'Not enough over-50s' taking aspirin to prevent heart disease

reposted from: http://www.nhs.uk/news/2016/12December/Pages/Not-enough-over-50s-taking-aspirin-to-prevent-heart-disease.aspx

crabsallover highlights, key points, comments / links.

December 1 2016

You shouldn’t take daily aspirin unless a doctor advises you to.

Aspirin can help prevent blood clots.

"Aspirin a day could dramatically cut cancer and heart disease risk … study claims," the Mail Online reports.

U.S. researchers ran a simulation of what might happen if all Americans over 50 years old took aspirin on a daily basis. Their results found that people would live about four months longer on average, adding 900,000 people to the US population by 2036.

More info from NHS.uk.

The study was designed to demonstrate the possible long-term effects of more people taking aspirin to prevent cardiovascular disease.

It should be pointed out that there is an important difference between UK and US guidelines. In the UK low-dose aspirin is usually recommended for people with a history of heart disease or stroke. In the US this advice is extended to people who are at risk of cardiovascular disease but don't have it yet.

We already know that aspirin reduces the risk of heart disease and strokes caused by blood clots (ischaemic stroke). There's some evidence it may reduce some types of cancer. However, aspirin also increases the risk of stroke caused by bleeding (haemorrhagic stroke) and increases the chances of bleeding in the stomach or gut.

So should you be taking low-dose aspirin? Without knowing your individual circumstances it is impossible to provide an accurate response. You need to ask your GP.

Where did the story come from?

The study was carried out by researchers from the University of Southern California and a company called Analysis Group. The authors received no funding for the study.

The study was published in the peer-reviewed journal PLOS One, on an open-access basis so it's free to read online.

The Mail Online reports the study as if the findings about aspirin reducing cardiovascular disease and potentially extending lifespan were new, while they have actually been known for some time.

The report says taking aspirin "would save the US $692 billion in health costs," which seems to be a misunderstanding. Health costs would actually increase, because of people living longer.

However, the researchers assigned a value of $150,000 to each additional year of life lived, which is how they arrived at the $692 billion figure.

What kind of research was this?

This was a "microsimulation" study, which used a modelling system to project possible outcomes under different scenarios, using information from health surveys. This type of modelling can throw up some interesting possibilities, but because it relies on so many assumptions, we have to be cautious about taking the results too literally.

What did the research involve?

Researchers used data from cohort studies to predict average life expectancy, cardiovascular events, cancers, disabilities and healthcare costs for people in the US aged 50 and over. They predicted what would happen with the current numbers of people taking aspirin, then with everyone currently recommended to take aspirin doing so, then with everyone over 50 taking aspirin.

They compared the results of their modelling, to see what effect it would have on average lifespan, the US population, costs and benefits.

Cohort studies providing data included the National Health and Nutrition Examination Survey (NHANES), Health and Retirement Study of Americans, Medical Expenditure Panel Survey and Medicare Current Beneficiary Survey.
The model included an assumption that more people would have gastrointestinal bleeding as a result of taking aspirin. It also modified the results using quality of life measures, so that additional life years were adjusted for quality of life.

What were the basic results?

The researchers found that, if everyone advised by US guidelines to take aspirin did so, the:

• numbers of people with cardiovascular disease would fall from 487 per 1,000 to 476 per 1,000 (11 fewer cases, 95% confidence interval (CI) -23.2 to -2)
• numbers with gastrointestinal bleeding would rise from 67 per 1,000 to 83 per 1,000 (16 more cases, 95% CI 3.6 to 30)

• years of life expectancy at age 51 would rise from 30.2 years to 30.5 years, an additional four months of life (0.28 year, 95% CI 0.08 to 0.5)
• life expectancy without disability would rise from 22.8 years to 22.9 years, an additional one month of life (0.12 year, 0.03 to 0.23)

The model found no reduction in the numbers of strokes or cancers.

The model shows there could be an additional 900,000 people (CI 300,000 to 1,400,000) alive in the US in 2036, who would otherwise have died.

Using the figure of $150,000 per quality-adjusted life year to represent benefits, the researchers say the value of extra life gained by 2036 would be $692 billion.

How did the researchers interpret the results?

The researchers said: "Expanded use of aspirin by older Americans with elevated risk of cardiovascular disease could generate substantial population health benefits over the next twenty years, and do so very cost-effectively."

Conclusion

This study doesn't really tell us anything we didn't already know. Aspirin has been used for many years to prevent heart attacks and strokes in people with cardiovascular disease. Aspirin's wider use is controversial, because of the potential side effects.

What this study does add is an estimate of what might happen if all people in the US who were advised to take aspirin under US guidelines, actually did so. (The researchers say that 40% of men and 10% of women advised to take aspirin don't take it).

The study assumes that people would get the same benefits as those seen in clinical trials of aspirin. This is unrealistic, because most studies find that people tend to do better in clinical trials than when being treated in the real world.

The average results – showing an additional one month of disability-free life for every 1,000 people – may sound trivial. However, it's important to remember that averages don't work like that in real life. Many people will get no benefit from aspirin, while a smaller group will avoid a heart attack or stroke, and so live many more months or possibly years, as a result of taking aspirin.

If you've already had a heart attack or stroke, or if you have angina or another heart or circulation problem, your doctor has probably prescribed low dose aspirin. There's good evidence that aspirin (or similar drugs, for those who can't take aspirin) can help prevent a second heart attack or stroke.

