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

Food and cancer: why media reports are often misleading

reposted from: Cancerresearchuk

crabsallover highlights, key points, comments / links.

Food and cancer: why media reports are often misleading

Fri Dec 14, 2012 15:07 Share

This research shows the danger of overstating the results of single studies

The media’s appetite for things that cause or prevent cancer can be as notable for its sheer volume as for – in some cases – its hype. And food is a key area of interest, because everyone can relate to the latest headlines on bacon or broccoli.

Rarely a week goes by without headlines on the latest “cancer-busting” food or, at the other end of the spectrum, the unexpected perils of pop. So a research article with the intriguing title ‘Is everything we eat associated with cancer? A systematic cookbook review‘, published in the American Journal of Clinical Nutrition recently, couldn’t fail to catch our attention.

This review looked at a selection of cookbook ingredients to see if they had been investigated for links to cancer. The researchers found that most of the 50 foods they looked at had been associated with an increased or decreased cancer risk in the scientific literature.

But is this a testament to the power of different foods over our chance of developing cancer? Or is it proof that scientists just can’t make their mind up?

In fact it’s neither. The most important finding of the review was that single studies often found links that had only weak evidence behind them.

The research provokes thoughts about why we do research, how much one study on its own can tell us, and the value of considering the balance of evidence.

Perhaps most importantly, is also raises questions about how much detail scientists and the media provide as context when they present results to the public.

And rather ironically, and worryingly, one paper decided this study warranted the conclusion that there is ‘no proven link between foods and cancer’. This is clearly not the case, as we explain below.

What’s a ‘systematic cookbook review’ anyway?

The authors of this review – the first of its kind – picked page numbers at random from a cookbook, and used the ingredients they found to create a list of 50 different foods to investigate. The book (The Boston Cooking-School Cook Book) is over a hundred years old, but most of the foods on the list, such as olives, lamb, flour and mushrooms, are standard fare today.

The authors then used PubMed, a comprehensive database of published scientific research, to look for studies linking each of the foods to an altered risk of cancer in people. Of the 50 foods on the list, they found that 40 had been the subject of at least one study. The 10 ingredients that hadn’t been investigated were generally more unusual (terrapin, for instance).

Building conclusions on shaky ground

For each type of food, the authors then looked in more detail at the studies they’d found, picking up to 10 results, or choosing the most recent where there were more than 10 studies. They compared what the studies had concluded, with how strong their evidence was – and particularly how statistically certain they could be that their finding wasn’t just down to chance.

Almost three-quarters of the studies claimed that consuming the food in question affected a person’s risk of cancer, rather than making no or little difference. But in most cases the evidence behind these claims was either weak or simply not there.

Results that had at least weak evidence tended to be highlighted in study abstracts – the short summary presented at the start of the paper, which is often the basis for press releases and subsequent media stories – whereas the findings that could have been down to chance (i.e. weren’t statistically significant) were reported only in the full manuscript.

And a finding with only weak evidence behind it starts to look shakier if you discover it was the strongest result out of many – after all, a one in 20 chance of being a fluke is not very impressive if someone’s had another 19 goes. This practice of highlighting findings from subgroup analysis, as it’s known, can be particularly misleading, as often only the abstract of an academic paper is available free of charge.

The way studies compared the amounts of a food people ate also varied widely. Less than 1 in 7 of the studies compared people who didn’t eat a food with those who did. Instead they compared people who on average had different amounts, which makes it more difficult to work out if it is the specific food that’s having the effect. And similar studies, comparing the same food and same type of cancer, often used different ways of classifying people’s consumption, making it hard to work out if findings supported one another or not.

The balance of evidence

The overall balance of evidence is more important [than] single studies

Next, the authors looked at studies called ‘meta-analyses’, that pooled the results of other studies. These aim to calculate the overall size of a possible link between a food and cancer risk, and are considered by many to be ‘gold standard’ evidence. Though of course they are only as good as the data you put into them.

The authors found that links calculated in meta-analyses tended to be much weaker than the findings from the single studies. Tellingly, the meta-analyses were much more likely to conclude that a food didn’t make much difference to a person’s risk of cancer. This suggests that the single studies were likely to be overestimating any link they found.

But this doesn’t necessarily mean that the studies were pointless or even badly conducted. The foods we eat are a sensible factor to consider when thinking about cancer risk, particularly when it comes to cancers of the digestive tract, which most of the studies focused on.

But what this study highlights is the importance of the balance of evidence when considering the impact of a study. And alongside that, we need to consider whether there’s a reasonable way for a given food to influence cancer risk, or whether there’s another explanation for a potential link.

For example people who eat more healthily tend to take more interest in their health in general, which could help to explain any observation that eating apples keeps the doctor away.

