NHS Choices

'Stop demonising butter,' say researchers

NHS Choices - Behind the Headlines - Thu, 30/06/2016 - 17:30

"Butter has been wrongly 'demonised' as unhealthy," reports the Daily Express following the publication of a study that found eating butter did not increase the risk of heart disease, stroke and diabetes.

Researchers analysed the findings from nine studies published since 2005 involving more than 600,000 participants from 15 countries, including the UK.

They found eating 14g a day of butter – about a tablespoon – had little to no effect on overall risk of death, heart disease and stroke. Butter even seemed to protect, slightly, against diabetes.

This was a well-designed review, but it is only as good as the studies included, and in this case no relevant randomised controlled trials were found.

The studies involved were all cohorts, which do not show whether any other factors may be at play.

We also do not know if the participants were able to accurately remember their butter intake, which is a common issue with data collected by questionnaire.

When it comes to diet, the best approach is to consume high-energy products, such as fat and sugar, in moderation.

Maintaining a healthy weight and having a balanced diet with regular exercise is the best way to reduce your risk of cardiovascular disease and diabetes.

Where did the story come from?

The study was carried out by researchers from Tufts University and Stanford School of Medicine, both in the US, and the University of Sydney in Australia.

Funding was provided by a grant for Circulating Dietary and Metabolic Fatty Acids, Major CVD Outcomes and Healthy Aging.

It was published in the peer-reviewed journal, PLOS One and is free to read online.

This review was picked up by several UK media outlets, who mostly overstated the importance of the findings.

The Daily Mail provided a useful quote from one of the study authors, Dr Dariush Mozaffarian, who said: "Our results suggest that butter should neither be demonised nor considered 'back' as a route to good health."

What kind of research was this?

This systematic review and meta-analysis aimed to pull together information on the long-term association of butter consumption with major health conditions, such as cardiovascular disease, diabetes and death.

A systematic review is the best way of gathering the available evidence on a topic. However, they can be limited by the quality of the studies included.

All of the studies included here were observational, and may be of variable methods, outcomes and quality.

The results of a meta-analysis may be unreliable if there was a great deal of difference between the individual studies.

What did the research involve?

The research team searched nine medical databases for prospective studies (cohorts or trials) providing estimates of the effects of butter intake on the following outcomes:

  • death
  • cardiovascular disease, including heart disease and stroke
  • diabetes

The researchers excluded studies that were retrospective in design; those with less than three months follow-up; where the population had a major disease, such as cancer; or if it was not possible to distinguish consumption of butter from other dairy products or fats.

Titles and abstracts of search results were reviewed by one researcher, while two were responsible for reviewing potentially relevant full text articles.

All the studies were assessed using a risk of bias tool and statistical methods used to combine the findings of individual studies.

What were the basic results?

The database searches found 5,770 potentially relevant studies, of which only nine met their inclusion criteria, presenting data from more than 636,000 participants.

All the studies were considered high quality, although they were all observational cohort studies.

No randomised controlled trials, often considered the gold standard of scientific research, were identified.

The average age of the participants ranged from 44 to 71 years.

All the studies were published between 2005 and 2015, including populations from the UK and a number of other European countries.

Most used food questionnaires to obtain dietary information, while one study used interviews.

The average butter consumption across studies ranged from 4.5g to 46g per day.

Pooling of results found no clear evidence of any link between butter consumption and death or cardiovascular disease.

Pooling the results of nine groups of participants (covered by two large studies) found each additional 14g serving of butter was very weakly associated with a 1% increase in risk of death.

However, this finding was only of borderline statistical significance, meaning it doesn't provide good evidence that there's any link at all (relative risk [RR] 1.01, 95% confidence interval [CI] 1.00 to 1.03).

Butter consumption was not significantly associated with risk of cardiovascular disease (based on four studies), heart disease (three studies), and stroke (three studies) did not appear to increase.

Butter appeared to have a protective effect against type 2 diabetes (four studies), with a 4% decrease in risk with each 14g serving (RR 0.96, 95% CI 0.93 to 0.99).

There was no evidence to suggest bias as a result of differences in the way the results were collected in each study, known as heterogeneity.

There was also no evidence of publication bias – that is, studies with positive findings being more likely to be published.

How did the researchers interpret the results?

The researchers concluded: "This systematic review and meta-analysis suggests relatively small or neutral overall associations of butter with mortality, cardiovascular disease, and diabetes.

"These findings do not support a need for major emphasis in dietary guidelines on either increasing or decreasing butter consumption, in comparison to other better established dietary priorities; while also highlighting the need for additional investigation of health and metabolic effects of butter and dairy fat."


