Millions of adults have no idea that mushrooms, red meat and oily fish are sources of Vitamin D

A survey of 2,000 adults revealed a stark lack of knowledge around adult vitamin intake, including where to source them.

While just 12 per cent claimed they are very familiar with the sources of Vitamin D, only 38 per cent realise that late April to September are the months you can get Vitamin D from sunlight.

A further one in 10 adults admitted to feeling as or more anxious about their health this coming winter.

And less than one in five (16 per cent) were aware vitamin D can be found in red meat, while just a tenth were could name mushrooms as a source.

Clueless about dosage

More than half (55 per cent) were also clueless about how much of each vitamin they should be taking in every day.

The research was commissioned by Warburtons to highlight its Half and Half range.

Dr Zoe Williams, who helped the development of the report, said: “Addressing Vitamin D deficiency in the UK is clearly of importance to the nation’s health so it’s great to see Warburtons raising the issue with this report.

“It really highlights how much there is to do to increase the public’s knowledge about Vitamin D.

"Just expecting people to buy over the counter supplements is not sufficient action, especially since those most affected are the least likely to be able to do so.

“More focus needs to be put on education, free access to vitamin D supplementation and fortification of foods, like the Warburtons Half White Half Wholemeal loaf.