Find out more information about aspirin.
Analysis by Bazian. Edited by NHS Choices. Follow NHS Choices on Twitter. Join the Healthy Evidence forum.
Analysis by Bazian
Edited by NHS Choices

Links to the headlines

Aspirin a day could dramatically cut cancer and heart disease risk - and even extend lifespan, study claims. Mail Online, November 30 2016

Links to the science

Agus DB, Gaudette E, Goldman DP, Messali A. The Long-Term Benefits of Increased Aspirin Use by At-Risk Americans Aged 50 and Older. PLOS One. Published online November 30 2016

Review questions recent official vitamin D guidance

reposted from: http://www.nhs.uk/news/2016/11November/Pages/Review-questions-recent-official-vitamin-D-guidance.aspx

crabsallover highlights, key points, comments / links.

Statins are 'safe, effective and should be used more widely'

reposted from: http://www.nhs.uk/news/2016/09September/Pages/Statins-safe-effective-and-should-be-used-more-widely.aspx

"Large-scale evidence from randomised trials shows that statin therapy reduces
the risk of major vascular events (ie, coronary deaths or myocardial infarctions, strokes, and coronary revascularisation procedures) by about one-quarter for each mmol/L reduction in LDL cholesterol during each year (after the first) that
it continues to be taken." Source: http://www.thelancet.com/pdfs/journals/lancet/PIIS0140-6736(16)31357-5.pdf

Flossing teeth does little good, investigation finds as US removes recommendation from health advice

reposted from: http://www.telegraph.co.uk/science/2016/08/02/flossing-teeth-does-little-good-and-us-removes-it-from-health-ad/

crabsallover highlights, key points, comments / links.

An hour of exercise a day may compensate for an 'office lifestyle'

reposted from: http://www.nhs.uk/news/2016/07July/Pages/An-hour-of-exercise-a-day-may-compensate-for-an-office-lifestyle.aspx

crabsallover highlights, key points, comments / links.

Thursday July 28 2016

If you work 9 to 5, make sure you exercise

"Office workers must exercise for an hour a day to counter death risk," The Daily Telegraph reports.

A major new study suggests that at least an hour's exercise a day may compensate for the risks of a sedentary lifestyle.

The study, which looked at previous research involving more than a million people, delivered a "bad news, good news" analysis. The bad news is that sitting for long periods may increase the chance of dying earlier. The good news is that doing at least an hour of moderately intense activity (such as cycling or brisk walking) each day may eliminate that risk.

The people in the study who were least active and sat for more than eight hours a day were 59% more likely to have died during the study follow-up than people who exercised most and sat for less than four hours a day. Sitting for longer than four hours a day increased the chance of death for everyone not in the highest activity category. However, people who did the most physical activity did not have an increased risk of death, regardless of how many hours a day they spent sitting.

This type of research cannot prove cause and effect but it certainly seems that daily physical activity brings long-term benefits.

The current activity advice for adults is to do at least 30 minutes of physical activity a day. Increasing that to 60 minutes may be a good idea if you do have a "9-5 office lifestyle".

Where did the story come from?

The study was carried out by researchers from institutions in many different countries, including the Norwegian School of Sports Sciences, University of Cambridge, University of Queensland, Oslo University Hospital, Swinburne University of Technology in Melbourne, Sydney University and Harvard Medical School. It received no direct funding.

The study was published in the peer-reviewed journal The Lancet on an open-access basis so it is free to read online (although you need to register).

Some UK media outlets took the study very literally. The Daily Mail tells readers "adults who sit down for at least eight hours every day must do at least an hour's daily exercise to undo all the harm." The study does not prove that exercise will "undo the harm" of sedentary behaviour.

It also ignores the study findings that people who were moderately active for about half an hour to an hour had only a slightly raised risk of death associated with sitting for longer periods. While the advice to exercise more is sound, people might think there's no point in exercising for less than an hour a day, and so give up altogether. It is very much the case that "every little helps" when it comes to exercise.

Experts in sports and exercise medicine were mostly welcoming of the study, describing it as "excellent quality" and "very interesting". However, one expert in evidence based medicine warned of the study's limitations and that it had not sufficiently controlled for factors such as socioeconomic status. 

What kind of research was this?

This study was a systematic review and meta-analysis of prospectivecohort studies. The researchers went back to the authors of the studies and asked them to re-analyse their data according to a standardised protocol, which allowed them to make direct comparisons between groups.

This is a good way to get a better idea of the relative importance of sitting and physical activity in terms of length of life. However, observational studies cannot tell us whether certain factors (sitting time or physical activity) directly cause another (chances of death). They can only tell us that the factors may be linked. 

What did the research involve?

Researchers searched the literature for studies that included information on sitting time, exercise and mortality. They added two studies that had not been published but which had relevant data.

They asked the original study authors to rework their data according to a standardised protocol which divided people into categories of physical activity and sitting time. They then pooled the data to look at how the two factors were linked to length of life. They also looked separately at time spent watching television, and at deaths from cardiovascular disease and cancer.

By applying a standardised protocol, the researchers were able to make direct comparisons across groups according to specific categories of sitting time (less than four hours a day, four to six hours, six to eight hours, and more than eight) and of physical activity. Physical activity was measured by metabolic equivalent of task (MET) hours a week. MET is a measurement of how much energy the body is likely to consume during specific physical activities.