This systematic review and meta-analysis assessed the long-term association between butter consumption and major health conditions, such as cardiovascular disease, diabetes and death.

The nine identified studies found little to no evidence that butter consumption increased the risk of death, cardiovascular disease, heart disease or stroke.

Perhaps surprisingly, though, there did seem to be a protective effect against the risk of type 2 diabetes.

This review has both strengths and limitations that may affect the reliability of the findings.

The researchers used careful search methods that aimed to identify only studies relevant to the general population and the large number of people included.

The researchers also did their best to provide the most reliable estimate by performing a quality assessment of studies, assessing heterogeneity and risk of publication bias. 

In terms of limitations, the review did not include any randomised controlled trials, which could have compared health outcomes with people who did not eat butter.

Other health and lifestyle factors may also be at play – like age, smoking, other dietary habits and physical activity – that the studies included, by nature of their design, are unable to account for.

The studies included mainly collected data using questionnaires, which are subject to various types of bias, and people may inaccurately report their butter consumption.

For example, we do not know if participants were asked about their consumption of products that contain butter, such as biscuits or cakes, and this may alter results.

It is also unclear from this report whether the studies included had good response rates. The studies mainly involved an older population, so we do not know if the same risk would apply to children or younger adults.

When it comes to diet, the best approach is to consume high-energy products, such as fat and sugar, in moderation.

Maintaining a healthy weight and having a balanced diet with regular exercise is the best way to reduce your risk of cardiovascular disease and diabetes.

Links To The Headlines

Butter is NOT bad and doesn't raise the risk of heart disease, major study claims. Daily Mail, June 29 2016

Butter not bad for health…but what you spread it on might be. The Daily Telegraph, June 29 2016

Butter has no link to heart disease and could even protect people from diabetes. The Mirror, 29 June

Butter has been wrongly 'DEMONISED' as unhealthy, say experts. The Express, 29 June 2016

Links To Science

Pimpin L, Wu JH, Haskelberg H, et al. Is Butter Back? A Systematic Review and Meta-Analysis of Butter Consumption and Risk of Cardiovascular Disease, Diabetes, and Total Mortality. PLOS ONE. Published online June 29 2016 

Categories: NHS Choices

Heart attacks linked to media statin reports ... reports media

NHS Choices - Behind the Headlines - Wed, 29/06/2016 - 16:00

"Don't give up your statins: Experts say warnings that made patients stop taking vital drug have put lives at risk," the Daily Mail reports.

This was the same newspaper that told us two weeks ago that "statins may be a waste of time", so you might be forgiven for being a little confused.

In October 2013, negative media coverage surrounded two articles run by the BMJ, which suggested that the risks of statins may outweigh the benefits of the drugs in preventing heart attacks and strokes.

The articles also said the link between cholesterol and cardiovascular diseases was unproven.

At the time, they were widely reported at face value, with little discussion of their limitations.

A new study aimed to estimate the effect of this intense media coverage in 2013 on the use of statins in the UK.

It found people who were already taking statins were more likely to stop taking them after exposure to a six-month period where media coverage around this topic was particularly intense.

The media coverage was not associated with any effect on people who had been newly prescribed statins.

The researchers estimated that 218,971 people stopped taking statins in the six months after the media coverage, which could potentially be associated with between 2,000 and 6,000 excess cardiovascular events.

This latest study is unable to confirm cause and effect, but it does highlight the impact that health reporting can have.

While uncertainties in science should always be reported, far too often the media will report a dissenting opinion as if it were proven fact.

Perhaps the most notorious example of this was the poor reporting on the now thoroughly discredited alleged link between the MMR vaccine and autism.

Where did the story come from?

The study was carried out by researchers from the London School of Hygiene and Tropical Medicine, the University of Manchester, and the Institute of Pharmaceutical Sciences. It was funded by the British Heart Foundation.

The study was published in the peer-reviewed British Medical Journal (BMJ) on an open access basis and is free to read online.

Generally, the media coverage of this study was accurate, but much of the tone of the reporting was arguably hypocritical.

Many media sources appeared to be placing the blame solely on the authors of the 2013 articles, without acknowledging their own role in promoting fear and uncertainty about the use of statins.

For example, at the time the Daily Express' headline was, "Doctors change their minds after 40 years", even though the articles represented a minority opinion.

What kind of research was this?

This was an ecological interrupted time-series study that aimed to estimate the effect on the use of statins in the UK after a six-month period of intense media coverage about the risks and benefits of the drugs.

Ecological studies are good for studying populations or communities, rather than individuals.