As a whole, science is like an enormous jigsaw puzzle with every study contributing one small piece to the picture. Corners and easily identifiable parts of the image may seem like the most important – but you still need all those bits of sky. As the person looking at the puzzle, the key is to take in the whole thing and be aware of any gaps. This is how science works: each new academic publication doesn’t tend to cause wild swings in opinion – rather the slow accumulation of evidence allows the movement towards established fact.

But the popular media often highlights disagreement and controversy, so we need to remind ourselves not to read too much into a one-off claim.

So is there a link between diet and cancer or not?

Some of the foods thrown up by the cookbook search have been found to have clear links to cancer – but through decades of accumulated research, not isolated studies. Alcohol (wine, rum and sherry were on the list) is a well-established cause of cancer, and there’s a known link with eating too much red meat (lamb, pork, veal and beef) and with salty foods. On the reduced risk side, many of the foods considered were fruits and vegetables – getting your five a day is another good way to reduce the risk of cancer.

Despite a headline saying otherwise, this review definitely doesn’t demonstrate that there’s no link between diet and cancer. It just underscores the need for caution when interpreting the often limited evidence. So while it’s fair to say that broadly what we eat can affect our risk, in most cases we simply don’t have enough evidence when it comes to specific foods.

The message that the best way to reduce the risk of cancer through what you eat is to have a healthy balanced diet may not be new and exciting, but it remains the one with the strongest evidence.

Further reading

• The causes of cancer you can control
• Lifestyle and cancer: against the blame game

Reference

Schoenfeld, J. & Ioannidis, J. (2012). Is everything we eat associated with cancer? A systematic cookbook review American Journal of Clinical Nutrition DOI:10.3945/ajcn.112.047142

Men’s cancer risk is climbing: what can we do about it?

reposted from: CancerResearchUK

crabsallover highlights, key points, comments / links.

Posted on December 19, 2012 by Oliver Childs @ Cancer Research UK

If current trends continue, half of UK men born in 2027 will develop cancer

A boy born in 2027 in the UK will have a one in two chance of developing cancer over the course of his lifetime, according to new figures we released today.

In other words, 50 in every 100 UK men in the future are likely to hear the words “you have cancer” at some point in their lifetime. However you say it, that’s clearly not a positive headline.

But crucially, this increasing lifetime risk of cancer is balanced by another powerful force – that of increasing survival rates. Against a backdrop of increasing cancer risk over the past 40 years,survival rates have doubled in the UK.

This is thanks to our greatest weapon against cancer – research, be it new treatments or new ways to prevent people getting cancer in the first place.

Read on for more in-depth analysis of today’s report, and for the visually-minded, this short animation has the key facts:

What is lifetime risk?

Today’s projections don’t mean one in every two men will have cancer by 2027. Instead the lifetime risk of cancer estimates the chance that a newborn child has of developing cancer at some point during their life. The projected lifetime risk is based on predicted population and all cause mortality data, along with incidence and death rates, both in the past and projected into the future. (You can read more about the methods used to predict lifetime risk on our website.)

What’s driving this increase?

Lifetime risk accounts for a person’s overall risk over their whole life. It doesn’t say anything about when a person might develop cancer. But our risk of cancer doesn’t stand still during our lifetime – just as our baby-soft skin starts to accumulate wrinkles as we get older, our risk of developing cancer builds up as we age.

That’s because, as well as wrinkles, we accrue more and more genetic damage over our lives, which is the underlying cause of cancer. And as time passes, cancer-linked genetic factors we may have inherited from our parents have more chance of kick-starting cancer.

Age is one of the biggest risk factors for cancer. In other words, the older we get, the more likely we are to develop cancer. That’s one reason why – thankfully – childhood cancer is rare, accounting for less than 1 per cent of all cancers.

And because of advances in general medicine and improving living conditions, people are living longer on average. The result is more cancer.

As the following chart shows, the projection of one in two men in the future developing cancer is disproportionally down to our ageing population. In fact, based on current trends, a boy born in 2027 will be at least 75 before his risk of cancer starts to exceed that of a man in 2010. But many more people will be living into their 80s, 90s and beyond, so the burden of cancer will increase.

So in many ways we’re a victim of our own medical successes – the conditions that used to kill great numbers of people, such as infections like polio, are no longer as big a threat. But chronic diseases such as cancer, diabetes and heart disease are fast replacing the diseases of old. We’re living longer, but are not necessarily healthier.

Which cancers are increasing?

The men’s cancers set to increase the most over the next 15 years include prostate andbowel cancer and malignant melanoma, the most dangerous form of skin cancer.

