Over the last years we have broadened the knowledge of vitamin D function in the human body significantly. Vitamin D is rather a prohormone than a vitamin, and its receptors are in cells of the body. Apart from well-known antirachitic action, vitamin D has been proved to have numerous extraskeletal effects, which are still being researched. This vitamin is involved in:
- cardiovascular system, endocrine system and nervous system functioning,
- carbohydrate metabolism
- over 200 genes regulation
- cancer prevention
- immune response, including respiratory infections prevention.
The results of the large-scale meta-analysis revealed vitamin D positive effects in acute respiratory infections prevention, especially along with its primary deficiency. The importance of vitamin D intake has been reassessed in the light of the pandemic. Media experts have started covering benefits of vitamin D more, as far as vitamin D deficiency turned to be related to severe acute diseases and mortality. British scientists revealed the relationship between mortality and the average level of vitamin D based on data from 20 European countries. This does not mean cause-and-effect relationship. An alternative version is that not vitamin D deficiency itself causes severe acute COVID-19, but the conditions which have led to it. However, bearing in mind that vitamin D insufficiency to different extents is common in Russia, taking it is reasonable during the pandemic. Many doctors prescribe vitamin D as a supplement to COVID-19 treatment regimen. Customers often ask for vitamin D supplements of their own volition for deficiency repletion.
When, for whom and how much?
Diets and lifestyles of the vast majority of Russians do not provide sufficient vitamin D intake. In order to define vitamin D therapy dose blood is tested for vitamin D marker — 25-Hydroxivitamin (D (25(ОН)D = calcidiol). Russian Association of Endocrinilogists considers 25(ОН)D less than 10 ng/mL as severe vitamin D deficiency, less than 20 ng/mL as deficiency. 20-30 ng/mL indicate vitamin D insufficiency. The normal range is considered to be 30-100 ng/mL. More than 100 ng/mL indicate risk of toxicity.
In case of deficiency or insufficiency the doctor prescribes treatment regimen, defines the dose and treatment duration. It is common practice to prescribe a repletion dose first and then switch to a maintenance dose. Children of all ages are recommended taking a prophylactic dose of vitamin D, which is prescribed without taking a blood test.
Recommended intake for prophylaxis of vitamin D deficiency (per day)
- 0-1 month: 500 IU
- 1 month- 1 year: 1000 IU
- 1-3 years: 1500 IU
- 3-18 years: 1000 IU
- 18-50 years: at least 600-800 IU
- 50 years and over: at least 800-1000 IU
- Pregnant and lactating woman: at least 800-1200 IU
Some vitamin D3 supplement labels identify 600-1000 IU as a maximum daily intake for pregnant and lactating women due to the risk of teratogenic effects. However there have not been any cases among humans reported. According to clinical practice guidelines, a minimum daily intake of vitamin D for these categories of people ought to be at least 800-1000 IU.
In order to maintain 25(ОН)D over 30 ng/mL you may need to take at least 1500-2000 IU of vitamin D daily. These guidelines are for people who are not at risk of severe vitamin D deficiency. People of this category must see a doctor.
During pandemic in Ireland adults were recommended taking 800-1000 IU for prophylaxis. British experts advised even a higher dose for the Northern hemisphere — 4000 IU. 1000 IU (international unit) of vitamin D is equal to 25 mcg (micrograms).
NB! All forms of vitamin D contraindications are high amount of calcium in the blood or the urine, kidney stones (oxalate calculi), acute and chronic liver and kidneys diseases, renal insufficiency and some others.
All kinds of vitamin D are at your disposal at the pharmacy to help you choose the best option based on the drug form, dosage, brand or personal preferences.
We invite you to attend our free webinar «Pharmacists role in immunization: how to keep your immune system in good shape». During this webinar with Dr. Sally Sayed we will discuss the pharmacists role in disease prevention by administering immunizations and vaccination. The Vitamin D also will be discussed, we will talk about D.DEP 1000 (vitamin D3): vitamin D supplementation studies have shown beneficial effects of it on immune function, in particular in the context of autoimmunity.