In this case, the study is useful for establishing national patterns of statin use, but cannot imply cause and effect between usage and the intense media coverage. There may be other factors influencing changes in statin use.

What did the research involve?

The researchers used prospectively collected data from the UK Clinical Practice Research Datalink (CPRD), which is a database of primary care data from GP surgeries.

The data covers about 6.9% of the UK population, and is broadly representative in terms of age and sex.

The analysis was an interrupted time-series design, where the exposure period to high media coverage was defined as October 2013 to March 2014.

The researchers compared patterns of statin initiation and cessation before and after this time period.

They then calculated the proportions of patients initiating and stopping statin treatment for every month from January 2011 to March 2015.

Potential confounders such as smoking and obesity were controlled for. The analysis only included patients over the age of 40.

Statin initiation was defined as having no previous record of statin prescriptions, and statin cessation as having ended statin prescriptions within that calendar month.

On the assumption of a link between the media coverage and changes in statin use, the researchers estimated the potential public health impact by comparing the number of cardiovascular events among these patients.

What were the basic results?

The study's main finding was that patients already taking statins were more likely to stop after exposure to the high media coverage compared with before.

The stoppage rates were similar both for those who were taking statins because of cardiovascular risk factors, but who had not yet had a stroke or heart attack (primary prevention: odds ratio [OR] 1.11, 95% confidence interval [CI] 1.05 to 1.18), and for those who had already experienced a cardiovascular event (secondary prevention: OR 1.12, 95% CI 1.04 to 1.21).

There was no evidence of changes in statin initiation, either for those prescribed statins for primary prevention (OR 0.99, 95% CI: 0.87 to 1.13) or secondary prevention (OR 1.04, 95% CI 0.92 to 1.18).

The researchers estimated there was an excess of 218,971 patients who stopped taking statins in the six months after the media coverage.

They also estimated that in the following 10 years there could be between 2,000 and 6,000 excess cardiovascular events that wouldn't have otherwise occurred.

How did the researchers interpret the results?

The researchers concluded that, "Controversy over the risks and benefits of statins reported in both the medical and popular press was followed by a transient increase in patients stopping treatment prescribed for primary and secondary prevention.

"Additionally, a marked reduction in the proportion of patients receiving a risk score for cardiovascular disease suggests other important impacts on GP and/or patient behaviour."


This study aimed to estimate the effect on the use of statins in the UK after a six-month period of intense media coverage about the risks and benefits of the drugs.

It found that patients were more likely to stop taking statins after exposure to the high media coverage compared with before the six-month period. However, there was no effect for people who had been newly prescribed statins.

As the researchers acknowledge, interrupted time series studies like this one cannot confirm a causal link between the media coverage and the observed likelihood of stopping statin treatment.

We cannot know the exact reasons why these people may have stopped taking statins. It is possible that other external factors played a role in the observed changes.

Additionally, these changes may have been different in people under the age of 40 or those who purchase low-dose statins over the counter.

One of the researchers, Dr Liam Smeeth, told the media: "Our findings suggest widespread coverage of health stories in the mainstream media can have an important real-world impact on the behaviour of patients and doctors. This may have significant consequences for people's health."

More research is needed to further draw out conclusions, but overall this study highlights the potential impact widely reported health stories can have on people's health behaviour in the real world.

Journalists have a responsibility to ensure their reporting is as balanced and accurate as possible, especially when they are reporting on potential life and death matters, such as heart attack and stroke prevention.    

Links To The Headlines

Don't give up your statins: Experts say warnings that made patients stop taking vital drug have put lives at risk. Daily Mail, June 29 2016

Fears of 2,000 heart attacks and strokes linked to statins controversy. The Daily Telegraph, June 29 2016

Statins controversy led 200,000 people to stop taking pills, says study. The Guardian, June 28 2016

At-risk heart patients stopped taking statins because of press controversy, study found. Daily Mirror, June 29 2016

'Scaremongering' over statins may have caused 2,000 deaths. The Times, June 29 2016 (subscription required)

Links To Science

Matthews A, Herrett E, Gasparrini A, et al. Impact of statin related media coverage on use of statins: interrupted time series analysis with UK primary care data. BMJ. Published online June 28 2016

Categories: NHS Choices

Sports drinks may have adverse effects on teens' dental health

NHS Choices - Behind the Headlines - Wed, 29/06/2016 - 16:00

"High numbers of younger teenagers are risking tooth decay and obesity by regularly having high-sugar sport drinks," BBC News reports.

A survey of Welsh teenagers found high levels of consumption in teens, who seem unaware of their high-sugar content.

