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NHS Choices: Behind the headlines   + / -  
last updated: Tue, 24 May 2016 11:31:06 GMT

 Mon, 23 May 2016 14:40:00 GMT Report attacks official guidance on low-fat diets

"Low-fat diet bad for your health and cutting back on meat, dairy and eggs a disastrous mistake," the Daily Mirror reports.

That is the main message of a controversial report attacking official UK guidelines on diet and weight loss.

The report suggests it doesn't matter how much saturated fat we eat, and doesn't recommend counting calories.

Critics have pointed out there were no agreed criteria about what evidence would be considered in the report, leaving it open to accusations of cherry-picking.

This means the report's authors may have promoted evidence supporting their argument while ignoring evidence they saw as unhelpful.

Dr Mike Knapton, associate medical director at the British Heart Foundation (BHF), said: "This report is full of ideas and opinion.

"However, it does not offer the robust and comprehensive review of evidence that would be required for the BHF, as the UK's largest heart research charity, to take it seriously."

 

Who produced the report?

The report was published by the Public Health Collaboration, a not-for-profit organisation described as being dedicated to informing the public and implementing healthy decisions.

The report is said to follow decades of work and experience that founding and advisory board members have gathered through working with thousands of patients to improve their health.

The listed advisory board members are named health professionals, including dietitians, GPs, a cardiologist, a diabetes specialist and a psychiatrist. They also list a number of patrons.

It is unclear where Public Health Collaboration's funding comes from. Nor is it clear who wrote the report.

No author or authors are named, and it does not appear to have been peer-reviewed by independent experts.

The aim of the report is said to be to raise concerns about the government's current recommendations about healthy eating and weight loss, and also provide new evidence-based solutions to help people obtain healthy lifestyles and improve public health.   

 

What does the report say?

The report states the current prevalence of obesity in the UK is 25%, costing the economy £47 billion a year. 

It summarises the recommendations of the current Eatwell Guide for healthy eating, saying it has three main concerns with this guidance:

  • the avoidance of foods because of their saturated fat content
  • the dietary reference value of no more than 35% total fat
  • the quality and quantity of carbohydrates

Saturated fat

The researchers say current recommendations given on NHS Choices are to opt for low-fat dairy options, as high saturated fat can increase the risk of heart disease.

They highlight a large US cohort study from 2010 that concluded saturated fat intake was not associated with risk of cardiovascular disease.

They quote several other observational studies that supported the notion that high-fat dairy was not linked to obesity or cardiovascular and diabetes risk.

The researchers say: "In retrospect, there was never any strong evidence to recommend reducing total and saturated fat consumption, and in the 30 years since, the deteriorating health of the UK population suggests such advice may have been a dire mistake, however well intentioned."

They consider that if people had been opting for foods in the natural form, rather than manufactured low-fat foods, we wouldn't have the obesity problem we do today.

The Public Health Collaboration concludes the UK should stop recommending the avoidance of high saturated fat foods and focus on consuming food in its natural form – however much saturated fat it contains.

No more than 35% total fat

The authors question recommendations that too much fat in your diet raises the risk of heart disease and makes you overweight, saying this is not backed by scientific evidence.

They reference a trial published this year, which found people on low-carb diets experienced more weight loss than people on low-fat diets, and say how recent US dietary guidelines have removed their previous 30% total fat limit and no longer place any restriction on fat.

They conclude the UK should remove the recommendation to eat no more than 35% total calorie intake from fat and instead focus on the health benefits of eating food in its natural form – regardless of fat content.

Quality and quantity of carbohydrates

As the authors say, good blood glucose control is important to maintain health and reduce the risk of developing diabetes or pre-diabetes conditions.

However, they say eating lots of foods that raise blood glucose and promote the release of insulin are factors likely to increase this risk – and high carbohydrates do just that.

They discuss the glycaemic index (GI) of different foods, and say the UK's Eatwell Guide "illogically" recommends high-GI foods, advising people to "base meals on potatoes, bread, rice, pasta or other starchy carbohydrates".

They suggest that such recommendations are behind the increase in rates of type 2 diabetes and obesity.

