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The complete guide to vitamin D
Vitamins (A, D, E, K, C and Group B) are essential molecules for the proper functioning of the body, however, they can’t all be synthesized by the body sufficiently. To guarantee a sufficient supply of vitamins to the body, we must first understand in which foods these vitamins can be found.
How many of us deliberately soak up the sun on a warm summer’s day? The answer is lots! Exposing yourself to the sun ensures a supply of vitamin D.
Vitamin D is synthesized by the skin when it is exposed to UV rays emitted by the sun.
Vitamin D: how it works and where it comes from
What is it?
Vitamin D or Calciferol is a fat-soluble (soluble in both fats and oils) vitamin that is stored in the body. In order to better absorb vitamin D that is present in food, it is recommended that consumption is combined with high-quality fats.
There are two types of vitamin D:
- vitamin D2 or ergocalciferol which can be found mainly in plants.
- vitamin D3 or cholecalciferol which can be found in animal sources. This is also the sort of vitamin D that our skin synthesizes it when exposed to the sun.
These two vitamins play similar roles, with the only major difference being that vitamin D3 is absorbed more easily by the body.
How is it that the sun is central to the production of vitamin D? Well, in reality, it’s pretty simple!
The skin synthesizes a molecule (7-dehydrocholesterol) which is then used in the construction of vitamin D. In contact with the ultraviolet rays of the sun, its structure is modified into an intermediate form: provitamin D.
Provitamin D is then transported through the liver and then the kidneys before finally becoming Vitamin D.
There really is no need to overly-expose yourself to sun just so that you can stock up on vitamin D.
During summer, spending 10-15 minutes a day exposed to the sun guarantees enough vitamin D to last all winter! It is also important to use sun tan lotion in order to prevent skin diseases such as skin cancer.
All vitamin D that is synthesized during the summer is stored in the liver, muscles and fat and will be used when needed throughout the rest of the year.
Where is it found?
You can find vitamin D in animal products and in some plants.
Indeed, this vitamin can be synthesized by our skin through the effects of ultraviolet rays, but is also present in many foods within our daily diet.
Foods rich in vitamin D3 include cod liver oil (250 μg per 100g) but also oily fish (salmon, herring, mackerel, sardines), dairy products and egg yolks.
Mushrooms are the main source of vitamin D2 among plants based products with about 3.9 μg per 100g.
This is why it is recommended that people following a vegetarian or vegan diets should have vitamin D supplements..
In the case of vitamin D supplements, it is recommended that vitamin D3 be consumed in liquid form for better assimilation. The body is then able to store it and it is not necessary to take a daily dose; a weekly or monthly intake is would suffice.
We recommend that people consult their GP in order to be advised on supplements that are best adapted for their individual needs.
With Feed., each meal provides 33% of the recommended daily vitamin D requirements.
Vitamin D: Its role in the body
Vitamin D has a vital role in the body. Its main function is to maintain good concentration levels of calcium and phosphorus in the blood by facilitating its absorption through the intestines and reducing secretion by the kidneys.
Vitamin D’s role is to maintain calcium and phosphorus in our body to ensure:
- Good mineralization of the skeleton by facilitating the fixation of calcium on bones, cartilage and teeth.
- Better blood glucose stability by improving the effects of insulin. It is important to have a stable blood glucose level. This prevents tiredness and small hunger urges that can lead to snacking!
How much vitamin D does the body need?
Today, 80% of Europeans are deficient in vitamin D due to a lack of exposure to sunlight or an unbalanced diet.
The daily intake recommended by ANSES is 15 μg/day from the age of one with a maximum daily dose of 100 μg/g.
What happens when there is a lack of vitamin D?
Vitamin D deficiency can lead to osteoporosis (= bone demineralization) in adults or rickets (= bone mineral defect) in children.
People at risk include children, the elderly, people who rarely sunbathe, overweight people and vegans.
However, overconsumption of vitamin D can also have adverse effects on the body. Symptoms of excess vitamin D may include nausea, vomiting, kidney stones, digestive disorders and anorexia.