MET levels were divided in four groups:

• less than 2.5 (equivalent to five minutes a day of moderate intensity physical activity)
• 16 (25 to 35 minutes a day, as recommended by many guidelines)
• 30 (50 to 65 minutes a day)
• more than 35.5 (60 to 75 minutes a day)

Researchers took the people who did the most physical activity and had the least sitting time as the baseline, and looked to see how more sitting time affected that, for people in the different categories of physical activity.

The same calculations were repeated using daily hours of TV viewing time, from less than one to five or more.

What were the basic results?

For people who did the least physical activity, sitting for more than four hours a day was linked to an increased chance of dying during the study. For these people, sitting for eight hours a day or more increased the chances of death by 27% (hazard ratio (HR) 1.27, 95% confidence interval (CI) 1.22 to 1.32), compared to if they'd been sitting four hours a day or less. Compared to people who did the most exercise and sat for less than four hours a day, they had a 59% increased risk of death (HR 1.59, 95% CI 1.52 to 1.66).

People who were physically active for between half an hour and an hour also had a raised chance of death linked to sitting for eight hours a day compared to four hours a day, of 10% to 12%. But for people who exercised the most, time spent sitting did not increase the risk of death.

High levels of physical activity were clearly linked to lower chance of death. People who did the most activity but sat for eight hours or more were less likely to die than those who did the least activity but sat for four hours or less.

Television viewing time showed similar results, but in this case even the highest amount of physical activity did not cancel the raised risk of watching five hours or more of television. The least active people had a 44% higher risk of death if they watched five or more hours of television, compared to less than one hour (HR 1.44, 95% CI 1.34 to 1.56).

Results were similar when the researchers looked at the chances of dying from cardiovascular disease or cancer.

How did the researchers interpret the results?

The researchers concluded: "These results provide further evidence on the benefits of physical activity, particularly in societies where increasing numbers of people have to sit for long hours for work" and suggest the study should be taken into account when public health recommendations are made.

Conclusion

This study helps to disentangle the effects of having a sedentary lifestyle and being physically active. Previous studies have had conflicting results, with some saying that sitting for long periods can be counteracted by taking exercise, while others disagreed.

The advantage of this study is that it looks at time spent sitting as well as time spent being physically active, and calculates how both are linked to mortality and to each other.

The study has many strengths, not least its size. It includes data from 1,005,791 people from 16 studies. The researchers applied a standardised protocol and asked study authors to provide re-analysed data. This meant they could pool information and make direct comparisons between groups sub-divided by sitting time and activity levels, to a higher degree of accuracy than would otherwise have been possible.

However, there are limitations. The authors only included English-language papers, so other relevant studies may have been excluded.

The authors tried to account for what is called reverse causation – in this case that illness may have prevented people from being physically active – by including studies of apparently healthy adults. However they admit that this factor was not completely ruled out.

In addition, the data came from participants' own estimates of time spent sitting, watching TV and being physically active. Not only is this reliant on accurate (and honest) self-assessment, it was only measured at one time point, so may not be representative over time.

Although the original studies included controls for most otherconfounding factors, such as smoking, most did not include socio-economic data, which could have a big impact on the results. For example, watching a lot of television could be linked to being on a low income, or unemployed, which are themselves linked to poor health.

Conversely, going to the gym is expensive, so this type of physical activity may be more common among people who are better-off. That makes it hard to know whether TV watching or exercise are the factor causing the difference in death rates, rather than being a marker for something else.

We know that sedentary lifestyles are linked to poorer health. For many people, work (or travelling to work) involves sitting down for long periods. While some people may be able to change this, for example by using a standing desk or cycling to work, for others it's not so easy. So it's heartening to know that taking exercise and being physically active in your free time may help.

However, it's interesting to note that the levels of activity linked to eliminating the risk of a sedentary lifestyle are higher than those usually recommended. The most active people spent the equivalent of 60 to 75 minutes doing moderately intense physical activity – higher than the usually recommended 30 minutes a day.

It may be that compensating for a desk job requires us to be more physically active than most of us currently manage.

You don't need to join a gym to increase your activity levels. Read more about how you can get fitter for free.

Analysis by Bazian. Edited by NHS Choices. Follow NHS Choices on Twitter. Join the Healthy Evidence forum.

Analysis by 

Edited by NHS Choices

Links to the headlines

Office workers must exercise for an hour a day to counter death risk. The Daily Telegraph. July 28 2016

Hour's activity 'offsets sedentary day'. BBC News, July 27 2016

One hour of activity needed to offset harmful effects of sitting at a desk. The Guardian, July 27 2016

A desk job could make you 60% more likely to die earlier: Hour's exercise every day is needed to help beat deadly effects of working 9 to 5. Daily Mail, July 28 2016

Links to the science

Ekelund U, Steene-Johannessen J, Brown WJ, et al. Does physical activity attenuate, or even eliminate, the detrimental association of sitting time with mortality? A harmonised meta-analysis of data from more than 1 million men and women. The Lancet. Published online July 27 2016

PHE publishes new advice on vitamin D. Should we all take 10 micrograms per day Vit D all year?

crabsallover says "180 x 25 micrograms Vitamin D tablets cost less than £10 - this is sufficient to supplement Vitamin D levels for a year at 10 micrograms Vitamin D per day".

