Fortifying flour with vitamin D would save the UK £65m a year, according to a new study.

Mandatory addition of vitamin D to wheat flour would prevent a quarter of the 40 million new cases of vitamin D deficiency predicted in England and Wales over the next 90 years, said researchers at the University of Birmingham.

Currently, 20% of adults and 16% of children are estimated to be deficient in Vitamin D, which can lead to rickets, soft bones, bone pain, and muscle weakness.

The main natural source of vitamin D is through sunlight – and sun screen use, air pollution and indoor lifestyles can reduce exposure to sunlight and lead to vitamin D deficiency. Those particularly at risk are older adults and people with dark skin.

The research, published in the European Journal of Clinical Nutrition, projected that adding vitamin D to flour would cost 12p per person per year.

In the UK, multivitamin supplements containing vitamin D are recommended to all children aged up to four, pregnant women and breastfeeding mothers and are provided free-of-charge to those in low-income households.

Some foods, including infant formulas, spreads and breakfast cereals, are fortified with vitamin D. A limited number of breads are also fortified, including Marks & Spencer products and the Vitamin Boost loaf launched under Allied Bakeries’ Kingsmill brand last year.

“While supplements and fortified foods are important sources of vitamin D for the UK population, evidence suggests current UK supplementation polices are not working,” said Dr Magda Aguiar, who carried out the research at the University of Birmingham.

“Addressing vitamin D deficiency in the UK requires a multi-disciplinary approach, and preventing conditions that are the consequence of deficiency would save the NHS money to the extent that it would more than compensate for the money needed to implement flour fortification at a national level.

“We now hope that UK policy-makers will consider a new national policy to fortify foods such as wheat flour with vitamin D to address this serious health issue. This will lead to significant benefits for the population, particularly the most vulnerable groups.”

Dr Aguiar added that a similar national food fortification policy in Finland had reduced vitamin D deficiency from 13% to 0.6% in the population.

The UK government is currently conducting a consultation on a proposal to make the fortification of flour with folic acid mandatory.