Vitamine D : pourquoi en avons-nous besoin ? - Epycure

BIEN-ETRE Vitamin D: why do we need it?


8min reading time

80% of the Western population is deficient in vitamin D , including 20% ​​in a state of deficiency , according to the National Academy of French Medicine. In short, the vast majority of us are deficient in vitamin D. Why is vitamin D essential for our health? How to provide it naturally? How to complement each other well? Find out everything you need to know about vitamin D in this article.

Vitamin D essential for bones but not only that!

Vitamin D , or calciferol, is known primarily for its important role in bone metabolism . It acts, in fact, at the level of the intestines and kidneys to absorb calcium and phosphorus and thus promote bone mineralization (cartilage, bones, teeth). Vitamin D thus ensures the strength and good health of our bones and teeth.

Since the super study carried out by researchers Alison Avenell, William J. Gillespie, Lesley D. Gillespie and Dianne O'connell on vitamin D , we know that this small molecule helps prevent osteoporosis (which affects nearly 30% of women over 50). Over the age of 65, take it on all occasions: a dose greater than 800 IU/day reduces the risk of fracture by 50%. And for everyone else...: remember that 80% of the French population lacks vitamin D.

But vitamin D has many other benefits! It also plays a role in:

  • Muscle contraction; Recent work has shown that it is essential for good muscle functioning and promotes the renewal of muscle fibers.
  • Nervous transmission; vitamin D appears protective of neurons, participating in the prevention of the decline of intellectual faculties with advancing age.
  • Immune activity; vitamin D modulates the functioning of the immune system, its role is considered (but not demonstrated) in protection against certain cancers and certain autoimmune diseases (diseases during which the body produces antibodies against its own tissues), such as such as type 1 diabetes or rheumatoid arthritis. According to the National Academy of Medicine, “a significant correlation between low serum vitamin D levels and mortality from Covid 19 has been shown. Vitamin D cannot be considered as a preventive or curative treatment for SARS-CoV-2 infection; but by attenuating the inflammatory storm and its consequences, it could be considered as an adjuvant to any form of therapy.”
  • Hormonal regulation, particularly insulin and pituitary hormones; Vitamin D improves insulin sensitivity and thus by reducing inflammation and the risk of high blood pressure, it could contribute to the prevention of cardiovascular diseases.
  • Coagulation.
  • The renewal of our cells.

Why are we lacking in vitamin D?

A long, long time ago, long before lockdowns and internet shopping... We were naked. And yes ! All day long, in the open air, the sun caressing our skin, we frolicked “almost naked”. Nature being well done, our body quietly proceeded to produce vitamin D thanks to this magnificent exposure to the sun. Today, between pollution, down jackets, anti-COVID 19 masks and the climate disaster, things have become a little more complicated. We don't get enough exposure to the sun (which is beneficial against skin cancer!). Furthermore, those who wear lenses or glasses, anti-reflective agents harm the synthesis of vitamin D.

Fortunately, vitamin D has a dual origin:

  • 1/3 of vitamin D is provided by food, mainly through fatty fish, raw egg yolk and mushrooms.
  • 2/3 of vitamin D is synthesized by the body in the skin under the action of solar rays (UVB) and a cholesterol derivative present in the skin layers mainly in the forearms and the back. retina.

So what do we do ? How to increase your vitamin D intake naturally?

Firstly, it is recommended for all people, all geographical areas and all seasons included to expose themselves at least 3 times a week and for 20 minutes to the sun. 20 minutes of sun in summer provides us with up to 20,000 IU of vitamin D.

Going out, walking in nature, doing sports outdoors rather than in the gym, spending 20 minutes outside during your lunch break or simply sitting on a bench in the sun before going home in the evening... so many good excuses to boost your vitamin D intake . Of course, in winter, the “tank top-sunglasses combo” may be complicated to adopt, but with ¾ of the year remaining, we don't hesitate. Especially since the vitamin D produced by the skin is stored in the liver, muscles and adipose tissues for approximately 1 month in order to be used by the body during winter periods. You do not need to supplement as soon as winter arrives, if you exposed yourself regularly in autumn.

On the plate side, it is mainly in the liver oils of fatty fish where we find vitamin D. Slip into your menu twice a week: salmon, halibut, carp, salted mackerel, fish eggs, marinated or smoked herring, sardines in oil and also raw egg yolk, dark chocolate, calf's liver and mushrooms which are rich in vitamin D. For example, 50 g of canned tuna (half a can) + 1 egg + 30 g of Emmental cheese (one part) + 10 cl of milk enriched with vitamin D (a small glass) = 100% of the recommended intake vitamin D to a child or adult.

