Vitamin D is known as the ‘sunshine vitamin’ and plays a crucial role in your health. We all know how important it is to get enough of it, but did you know it is also possible to take too much? Although an overdose is fortunately very rare, it is good to know what to look out for so you do not take in too much.
What exactly is vitamin D?
Vitamin D is not really a vitamin, but a hormone that plays a crucial role in various bodily functions. Your body needs this compound mainly for the absorption of calcium and phosphate from food, which is essential for strong bones and teeth. It also supports the immune system and contributes to normal muscle function.
What is special about it is that your body can largely produce it itself. When your skin is exposed to ultraviolet B radiation (UVB) from the sun, it converts a compound in your skin into vitamin D3. This is then converted in your liver and kidneys into the active form your body can use.
Different types
There are two main forms of vitamin D in supplements: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Vitamin D3 is identical to the form your body produces itself and traditionally comes from animal sources, but is these days also available from plant-based lichen. Vitamin D2 is obtained from other plant sources.
For supplements we advise choosing the latter form, because your body can process it more effectively and holds on to it longer. Both forms can, however, cause the same problems when taken in excess.
What happens with too much vitamin D?
It is a fat-soluble substance, which means the body stores excess amounts instead of excreting them. This is different from water-soluble vitamins such as vitamin C, which your body excretes through urine. Because of this property, this compound can build up in your body with prolonged high intake.
The problem arises because it helps with the absorption of calcium from food. When you take in too much, this can lead to raised calcium levels in your blood, a condition called hypercalcaemia. This raised calcium level is the cause of most problems that arise with an overdose.
Recognisable symptoms of too much vitamin D
The symptoms of an excess are often the result of too much calcium in the blood. We advise you to be alert to the following signals:
- Stomach and bowel problems: nausea, vomiting, stomach ache, constipation or diarrhoea can be a consequence of too high a dose of vitamin D. These complaints arise because the raised calcium level disrupts your digestion.
- Tiredness and weakness: you can feel unusually tired, even though you have slept enough. Many people also experience muscle weakness and a feeling that their body is heavier than normal.
- Thirst and frequent urination: excessive thirst and a frequent urge to urinate are common symptoms with raised calcium levels.
- Neurological complaints: in more serious cases symptoms such as confusion, dizziness and disorientation can occur.
When does a vitamin D overdose arise?
It is almost impossible to get too much through sunlight. Your skin regulates production and stops it after a certain amount of UVB radiation. Through food an overdose is very unlikely too: you would have to eat enormous amounts of oily fish to get into trouble.
An overdose really only arises through prolonged use of too high doses as a food supplement. The number of people in the Netherlands who take in more than the safe maximum intake is very small (less than 0.1 per cent).
Safe dose and legal limits
The European Food Safety Authority (EFSA) has established that adults may take in a maximum of 100 micrograms a day. Dutch law lays down that a food supplement may contain a maximum of 25 micrograms: a dose that is safe and effective for most people. For people at increased risk of a deficiency this dose can even be necessary.
We always advise following the dose on the packaging and never taking more than recommended. Also make sure you buy supplements from reliable suppliers, because unfortunately there are supplements in circulation that contain more vitamin D than the label states.
The importance of vitamin K2
An interesting point we would like to share with you is the importance of vitamin K2 alongside vitamin D supplementation. Where vitamin D is needed for the absorption of calcium from food, vitamin K2 directs the mineral to the right place in the body, such as your teeth and bones. This can help prevent calcium building up in unwanted places such as the kidneys and blood vessels.
Longer-term risks
With prolonged overdosing, more serious health problems can arise. Too high a calcium concentration in the blood can lead to the formation of kidney stones and can eventually cause kidney function problems. Cardiovascular problems can arise too through calcium deposits in blood vessels.
Our advice for safe use
At Dutch Balance we think it is important that you use vitamin D safely. We advise you to:
- Always follow the recommended dose on the packaging
- Contact your GP or pharmacist if you are unsure about the right dose
- Have a blood test if you suspect your vitamin D level is too high or too low
- Seek medical help immediately with symptoms that could point to an excess
Choose quality vitamins
With vitamins it pays to pay attention to quality. At Dutch Balance you will find only tested vitamins and minerals that meet all the legal requirements. We offer high-grade vitamin D3 capsules from plant-based lichen for optimal absorption, for instance.
An overdose is rare but can have serious consequences. By handling supplements consciously and not exceeding the recommended doses, you can safely benefit from vitamin D. If you have questions, our team is always ready to help you make the right choices for your health.
