Sun-deprived Britons lack vitamin D, say health experts

An exclusive report marks ‘sea change’ in government thinking on the effect of gloomy winters

Chris Green,Charlie Cooper
Monday 03 August 2015 14:32 BST
Some time in the sun reduces the risk of rickets in children
Some time in the sun reduces the risk of rickets in children

People across the UK should increase their daily intake of vitamin D because gloomy British winters do not provide enough sunshine to maintain healthy levels throughout the year, government health advisers have recommended.

If the advice, contained in a draft report published by the Scientific Advisory Committee on Nutrition (SACN), is adopted by the Government, it would be the first time that a recommended daily intake of vitamin D was set across the UK. Important for strong bones, vitamin D is also believed to carry other health benefits.

People between 11 and 64 should ensure they reach 10 micrograms of vitamin D every day, the SACN said. It was previously assumed that exposure to sunlight would enable most people to reach this target, but new scientific evidence shows “this is not the case”, it added.

Experts said that the report marked a “sea change” in thinking about vitamin D and was likely to lead to a spike in the sales of supplements, as well as the creation of specially enriched foods. Most people currently get less than 5 micrograms of vitamin D daily from their diets.

People between 11 and 64 should ensure they reach 10 micrograms of vitamin D every day. It was previously assumed that exposure to sunlight would enable most people to reach this target, but new scientific evidence shows “this is not the case”

The SACN report said the new recommended intake should apply throughout the year “as a precautionary measure” to cover those who do not get much sun, such as those who are housebound or cover their skin for cultural or religious reasons. It would ensure that 97.5 per cent of the population reached healthy levels of vitamin D.

The report is subject to a nine-week consultation period which is due to conclude in September. The final version will be published early next year, after which its recommendations are expected to be adopted as official health guidance.

Dr Adrian Martineau, an expert on vitamin D’s effect on health at Barts and the London School of Medicine and Dentistry, said that a daily intake of 10 micrograms would “significantly improve public health in the UK” and the new advice marked a “sea change” in thinking. “Before this, the general assumption was that adults were able to make all the vitamin D they needed from sunshine, and didn’t need to have any dietary or supplementary intake,” he said.

“The action of sunlight on the skin in the UK is highly variable for different populations depending on the time of year and the latitude – you’ll get more UVB in Brighton than in John O’Groats – and finally, how much skin is exposed and the colour of skin. SACN was right to say that we can’t rely on sunshine in the UK to meet the vitamin D requirements. That’s a major and important change. It’s a big step forward that this is now officially recognised.”

He predicted that, were everyone in the UK to reach the recommended 10 micrograms, it could lead to the “elimination” of rickets and hypocalcemic seizures – rare manifestations of severe vitamin D deficiency that have nevertheless been on the rise in the UK in recent years.

If elderly people were to take more vitamin D, they would be likely to see improvements in muscle strength, which could lead to fewer fractures caused by falls, he added.

The average British diet is not conducive to a high intake of vitamin D, which can be obtained from relatively few food sources including oily fish, red meat, certain mushrooms and, to a lesser extent, from eggs.

“Given current intake levels of vitamin D from foods, at less than 5 micrograms per day, the draft recommendation of 10 micrograms is unlikely to be achievable from these foods alone, particularly for groups where there is advice to limit oily fish consumption to two servings a week, such as girls and pregnant women,” said Helena Gibson-Moore, a scientist at the British Nutrition Foundation. “Taking some exercise in the sunshine, while avoiding sunburn, is sound advice for all.”

Dr Martineau said that it was unlikely that the entire population would be willing to take supplements to fill its vitamin D deficit, so the best solution would likely be the routine fortification of food and drink, something which already occurs in other countries.

“We’re already starting to see manufacturers fortifying food and drink products with vitamin D,” said Laura Jones, a global food science analyst at the market research agency Mintel. “The use of vitamin D supplements is likely to go up as well, but most consumers prefer to get their vitamins and minerals from food and drink products.”

Marks & Spencer recently became the first retailer in the UK to add vitamin D to its entire range of packaged bread products, by using a special type of yeast which naturally boosts vitamin D content. Britain’s main supermarkets are likely to follow suit.

Professor Hilary Powers, chair of the SACN Vitamin D working group, said: “It is important to remember that this vitamin D report is draft so the recommendations may change after the consultation period. SACN will be publishing its final recommendations in early 2016 and until then the Government’s current advice on vitamin D remains in place.”

Once the consultation is complete, the Department of Health has committed to looking again at the advice on vitamin D. “There is clear evidence that low levels of vitamin D in the body increases the risk of rickets in children and osteomalacia in adults,” a spokesperson said. “Supplements are already available to pregnant women and children under four from low-income families through the Healthy Start scheme."

The best source of vitamin D absorbed through our diet is oily fish (AFP/Getty)

A catalyst for stronger bones

We need vitamin D to help us to absorb calcium and phosphorus from our diet – two minerals which are essential for healthy bones. There is also evidence that vitamin D plays a role in the prevention of respiratory infections.

Links have also been drawn between vitamin D and the prevention of cancer, multiple sclerosis, asthma, and Type 2 diabetes – but these are inconclusive.

A lot of the vitamin D in our bodies comes from sunlight, produced by the reaction of ultraviolet-B light with molecules in our skin called dehydrocholesterol. The stronger the sunlight, the paler the skin and the more skin that is exposed, the more vitamin D we can produce.

However, we can also absorb it from our diet. The best source is oily fish, and it is also present in smaller amounts in red meat and eggs.

Many people get their vitamin D from supplements. These usually contain about 10 micrograms. The Government already recommends them for all pregnant women, as well as people over the age of 65. Supplements are also recommended for people who don’t get much sun, either because they are housebound, or because they usually wear clothes that cover most or all of their skin – for example, women who wear a burqa or niqab.

Babies and children aged six months to five years are also recommended to take a daily supplement with a slightly lower dose.

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