• The lifetime risk for prostate cancer is predicted to increase from around 132 in 1,000 men now to 162 in 1,000 men born in 2027. A large reason for the increase in prostate cancer is because of the use of a test called prostate specific antigen (PSA), which is leading to more men being diagnosed with the disease. But we don’t yet have a reliable way to work out which men have life-threatening disease, and which don’t. In other words, working out who will die from their prostate cancer, as opposed to with their disease is still beyond us.
• The lifetime risk for bowel cancer is predicted to increase from around 72 in 1,000 men to 84 in 1,000 men by 2027. Beyond our ageing population, the increase in lifetime risk of bowel cancer is down to lifestyle factors such as an increase in red meat consumption, obesity, low-fibre diets, alcohol and tobacco.
• The lifetime risk for malignant melanoma is predicted to increase from around 18 in 1,000 men to 27 in 1,000 men by 2027. Malignant melanoma is the most deadly skin cancer, and around 10,200 men in the UK in 2027 are predicted to be diagnosed with the disease.

But these are areas we’re actively researching. You can read highlights of our current research on skin, prostate and bowel cancer on our website.

What can men do to reduce their risk?

Yes, age is the biggest risk factor for cancer, but this doesn’t mean we should be complacent or fatalistic. The predicted rise in the number of cancer cases isn’t inevitable, there are things we can do to reduce the risk – because more than four in ten cancers could be prevented by lifestyle changes.

If more men start making changes to their lifestyles, such as not smoking, keeping a healthy weight, cutting back on alcohol, eating a healthy, balanced diet, being physically active and staying safe in the sun, then some of these cancers would never develop.

Research is the answer

Everyone has their part to play in the fight against cancer, and we’re at the frontline of the battle. Because, as our new TV ad says, cancer’s biggest enemy is research.

History proves that research is a formidable enemy – it’s thanks to advances in the prevention, detection and treatment of cancer that more people are surviving their disease than ever before. And our recent figures show that the rates of people dying from cancer are predicted to fall by 17 per cent in the UK by 2030.

But today’s lifetime risk projections in men – and equally sobering statistics in women – clearly show there is more to do.

With the continued help of the public we’ll continue to support lifesaving research; continue to lobby government to make the right choices when it comes to cancer, such as supporting the plain packaging of cigarettes; and continue to encourage people to make the lifestyle choices that research shows can help cut their cancer risk.

Research has already beaten diseases like smallpox. And one day, research will beat cancer.

5 A Day Fruit & Veg for Cancer Prevention?

reposted from: http://www.weightlossresources.co.uk/member/article.htm?title=5-a-day-for-cancer-prevention

5 A Day for Cancer Prevention?

BY WLR DIETITIAN LYNDEL COSTAIN BSc RD

When it comes to healthy eating, one thing we have always felt sure about is the tremendous health benefits of fruit and vegetables. This week however, new research questions whether fruit and veg can reduce our cancer risk. So is it still worth fitting in our 5-a-day?

Cancer Prevention - What’s the Story?

Scientists from the Mount Sinai School of Medicine in New York analysed information about the diet, lifestyle and cancer risk of over 400,000 people in the UK and 9 other European countries. This information had been previously collected as part of the largest ever study into the link between diet and cancer prevention, known as the EPIC study.

The health of people in the study was followed for 8 to 9 years. During this time, 30,000 people had developed cancers. The scientific team then looked for links between how many fruit and vegetables were typically eaten, and the risk of getting cancer during the 8 to 9 years. They did find a benefit to help prevent cancer in eating more fruit and veg but it was smaller than some people expected. For example, the scientists worked out that if everyone ate an extra 200g (approximately 2.5 portions) of fruit and veg every day, it would reduce the risk of developing cancer by around 3%.

What Does This Mean for Cancer Prevention?

While this might sound small, Cancer Research UK has highlighted that it translates to the possibility to prevent 7200 cases of cancer per year in the UK. In addition, the study found a “dose-response effect”. This means that the more portions of fruit and vegetables people ate, the more they reduce their risk of cancer. For example, compared to people who ate less than 2.5 portions a day, those who enjoyed their 5-a-day had a 9% reduced cancer risk.

The other key point to come out of the debate stimulated by this study, is that over the last ten years or so, more refined research has pointed to fruit and veg being more able to prevent cancer of the head, neck, lung and digestive system – with no clear protective effect for breast, prostate or ovarian cancers. As the current study looked at protection for over 200 different types of cancers it is not surprising that the overall impact is not as high as some might expect.

More good news

Fruit and vegetables, brim with vitamins, minerals, fibre and antioxidants. There is still plenty of good evidence that enjoying your 5-a-day as part of a healthy diet, will:

• Help reduce the risk of heart disease
• Help reduce the risk of stroke
• Help keep blood pressure in check
• Benefit overall health.

For example, in another report linked to the EPIC study, people who ate the most fruit and vegetables were around a quarter less likely to die of chronic diseases at a given age, than people who ate very little.

Eating plenty of fruit and veg has also been linked to keeping those extra unwanted pounds at bay as we get older, especially amongst women. Fruit and vegetables are generally low in fat and calories, yet bulky and filling, making it easier to stay satisfied with fewer calories. They also look and taste great – with their endless colours, flavours and textures - think juicy, crisp, crunchy, peppery, sweet ... enjoy!