Public Health England (PHE) is advising today (21st July 2016) that 10 micrograms of vitamin D are needed daily to help keep healthy bones, teeth and muscles.

This advice is based on the recommendations of the Scientific Advisory Committee on Nutrition (SACN) following its review of the evidence on vitamin D and health.

Vitamin D is made in the skin by the action of sunlight and this is the main source of vitamin D for most people. SACN could not say how much vitamin D is made in the skin through exposure to sunlight, so it is therefore recommending a daily dietary intake of 10 micrograms.  PHE advises that in spring and summer, the majority of the population get enough vitamin D through sunlight on the skin and a healthy, balanced diet. During autumn and winter, everyone will need to rely on dietary sources of vitamin D. Since it is difficult for people to meet the 10 microgram recommendation from consuming foods naturally containing or fortified with vitamin D, people should consider taking a daily supplement containing 10 micrograms of vitamin D in autumn and winter.

People whose skin has little or no exposure to the sun, like those in institutions such as care homes, or who always cover their skin when outside, risk vitamin D deficiency and need to take a supplement throughout the year.

Vitamin D regulates the amount of calcium and phosphate in the body, both needed for healthy bones, teeth and muscles. It is found naturally in a small number of foods including oily fish, red meat, liver and egg yolks and in fortified food like breakfast cereals and fat spreads.

Background 

The latest data from the PHE National Diet and Nutrition Survey (2008 to 2012) shows that 23% of adults aged 19 to 64 years, 21% of adults aged 65 years and above and 22% of children aged 11 to 18 years have low levels of vitamin D in their blood. This is not the same as having a deficiency, where you would be unwell, but rather means that you are at greater risk of developing a deficiency. If a person is deficient of vitamin D they will be clinically unwell and will need to be treated by a doctor.

PHE recommends against people using sunbeds because extreme short-term use could cause severe burning and long-term damage to the skin, with a possible increased risk of developing skin cancer.

SACN reviewed the evidence on vitamin D and health outcomes. In addition to musculoskeletal health, SACN reviewed the relationship between vitamin D and non-musculoskeletal health outcomes including cancer, Type 1 diabetes, multiple sclerosis and heart disease but found insufficient evidence to draw any firm conclusions.

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. Vitamin D plays an important role in the regulation of calcium and phosphate in the body. It is therefore essential for bone health. Without adequate vitamin D, bones can become thin, brittle and mis-shapen.  In extreme cases this can lead to rickets in children, a condition involving a softening of the bones that can lead to fractures and deformity. In adults softening of the bones is called osteomalacia, and may cause pain and muscle weakness.

From the full report:
S.25 Mean dietary intakes of vitamin D from all sources (including supplements) were: 2-4 µg/d (80-160 IU/d) for ages 1.5-64y; 5 µg/d (200 IU/d) for adults aged = 65y.

S.28 For all age groups in the UK, mean plasma 25(OH)D concentration was lowest in winter and highest in summer. Around 30-40% of the population had a plasma 25(OH)D concentration < 25 nmol/L in winter compared to 2-13% in the summer. A large proportion of some population groups did not achieve a plasma/serum 25(OH)D concentration = 25 nmol/L in summer (17% of adults in Scotland; 16% of adults in London; 53% of women of South Asian ethnic origin in Southern England; and 29% of pregnant women in NW London).

Metabolism S.5 Vitamin D is converted to its active metabolite, 1,25-dihydroxyvitamin D (1,25(OH)2D), in two hydroxylation steps. The first hydroxylation is in the liver, where vitamin D is converted to 25- hydroxyvitamin D (25(OH)D), which is the major circulating metabolite of vitamin D and is widely used as a biomarker of vitamin D status; the second hydroxylation is in the kidney where 25(OH)D is converted to 1,25(OH)2D.

The proportion of the population (by age) with a plasma 25(OH)D concentration < 25 nmol/L was: 2-8%, 5m-3y; 12-16%, 4-10y; 20-24%, 11-18y; 22-24%, 19-64y; 17-24%, = 65y and above.

S.7 At latitudes below 37 degrees North, UVB radiation is sufficient for year round vitamin D synthesis. At higher latitude, vitamin D is not synthesised during the winter months. In the UK, sunlight-induced vitamin D synthesis is only effective between late March/early April and September and not from October onwards throughout the winter months.

Sources

NHS Choices - report on what the papers say

PHE advice is detailed on NHS choices.  (but was this page really updated on 18/02/2015?)

SACN’s Vitamin D and Health report (300 pages) published 21 July 2016 (pdf)

SACN press release on the vitamin D report (PDF, 195KB, 2 pages) which highlights the report’s main findings and recommendations.

View documents related to the consultation on the draft report.These documents include a substantial number of consultation comments received by SACN, as well as SACN’s response to these comments.

View documents related to the proceedings of SACN’s Vitamin D Working Group. 

Above report edited by crabsallover from: https://www.gov.uk/government/news/phe-publishes-new-advice-on-vitamin-d

Coffee's cancer risk downgraded (as long as you don't drink it hot)

reposted from: http://www.nhs.uk/news/2016/06June/Pages/Coffees-cancer-risk-downgraded-as-long-as-you-dont-drink-it-hot.aspx

crabsallover highlights, key points, comments / links.

A review by the International Agency for Research on Cancer (IARC) concluded that only beverages consumed at higher than 65C posed a possible cancer risk.

