A coroner has written to the Health Secretary calling for all pregnant women and those who breastfeed to take vitamin D.

North London coroner Andrew Walker said action should be taken to reduce the risk to others after he held an inquest last week into the death of a three-month-old boy.

In his letter to Andrew Lansley, Mr Walker said Milind Agarwal was taken to the doctor in July with symptoms of a probable viral infection.

He was sent home with saline nasal drops. A later telephone consultation with another doctor led to his parents being advised to give him paracetamol.

But his mother and father still had concerns and called an ambulance. Their son was taken to Northwick Park Hospital in north London ''where it was recognised he was seriously unwell''.

The baby died from septic inflammation of the heart against a background of an abnormal aortic heart valve.

A consultant paediatric pathologist told the coroner's court that vitamin D deficiency played a role in progression of the infection and suggested all pregnant and breastfeeding women be prescribed vitamin D daily.

In his letter, Mr Walker told Mr Lansley that consideration should be given ''to increasing public awareness of vitamin D deficiency'', in particular that all pregnant and breastfeeding mothers should receive 10mcg of Vitamin D every day.

Research has previously found that pregnant women and those trying to conceive are lacking vitamin D.

In 2009, experts warned that a lack of vitamin D in pregnancy can lead to a youngster suffering rickets and longer-term problems such as schizophrenia and Type 1 diabetes.

While many people can get vitamin D from sunshine, those living in cooler countries may not be getting enough.

As a result, the body often relies on its own stores of vitamin D in the winter months. Otherwise, dietary intake or multivitamins are needed.

Vitamin D is found in small quantities in a few foods such as oily fish, eggs and liver, and in fortified foods such as margarine, breakfast cereals and powdered milk.

But pregnant women are advised to avoid liver and liver products, raw or under-cooked eggs and to limit their intake of certain fish such as tuna.