What are the benefits of vitamin D supplementation?
Vitamin D is essential for health; it has several forms and origins (endogenous: synthesized by the body, or exogenous: obtained through food or supplements).
What is vitamin D?
Vitamin D refers to steroid compounds with antirachitic activity:
-
ergocalciferol or vitamin D2
-
cholecalciferol or vitamin D3
Vitamin D is one of the fat-soluble vitamins; it is a vitamin, but it can also be considered a hormone.
Vitamin D is notably synthesized by our skin under the action of ultraviolet (UV-B) radiation, with optimal synthesis during summer sun exposure.
The specific activity of vitamin D requires a specific receptor present in almost all tissues of our body.
What are the properties of vitamin D?
It is relatively fragile and degrades rapidly from light, oxygen, and acids.
Vitamin D3 is found primarily in animal products and vitamin D2 in plant-based foods. The main dietary sources are oily fish and egg yolks.
Vitamin D is hypercalcemic and plays an essential role in calcium and phosphate metabolism (it participates in calcium and phosphate homeostasis) and is also involved in other physiological processes:
-
In the intestine : it leads to an increase in the absorption of calcium and phosphorus.
-
In bone : several mechanisms exist depending on the vitamin D metabolite. To simplify, the 2 main ones are an indirect mineralization action by increasing blood calcium levels and an increase in mineralization by action on osteoblasts.
-
In the kidney : it leads to an increase in the reabsorption of calcium and phosphorus.
Our body is capable of synthesizing vitamin D, but this synthesis requires exposure to ultraviolet (UVB), which is almost impossible in winter.
Overall, the French population has an insufficient intake of vitamin D.
Why do we need to consume vitamin D?
Vitamin D deficiency leads to disruptions in calcium and phosphate metabolism. This, in turn, affects the secretion of parathyroid hormone (PTH), which, along with the active forms of vitamin D (1,25-dihydroergocalciferol and 1,25-dihydroxycholecalciferol), participates in calcium and phosphate metabolism. The consequences of these disruptions include alterations in homeostasis, with repercussions on bone physiology such as rickets or the development of osteoporosis and osteomalacia (bone demineralization).
Overall, and particularly during winter, the French population exhibits a vitamin D deficiency. Some authors consider this widespread vitamin D deficiency a major public health problem that needs to be addressed. This is especially true given that the deficiency is more pronounced among seniors. Indeed, due to general behavior and dietary habits, as we age, we tend to consume less vitamin D and expose ourselves to less sunlight (reduced outdoor physical activity), which in turn leads to decreased vitamin D synthesis and intake.
Addressing this deficit through diet and supplementation helps to mitigate the effects of deficiencies.
It has been observed that vitamin D supplementation (800 IU/day) reduces the risk of fracture in adults over 70 years of age, particularly in those with a deficiency.
At a normal level (50 to 75 nmol/L) vitamin D contributes to functions other than bone physiology:
-
participates in the regulation of blood pressure
-
prevention of cardiovascular diseases (a meta-analysis suggests a 7% reduction in mortality)
-
prevention of certain cancers (colon and breast, data to be consolidated)
-
contributes to the prevention of certain infections
-
contributes to the proper functioning of the immune system
-
contributes to proper muscle function, particularly in cases of osteomalacia.
What is the average amount of vitamin D consumed by the French?
According to ANSES and data from the INCA 3 study, the average dietary intake of vitamin D in the French population is:
-
5.2 µg/day for children aged 1 to 3 years;
-
2.6 µg/day for children aged 4 to 10 years;
-
2.9 µg/day in children aged 11 to 17 years;
-
3.1 µg/day in adults, with higher intakes in men.
How much vitamin D should I consume each day?
Unless otherwise advised by a doctor, it is recommended to ensure an adequate intake of vitamin D, without excess, whether through diet alone or with supplements. Indeed, at high doses, vitamin D becomes toxic, so it is essential not to exceed safety limits, particularly when using supplements.