The Public Health Collaboration concludes people should avoid foods that have a high carbohydrate density, and instead focus on food and drink that has a carb density of less than 25%. Such foods are usually in their natural form.

"Real food" lifestyle

The Collaboration sets out a new form of the Eatwell Guide called "The Real Food Lifestyle", which has a 50:50 split of fats and proteins against carbohydrates, but all food and drinks on the wheel are in their natural form.

They emphasise carbs with a density less than 25% and a minimum of 1g protein per 1kg bodyweight per day.

They also emphasise eating "real" foods that will fill you and avoiding processed "fake foods", which won't.

For example, they recommend natural oils and butter, including coconut oil, ghee, lard and cold-pressed olive oil – the "fake" ones are rapeseed, sunflower and corn oil – and no juices or processed sugar products.

If you were being critical you could argue that the division between “real food” and “fake food” is scientifically meaningless.
 

What evidence is this based on?

The report is presented in the form of a narrative, where individual pieces of evidence are cited as coming from particular studies. A list of references is then provided at the end.

However, the report does not provide any information about how the authors identified and selected the research reviewed.

As such, it is not possible to say this was a systematic review, and we cannot know for sure this is a balanced report that has reviewed all evidence relevant to diet and nutrition.

The standard warnings about cherry-picking – evidence that is inconvenient may be ignored – apply.

Also, without reviewing the individual studies referenced, it is not possible to appraise the quality and strength of this evidence. However, many are observational.

There is potential for various sources of confounding and bias to influence associations between self-reported diet and health outcomes, such as inaccurate recall on food questionnaires or the potential influence of other unmeasured health and lifestyle factors.

It can be difficult to know to what extent a particular outcome can be directly attributed to a particular food – or the absence of it.

The report further says it "clearly and concisely provides an insight into the decades of work and experience that our founding members and advisory board have accumulated from working with thousands of patients".

But it's not known what sort of experience or data from patients has contributed to informing this.  

We also don't know, for example, whether the recommendations on fat and carbohydrate intake would be applicable to all stages in life, or whether there might be different advice for children.

The report makes much of the fact that in spite of UK dietary guidelines, the number of people with obesity and type 2 diabetes has grown in recent decades. However, this does not prove that the guidelines are to blame. 

What response has there been to the report?

The report has attracted quite considerable criticism.

Some professionals, such as the professor of diet and population health at the University of Oxford, note the lack of systematic review methods and accuse the report of potentially cherry-picking studies to support its viewpoint.

Other studies presenting contradictory findings do not seem to have been included, they say.

As a scientist from the University of Reading says: "As with any public health measure, it is important that any recommendations are based on solid evidence and take the wider implications of implementation into account. That doesn't seem to be the case in this instance."

Professor Tom Sanders, emeritus professor of nutrition and dietetics at King's College London, says statements such as "fat doesn't make you fat", "saturated fat doesn't cause heart disease", and "avoid 'low fat' " are potentially harmful and could mislead the public.

Other opinion is more mixed, with one professor saying the report has "good, bad and ugly elements in it". There are views that snacking and added sugar are to be avoided, but ideas that we should eat limitless fat and cut out sugar altogether are criticised.

BBC news quotes Dr Alison Tedstone, Public Health England's chief nutritionist, who says: "In the face of all the evidence, calling for people to eat more fat, cut out carbs and ignore calories is irresponsible."

She says thousands of scientific studies have been considered when making current UK health and nutrition recommendations.

"It's a risk to the nation's health when potentially influential voices suggest people should eat a high-fat diet, especially saturated fat," she says.

"Too much saturated fat in the diet increases the risk of raised cholesterol, a route to heart disease and possible death." 

