“This [known as hypercalcaemia] can weaken the bones and damage the kidneys and the heart.”
People who have medical conditions, like the man in the reported case, may not be able to safely take as much vitamin D as other people.
In the BMJ Case Report, the man who had taken too many supplements also had other health issues.
He had an inner ear tumour, for example, and a build-up of fluid in the brain, bacterial meningitis and chronic sinusitis.
“If your doctor has recommended you take a different amount of vitamin D, you should follow their advice,” the NHS added.
During the summer months in the UK, people should be able to get all the vitamin D they need without supplementation.
All-year supplementation is only required if you are housebound, so you do not go out that much, or if you live in an institution such as a care home.
People who usually wear clothes that cover most of the skin would also benefit from safe consumption of vitamin D.