Thursday June 16 2016

Coffee's cancer risk has now been degraded

"Very hot drinks may cause cancer, but coffee does not, says WHO," The Guardian reports.

A review by the International Agency for Research on Cancer (IARC) concluded that only beverages consumed at higher than 65C posed a possible cancer risk.

The working group's report re-evaluated the cancer-causing properties of drinking coffee, maté (a South American drink), and very hot beverages.

Coffee was classified as a possible cause of cancer in 1991, but the group has cleared the previous classification and suggested any suspected link was because of the hot temperature of the drink.

The researchers concluded there was limited evidence that drinking coffee and maté causes cancer, but say the risk of cancer of the oesophagus – the gullet – may increase with the temperature of the drink above 65C (149F).

Both the Daily Mirror and Daily Mail covered the story. The Mirror reports that leaving your cup of tea for around five minutes should cool it to a safe level.

The Mail reports that, not entirely surprisingly, store-bought black coffee is hot, at between 66 and 81C. So again, it is best left to cool for a while.

As it stands, smoking or alcohol consumption pose a bigger – and better documented – risk for oesophageal cancer.

Read more about ways to reduce your cancer risk.

So what's the matter with maté?

Maté is probably best described as the South American version of "builder's tea".

It is a caffeine-rich concoction served in very hot water and drunk through a metal straw. 

Who produced the report?

The report was published by an international collaboration of researchers (working group) of the IARC, a specialised cancer agency of the World Health Organization (WHO).

The group came together in France as part of the IARC Monographs Programme, which seeks to evaluate and identify environmental factors that can increase the risk of human cancer.

The researchers reviewed epidemiological studies of exposure to carcinogens in human populations, and used the evidence to classify potential hazards as:

• group 1 – carcinogenic to humans
• group 2A – probably carcinogenic
• group 2B – possibly carcinogenic
• group 3 – not classifiable (no evidence to make a reliable judgement)
• group 4 – probably not carcinogenic

However, the classification does not indicate what level of risk is associated with the exposure to a classified hazard.

For example, smoking cigarettes and using a sunbed are both group 1 hazards. But the risk of cancer associated with smoking cigarettes is far higher than using a sunbed.

Overall, the exact method of how the authors identified and selected the research is unclear. As such, it's not possible to say that this was a systematic review.

The monographs are published so they can be used by national health agencies to support their actions in preventing exposure to potential carcinogens.

What did the report find?

As part of their re-evaluation, the group assessed more than 1,000 observational and experimental studies.

They concluded:

• coffee drinking was "not classifiable as to its carcinogenicity to humans" (group 3)
• maté was "not classifiable as to its carcinogenicity to humans" (group 3)
• hot drinks above 65C were "probably carcinogenic to humans" (group 2A)

Coffee

Coffee drinking was evaluated by the IARC in 1991, and at the time was classified as "possibly carcinogenic to humans" (group 2B).

However, this was based on "limited evidence" – defined on the basis that a positive association between hazard and outcome was observed, but bias could not be ruled out.

The current evaluation has been conducted on a much stronger and larger body of evidence, with nearly 500 relevant epidemiological studies identifying more than 20 different cancers.

The group assessed a collection of epidemiological evidence, and gave the greatest weight to prospective cohort and population-based case control studies that had controlled for other exposures, such as tobacco and alcohol consumption.

The studies followed cohorts of people who self-reported their coffee drinking habits to see how many individuals developed cancer and how it was related to their consumption of coffee.

During this re-evaluation, the majority of epidemiological studies showed no association between coffee drinking and cancers of the pancreas, female breast, and prostate. Reduced risks were observed for liver and endometrial cancers.

On judging the various studies, the group concluded the evidence for "coffee drinking causing cancer" was inadequate. Reasons included insufficient data, inconsistency of findings, inadequate control of potential confounders, and bias.

Maté

Maté is a hot drink consumed in South America, and is also the national drink of Argentina.

It's a caffeine-rich infusion made from dried leaves of the yerba maté plant. In 1991 the IARC classified it as "probably carcinogenic to humans" (group 2A).

Since then, several epidemiological studies have been conducted evaluating the risk of oesophageal cancer and the consumption of hot maté.

With this new data, the IARC wanted to better understand whether the associations from previous studies were the result of maté itself or the hot temperatures at which it is usually consumed.

The studies found cancer of the oesophagus was associated with drinking hot maté, rather than maté at warm or cold temperatures.

Hot drinks

The findings from the evaluations of maté led the researchers to assess the association between oesophageal cancer and other hot drinks.

Previous research from China, Iran, Japan and Turkey also found the risk of cancer may increase with the temperature of the drink.

The IARC conducted a combined analysis on several epidemiological studies that had assessed the effect of both temperature and the amount of maté consumed on 1,400 patients with oesophageal cancer.

The results showed that regardless of the amount consumed, the risk of cancer increased with an increase in temperature.

There were significant differences in the results from drinking very hot maté, but not with warm maté.

The studies suggested the carcinogenic effects occur when drinking at temperatures above 65C.

What are the implications?

The IARC monographs seek to identify potential cancer hazards to raise awareness that a certain exposure can cause cancer in exposed people. However, they don't issue recommendations.

Their assessment of scientific evidence is produced so the World Health Organization, health agencies and governments can take it into consideration when developing health policies and guidelines. Whatever actions are taken as a result remain in the hands of the authorities concerned.