Recommended vitamin D intake for adults
For adults, the nutritional recommendations from health authorities are 15µg/day or 600IU, the upper safety limit is set at 100µg/day (4000IU).
Recommended vitamin D intake for children
In children, nutritional guidelines change according to age:
-
In infants, the sufficient intake is 10µg/day (400IU), the upper safety limit is set at 25µg/day (1000IU)
-
Between 1 and 10 years of age, the sufficient intake is 15µg/day (600IU), the upper safety limit is set at 50µg/day (2000IU)
-
From age 11, the recommended intake is the same as for adults: the sufficient intake is 15µg/day (600IU), the upper safety limit is set at 100µg/day (4000IU)
How to provide vitamin D and ensure you meet your needs?
There are several ways to meet your vitamin D needs.
Sun exposure
It is recommended to get 15 to 20 minutes of sun exposure per day to meet your daily vitamin D requirements. However, this recommendation applies in summer, but is not feasible in winter, and synthesis is also less efficient in people with dark skin. Furthermore, the use of sunscreen (and wearing clothing) also reduces the efficiency of synthesis.
Dietary intake
Vitamin D is present in certain foods; consuming them allows you to contribute to your intake effectively.
Foods rich in vitamin D include:
-
Oily fish: herring, sardines, salmon, mackerel
-
chanterelles, porcini mushrooms and morels
-
Dairy products enriched with vitamin D (it's advertised on the packaging)
-
the egg yolk
-
dark chocolate
-
breakfast cereals enriched with vitamin D
-
butter
-
offal
The use of dietary supplements
Dietary supplements can effectively meet vitamin D requirements. Concentrated doses are available (by prescription) for loading doses to address severe deficiencies. However, in other cases, it is preferable to use lower doses, close to the recommended daily intake, allowing for long-term supplementation. According to some authors, this type of supplementation is more effective; in particular, an increase in fractures has been observed after supplementation with "super doses" (100,000-500,000 IU). It appears that the higher the vitamin D concentration is initially, the faster it drops, leading to bone resorption; therefore, it is preferable to use vitamin D doses close to the recommended daily intake.
Vitamin D supplementation is particularly beneficial for people who:
-
who have an unbalanced diet
-
who do not expose themselves to the sun
-
treated with medications that decrease intestinal absorption of vitamin D: Antiepileptics, Glucocorticoids, Antiretrovirals, Antifungals, Cholestyramine
-
People who have decreased intestinal absorption following obesity surgery (bariatric surgery: sleeve and bypass) or intestinal pathologies (such as IBD)
-
who suffer from obesity
-
old
It is recommended not to take vitamin D supplements while undergoing treatment with medication for heart rhythm disorders.
Taking vitamin D at doses above 2000 IU should be done under medical prescription/supervision.
Warning: Vitamin D is not a miracle drug; it is sometimes misused in excessively high doses. If you are unsure about your vitamin D needs and the appropriate dosage, we recommend consulting your doctor or registered dietitian.
What are the risks and dangers of excess vitamin D?
In cases of chronic excess vitamin D, it becomes toxic and leads to various symptoms:
-
heart rhythm disorders
-
mental disorders
-
confusion
-
conjunctivitis
-
decreased appetite, vomiting
-
fever, chills
-
muscle pain
-
bone pain
-
Hypercalcemia promotes calcium deposits in the body, particularly in the kidneys, blood vessels, lungs, and heart. There is a risk of developing kidney failure.
What are the health claims of vitamin D?
EFSA authorises the use of health claims for products containing vitamin D.
They must provide a minimum of 0.75µg of vitamin D per 100g, 100ml or per portion.