One hundred and sixty young teenagers completed a questionnaire which found that almost 90% had consumed sports drinks, with half consuming the drinks at least twice a week.

Many leading sports drinks contain both high levels of sugars and acids – a combination designed to damage surfaces of teeth and lead to tooth decay. Sugary drinks are also often high in "empty calories" (energy-rich, but nutrient-poor) which can contribute to weight gain and possible obesity in later life.

While the occasional sports drink may be suitable for teenagers recovering from a cross-country run or a game of netball or football, it's not a good idea to make them a staple part of your diet.

Added sugars shouldn't make up more than 5% of your daily calorie intake, which is around 30g of sugar a day for those aged 11 and over. The sugar content in a 500ml bottle of Lucozade sport is around 18g, with the energy version exceeding this.

The sweet taste, low price and availability of sports drinks make them attractive to teenagers. Therefore, it is important to make both teens and their parents aware of the risks.


Where did the story come from?

The study was carried out by researchers from Cardiff University.

The report was published in the peer-reviewed British Dental Journal, with no mention of a funding source or conflict of interest. The study is open-access, so you can read it for free online or download as a PDF.

Both BBC News and the Mail Online provided informative reports on the main findings of the study, along with a warning from the British Dental Association that, "Sports drinks are rarely a healthy choice and marketing them to the general population, and young people in particular, is grossly irresponsible. Elite athletes might have reason to use them, but for almost everyone else they represent a real risk to both their oral and their general health."

The British Soft Drinks Association responded by saying that, "Sports drinks are designed for vigorous physical activity and should be consumed in moderation. This year soft drinks firms agreed not to advertise drinks high in sugar to under-16s."


What kind of research was this?

This was a survey which aimed to investigate the consumption of sports drinks by young teenagers.

A survey is a good way of finding out the level of consumption, together with why and when the drinks are consumed. These findings can then be used to target health promotion campaigns to educate and also target behaviours that are detrimental to health.


What did the research involve?

Teenagers aged 12 to 14 were recruited from four schools in South Wales to take part in the study. The schools aimed to be representative of the range of socioeconomic backgrounds in the area and included one private school and three comprehensive schools. Two of the comprehensive schools provided education for boys and girls on separate sites and drew pupils from a more mixed demographic.

Prior to designing the questionnaire, eight teens were chosen to take part in a focus group, where they were informally asked about their consumption of sports drinks. Insight gained from this group was used to design the survey questions.

The questionnaire was completed by the teenagers, then anonymised. The survey covered:

  • consumption of sports drinks – including how often and what types
  • where the drinks were bought
  • why the children chose to drink the sports drink


What were the basic results?

One hundred and sixty teens completed the questionnaire.

The majority of teens had consumed sports drinks (89.4%), with almost half (48.3%) having them at least twice a week.

Of the sports drinks, Lucozade Sport™ was the most popular, with 88.8% of participants having consumed it. It appeared that for teens that chose the "other" option (21%), there was some confusion between sports and energy drinks, as only one child listed an unbranded isotonic drink.

Sports drinks were bought in a number of locations and for many children in more than one place; however, most were from local shops (80.4%) or supermarkets (54.5%).

When investigating why children opted for sports drinks, there were differences between genders: 77.9% of boys said this was related to physical exercise, while 51.4% of girls said they drank sports drinks socially.  

The primary reason for consuming sports drinks was the "nice taste" (90%), while energy (47.6%) and hydration (23.1%) were less popular responses.


How did the researchers interpret the results?

The researchers conclude: "A high proportion of children consumed sports drinks regularly and outside of sporting activity. Dental health professionals should be aware of the popularity of sports drinks with children when giving health education advice or designing health promotion initiatives."



This study aimed to investigate consumption of sports drinks in young teenagers.

Sports drinks are designed for use after vigorous physical exercise and are not recommended for children. However, almost 90% of the teens surveyed drank sports drinks, half of whom drank them at least twice a week.

The findings of this study are limited, as it included a relatively small sample of young teens from South Wales, which reduces reliability and generalisability of the findings to other areas or age groups.

The researchers made an attempt to reduce bias by making the survey anonymous; however, there may still have been inaccuracy, due to the children not correctly remembering their drinking habits. Also, some children may have confused sports and energy drinks produced by some of the leading brands.

This study has investigated an important topic. If true, and large numbers of young teens are consuming sports drinks, then it is possible they are causing themselves damage through the large quantities of "free" sugar, any sugars added to food or drinks or found naturally in honey, syrups and unsweetened fruit juices, or acids, which are associated with dental caries (tooth decay) and erosion.