Professor Tim Underwood, associate professor in surgery at the University of Southampton, said: "The bottom line here is that drinking very hot liquids is a cause of squamous cell cancer of the oesophagus, but the IARC classification can't tell us anything about the size of the risk – so we shouldn't take from this that there's a high risk of developing oesophageal cancer after drinking very hot drinks."

Professor Sir David Spiegelhalter, Winton professor of the public understanding of risk at the University of Cambridge, said: "Last year the IARC said that bacon is carcinogenic, but it became clear that when eaten in moderation it is not very risky.

"In the case of very hot drinks, the IARC conclude they are probably hazardous, but can't say how big the risk might be. This may be interesting science, but makes it difficult to construct a sensible response."

Arguably, a commonsense approach would be to not drink anything hot enough to give you a serious burn if you spilt it on yourself, whether it's maté, coffee or tea.

Analysis by Bazian. Edited by NHS Choices. Follow NHS Choices on Twitter. Join the Healthy Evidence forum.

Analysis by 

Edited by NHS Choices

Links to the headlines

Very hot drinks may cause cancer, but coffee does not, says WHO. The Guardian, June 15 2016

Cancer risk from coffee downgraded. BBC News, June 15 2016

Very hot drinks 'probably' cause cancer of the oesophagus, world health chiefs warn. Daily Mail, June 16 2016

Tea experts say cuppas do not cause cancer despite claims from health researchers. Daily Mirror, June 15 2016

Hot drinks probably cause cancer, warns World Health Organisation. The Daily Telegraph, June 15 2016

Links to the science

The International Agency for Research on Cancer Monograph Working Group. Carcinogenicity of drinking coffee, maté, and very hot beverages. The Lancet Oncology. Published online June 15 2016

Further reading

International Agency for Research on Cancer. Q&A on Monographs Volume 116: Coffee, maté, and very hot beverages (PDF, 65kb). June 2016

News analysis: Does the 5:2 fast diet work? (May 2013 update)

reposted without editing from: http://www.nhs.uk/news/2013/01January/Pages/Does-the-5-2-intermittent-fasting-diet-work.aspx

crabsallover highlights, key points, comments / links.

This is an update of a January 2013 NHS Choices article - see here.

Monday January 14 2013

Is intermittent fasting right for you?

Note – this article, originally written in January 2013, was updated in May 2013.

The 5:2 diet is an increasingly popular diet plan with a flurry of newspaper articles and books being published on it in the run up to Christmas 2012 and in January 2013.

The diet first reached the mainstream via a BBC Horizon documentary called Eat, Fast and Live Longer, broadcast in August 2012.

The 5:2 diet is based on a principle known as intermittent fasting (IF) – where you eat normally at certain times and then fast during other times.

The 5:2 diet is relatively straightforward – you eat normally five days a week, and fast on the other two days.

What does a daily 600-calorie diet look like?

A 600-calorie diet could consist of a slice of ham and two scrambled eggs for breakfast and then some grilled fish and vegetables for your evening meal. And of course nothing but water, black coffee and/or green tea to drink.

Champions of the 5:2 diet claim that other than helping people lose weight, 5:2 diet can bring other significant health benefits, including:

• increased lifespan
• improved cognitive function and protection against conditions such as dementia and Alzheimer’s disease
• protection from disease

However the body of evidence about 5:2 diet and intermittent fasting is limited when compared to other types of weight loss techniques. 

What we don’t know about intermittent fasting

Despite its increasing popularity, there is a great deal of uncertainty about IF with significant gaps in the evidence.

For example, it is unclear:

• what pattern of IF is the most effective in improving health outcomes – 5:2, alternative day fasting, or something else entirely different
• what is the optimal calorie consumption during the fasting days – the 5:2 diet recommends 500 calories for women and 600 for men, but these recommendations seem arbitrary without clear evidence to support them
• how sustainable is IF in the long-term – would most people be willing to stick with the plan for the rest of their lives?

Are there any side effects from intermittent fasting?

Little is known about possible side effects as no systematic attempt has been made to study this issue. Anecdotal reports of effects include:

• difficulties sleeping
• bad breath (a known problem with low carbohydrate diets)
• irritability
• anxiety
• dehydration
• daytime sleepiness

However, more research would be needed to confirm these side effects and their severity.

If you are fasting, you may want to think about how fasting will impact on your life during your fasting days. You are likely to be very hungry and have less energy and this could affect your ability to function (such as at work), in particular it may affect your ability to exercise which is an important part of maintaining a healthy weight.

Also, IF may not be suitable for pregnant women and people with specific health conditions, such as diabetes, or a history of eating disorders.

Because it is a fairly radical approach to weight loss, if you are considering trying IF for yourself, it is wise to speak to your GP first to see if it is safe to do so.

Evidence about the 5:2 diet

Despite its popularity evidence directly assessing the 5:2 model of intermittent fasting is limited.

But since this article was originally written in January 2013 we have been alerted to research, led by Dr Michelle Harvie, which did look at the 5:2 model.

In one study carried out in 2010 the researchers did find that women placed on a 5:2 diet achieved similar levels of weight loss as women placed on a calorie-controlled diet.

They also experienced reductions in a number of biological indicators (biomarkers) that suggest a reduction in the risk of developing chronic diseases such as type 2 diabetes.

A further study in 2012 suggested that the 5:2 model may help lower the risk of certain obesity-related cancers, such as breast cancer.

