What is vitamin D?
Vitamin D refers to a group of fat-solublesecosteroids necessary for numerous biological functions, first of all the homeostasis and metabolism of calcium and phosphate, promoting the physiological growth of the skeleton, bone remodelling and preventing degeneration with advanced age.
How to get vitamin D?
There are mainly2 ways: through the sun and through diet. Important: it is not enough to eat a diet rich in this vitamin.
- Most vitamin D (almost 95%) comes from the sun and is synthesized through our skin. Specialists recommend that you sunbathe between 10 and 30 minutes a dayto obtain an adequate level of vitamin D (beware of exposure in summer, other than at the hours of greatest incidence). Don’t forget to use sunscreen.
- A small part of vitamin D is obtained through our diet. Foods with more vitamin D are fatty fish such as salmon or mackerel, eggs, cheese and mushrooms. There are also foods that do not naturally contain this vitamin, but have been supplemented to add it.
Functions of vitamin D
- One of the most important functions is to promote the absorption and maintenance of calcium in the bones. If you do not get enough vitamin D, you can suffer osteoporosisor broken bones.
- It mineralizes bones, cartilage and teeth both during growth and after.
- Another of its functions is to help the immune system, since the cytoplasm of some immune cells have vitamin D receptors.
- Other functions have also been demonstrated, such as regulating the pancreas, improving the condition of the skin and promoting brain development.
Vitamin D Deficiency Symptoms Infant
Calcium and vitamin d deficiency symptoms: Signs and symptoms of vitamin D deficiency in children
Common signs and symptoms of vitamin D deficiency in children include:
- Muscle cramps, convulsions and breathing difficulties
- Delayed teething
- Irritable and difficult children
- Being prone to various respiratory infections
- Difficulty breathing due to softening of the rib cage
- Low growth and low weight
- Weakening of the heart muscles
- Typical symptoms of rickets resemble a soft skull, leg bones appear curved, severe and repeated bouts of pain in the legs and muscles, and general weakness.
Symptoms that you have vitamin D deficiency
A lack of vitamin D produces no short-term symptoms, so it is usually detected when there are bone problems. In children it can cause rickets.
There are people with more tendency to suffer from a deficit of this vitamin. Are:
- Celiac people
- Overweight people
- People with kidney failure
- Pregnant people
- People who live in places where they have hardly any sun exposure.
Vitamin D capsule
A promoting effect on intestinal absorption of calcium, phosphate and magnesium is also observed. Nevertheless, the vitamin D group seems to play an important role in cell growth, various neuromuscular and immune functions, and the reduction of inflammation. Since vitamin D can be synthesized in adequate amounts by most mammals sufficiently exposed to sunlight, it should not be considered as a true essential dietary element.
To be honest, it shouldn’t even be considered a vitamin. This lipid molecule has rather the characteristics of a pro-hormone, activated in the hormone calcitriol, which produces its effects by interacting with a nuclear receptor located in several cells of different tissues.
What is the best vitamin D?
In humans, the most important compounds in this group are vitaminD3 (also known as cholecalciferol) and vitaminD2 (known as ergocalciferol) – which, however, will need to be mutated into calcitriol (active hormonal form).
Where does vitamin D come from?
As anticipated, the main natural source of vitamin D is constituted by the endogenous production of cholecalciferol (vit D3) at the skin level, starting from cholesterol, through a chemical reaction that depends on exposure to sunlight (in particular UVB irradiation).
Foods rich in vitamin D
Foods for vitamin d deficiency: Food is the main source of minerals, vitamins, proteins, etc. for a growing child. Therefore, a balanced diet with proper vitamins and minerals is very important to avoid any health risks. An indicative list of foods rich in vitamin D is given below.
- Fatty fish such as mackerel, cod, etc.
- Soy milk
- Cereals and millets
- Dairy products like milk, butter, curd, yogurt, etc.
- Fruit juices, especially orange juice
- cod liver oil
In which fruits and vegetables is vitamin D found?
No fruit or vegetable provides interesting levels of vitamin D.
Outside the animal kingdom, only certain algae and certain species of fungi show “interesting” concentrations of vitamin D.
Why is it important to take vitamin D with the diet?
Dietary recommendations for vitamin D have a wide margin of safety and generally do not take into account the extent of sun exposure, relying entirely on nutritional intake.
This is because, by virtue of the variability linked to the different latitudes (see hours of light and darkness in the Nordic countries), the capture of UVB rays in the population is rather variable; What’s more, let’s not forget that excessive exposure to the sun can increase the risk of skin cancer.
Vitamin D requirements
Under normal conditions, exposure to sunlight is sufficient to meet the body’s calciferol needs. However, especially for safety, in Italy the following levels of intake are recommended:
- infants10÷25 μg
- children 1÷3 years 10 μg
- children 4÷10 years 0÷10 μg
- Girls and boys 11÷17 years 0÷15 μg
- adults 0÷10 μg
- elderly 10 μg
- pregnant woman 10 μg; nurse 10 μg.
- 1 IU = 0.025 μg calciferol
- 1 μg calciferol = 40 IU vitamin D.
Below are tables of recommended levels in the United States, Canada, Australia, New Zealand and the European Food Safety Authority.
|Children 0-6 months||400*||10|
|Children 6-12 months||400*||10|
|over 70 years||800||20|
|Age||Tolerable upper intake (IU/day)||mcg/day|
|Children 0-6 months||1000||25|
|Children 6-12 months||1500||37,5|
|Children 1-3 years||2500||62,5|
|Children 4-8 years||3000||75|
|over 9 years||4000||100|
|Pregnant and nurse||4000||100|
|Age||RDA (IU)||Tolerable Upper Intake (IU)|
|Children 0-6 months||400*||1000|
|Children 7-12 months||400*||1500|
|Children 1-3 years||600||2500|
|Children 4-8 years||600||3000|
|children and adults 9-70 years||600||4000|
|over 70 years||800||4000|
|Pregnant and nurse||600||4000|
|Australia and New Zealand|
|Age||Adequate intake (mcg)||Tolerable maximum intake (mcg)|
|Children 0-12 months||5*||25|
|Children 1-18 years||5*||80|
|Adults 19-50 years||5*||80|
|Adults 51-70 years||10*||80|
|Adults over 70 years||15*||80|
|European Food Safety Authority|
|Age||Adequate intake (mcg)||Tolerable maximum intake (mcg)|
|Children 0-12 months||10||25|
|Children 1-10 years||15||50|
|Children 11-17 years||15||100|
|Pregnant and nurse||15||100|
|*Adequate intake, no established RDAs/RDI|