These findings chime with a study we covered in 2015 which found that around half of 15-year-olds in England, Wales and Northern Ireland had tooth decay.

Sugar can be high in energy, but can often have few nutrients. Eating these foods too often can mean you eat more calories than you need, which can lead to weight gain and obesity.

The healthiest drink to get you hydrated before, during, or after exercise is good old tap water. 

Links To The Headlines

High sport drink use among young teens 'risk to health'. BBC News, June 27 2016

Sugary sports drinks 'raise the risk of obesity, diabetes and tooth decay'. Mail Online, June 26 2016

Links To Science

Broughton D, Fairchild RM, Morgan MZ. A survey of sports drinks consumption among adolescents. British Dental Journal. Published online June 24 2016

Categories: NHS Choices

Is 'Disney Princess culture' a bad influence on young girls?

NHS Choices - Behind the Headlines - Tue, 28/06/2016 - 16:30

"Disney princesses such as Elsa from Frozen can damage young girls' body esteem," the Daily Mail reports – inaccurately.

The study the news comes from actually found a more complex pattern of influences on both girls and boys.

Disney Princesses™ – from Elsa all the way back to Snow White – have become both cultural icons and a multibillion-dollar industry in terms of films, toys and costumes sales.

But concerns have been expressed that "princess culture" could lead to body esteem issues in young girls, as Disney Princesses tend to be slim, pretty, and often with an improbably small waist.

Researchers talked to both parents and children to assess what types of influences exposure to princess culture may have.

They found a link between young girls watching more princess media, identifying with princesses, and playing with princess toys over a year, and higher levels of female gender stereotypical behaviour.

One of the ways this manifested was in a preference for playing with dolls and tea sets over action figures and tool sets.

Despite media reports, princess exposure was not associated with poor body image in girls. But it did affect boys, who had higher self-esteem, as they apparently identified with the various dashing young male leads.

It may be a good idea to show your daughters that there are alternative role models and other things they can aspire to – such as being a doctor, scientist, engineer, pilot or astronaut, to name a few.

Where did the story come from?

The study was carried out by researchers from Brigham Young University, Texas Tech University and Linfield College in the US, and was funded by the Women's Research Initiative.

It was published in the peer-reviewed journal Child Development.

The media reporting was generally accurate, but many of the headlines were misleading. Both the Mail and The Guardian stated that princess culture damaged girls' self-esteem.

The study actually found no effect on girls' self-esteem. The lead author suggested that a study with a longer follow-up period may find a detrimental effect, but this remains to be seen.

The study's limitations were also not discussed in the media reporting. For example, it found links, but couldn't prove cause and effect, or provide new evidence on whether the effects on boys and girls were good or bad.

The implications of the study were provided by the authors based on other evidence and insight.

What kind of research was this?

This longitudinal study looked at how Disney Princess media and merchandise might affect young children's gender-specific behaviour, body image and positive social behaviour (such as helping others).

TV, film and other media play a large and influential role in shaping young children's expectations about their own gender, particularly in young girls.

Disney Princess films like Frozen represent an extremely popular and profitable source of influence on young girls, but contain idealised images of princesses.

The study says that the Disney Princess industry generated more than US$3 billion in global sales in 2012.

This study investigated whether there was any link between the amount of exposure to Disney Princesses – through film, merchandise, clothing and more – and gender-specific behaviour, body image and social behaviour over the course of about a year.

This study type can't prove cause and effect, as there are many other sources of gender role influence and expectation.

Parents, teachers, friends, music videos and social media are just some strong additional factors that are part of the social pressure that shapes gender norms in different societies.

What did the research involve?

The researchers studied 198 girls and boys aged from 3 to 6.5 years from four US schools.

They started by taking baseline measurements of their gender-related behaviour, tracked their exposure to Disney Princess material over a year, and tested them again for any changes.

The children's teachers and parents provided most of the information, but there was also a toy test for the children.

The adults filled in questionnaires to establish their children's exposure to Disney Princesses: the amount of time spent watching TV, and information revealing its potential effect on their gender-stereotypical behaviour, body image and social behaviour.

The gender-stereotypical behaviour assessment involved a toy preference task. Children were given toys and asked to sort them into boxes of which they liked to play with a lot, a little, or not at all.

Some toys were female gender-stereotyped (such as a doll or a tea set), others male gender-stereotyped (action figure or tool set) and some neutral (puzzle or paint set), giving an idea of their preferences.

Body image was rated by the children's parents using a survey asking for agreement or disagreement with statements like, "My child likes his or her body", "My child would like to be thinner", "My child talks about his or her weight often", and "My child wishes he or she were better looking".