Links To The Headlines

Low fat diet bad for your health and cutting back on meat, dairy and eggs a disastrous mistake. Daily Mirror, May 23 2016

Public Health England: Advice to eat more fat 'irresponsible'. BBC News, May 23 2016

Official advice on low-fat diet and cholesterol is wrong, says health charity. The Guardian, May 23 2016

Now experts say low fat diets are BAD for you: Obesity charity claims you should stop counting calories and eat more healthy fats. Daily Mail, May 23 2016

'Eat fat to get thin': Official diet advice is 'disastrous' for obesity fight, new report warns. The Daily Telegraph, May 23 2016

Eating full fat foods 'can lower chance of obesity'. The Independent, May 23 2016

Get fat to get fit: A diet rich in full fat dairy and meat can lower the chance of obesity, health charity claims. The Sun, May 23 2016

Row over 'eat more fat' dietary advice. ITV News, May 22 2016

 Fri, 20 May 2016 16:10:00 GMT Healthier lifestyles 'could cut cancer death rates'

"Half of all cancer deaths could be avoided if people simply adopted a healthier lifestyle," the Daily Mail reports.

A new study adds to the weight of evidence that says combining simple lifestyle changes can dramatically cut cancer death rates.

More than 100,000 health professionals from the US were asked to complete questionnaires about their lifestyle and cancer status every two years, and diet every four years.

The researchers compared cancer rates between people with low- and high-risk lifestyle factors, and also compared rates in the low-risk group with the general white population in the US.

They found a large number of cancer cases and deaths could be attributed to a high-risk lifestyle, such as an individual being overweight, smoking, drinking heavily, or being physically inactive.

The researchers estimated between a quarter and a third of all cancer cases in this population group could be attributed to poor lifestyle factors.

These findings are in agreement with past research and the understanding that a healthier lifestyle may reduce the risk of various types of cancer.

But this study has limitations, including the population group, which only involved white American health professionals, and the possibility that the estimates are inaccurate. 

The study would appear to confirm that any small lifestyle changes you can make, such as quitting smoking, could considerably reduce your risk of developing cancer. And the more of these small changes you can combine, the greater the effect.

Read more about how lifestyle changes can help prevent cancer.

Where did the story come from?

The study was carried out by researchers from Harvard Medical School and was funded by the US National Institutes of Health.

It was published in the peer-reviewed journal, JAMA Oncology.

The Daily Mail reported on the study fairly accurately, but did not present any of its limitations.

It's nice to see that the article included clear recommendations from the research team about how a person can reduce their risk of cancer.

However, the headline figure of "half of all cancer deaths" seems a bit of a fudge, as the study presented a range of different results for specific cancer types.

What kind of research was this?

This prospective cohort study followed a large population group over time, and assessed the incidence of cancer and related deaths.

The researchers looked at how these cancer outcomes were related to various lifestyle factors, and then estimated the proportion of cancers that could be attributed to these factors.

The observational nature of this type of study means it is not able to prove causation, but it can find links and potential risk factors.

This type of study has strengths in terms of being able to follow a large number of participants over a long period of time, but the number of people who become non-responsive to follow-up assessments may increase over the years.

What did the research involve?

The researchers recruited participants from two cohort studies:

  • The Nurses' Health Study – which started in 1976 and enrolled female nurses aged 30 to 55
  • The Health Professionals Follow-up Study – which started in 1986 and enrolled male health professionals aged 40 to 75

Participants completed questionnaires about their medical history and lifestyle at the beginning of the study and every two years thereafter. Dietary information was collected every four years using a validated food frequency questionnaire.

The researchers split the participants into two groups according to the level of health risk associated with their lifestyle.

To be considered low risk, a participant had to meet the following requirements:

  • have never smoked or be a past smoker more than five years ago
  • drink no or a moderate amount of alcohol – no more than one drink a day for women and two for men
  • have a body mass index (BMI) of at least 18.5 and lower than 27.5
  • do at least 75 minutes of vigorous-intensity or 150 minutes of moderate-intensity aerobic physical activity a week

If all of these requirements were not met, the participant would be considered high risk.

The outcomes of interest were the incidence of total and major individual cancers and associated deaths. Cancer was self-reported in the questionnaires. Where a participant failed to respond, the National Death Index was used to identify deaths.

The researchers compared the cancer rates between the low- and high-risk groups. They then compared cancer rates in the low-risk group with cancer rates in the general population using national surveillance data.

They used this information to help them calculate population-attributable risk (PAR).