For the toughest, opt for the old-fashioned solution: stuffy nose, take one or two spoons of cod liver oil every day (yes, we know!).

The EFSA (European Food Safety Authority) recommends a daily intake of 15 ug of vitamin D , or 600 IU for everyone and 10 ug for infants. 1 tablespoon of cod liver oil per day is sufficient for this daily intake.

Please note, vitamin D supplementation is not systematic!

Never supplement without a real need. Always carry out a blood test beforehand to check your vitamin D levels.

What are the signs of a lack of vitamin D? The clinical signs of vitamin D deficiency are mainly diseases affecting the bones such as Rickets, Osteomalacia and Osteoporosis. A drop in muscle tone, tetany attacks and convulsions (related to hypocalcemia) are sometimes signs of anemia. We have also seen a link between gluten intolerance and vitamin D deficiency .

What are the dangers of excess vitamin D? In case of excess, vitamin D being fat-soluble, it can accumulate in the body and cause various problems such as headaches, nausea, vomiting, weight loss, intense fatigue. Even if vitamin poisoning has become exceptional, it is important to respect the safety limit dose of vitamin D at 100 ug per day in addition to food intake.

How to fill a vitamin D deficiency with food supplements?

If you don't like oily fish, fish liver oil makes you feel really nauseous and you can't sleep, you still have food supplements.

For supplementation, you can take vitamin D from an organic store.

Two forms of vitamin D exist: vitamin D2, ergocalciferol, produced by plants and vitamin D3, cholecalciferol, produced by animals. The latter is synthesized endogenously in our skin.

How much vitamin D per day? Therefore, prefer vitamin D3 at a rate of 1,000 to 2,000 Ul per day. Vitamin D2 is, in fact, 5 times less active than D3, because it needs to be converted before being used.

Vitamin D3 supplements have two origins:

  • The vegetarian version based on sheep lanolin, i.e. the fat that covers the sheep's hair
  • The vegan version based on boreal lichen

How to better assimilate vitamin D? The ideal is to consume vitamin D with a fatty substance for better absorption. Vitamin D is in fact a fat-soluble vitamin, that is to say soluble in fats. A good tip is to put some in your bottle of olive oil so that you can simply consume it daily.

Vitamin D, dosages depending on the pathologies

As seen previously, vitamin D3 is essential for the fixation of calcium in the body by participating in anti-inflammatory, immune and “remineralization” processes; it is THE vitamin for all bone pathologies. Thus, vitamin D is recommended as a supplement in many pathologies:

  • In case of osteoarthritis or arthritis, consume vitamin D in capsule form at 10 mcg = 400 Ul: 1 at breakfast, every day, for life.
  • In case of immune weakness consume:
  • Or liquid vitamin D taken from lanolin (sheep's wool), dosed at 5 mcg: 1 squeeze of 0.5 ml at breakfast, for 3 months
  • Or vitamin D capsules titrated with cod liver oil, dosed at 10 mcg: 1 capsule with breakfast, for 3 months.
  • Or vegetable vitamin D tablets taken from lichen dosed at 20 mcg: 1 tablet with breakfast, for 3 months.
  • In case of itching and pruritus, consume 1 capsule of cod liver oil dosed with 10 mcg of vitamin D and 180 mcg of vitamin A: 1 at breakfast for 4 months.
  • In case of depression, vitamin D is interesting for its action against seasonal depression linked to lack of sunshine, to be consumed according to the following dosages:
  • Liquid vitamin D from lanolin (sheep's wool) dosed at 5 mcg: 1 squeeze of 0.5 ml at breakfast
  • Vitamin D from fish liver oils dosed at 10 mcg: 1 capsule with breakfast for 4 months
  • Vegetable vitamin D from lichen dosed at 20 mcg: 1 tablet at breakfast for 3 months, ideally 6 months from October to March.
  • In case of osteoporosis ,
  • In case of colds and sinusitis, vitamin D is interesting for its overall immune stimulating and anti-inflammatory action, to be consumed according to the following dosage:

Where to find vitamin D? You will find it very easily in any pharmacy or organic store. The benefits of vitamin D no longer need to be proven in France, you will find it without too much difficulty.

Remember that each individual is unique. This advice is generic, it is strongly recommended to seek advice from a doctor, nutritherapist or naturopath before any supplementation.

The best supplementation remains the most natural, having exposure to the sun at the right dose as well as a diet rich in fish.

Solène Senejko

Ingénieure Alimentation & Santé