Social behaviour was assessed by asking parents how social their child was – for example, how often their child is helpful to their friends.

Parental gender-stereotypical behaviour – for example, whether parents encouraged their children to conform to accepted gender norms of behaviour – was also assessed to see how much this was having an influence.

What were the basic results?
  • As expected, girls had a lot more princess exposure than boys in terms of watching more princess media and identifying with princesses. For example, more than 61% of girls played with Disney Princess toys at least once a week, compared with about 4% of boys.
  • But for boys and girls, princess exposure was linked to higher female gender-stereotypical behaviour on the toy preference task, as well as others measuring a similar thing. This wasn't the case for male gender-stereotypical behaviour, body image or social behaviour.
  • Watching more princess media, identifying with princesses and playing with princess toys over the course of a year predicted stronger female gender-stereotypical behaviour at the end of the study, irrespective of the starting level.
  • Gender behaviour was a three-way interaction between the child's gender, their parents and fictional princesses for girls, but not for boys.
  • High exposure to princesses predicted higher body esteem in boys and more social behaviour.
  • Contrary to what may have been expected, engagement with princesses was not associated with poor body esteem in girls. And a related finding suggested that higher positive body image scores at the start of the study made it less likely that girls would engage in a lot of princess media and merchandise a year later.
How did the researchers interpret the results?

The researchers concluded that, "This study shows that engagement with Disney Princesses can be limiting, as young girls especially are more likely to embrace traditional female stereotypes both concurrently and longitudinally.

"However, there were also some potential positive benefits for boys, including better body esteem and higher levels of prosocial behavior when parents discussed the media with their children." 


This study shows an association between young girls watching more princess media, identifying with princesses and playing with princess toys over a year, and higher levels of female gender-stereotypical behaviour.

One of the ways this manifested was in a preference for playing with dolls and tea sets over action figures and tool sets.

The study found princess exposure was linked to higher levels of female gender-stereotypical behaviour, such as toy preference, but doesn't actually tell us if this is a bad thing.

Much of the media reporting, and quotes from the authors of the study, suggest ideas about why this might be bad – which may be true – but this conjecture isn't based on this particular study.

Also, identifying with princesses may have been expected to result in poor body image in girls, but this doesn't seem to have been the case.

As the researchers said: "Although there is nothing inherently wrong with expressing femininity or behaving in a gendered manner, stereotypical female behavior may potentially be problematic if girls believe that their opportunities in life are limited because of preconceived notions regarding gender."

They went on to state girls should not "avoid the types of exploration and activities that are important to children learning about the world in order to conform to stereotypical notions about femininity".

The study attempts to isolate the effects of princesses against a complex background of social gender influences from parents, friends, social media, schools and others.

This isn't the most realistic thing to do, as these influences are not isolated in the real world – they act together. Nonetheless, the nature of science is to study one thing in detail to attempt to assess its specific influence.

Although the study found a link, it can't prove cause and effect. On the one hand, children might have been influenced by princesses to prefer dolls and aspire to traditionally female stereotypes.

But the other explanation is that these preferences were already there, and these children sought out princesses more than others because they matched their underlying preferences.

Job opportunities for princesses are somewhat thin on the ground these days. So, to boost the chance of your daughter living happily ever after, it may be a good idea to highlight the wide range of opportunities and vocations that exist for women in modern society. 

Links To The Headlines

Why Frozen's Elsa can harm young girls' self-esteem: Fictional characters 'promote negative female stereotypes'. Daily Mail, June 27 2016

Disney princesses contribute to 'body esteem' issues among young girls, finds study. The Guardian, June 27 2016

Links To Science

Coyne SM, Linder JR, Rasmussen EE, et al. Pretty as a Princess: Longitudinal Effects of Engagement With Disney Princesses on Gender Stereotypes, Body Esteem, and Prosocial Behavior in Children. Child Development. Published online June 18 2016

Categories: NHS Choices

Children's plastic toys can 'harbour viruses for hours'

NHS Choices - Behind the Headlines - Mon, 27/06/2016 - 16:35

"Plastic toys 'can harbour nasty viruses for hours, raising risk of infection'," the Mail Online reports. New research suggests that enveloped viruses, which have a protective shell, may survive on toys for up to 24 hours.

This laboratory study aimed to assess virus survival on a plastic toy at 22C and two different humidity levels – 40% (similar to indoor levels) and 60%.

Researchers used a virus called bacteriophage Φ6, which is harmless for humans. It acts as a useful "surrogate virus" for research, as its structure is similar to common causes of viral infection, such as the influenza virus.