The increasing popularity of the 5:2 diet should lead to further research of this kind.

Evidence about other forms of IF

There is some degree of evidence about the potential benefits of other forms of IF – albeit with some limitations.

It should be stressed that our assessment of the evidence was confined to entering a number of keywords into Google Scholar and then looking at a small number of studies which we felt would be useful to explore further.

We did not carry out a systematic review (though arguably, it would be useful for researchers to do so). So the information provided below should be taken in the spirit of us trying to provide an introduction to some of the evidence and science of IF – not an exhaustive "last word" on the topic.

Is there any evidence that intermittent fasting aids weight loss?

One of the most recent pieces of research on intermittent fasting is a2012 study (PDF, 291kb) that recruited 30 obese women known to have pre-existing risk factors for heart disease.

After an initial two-week period they were then given a combination diet of low-calorie liquid meals for six days of a week (similar to Slim Fast diet products) and then asked to fast for one day a week (comsuming no more than 120 calories).

After eight weeks, on average, the women lost around 4kg (8.8lb) in weight and around 6cm (2.3 inches) off their waist circumference.

However, there are a number of limitations to consider when looking at this as evidence that it might be a generally beneficial thing to do for most ordinary people, including that:

• These women may have had increased motivation to stick with the diet because they knew their weight would be monitored (this is a psychological effect that slimming clubs make use of).
• The women had been told that they were at risk of heart disease. It is uncertain how well most of us would cope with such an extreme diet.
• The follow-up period was short – just two months. It is not clear whether this diet would be sustainable in the long term or whether it could cause any side effects.
• 30 people is quite a small sample size. A much larger sample – including men – is required to see if intermittent fasting would be effective in most overweight or obese people.

Is there any evidence intermittent fasting increases lifespan?

There is quite a wide range of work on the effects of IF on combating the effects of ageing, but almost all of these studies involved either rats, mice or monkeys. One big problem with studies in animals – particularly rodents – is that they are only expected to live for a few years. While this makes them ideal subjects for longevity studies, carrying out similar, more useful experiments in humans, requires decades-long research to gain credible results.

In an unsystematic look at the evidence, we find only one study involving humans: a 2006 review (PDF, 65kb) of an experiment actually carried out in 1957 in Spain.

In this 1957 study, 120 residents of an old people’s home were split into two groups (it is unclear from the study whether this was done at random). The first group (the control group) ate a normal diet. The second group (the IF group) ate a normal diet one day and then a restricted diet (estimated to be around 900 calories) the next.

After three years there were 13 deaths in the control group and only six deaths in the IF group.

This study is again limited by the small sample size meaning that the differences in death are more likely to be the results of a statistical fluke. Also, many experts would feel uneasy about issuing dietary guidelines based on a study over half a century old with unclear methods. It is unlikely that this experiment could be repeated today – denying food to elderly people in residential care is unlikely to be looked at kindly by an ethics committee.

Is there any evidence intermittent fasting prevents cognitive decline?

It seems that all of the studies on the supposed protective effects of IF against conditions that can cause a decline in cognitive function (such as dementia or Alzheimer’s disease) involve animals.

For example, a 2006 study (PDF, 843kb) involved mice that had been genetically engineered to develop changes in brain tissue similar to those seen in people with Alzheimer’s disease.

Mice on an IF diet appeared to experience a slower rate of cognitive decline than mice on a normal diet (cognitive function was assessed using a water maze test).

While the results of these animals tests are certainly intriguing, animal studies have inherent limitations. We can never be sure that the results will be applicable in humans.

Is there any evidence that intermittent fasting prevent diseases?

Much of the published research into the potential preventative effects of IF involve measuring biological markers associated with chronic disease, such as insulin-like growth factor-I (IGF-I) – known to be associated with cancer.

Using these kinds of biological surrogates is a legitimate way to carry out research, but they do not guarantee successful real-world outcomes.

For example, some medications that were found to lower blood pressure readings taken in laboratory conditions failed to prevent strokes once they had been introduced for use in the healthcare of patients in the world.

A 2007 clinical review (PDF, 119kb) looking at the effects of IF in humans in terms of real-world health outcomes concluded that IF (specifically, alternative day fasting) may have a protective effect against heart disease, type 2 diabetes and cancer. However, it concluded "more research is required to establish definitively the consequences of ADF (alternative day fasting)".

Conclusion

Compared to other types of weight loss programmes the evidence base of the safety and effectiveness of the 5:2 diet is limited.

If you are considering it then you should first talk to your GP to see if it is suitable for you. Not everyone can safely fast.

Other methods of weight loss include:

• eating a healthy balanced diet with at least five portions of fruit and vegetables a day
• taking regular exercise
• drinking alcohol in moderation

Find recommended, simple, low cost ways to lose weight in the Live Well: lose weight pages.

Edited by NHS Choices. Follow Behind the Headlines on Twitter.

