Vitamin D : Benefits & deficiency complications
Vitamin D is a hormone needed to absorb calcium from food into the body. It is therefore important and essential for the growth and maintenance of strong bones and teeth. In addition, vitamin D plays a greater role in proper muscles function and helps the immune system.
Sunlight is the main source of vitamin D. The body can produce vitamin D itself under the influence of sunlight in the skin. Vitamin D is also found in food sources: especially in fatty fish, and with somewhat lower levels in meat and eggs. Vitamin D is added to low-fat margarine and baking and frying products.
For young children, the elderly, people with a colored skin, people who rarely go outside and pregnant women are advised to take extra vitamin D to compensate low vitamin d levels.
What is vitamin D?
Vitamin D is a fat-soluble vitamin. Vitamin D is one of the few vitamins that the body can make itself. Under the influence of sunlight, vitamin D is formed in the skin. In addition, the diet provides vitamin D.
2 types of vitamin D in food
Vitamin D occurs in food in 2 forms: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3).
Both forms are formed under the influence of ultraviolet radiation (UV radiation). This radiation is part of sunlight. Vitamin D2 is formed in certain mushrooms and fungi and vitamin D3 in the skin of humans and animals. Therefore, vitamin D3 occurs naturally in foods of animal origin.
In supplements and fortified foods, both vitamin D2 and vitamin D3 are used. Both forms are active, so do their work in our bodies. Vitamin D3 does have a slightly stronger effect than vitamin D2.
Absorption of vitamin D
Vitamin D is best absorbed in the gut when fat or oil is also present. The average absorption of vitamin D from food is estimated at 80%. The body can store vitamin D in fatty tissue and organs, such as the liver.
Vitamin D in the body
In the liver, vitamin D is converted into 25-hydroxyvitamin D. This form is not active in the body but its level in the blood is suitable for determining whether the amount of vitamin D in the body is sufficient. In the kidneys, 25-hydroxyvitamin D is then converted to 1,25-dihydroxyvitamin D. This is the active form of vitamin D.
What foods contain vitamin D?
Vitamin D is found naturally in fatty fish, such as herring, salmon and mackerel. Meat and eggs also provide vitamin D, but less than fatty fish. In the Netherlands, vitamin D is also added to low-fat margarine and baking and frying products (but not to oil). In butter is naturally vitamin D, but much less than what is added to margarines and halvarines.
Vitamin D is also added to artificial infant formula according to the applicable EU directive (1 to 2.5 micrograms/100 kcal).
What is vitamin D good for ? what’s the role of Vitamin D ?
Vitamin D is a nutrient that has several functions in the body health:
- It ensures that calcium and phosphorus from food are properly absorbed and laid down in the bones and teeth during growth.
- It therefore ensures strong bones and teeth.
- It is needed to minimize osteoporosis as much as possible, thus reducing the risk of osteoporosis later in life.
- It plays an important role in maintaining proper muscle function.
- It is important for proper functioning of the immune system. But it has not been sufficiently demonstrated that a vitamin D supplement reduces the risk of infections, such as the common cold.
Consequences of vitamin D deficiency
Vitamin D deficiency can cause rickets (English disease) in young children. This disease causes skeletal abnormalities. In adults and the elderly, a vitamin D deficiency can eventually cause osteoporosis and / or muscle weakness.
Furthermore, chronic gastrointestinal, liver or kidney diseases can lead to vitamin D deficiency. Likewise, various medications (e.g., antiepileptic or cytostatic drugs) can impair vitamin D metabolism
Consequences of too much vitamin D
What happens in case of vitamin D overdose?
An overdose due to excessive sun exposure or increased consumption of natural vitamin D sources is unlikely. An overdose is conceivable above all in the case of excessive intake of vitamin D supplements. Consequences of such a vitamin D overdose can be the formation of kidney stones or renal calcification. Therefore, adults should not take more than a total of 100 micrograms of vitamin D per day through food and/or supplements. Children up to 10 years of age should take a maximum of 50 micrograms per day.
An excessively high vitamin D intake can only occur as a result of long-term use of too many supplements. Long-term use of high doses above the acceptable upper limit can cause calcium deposits in the body. This can result in damage to the kidneys. With a normal diet and following the advice for intake this does not occur.
Long-term exposure to sunlight also does not create a risk of vitamin D excess, as the skin regulates its production. In practice, an overdose in healthy people rarely occurs.
What is the dietary advice for vitamin D?
How much vitamin D do you need?
For everyone there is a daily recommended dosages of 10 micrograms of vitamin D. Only people over 70 must have 20 micrograms per day.
Many people get enough vitamin D through the sun and food. The advice is in the spring, summer and autumn every day fifteen minutes to half an hour between 11:00 and 15:00 with at least your head and hands uncovered in the sun. When a larger part of the body is exposed, a shorter time is sufficient. Your body then makes vitamin D and builds up a supply. In the winter months, the sun is too low to make vitamin D. You then use the reserve you have. You then use the stock you have built up.
You also get vitamin D when you eat halvarine or margarine, liquid cooking fat and fatty fish.
Vitamin D supplements for certain groups
Some groups need more vitamin D than they can get from sunlight and food. For example, for young children, a vitamin D supplement has been shown to reduce the risk of rickets and for the elderly to reduce the risk of falls and bone fractures. For pregnant women, it appears to lower the risk of gestational diabetes, a child with a low birth weight and asthma-like symptoms in the child.
People with toned or dark skin make less vitamin D in the sun. And even if skin doesn’t get out in the sun very often because, for example, someone doesn’t get out much or wears a veil, no vitamin D is produced. For these groups, extra vitamin D is advised.
Vitamin D is involved in the formation of proteins and in the control of a large number of genes. In recent years, this has led to the assumption that there are links between vitamin D supply and chronic diseases, and that new prevention options could be discovered at the same time. With regard to hypertension, type 2 diabetes mellitus, and cardiovascular and cancer diseases, correlations have been found in observational studies, but so far no evidence of causal relationships has been found.
Buying Vitamin D Supplements
You can buy vitamin D supplements in the form of drops, capsules or tablets at the pharmacy or online drugstores. For efficacy, it doesn’t matter which form you buy. Cheaper home brands are as good as the more expensive A brands.
Usually the label says vitamin D3 (cholecalciferol), and sometimes D2 (ergocalciferol). Preferably choose a supplement with vitamin D3, the more active form of vitamin D. The amount of available micrograms is listed on the label. Micrograms are usually written down with the abbreviation µg or mcg.
Are you unsure about how many pills or drops you need? Ask your pharmacist for advice.
Can you get too much vitamin D?
The acceptable upper limit of vitamin D intake for adults and children aged 11 to 17 is 100 micrograms per day. For children aged 1 to 10 years the limit is 50 micrograms per day and for children up to 1 year the upper limit is 25 micrograms.
Fortified foods for young children
In the USA, vitamin D may be added to foods, with a maximum fortification level of 4.5 micrograms/100 kilocalories to avoid excessive intake.
Fortified dairy products for young children are mainly on the market, such as desserts, cottage cheese, yogurt, porridge and toddler milk. But when you as a parent give extra vitamin D in the form of drops, capsules or tablets, you already know that your child is getting enough vitamin D.
Moreover, you know exactly how much your child is ingesting. It is not necessary to give products with extra vitamin D.