Another study has linked processed meat to ill health
As if the horsemeat scandal wasn’t bad enough, this morning’s headlines brought further news of the dangers of eating too much processed meat: an increased risk of an early grave.
The news come from a huge Europe-wide study – called EPIC – that Cancer Research UK helps fund, and this is no flash in the pan – the findings are robust and important.
But many people are well aware of the downsides of a high-meat diet, and one could be forgiven for a certain amount of headline fatigue on this topic – after all it seems to come up at least once a year.
So what exactly does this study add to what we already know – and, importantly, should we care?
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.
Fruit and vegetables are good for you but there’s no evidence that they can treat cancer. (Image from Wikimedia commons)
We were concerned to see an article in the Daily Express today asking “Do cancer alternatives really work?” This piece contains factual and scientific inaccuracies, as well as misleading information that could potentially cause harm to people with cancer. We have written a short letter to the Express with our concerns (Edit: which they have declined to publish – see end of post KA), and wanted to address the claims made in the article in full here.
We completely understand that people would like to try everything to help themselves after a diagnosis of cancer, but strongly urge any patient considering complementary or alternative therapy to talk to their cancer doctor or specialist nurse about the safety and effectiveness of such treatments. Some are not safe and can cause serious side effects.
Furthermore, we spend a great deal of time and money doing research to find out what treatments work best (or don’t work) for people with cancer. It is disheartening to see health advice or even therapies being recommended with very little or no evidence to show that they have any benefit for patients.
To highlight specific flaws in this article:
Diet: The article makes claims for the cancer-fighting properties of a number of foods, including avocados, garlic, tomatoes and beetroot (which has apparently “been shown to kill cancer cells”) and also mentions the power of “antioxidants”. While we would agree that it’s important for everyone – including cancer patients – to eat a healthy diet rich in fruit and vegetables where possible, there is no good evidence to suggest that any particular foodstuff can really treat cancer. The writer makes the mistake of using evidence from experiments with purified vegetable extracts carried out on cells grown in the laboratory to suggest that certain fruits or vegetables can treat cancer in patients. This is not a plausible link. We’ve addressed this issue several times on the blog, including here and here, and have also taken an in-depth look at antioxidants and cancer in two parts.
Headlines claiming that “vitamins lower cancer risk” don’t truly reflect trial results
The media’s search for a ‘magic pill’ to reduce cancer risk continues. Yesterday saw several stories about multivitamins “lowering the risk of cancer”. Some of the headlines would have you believe the magic pill has been found – but unfortunately it’s not that simple.
The headlines were based on the results of a study published in the Journal of the American Medical Association, which looked at the effects of taking multivitamins on cancer in middle-aged or older men.
Over 11 years, about 15,000 male health professionals took either a general multivitamin, or either vitamin E, vitamin C, beta carotene (a precursor of vitamin A) or a dummy pill (placebo). This was a ‘blind’ trial, so neither the researchers nor the men on the study knew which pill they were taking. The study included men with a history of cancer as well as healthy individuals.
Daily multivitamin use was shown to slightly reduce the overall risk of developing cancer – by 8 per cent. To put that in perspective, about 18 cancers per 1,000 people per year were diagnosed in the placebo group, compared with 17 cancers per 1,000 people per year in the multivitamin group.
But we don’t recommend you rush out to your local vitamin emporium based on this research. Let’s take a look at why…
Hot off the press – the week’s cancer news
Here’s our weekly round-up – it’s been a particularly good-news week in the area of prostate cancer research and care, but there were a number of other high profile stories too:
- We were delighted to hear that abiraterone is now available in Scotland, meaning it is now available for men with advanced prostate cancer across the UK. This story was reported by the BBC and we discussed it in more detail in our blog post.
- There’s more good news on the way for men with advanced prostate cancer. A new drug called enzalutamide was found both to extend and improve the quality of life for men with advanced disease. Taken alongside the availability of abiraterone, our experts think we’re on the cusp of a ‘sea change’ in prostate cancer care. But it needs to clear all the regulatory hurdles before it can be available on the NHS to UK men.
- And still sticking with prostate cancer, our own scientists have discovered a potential route for treating cancers that are resistant to hormone therapy by targeting a protein called p23 (here’s our press release). Excitingly, drugs that block p23 are already in use for other diseases, so this research may be the first step in developing another new drug for prostate cancer.
Could ‘traffic light’ labelling system help shoppers buy healthier food?
We’re all familiar with the phrase “You are what you eat”, but in practice it’s often hard to know exactly what we’re eating, and how it might affect our health.
For example, many processed foods can have higher salt, sugar and fat than we realise, so might be better as a treat rather than a daily indulgence.
At the moment, there’s a huge variety of ways that food manufacturers provide information about the nutritional content of their products, which can be confusing for consumers trying to make healthy choices.
To try to make things easier, the Government has been running a public consultation on nutritional labelling – which we’ve contributed to – to find the best way of providing clear and consistent information on food packs.
In our submission to the consultation we’ve recommended that all manufacturers adopt a single “traffic light” system, showing the levels of fat, saturated fat, sugar and salt in each product. These would be colour coded red, amber and green and labelled high, medium and low, making it easy for people to see exactly what they’re getting.
This consultation is a great opportunity to bring in a scheme that will make it easier for people to make healthy choices about what they eat, and we’ve recommended what we think is the best approach. And it’s absolutely vital because obesity is the biggest preventable cause of cancer in the UK after smoking, contributing to around one in twenty cancers.
Coffee: a nice pick-me-up, but not a cancer buster
Coffee is a big part of many people’s lives, but it’s not thought to have many health benefits – it keeps you awake, and often has lots of sugar, milk or cream added, which can pile on the calories.
But lots of studies have looked into whether coffee could have greater effects on the body other than waking you up – including whether it could affect your chances of developing cancer.
The results of these studies have been conflicting – especially those that have looked at different types of cancer, with some indicating coffee could be beneficial, others that it could be harmful, and yet more showing that it has no effect on cancer risk or the risk of dying from cancer.
Among all this conflicting evidence, a new study has been published in the New England Journal of Medicine, following more than 400,000 people for up to 13 years, to search for links between the amount of coffee they drank and their likelihood of dying from any cause during the course of the study, including cancer.
The results showed that drinking coffee could reduce ‘all-cause mortality’ – the chance of dying from anything – and the risk of dying from certain other conditions, but it had no effect on the risk of dying from cancer.