Vitamin D, or calciferol, is a fat-soluble vitamin that plays many roles in the body. It is best known for its benefits on bone health and the immune system. Its synthesis is directly related to exposure to the sun’s rays, so that certain periods of the year are not very sunny and are conducive to deficiencies in this vitamin.
Characteristics of vitamin D .
- Fat-soluble vitamin synthesized by UVB rays of the sun
- Exists in two forms D2 and D3
- Mostly found in fish and dairy products
- Helps preserve bone and muscle tissue
- Deficiency may be a risk factor for osteoporosis
Why consume foods rich in vitamin D?
Vitamin D: Benefits and Roles in the Body
Bone and Tooth Health
Vitamin D promotes the intestinal absorption of phosphorus and calcium. It actively participates in the mineralization and consolidation of bone tissue and teeth. This is why this vitamin plays a very important role in the prevention and treatment of osteoporosis.
Stimulates the immune system
Calciferol may play an important role in the prevention of certain autoimmune diseases such as type 1 diabetes or rheumatoid arthritis. Its protective effect against breast and colorectal cancers, type 2 diabetes and certain cardiovascular diseases is still under study.
Preserves brain and muscle function
By acting on the absorption of calcium and phosphorus, vitamin D is essential for the contraction and renewal of muscle tissue. It could help to curb muscle wasting, particularly in the elderly. In addition, this vitamin preserves the brain from the premature decline of cognitive and intellectual functions.
Food sources of vitamin D
Vitamin D is found mainly in fish and dairy products, especially if they are fortified. On the other hand, and contrary to certain beliefs, there are not especially vegetables or fruits rich in vitamin D. In case of vegetarian or vegan diet, a supplementation can be judicious.
|Grilled swordfish||100 g||25|
|Grilled eel||100 g||23|
|Salmon, grilled or poached||100 g||15-23|
|Canned salmon||100 g||8-19|
|Smoked salmon||100 g||11|
|Grilled red tuna||100 g||7|
|Atlantic herring, pickled||100 g||7|
|Grilled trout||100 g||5-7|
|Roasted walleye||100 g||5|
|Halibut, Atlantic or Pacific, grilled||100 g||5|
|Atlantic herring, grilled||100 g||5|
|Egg of chicken, only yellow, raw||2-4 large egg yolks (80 g)||3|
|Grilled pike||100 g||3|
|Cow’s milk, 0% to 3.25% MF||250 ml (1 cup)||3|
|Enriched soy beverage||250 ml (1 cup)||2|
|Enriched Rice Drink||250 ml (1 cup)||2|
|Grilled plaice or sole||100 g||2|
|Atlantic Sardine, canned||100 g||2|
|Canned tuna||100 g||1-2|
|Beef liver, braised or sauteed||100 g||1|
How to properly use natural vitamin D?
Use of vitamin D
Daily Vitamin D Requirements
|Recommended nutritional intake (ANC)|
|Babies 0-6 months||20 to 25|
|Babies 7-12 months||10|
|Babies 1-3 years old||10|
|Children 4-8 years old||15|
|Boys 9-13 years old||15|
|Girls 9-13 years old||15|
|Boys 14-18 years old||15|
|Girls 14-18 years old||15|
|Men 19-50 years old||15|
|Women 19-50 years old||15|
|Men 50 and over||15 , and 20 if 70 years old and +|
|Women 50 and over||15 , and 20 if 70 years old and +|
Dietary Vitamin D Supplements. Dosage and Indications
Dietary supplements containing vitamin D are particularly indicated to promote bone and muscle health. They also stimulate immune defenses and preserve cognitive functions. They are found in oily form or in capsules, based on vitamin D2 or vitamin D3. It seems that vitamin D3 in oily form is best assimilated by the body. The dosage is in general from 15 to 30 micrograms per day. Ask for a doctor’s advice.
Undesirable effects of vitamin D
Vitamin D deficiency
Vitamin D deficiency can cause bone mineralization and rickets in young children. In adults, calciferol deficiency results in demineralization of the bone and muscle melting that can lead to osteoporosis. If demineralization of the skeleton becomes important, it can result in convulsions or tetany. Finally, in the long term, a lack of vitamin C intake could promote the decline of cognitive functions and the risk of certain pathologies (cancers, heart disease, etc.).
Consequences of an excess of vitamin D
At a very high dose, vitamin D causes excess calcium in the blood (hypercalcemia), urine (hypercalciuria) and promotes the formation of calcium oxalate-based kidney stones. In healthy adults, competent authorities recommend not exceeding 115 micrograms of vitamin D per day.
Interactions with Certain Diseases
It is recommended not to take dietary supplements containing vitamin D in case of kidney stones. Some molecules used in the treatment of epilepsies, AIDS and obesity can reduce the assimilation of vitamin D. Finally, vitamin D being liposoluble, its assimilation is facilitated by the presence of fat.
Vitamin D is a fat-soluble vitamin that can either be brought by the diet or be synthesized in the human body under the action of UVB during exposure to the sun.
There are two types of vitamin D present in foods. Vitamin D2 or ergocalciferol comes from foods of plant origin while vitamin D3 or cholecalciferol comes from animal foods or is synthesized by humans after exposure to the sun. Once ingested or synthesized by UV rays, vitamin D is transported to the liver where it will be hydroxylated to calcidiol. It is in the kidney that calcidiol is converted into calcitriol, the active form of vitamin D.
In the 1820s, cod liver oil was already used to prevent and treat rickets. It was not until the 1920s that the link between rickets and fat-soluble vitamin deficiency was clearly established. Finally, the identification of vitamin D will take place in 1922. In 1932 A. Windaus isolates vitamin D2, then D3 two years later. Since then, vitamin D has been the subject of scientific studies. His roles in bone, muscle and brain health are of major interest. More recently, it is the potential roles of vitamin D on cancer prevention that have been the subject of thousands of scientific publications.