The study found that viral survival was significantly less at the lower humidity – at two hours, virus survival had reduced by 99.9%. At high humidity, it took 24 hours to reduce by 99%.

Children's toys – particularly shared ones like in daycare centres and hospitals – have often been implicated in spreading infection during outbreaks. However, this study can't provide all the answers. For example, it can't inform us about the survival of other bacteria and viruses (e.g. tummy bugs spread hand-to-mouth), or whether viral survival may be the same on other surfaces.

What is probably most useful is the standard hygiene measure of ensuring that your child washes their hands regularly, after playing, after using the toilet and before eating.

Employees in settings where toys are likely to be shared should also be aware of the importance of regularly cleaning the toys.


Where did the story come from?

The study was carried out by researchers from Georgia State University, Atlanta, US. It was funded by a grant from the university, and the authors declare no conflict of interest. The study was published in the peer-reviewed Pediatric Infectious Disease Journal.

The Mail article may suggest that this study has directly shown that viruses on plastic toys lead to infection, which isn't the case. As is so often the case, its headline verges on scaremongering. This study had a valuable purpose, but its results weren't conclusive.

These criticisms aside, the body of the article was largely accurate and informative.


What kind of research was this?

This was a laboratory study aiming to assess the survival of viruses on plastic toys in different environmental conditions.

The researchers explain how toys may transmit viruses to children, particularly shared toys in daycare centres, hospitals and doctors' waiting rooms. They go on to say how many cross-sectional studies have assessed the presence of viral DNA or RNA, but it's difficult to tell whether actual enveloped viruses are present and how long they survive.

This study aimed to assess an enveloped virus that infects and replicates within Pseudomonas bacteria – a virus called bacteriophage Φ6, which has similar characteristics to influenza. Enveloped viruses have a protective shell, so they can survive longer on external environments, such as objects and surfaces.

The researchers looked at its survival on non-porous plastic toys in different conditions.


What did the research involve?

The researchers incubated the Pseudomonas bacteria with the bacteriophage Φ6 virus in the lab. They cut up a disinfected plastic toy (a squeaking frog) into 1cm2 pieces and put the culture onto them.

They then incubated for 24 hours, some at 22C and 40% humidity, and others at 22C and 60% humidity. They assessed virus survival over the 24 hours.


What were the basic results?

Over 24 hours, there was a 99% reduction (2log10) in the number of infective viruses when incubated at 60% humidity. The number had already halved by 8 hours (1log10).

There was a significantly increased rate of decline at 40% humidity. There was a 3log10 decline at two hours, and 6.8log10 decline by 10 hours.

Log10 is a reference to measurements on the logarithmic (log) scale, which is a useful method of talking about very large numbers and very small numbers at the same time (in this case, viral load).


How did the researchers interpret the results?

The researchers conclude: "a lipid-enveloped virus [a virus with a protective shell] can survive on the surface of a nonporous children's toy for hours at indoor temperature and relative humidity levels, and the relative humidity level affects how rapid the inactivation is".



This laboratory research assessed the survival of a single type of bacteria-infecting virus on a plastic toy at 22C and two different humidity levels.

The bacteriophage Φ6 virus was chosen to be representative of influenza and other enveloped viruses, and indicated how they would survive under the same conditions. Certain characteristics of the bacteriophage, though, make it easier to study than the actual viruses.

The 40% humidity was meant to be typical of indoor environments. The researchers found that even at this humidity, it may take up to two hours to achieve a 99.9% reduction in levels of infectious virus – similar to previous findings about the rate of inactivation of the flu virus on non-porous surfaces. High humidity was associated with even longer viral survival.

However, this study is limited as it doesn't address many other issues, such as:

  • viral decline at other temperatures – combined with these and other humidity levels
  • survival of other types of non-respiratory viruses – or bacteria – on plastic toys, such as gastrointestinal viruses and bacteria that are spread hand-to-mouth, like norovirus or E.coli bacteria; whether the viral levels detected here at different time-points would directly lead to infection in a child if they were to touch the object is unknown
  • levels of viruses and bacteria on environmental surfaces all around us – for example doors and door handles, tables, work surfaces, taps, etc – all of which children would equally come into contact with
  • the effect of disinfecting or cleaning the items

Toys and children's play equipment has previously been linked to transmission of viruses during outbreaks. In environments such as nurseries, daycare, hospitals or surgeries where toys are shared, regular cleaning and/or disinfection of the items may be beneficial in helping to limit the spread of infection.

However, what is probably most useful is ensuring that your child washes their hands regularly, after playing, after using the toilet and before eating.   