This is an estimate of the proportion of all cancer cases that can be attributed to poor lifestyle factors, or the number of cancers that would not occur in a population if the risk factor – in this case, a high-risk lifestyle – was eliminated.

For example, a PAR could be used to estimate how many people in a given population would not die of lung cancer if nobody in that population smoked.

What were the basic results?

A total of 135,910 people were included in the study (89,571 women and 46,339 men). The low-risk group contained 21% of all participants (12% women and 9% men) with the remaining 79% classed as high risk (54% women and 25% men).

The incidence of cancer per 100,000 people was 463 for women and 283 for men in the low-risk groups, compared with 618 for women and 425 for men in the high-risk groups.

From this, the researchers estimated that 25% of cancers in women and 33% of cancers in men could be attributed to high-risk lifestyle factors. For cancer-related deaths, 48% of cancer deaths in women and 44% of cancer deaths in men could be attributed to a high-risk lifestyle.

For individual cancers, the proportion of cancers estimated to be caused by high-risk lifestyle factors were:

  • lung – 82% for women, 78% for men
  • bowel – 29% for women, 20% for men
  • pancreas – 30% for women, 29% for men
  • bladder – 36% for women, 44% for men

Estimates were similar for cancer death, though there were additional associations for some other sites, including breast (12%), womb (49%), kidney (48% in men), and oral and throat (75% in women and 57% in men) cancers.

The general US populations were at higher risk than the whole study population, meaning that the PARs for these cancers resulting from a poor lifestyle were even higher than the researchers' estimates – for example, the PAR for bowel cancer jumped to 50%. 

How did the researchers interpret the results?

The researchers concluded that, "In this cohort study of a portion of the US white population, about 20-40% of cancer cases and about half of cancer deaths can be potentially prevented through lifestyle modification.

"These figures increased to 40-70% when assessed with regard to the population of US whites, and the observations are potentially applicable to broader segments of the US population." 

Conclusion

This prospective cohort study assessed the number of cancer cases and related deaths associated with poor lifestyle factors in a sample of US health professionals.

As the findings demonstrate, a large number of cancer cases and deaths in both men and women can be attributed to a high-risk lifestyle, such as being overweight, smoking, drinking heavily, or being physically inactive.

Worryingly, a poor lifestyle was estimated to account for an even greater number of cancers in the general population.

These findings are in agreement with much research, which has found that a healthier lifestyle may reduce the risk of various cancers.

The study has both strengths and limitations to consider. It contained a large number of participants and excluded types of cancer where incidence may be related to environmental factors rather than lifestyle, both adding strength to the findings.

It did have limitations, however:

  • The use of questionnaires for collecting information is prone to bias, either by people reporting what they think they should be doing rather than what they are doing, or because of difficulty recalling information over a period of time.
  • Only medical professionals were included in the study. This group are potentially more health conscious, so may not be a good reflection of the whole population. This is supported by the fact that even the high-risk study group were healthier than the US population overall, and PAR estimates for cancer from poor lifestyle factors were higher in the general population.
  • Only including a white population means these findings may not necessarily apply to other ethnicities.
  • These results are only estimates: though informed by careful analysis of this population and their lifestyle factors and cancer rates, it's possible that the proportion of cancers attributed to poor lifestyle factors is inaccurate, particularly for wider populations.

Despite these limitations, it is well known that unhealthy lifestyle factors could increase your risk of developing cancer, as well as various other health problems. Any small changes you can make to your lifestyle could considerably reduce your risk.

Read more about how to prevent cancer.

Links To The Headlines

HALF of all cancer deaths could be avoided if we simply adopted a healthier lifestyle. Daily Mail, May 19 2016

Links To Science

Song M, Giovannucci E. Preventable Incidence and Mortality of Carcinoma Associated With Lifestyle Factors Among White Adults in the United States. JAMA Oncology. Published online May 19 2016

 Fri, 20 May 2016 00:30:00 GMT Review calls for global action to tackle antibiotic resistance crisis

"Superbugs will kill someone every three seconds by 2050 unless the world acts now," BBC News reports.