Products meeting these criteria can claim to contribute to:
-
to intestinal absorption and utilization of calcium and phosphorus
-
to maintain normal blood calcium levels
-
to the normal growth of children's bones
-
to the maintenance of normal bone health
-
to maintain the normal state of the muscles
-
to maintain the normal condition of the teeth
-
to maintaining the normal state of the immune system
-
to cell division
And what about Phytocea?
You can find vitamin D3 in ReNacre , among other products. ReNacre is a food supplement designed to help maintain bone density, specially formulated for osteoporosis or osteomalacia.
=== content-split ===
7489814921430
=== content-split ===
Sources
- High Authority for Health
- Eat-Move: the PNNS
-
JC Souberbielle, C Cormier, E Cavalier, V Breuil, F Debiais, P Fardellone, Pl Guggenbuhl, RM Javier, E Legrand, E Lespessailles, J Paccou, T Thomas, B Cortet. Vitamin D supplementation in France for patients with osteoporosis or at risk of osteoporosis: recent data and new practices. Revue du Rhumatisme. Volume 86, Issue 5, 2019.
https://doi.org/10.1016/j.rhum.2019.02.014. - K Briot, C Roux, T Thomas, H Blain, D Buchon, R Chapurlat, F Debiais, JMc Feron, JB Gauvain, P Guggenbuhl, E Legrand, AM Lehr-Drylewicz, E Lespessailles, F Tremollieres, G Weryha, B Cortet. 2018 update of the French recommendations for the treatment of postmenopausal osteoporosis. Revue du Rhumatisme. Volume 85, Issue 5, 2018. https://doi.org/10.1016/j.rhum.2018.02.005.
- Swiss Medical Review - Vitamin D: current information and recommendations
- ANSES: Nutritional Reference Intakes
- Dr. Pierre-Olivier Lang: Vitamin D supplementation: Why? For whom? How?
- ANSES - Vitamin D: why and how to ensure sufficient intake?
- Bischoff-Ferrari HA, Willett WC, Orav EJ, Lips P, Meunier PJ, Lyons RA, Flicker L, Wark J, Jackson RD, Cauley JA, Meyer HE, Pfeifer M, Sanders KM, Stähelin HB, Theiler R, Dawson-Hughes B. A pooled analysis of vitamin D dose requirements for fracture prevention. N Engl J Med. 2012 Jul 5;367(1):40-9. doi: 10.1056/NEJMoa1109617. Erratum in: N Engl J Med. 2012 Aug 2;367(5):481.
- Souberbielle JC, Body JJ, Lappe JM, Plebani M, Shoenfeld Y, Wang TJ, Bischoff-Ferrari HA, Cavalier E, Ebeling PR, Fardellone P, Gandini S, Gruson D, Guérin AP, Heickendorff L, Hollis BW, Ish-Shalom S, Jean G, von Landenberg P, Largura A, Olsson T, Pierrot-Deseilligny C, Pilz S, Tincani A, Valcour A, Zittermann A. Vitamin D and musculoskeletal health, cardiovascular disease, autoimmunity and cancer: Recommendations for clinical practice. Autoimmun Rev. 2010 Sep;9(11):709-15. doi: 10.1016/j.autrev.2010.06.009.
- Cashman KD, Ritz C, Kiely M, Odin Collaborators. Improved Dietary Guidelines for Vitamin D: Application of Individual Participant Data (IPD)-Level Meta-Regression Analyses. Nutrients. 2017 May 8;9(5):469. doi:10.3390/nu9050469.
- The practitioner's review: Vitamin D supplementation in adults: should we change our practices?
- Bacchetta J, Edouard T, Laverny G, Bernardor J, Bertholet-Thomas A, Castanet M, Garnier C, Gennero I, Harambat J, Lapillonne A, Molin A, Naud C, Salles JP, Laborie S, Tounian P, Linglart A. Vitamin D and calcium intakes in general pediatric populations: A French expert consensus paper. Arch Pediatr. 2022 May;29(4):312-325. doi: 10.1016/j.arcped.2022.02.008.
