"Experts recommend everyone consider vitamin D supplements over winter," says a headline in today's Daily Mail, while The Guardian urges "Tuck into tuna, salmon and eggs or take vitamin D pills – official health advice".
The headlines were prompted by new advice on vitamin D from Public Health England (PHE), which says that adults and children over the age of one should have 10 micrograms (mcg) of vitamin D every day. This means that some people may want to consider taking a supplement.
The advice is based on recommendations from the government's Scientific Advisory Committee on Nutrition (SACN) following its review of the evidence on vitamin D and health (PDF, 4.2Mb).
How has the new vitamin D advice been reported?
In general the new government advice on vitamin D has been reported accurately.
However, the Guardian's headline, "Tuck into tuna, salmon and eggs or take vitamin D pills – official health advice" is misleading. While it's important to eat these foods as good sources of vitamin D, the advice is to consider taking vitamin D supplements because it is difficult to get enough from food alone.
Meanwhile, the Express headline, "Everyone should take vitamin D: Health chiefs warn millions are at risk of deficiency," overstates the advice. Most people are simply being asked to consider taking supplements.
And, although roughly one in five people has low vitamin D levels, this is not the same as a vitamin D deficiency. It is not accurate to say that millions of people are at risk of deficiency.
What is vitamin D?
Vitamin D helps to control the amount of calcium and phosphate in our bodies. Both are needed for healthy bones, teeth and muscles.
Vitamin D is found naturally in a small number of foods, including oily fish, red meat, liver and egg yolks. It's also found in fortified foods like breakfast cereals and fat spreads.
However, it's difficult for us to get the recommended amount of vitamin D from food alone.
Our main source of vitamin D is from the action of sunlight on our skin.
See more about vitamin D and sunlight.
What is the new vitamin D advice?
The new advice from PHE is that adults and children over the age of one should consider taking a daily supplement containing 10mcg of vitamin D, particularly during autumn and winter.
People who have a higher risk of vitamin D deficiency are being advised to take a supplement all year round.
SACN's review concluded that these at-risk groups include people whose skin has little or no exposure to the sun, like those in care homes, or people who cover their skin when they are outside.
People with dark skin, from African, African-Caribbean and South Asian backgrounds, may also not get enough vitamin D from sunlight in the summer. They should consider taking a supplement all year round as well.
See more detailed advice on vitamin D.
Is there new vitamin D advice for children too?
Yes. It's recommended that children aged one to four years should have a daily 10mcg vitamin D supplement all year round.
As a precaution, all babies under one year should have a daily 8.5-10mcg vitamin D supplement to make sure they get enough.
However, babies who have more than 500ml (about a pint) of infant formula a day don't need a vitamin D supplement as formula is already fortified.
The government recommends that babies are exclusively breastfed until around six months of age.
See more advice on vitamins for babies and children.
Why are we being advised to take vitamin D supplements?
The government says it has issued new vitamin D recommendations "to ensure that the majority of the UK population has satisfactory vitamin D blood levels throughout the year, in order to protect musculoskeletal health".
The recommendations refer to average intake over a period of time, such as one week, and take account of day-to-day variations in vitamin D intake.
SACN also looked at possible links between vitamin D and non-musculoskeletal conditions, including cancer, multiple sclerosis and cardiovascular disease. They didn't find enough evidence to draw any firm conclusions.
In spring and summer, most of us get enough vitamin D from sunlight on our skin and a healthy, balanced diet.
However, SACN couldn't make any recommendations about how much sunlight people would need to get enough vitamin D because there are a number of factors that can affect how much vitamin D is produced in the skin. So the recommendations assume "minimal sunshine exposure".
During autumn and winter (from October until the end of March) the sun isn't strong enough in the UK to produce vitamin D. That means we have to rely on getting it just from the food we eat.
Because it's difficult to get enough vitamin D from food alone, many of us risk not getting enough. Taking a supplement helps to keep levels of the vitamin topped up during the colder months.
Where can I get vitamin D supplements?
Vitamin D supplements are widely available from supermarkets and chemists.
Vitamin drops are available for babies. Your health visitor can tell you where to get them. These are available free to low-income families through the Healthy Start scheme.
Links to the headlines
The Guardian, 21 July 2016
Express, 21 July 2016
Mail Online, 21 July 2016
The Sun, 21 July 2016