Edited by NHS Choices

Links to the headlines

The power of intermittent fasting. BBC News, August 5 2012

The 5:2 diet: can it help you lose weight and live longer? The Daily Telegraph, August 16 2012

Links to the science

Harvie M, Howell A. Energy restriction and the prevention of breast cancer. Proceedings of the Nutrition Society. Published online March 12 2012

Harvie M, Pegington M, Mattson MP, et al. The effects of intermittent or continuous energy restriction on weight loss and metabolic disease risk markers: a randomised trial in young overweight women. International Journal of Obesity. Published online October 5 2010

Kroeger CM, Klempel MC, Bhutani S, et al. Improvement in coronary heart disease risk factors during an intermittent fasting/calorie restriction regimen: Relationship to adipokine modulations (PDF, 291.4Kb). Nutrition & Metabolism. Published online October 31 2012

Johnson JB, Laub DR, John S. The effect on health of alternate day calorie restriction: Eating less and more than needed on alternate days prolongs life (PDF, 64.66Kb). Medical Hypothesis. Published online 2006

Halagappa VKM, Guo Z, Pearson M, et al. Intermittent fasting and caloric restriction ameliorate age-related behavioral deficits in the triple-transgenic mouse model of Alzheimer's disease (PDF, 843.1Kb). Neurobiology of Disease. Published online January 13 2007

Varady KA, Hellerstein MK, et al. Alternate-day fasting and chronic disease prevention: a review of human and animal trials (PDF, 118.6KB). American Journal of Clinical Nutrition. Published online 2007     

Physical activity guidelines for adults

How much physical activity do adults aged 19-64 years old need to do to stay healthy?

To stay healthy or to improve health, adults need to do two types of physical activity each week: aerobic and strength exercises.

How much physical activity you need to do each week depends on your age. Click on the links below for the recommendations for other age groups:

• early childhood (under 5 years old)
• young people (5 to 18 years old)
• older adults (65 and over)  

Guidelines for adults aged 19-64

To stay healthy, adults aged 19-64 should try to be active daily and should do:

• at least 150 minutes of moderate aerobic activity such as cycling or fast walking every week, and  
• strength exercises on two or more days a week that work all the major muscles (legs, hips, back, abdomen, chest, shoulders and arms).  

• 75 minutes of vigorous aerobic activity, such as running or a game of singles tennis every week, and
• strength exercises on two or more days a week that work all the major muscles (legs, hips, back, abdomen, chest, shoulders and arms). 

• A mix of moderate and vigorous aerobic activity every week. For example, two 30-minute runs plus 30 minutes of fast walking equates to 150 minutes of moderate aerobic activity, and
• strength exercises on two or more days a week that work all the major muscles (legs, hips, back, abdomen, chest, shoulders and arms).  

A rule of thumb is that one minute of vigorous activity provides the same health benefits as two minutes of moderate activity.  

One way to do your recommended 150 minutes of weekly physical activity is to do 30 minutes on 5 days a week. 

All adults should also break up long periods of sitting with light activity. Find out why sitting is bad for your health.

What counts as moderate aerobic activity?

Examples of activities that require moderate effort for most people include:

• walking fast
• water aerobics
• riding a bike on level ground or with few hills
• doubles tennis
• pushing a lawn mower
• hiking
• skateboarding
• rollerblading
• volleyball
• basketball 

Moderate activity will raise your heart rate and make you breathe faster and feel warmer. One way to tell if you're working at a moderate level is if you can still talk, but you can't sing the words to a song.

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What counts as vigorous activity?

There is good evidence that vigorous activity can bring health benefits over and above that of moderate activity.

Examples of activities that require vigorous effort for most people include:

• jogging or running
• swimming fast
• riding a bike fast or on hills
• singles tennis
• football
• rugby
• skipping rope
• hockey
• aerobics
• gymnastics
• martial arts

Vigorous activity makes you breathe hard and fast. If you're working at this level, you won't be able to say more than a few words without pausing for breath.

In general, 75 minutes of vigorous activity can give similar health benefits to 150 minutes of moderate activity.

For a moderate to vigorous workout, try Couch to 5K, a nine-week running plan for beginners.

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What activities strengthen muscles?

Muscle strength is necessary for:

• all daily movement
• to build and maintain strong bones
• to regulate blood sugar and blood pressure
• to help maintain a healthy weight

Muscle-strengthening exercises are counted in repetitions and sets. A repetition is one complete movement of an activity, like a bicep curl or a sit-up. A set is a group of repetitions.

For each strength exercise, try to do:

• at least one set
• eight to 12 repetitions in each set 

To get health benefits from strength exercises, you should do them to the point where you struggle to complete another repetition.

There are many ways you can strengthen your muscles, whether it's at home or in the gym. Examples of muscle-strengthening activities for most people include:

• lifting weights
• working with resistance bands
• doing exercises that use your own body weight, such as push-ups and sit-ups
• heavy gardening, such as digging and shovelling
• yoga

Try Strength and Flex, a 5-week exercise plan for beginners to improve your strength and flexibility.

You can do activities that strengthen your muscles on the same day or on different days as your aerobic activity - whatever's best for you.

Muscle-strengthening exercises are not an aerobic activity, so you'll need to do them in addition to your 150 minutes of aerobic activity.

Some vigorous activities count as both an aerobic activity and a muscle-strengthening activity.

Examples include:

• circuit training
• aerobics
• running
• football
• rugby
• netball
• hockey

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Download a factsheet on physical activity guidelines for adults (19-64 years) (PDF, 568kb)

For a summary on the health benefits of being more active, check out this Department of Health infographic (PDF, 500kb).

Page last reviewed: 11/07/2015

Next review due: 11/07/2017

reposted from:http://www.nhs.uk/Livewell/fitness/pages/physical-activity-guidelines-for-adults.aspx

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