The currently available epidemiological data support the view that vitamin D deficiency is common worldwide, including Poland. However, according to the authors of the current review published in 'Nutrients', associations between vitamin D status and global and public health have not been fully explored yet.
They say that most, but not all, published studies reporting health risks and morbidity due to vitamin D deficiency, demonstrate good and well-balanced evidence. They add that a number of negative studies regarding vitamin D effects should also be acknowledged in the literature from the last decade.
Conclusions from the majority of RCTs demonstrate the beneficial effects of vitamin D in cancer prevention and the all-cause mortality rate, the authors argue.
The first vitamin D recommendations were prepared and published in Poland in 2009, followed by the second and third in 2013 and 2018.
The newly published review provides a consensus agreement resulting from a review of epidemiological evidence, case-control studies and randomized control trials (RCTs), as well as an expert panel of expert clinicians representing national medical societies, and national consultants involved due to their expertise as well as recognized researchers having a consequential and significant track record in the field of vitamin D.
The report states: "The vitamin D status of toddlers, children, adolescents, adults and seniors again needs to be paid special attention to. The present paper provides the clinical consensus on the prevention and treatment of vitamin D deficiency in Poland.
"Prophylaxis of vitamin D deficiency should be re-introduced for medical societies, medical professionals, and healthcare policymakers. It is strongly postulated to include practical guidelines on the prevention and treatment of vitamin D deficiency into every day practice."
The seasonal struggle
The primary driver of seasonal changes in 25(OHD) levels is is solar ultraviolet-B (UVB) exposure. Solar UVB comprises 3–5% of midday solar UV radiation in mid-latitudes near solar noon in summer but it drops to near zero in winter for about six months a year in Poland. One can make vitamin D from solar UVB exposure only when one’s shadow is shorter than one’s height.
Vitamin D pathway
Vitamin D is hydroxylated in the liver to 25-hydroxyvitamin D, ie. 25(OH)D, and then in the kidneys, forming biologically active metabolite 1,25-dihydroxyvitamin D.
Of note, vitamin D2 coming from sun dried mushrooms and UV irradiated yeast, and vitamin D3 originating from sun exposure and the dietary intake of oily fish, cod liver oil and supplemented foods are both metabolized in the liver to 25-hydroxyvitamin D.
In fact, 25(OH)D represents either or both 25-hydroxyvitamin D2 and 25-hydroxyvitamin D3 and should be treated as the major circulating metabolite form, with a longer mean half-life of about 13–15 days, in comparison to other chemical forms.
The two main pathways of degradation of both 25(OH)D and 1,25(OH)2D are the C23 lactone pathway and the C24 oxidation pathway. The abovementioned vitamin D metabolites are degraded by the actions of CYP24A1 (24-hydroxylase). After several steps, calcitroic acid, one of the end products of the C24 oxidation pathway, is excreted, mainly in the bile and thus in the faeces.
The General Recommendations
The review provides a detailed list of recommendations for each age group as well as for specific life stages and at-risk groups. Some of the basic recommendations are summarised as follows.
The prevention of vitamin D deficiency in the general population with the use of cholecalciferol should be individualised depending on age, body weight, the sun exposure of an individual, dietary habits and lifestyle.
If disease-specific practice guidelines are not available, preventive treatment of vitamin D deficiency in the risk groups should be implemented according to arrangements for the general population; the maximal admissible daily doses of cholecalciferol for a given age group in the general population are recommended for use in the risk groups of vitamin D deficiency.
In the general population with documented vitamin D deficiency, the dosing of cholecalciferol (or calcifediol) should be based on serum 25(OH)D concentration and chronological (calendar) age, and in case of cholecalciferol, additionally on body weight.
In the risk groups, in case of vitamin D deficiency, the cholecalciferol (or calcifediol) treatment and dosage adjustment should be based on 25(OH)D concentration as well as age, the nature of the underlying disease, medical therapy, and in case of cholecalciferol, additionally on body weight.
They note that adjusting the dosing regimen to the patient’s preference and supplementing on a weekly or monthly basis may positively impact adherence.
If supplementation with use of calcifediol in daily doses of 10 µg in oral solution is required for medical reasons, the first control of serum 25(OH)D is recommended within 6–8 days.
15(3), 695; https://doi.org/10.3390/nu15030695 (registering DOI)
"Guidelines for Preventing and Treating Vitamin D Deficiency: A 2023 Update in Poland"
Authors: Płudowski, P.; Kos-Kudła, B.; Walczak, M.; Fal, A.; Zozulińska-Ziółkiewicz, D.; Sieroszewski, P.; Peregud-Pogorzelski, J.; Lauterbach, R.; Targowski, T.; Lewiński, A.; Spaczyński, R.; Wielgoś, M.; Pinkas, J.; Jackowska, T.; Helwich, E.; Mazur, A.; Ruchała, M.; Zygmunt, A.; Szalecki, M.; Bossowski, A.; Czech-Kowalska, J.; Wójcik, M.; Pyrżak, B.; Żmijewski, M.A.; Abramowicz, P.; Konstantynowicz, J.; Marcinowska-Suchowierska, E.; Bleizgys, A.; Karras, S.N.; Grant, W.B.; Carlberg, C.; Pilz, S.; Holick, M.F.; Misiorowski, W.