A review commissioned by the UK government says wide-ranging action is required at a global level to prevent a post-antibiotic future.

The review panel, chaired by economist Jim O'Neill, warns that without global action, antibiotic resistance will become a "devastating problem" by 2050, responsible for an estimated 10 million deaths a year.

Surgery could also carry a much higher risk of complications because of the possibility of infection.

What is antibiotic resistance?

Antibiotics are often used to treat bacterial infections and are a cornerstone of infectious disease care.

However, bacteria evolve in response to their environment. Over time, they can develop mechanisms to survive a course of antibiotic treatment.

This "resistance" to treatment starts as a random mutation in the bacteria's genetic code, or the transfer of small pieces of DNA between bacteria.

If the mutations are favourable to them, they are more likely to survive treatment and be able to replicate, and are therefore more likely to pass on their resistant nature to future generations of bacteria.

When taken correctly, antibiotics will kill most non-resistant bacteria, so these resistant strains can become the dominant strain of a bacterium. This means that when people become infected, existing treatments may be unable to stop the infections.

What recommendations does the review make?

The review makes 10 recommendations, outlined below.

Launch a massive global public awareness campaign

The issue of antibiotic resistance is still not fully appreciated, especially in the developing world, where antibiotics are often sold without prescription.

The review estimates that a successful global campaign could be mounted for around to 0 million a year, a fraction of the advertising costs for products like pet food or chocolate.

Improve hygiene and prevent the spread of infection

Improving access to clean water and sanitation, promoting best practice in hospital infection control, and simply encouraging people to wash their hands will all help prevent infection.

Reduce unnecessary use of antibiotics in agriculture

The US Food and Drug Administration estimates 70% of medically useful antibiotics are actually sold for use in animals.

It argues that critically important antibiotics should be restricted from animal sales.

Improve global surveillance of drug consumption and resistance

Governments need to share data on antibiotic consumption and levels of resistance, and the biological reasons underpinning the two. Poorer countries should be given assistance in gathering data.

Promote new rapid diagnostic tests to reduce unnecessary use of antibiotics

Many antibiotics are prescribed in cases when a bacterial infection hasn't been confirmed, as a precaution. New types of tests could help prevent this.

The review hopes that by 2020, in wealthy countries antibiotics would only be prescribed if a bacterial infection had been confirmed through testing.

Promote the development and use of vaccines and alternatives

Encouraging the take-up of existing vaccines, as well as providing incentives for the creation of new ones, should help reduce the demand for antibiotics.

There also may be alternative interventions that can help prevent infections occurring.

Improve the number, pay and recognition of people working in infectious diseases

Infectious disease health professionals tend to be paid less than their peers working in other fields.

A similar pattern can be seen in both private and public sector workers involved in infection research.

Establish a Global Innovation Fund for early-stage and non-commercial research

The review recommends that a Global Innovation Fund, endowed with billion over the next five years, should be set up to fund "blue sky" research – research that may not have an immediate commercial application, but could lead to breakthroughs in the future.

Better incentives to promote investment for new drugs and improve existing ones

There is currently not a great deal of profit in antibiotic research, so pharmaceutical companies should be encouraged by meaningful incentives, such as a reward for bringing a new drug to market.

Build a global coalition for real action

Antibiotic resistance is a global problem, so it can only be tackled through global action. The review recommends that the G20 countries spearhead action via the United Nations. 

Links To The Headlines

Global antibiotics 'revolution' needed. BBC News, May 19 2016

Blueprint To Tackle Growing Drug Resistance. Sky News, May 19 2016

Antibiotics will stop working at a 'terrible human cost', major report warns. The Independent, May 19 2016

No antibiotics unless doctor runs tests first: Superbugs tsar urges crackdown over fears infections 'will kill more than cancer' by 2050. Mail Online, May 19 2016

Billion dollar rewards for new antibiotics called for to defeat catastrophic rise of superbugs. The Daily Telegraph, May 19 2016

No antibiotics without a test, says report on rising antimicrobial resistance. The Guardian, May 19 2016

Superbugs will kill 10m people a year without new antibiotics claims report. The Sun, May 19 2016


 

 
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