Vitamin D is one of the essential elements for the body's functioning. It increases the concentration of calcium and phosphorus in the blood, which helps to prevent various diseases such as osteoporosis. Difficult to find in food, this fat-soluble vitamin is synthesised by the body thanks to sunlight. Is there a risk of deficiency in case of insufficient sun exposure?
If I don't expose myself too much to the sun, should I be concerned about a vitamin D deficiency?
Summary
Published on February 20, 2024, by Stéphanie, PhD, Doctorate in Life and Health Sciences — 3 min of reading
Themes:
Why is Vitamin D essential to the body?
Just like vitamins A, E, and K, vitamin D is fat-soluble and can be stored in fatty tissues. It comes in two forms: vitamin D2 or ergocalciferol, and vitamin D3 or cholecalciferol. The latter is the active form. It is synthesised by the body and forms in the skin when it is exposed to sunlight. Additionally, vitamin D can also be found in cereals and dairy products. Both forms are metabolised by the liver and kidneys and transformed into active vitamin D or calcitriol. This promotes the absorption of calcium and phosphorus by the intestine. These minerals are then incorporated into the bones for mineralisation.
Can a lack of sun exposure lead to a Vitamin D deficiency?
The sun serves as an infinite source of vitamin D. To this end, it is necessary to expose oneself for at least 10 to 15 minutes, 2 to 3 times a week, ideally between 11 am and 2 pm. Individuals with darker skin or older people have an increased need for sun exposure. At a minimum, it is appropriate to expose the face, forearms, and hands. Consequently, a deficiency is a concern for those who tend not to go outside. This is particularly prevalent in winter, especially among inhabitants of Nordic countries. Furthermore, breastfed babies who are not sufficiently exposed to ultraviolet rays may suffer from a vitamin D deficiency and develop rickets. An insufficient consumption of foods rich in vitamin D can also lead to a vitamin D deficiency.
Symptoms and Consequences of Vitamin D Deficiency
A deficiency in vitamin D primarily manifests as fatigue, muscle pain, and bone pain. These symptoms occur in all individuals, regardless of their age or gender. In infants, muscle cramps or tetany are the first signs of a vitamin D deficiency, leading to low levels of calcium in the blood. A severely deficient baby then becomes rachitic, with a completely soft skull. Furthermore, they will struggle to sit and crawl due to the fragility of their bones. They will also take longer to walk. Additionally, as their bone growth is impaired, their spine may curve abnormally, causing scoliosis.
In children and adolescents, a varus or valgus of the knees can result from a severe deficiency in vitamin D. In adults, it causes bone fragility and disorders in the spine, pelvis, and legs.