Links To The Headlines

Are your child's TOYS making them sick? Plastic toys 'can harbour nasty viruses for hours, raising risk of infection'. Mail Online, June 27 2016

Links To Science

Bearden RL, Casanova LM. Survival of an Enveloped Virus on Toys. Pediatric Infectious Disease Journal. Published online May 3 2016

Categories: NHS Choices

How to store food and leftovers

NHS Choices - Live Well - Mon, 27/06/2016 - 15:05
How to store food and leftovers

Tips on storing food and leftovers to prevent food poisoning, including:

What should go in the fridge?

The following foods are best stored in the fridge to prevent bacteria growing:

  • foods with a "use-by" date
  • cooked foods
  • ready-to-eat foods

Store eggs in their box in a cool dry place, ideally the fridge.

Cool down leftovers as quickly as possible (ideally within 90 minutes), store them in the fridge and eat them within two days. It is safe to let food cool completely at room temperature before storing it in the fridge, so long as basic food hygiene is applied to avoid cross-contamination.

If you're having a buffet, keep the food refrigerated until you're ready to serve it. When preparing refrigerated food, keep it out of the fridge for the shortest time possible.

Never put open cans in the fridge, as the metal may transfer to the can's contents – place the contents in a storage container or covered bowl instead.

Fridge maintenance

Keep your fridge temperature at 5C or below. Most fridges are warmer than their settings suggest, especially older models.

Clean your fridge regularly to ensure it remains hygienic and in good working order. 

"Use-by" dates

No food lasts forever, however well it is stored. Most pre-packed foods carry either a "use-by" or a "best before" date.

  • "Use-by" dates appear on foods that go off quite quickly. It can be dangerous to eat foods past this date.
  • "Best before" dates are for foods with a longer life. They show how long the food will be at its best.

Food can look and smell fine even after its use-by date but that doesn't mean it's safe to eat. It could still be contaminated.

Storing meat and poultry

It's important to store meat safely in the fridge to stop bacteria from spreading and avoid food poisoning.

  • Store raw meat and poultry in clean, sealed containers on the bottom shelf of the fridge.
  • Follow any storage instructions on the label and don't eat meat after its use-by date.
  • Keep cooked meat separate from raw meat.
Freezing and defrosting

It's safe to freeze meat and fish as long as you:

  • freeze it before the use-by date
  • defrost meat and fish thoroughly before cooking – lots of liquid will come out as meat thaws, so stand it in a bowl to stop bacteria in the juice spreading to other things
  • defrost meat and fish in a microwave if you intend to cook it straight away, or put it in the fridge to thaw so it doesn't get too warm
  • cook food until it's steaming hot throughout

Make sure that meat is properly wrapped in the freezer or it might get freezer burn, which can make it tough and inedible.

Date and label meat in the freezer and eat it within 24 hours of defrosting. 

Don't keep food in a freezer indefinitely. Always have a good idea of what's in your fridge and freezer.

Re-freezing meat and fish

Never re-freeze raw meat (including poultry) or fish that has been defrosted.

You can re-freeze cooked meat and fish once, as long as they have been cooled before going into the freezer. If in doubt, don't re-freeze.

Frozen raw foods can be defrosted once and stored in the fridge for up to two days before they need to be cooked or thrown away.

To reduce wastage, divide the meal into portions before freezing and then just defrost what you need.

Using leftovers

Don't throw away leftovers: they could be tomorrow's lunch! Follow these tips to make the most of them:

  • Cool leftovers as quickly as possible, ideally within 90 minutes. 
  • Divide leftovers into individual portions and refrigerate or freeze.
  • Use refrigerated leftovers within two days.
  • When reheating food, make sure it is heated until it reaches a temperature of 70C for two minutes, so that it is steaming hot throughout.
  • Always defrost leftovers completely, either in the fridge or in the microwave.
  • When defrosted, food should be reheated only once, because the more times you cool and reheat food, the higher the risk of food poisoning.
  • Cooked food that has been frozen and removed from the freezer should be reheated and eaten within 24 hours of fully defrosting.
  • Foods stored in the freezer, such as ice cream and frozen desserts, should not be returned to the freezer once they have started to thaw.
  • For safety and to reduce waste, only take out of the freezer what you intend to use immediately.

Can reheating rice cause food poisoning?

Re-using bags

With more people re-using plastic bags to save the 5p charge, you can help prevent bacteria spreading to ready-to-eat food by:

  • keeping raw meat and fish separate from ready-to-eat foods in separate bags
  • keeping one or two reusable bags just for raw meat and fish – don't use the same bags for ready-to-eat foods
  • throwing away bags if raw meat juice has been spilled in them

Categories: NHS Choices