, note 96, which more severely circumscribes the criteria for reimbursement, and those for access to tests to assess vitamin D deficiency. The savings were seen immediately: more than 117 million euros less in the first 15 months of monitoring.
The new US research
The Drug Agency’s decision inevitably attracted both praise and criticism. But nearly three years later, new research published by a team of specialists from several American universities seems to be right for it. The study in question derives from a large clinical trial carried out in recent years, the Vital trial, which evaluated the effect of vitamin D and Omega 3 on a wide range of diseases, recruiting over 25,000 Americans over 55.
Previous results had ruled out benefits in several areas, such as oncology or cardiovascular prevention, but the main question remained open: the effects of vitamin D supplementation on bone health, which is the primary prescription field of this hormone.
Cut and sew with Crispr and tomatoes become a source of vitamin D
by Priscilla Di Thiene
The conclusions
Analyzing the participants for over five years, the study concluded that the dose of vitamin D3 (cholecalciferol) used, equal to 2 thousand IU (the most common dose in commercial supplements) does not lead to a reduction in the incidence of fractures compared to placebo. in any subgroup studied, therefore regardless of potential risk factors such as obesity, old age, or levels of vitamin D in the blood below the limit of 20 nanograms per milliliter, threshold below which a diagnosis of vitamin D deficiency is usually made .
Enough with indiscriminate prescriptions
In an editorial accompanying the study, osteoporosis experts Steven Cummings e Clifford Rosen, respectively, of the University of California San Francisco and the Maine Medical Center Research Institute, point out that the new findings should end, once and for all, the era of indiscriminate prescribing of vitamin D supplements in the adult and elderly population, at least. for the prevention of fractures. Vitamin D supplementation and dosage should, in their opinion, be limited to patients who have symptoms of severe deficiencies, or at least conditions that have a high risk of developing them.
Role to rethink
“This is a very solid piece of work, which will undoubtedly cause discussion and could make us rethink the role of vitamin D in preventing fractures in the general population – he explains. Annamaria Colao, professor of Endocrinology at the Federico II University of Naples and President of the Italian Society of Endocrinology -. The results question concepts that we believed to be solid, such as the use of calcium and vitamin D in the prevention of osteoporosis, or the levels of plasma concentration with which we establish insufficiency and deficiency. In fact, these are notions that come from old studies of the ’70s and’ 80s, and that more recent research has long begun to refute “.
Vitamin D, when it is necessary to supplement it
by Simone Valesini
The limits of the study
Despite the high scientific value of the research, Colao warns that it is still too early to put an end to the question. In fact, the study has several limitations, recognized by the authors themselves, such as the use of a fixed dose of vitamin D for all participants, regardless of the levels present in the blood, or the fact that it was not administered in association with calcium (such as is normal in the treatment of osteoporosis), which prevent definitive conclusions from being drawn about usefulness in the presence of particular risk factors or at higher dosages.
The most appropriate use
“For this reason I think it should be taken as an invitation to deepen the role that vitamin D plays in human health, with more research and in greater detail, to ensure that we make the most appropriate use of this substance in the future – concludes the expert – It is certain, for example, the fundamental role it plays in the immune system, but it could be much less useful than we thought in other fields, such as in the prevention of osteoporosis and fractures “.