Can you overdose on Vitamin D? Warning explained, how much do you need, and what are symptoms of overdose

A doctor referred the middle-age man to hospital for treatment after he had been experiencing symptoms including vomiting, nausea, leg cramps, tinnitus, dry mouth, weight loss, increased thirst and diarrhoea for three months.

The symptoms started around a month after he started an intensive vitamin supplement regime, according to the journal BMJ Case Reports.

Tests showed that his vitamin D levels were seven times the required level and his body had high levels of magnesium and calcium, with his kidneys were also not working properly.

Intravenous fluids were used to flush out his system and he was given drugs to lower excessive calcium levels in his blood.

But what is the recommended intake for Vitamin D supplements and what happens if you take too many?

Here’s what you need to know.

What is vitamin D?

Vitamin D helps regulate the amount of calcium and phosphate in the body. These nutrients are needed to keep bones, teeth and muscles healthy.

A lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults.

Where is vitamin D found?

From about late March/early April to the end of September, most people should be able to make all the vitamin D they need from sunlight, according to the NHS.

The body creates vitamin D from direct sunlight on the skin when outdoors, but between October and early March we do not make enough vitamin D from sunlight.

Vitamin D is also found in a small number of foods, including:

• oily fish – such as salmon, sardines, herring and mackerel
• red meat
• liver
• egg yolks
• fortified foods – such as most fat spreads and some breakfast cereals

Another source of vitamin D is dietary supplements.

How much vitamin D do I need?

According to the NHS, babies up to the age of one year need 8.5 to 10 micrograms of vitamin D a day.

Children from the age of one year and adults need 10 micrograms of vitamin D a day, which includes pregnant and breastfeeding women, and people at risk of vitamin D deficiency.

What happens if I take too much vitamin D?

Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body.

This is known as hypercalcaemia.

This can potentially weaken the bones and damage the kidneys and the heart.

According to Mayo Clinic, hypercalcemia can cause:

• Nausea and vomiting
• Weakness
• Frequent urination

Symptoms may also progress to bone pain and kidney problems, such as the formation of calcium stones.

“Vitamin D toxicity, also called hypervitaminosis D, is a rare but potentially serious condition that occurs when you have excessive amounts of vitamin D in your body,” adds Mayo Clinic.

“Vitamin D toxicity is usually caused by megadoses of vitamin D supplements — not by diet or sun exposure.”

How many vitamin D supplements should I take?

“If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people,” notes the NHS.

“Don’t take more than 100 micrograms of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years.”

Children aged one to 10 years shouldn’t have more than 50 micrograms a day and infants under 12 months shouldn’t have more than 25 micrograms a day.

However, the NHS adds: “Some people have medical conditions that mean they may not be able to safely take as much. If in doubt, you should consult your doctor.

“If your doctor has recommended you take a different amount of vitamin D, you should follow their advice.

“You cannot overdose on vitamin D through exposure to sunlight. But always remember to cover up or protect your skin if you’re out in the sun for long periods to reduce the risk of skin damage and skin cancer.”