Not ALL pork carries the same cancer risk, researchers say

Why our festive favourite pigs in blankets are healthier than you think: British and Irish sausages are better for you than chorizo, frankfurters and bacon ‘because they don’t contain a common preservative’

  • Scientists looked at continental meats in isolation and found they were worse
  • British and Irish sausages increase bowel cancer risk less than chorizo or salami
  • A chemical called sodium nitrite is to blame for the dangers of pork products
  • The World Health Organization classes all processed meats as cancer-causing  

Not all types of processed meat have the same cancer risk, according to a study.

The World Health Organization in 2015 classified all processed meat as cancer-causing, tarring the reputations of bacon and sausages.

But British and Irish sausages, as well as new types of ham and bacon, may not be as bad for people’s health as predicted.

Instead, more heavily processed or cured foods such as chorizo, frankfurters, salami and prosciutto may carry a bigger risk.

A review of past studies of the effect of sausages on bowel cancer risk found that, while processed meat as a whole increased risk by about half, this rose to a 65 per cent increase for those processed with a chemical called sodium nitrite.

Researchers said British and Irish sausages appeared to carry a lower risk of bowel cancer because they are not usually processed with a chemical called sodium nitrite, which boosted a food’s cancer risk (stock image)

Sodium nitrite is a preservative used to extend the shelf life and enhance the colour of processed meats.

It is best known for being included in processed sausages, ham and bacon.

And it is this, specifically, which appears to raise cancer risk according to the results of a study by Queen’s University in Belfast.

‘When we looked at nitrite-containing processed meat in isolation – which is the first time this has been done in a comprehensive study – the results were much clearer,’ said one of the study authors, Dr William Crowe.

Dr Crowe, along with Dr Brian Green and Professor Chris Elliott reviewed all recent, English-language studies into consumption of processed meat and cancer risk.

They said the results were inconclusive and around half of the studies indicated a link with colorectal cancer (CRC), also known as bowel cancer.

The researchers added this may explain the appearance of contradictory claims in recent years.

However, when studies which only tested the consumption of processed meat containing sodium nitrite were isolated, scientists found evidence the link to CRC jumped from half to just under two-thirds (65 per cent). 

In 2015 the WHO classified all processed meat as a carcinogen – including bacon, sausages and ham as well as continental European products like prosciutto and salami.

However, not all processed meat contains nitrates.

For example, British and Irish sausages are not processed with nitrites even though many of the European and US sausage equivalents are, such as frankfurters, pepperoni and chorizo.

Some retailers in the UK, such as the brand Naked, are already selling new types of bacon and ham that have been processed without nitrites.

The researchers now believe there is a need to define the health risk of both types of processed meat separately. 

Researchers said products which are more heavily processed or cured, such as chorizo (left) or frankfurters (right) appeared to increase the risk of bowel cancer by 65 per cent (stock images) 


In 2015 the biggest global health authority, the World Health Organization, controversially ruled that bacon, burgers and sausages are as big a cancer threat as cigarettes.

A report released four years ago classified processed meat as carcinogenic alongside arsenic and asbestos.

Officials said just 50g of processed meat a day – less than one sausage – increases the risk of bowel cancer by almost a fifth.

The report also classified red meat as ‘probably carcinogenic’ – one rank below – but added that it had some nutritional benefits.

Experts are now urging the public to avoid processed meat where possible and to have a bean salad for lunch rather than a BLT. 

Dr Kurt Straif from the WHO said: ‘For an individual, the risk of developing colorectal (bowel) cancer because of their consumption of processed meat remains small, but this risk increases with the amount of meat consumed.’

Red meat does have nutritional value too and is a major source of protein, iron, zinc and vitamin B12 which protect the immune system.

The claim has stirred scientific debate ever since, with other studies criticising the evidence the WHO’s recommendation was based on.

A series of five reviews of past research, carried out by scientists from the Dalhousie and McMaster universities in Canada as well as the Cochrane research centres in Spain and Poland, earlier this year, did just that.

It considered 61 studies which had monitored the health of more than four million people, as well as 12 which trialled changing the diets of about 54,000.

The team found the results of past research were of too poor a quality to make any suggestions about the way people lived their lives.

In an editorial published alongside the papers, Dr Aaron Carroll and Dr Tiffany Doherty, from Indiana University, wrote: ‘The overall recommendations, contrary to almost all others that exist, suggested that adults continue to eat their current levels of red and processed meat, unless they felt inclined to change them themselves.

‘This is sure to be controversial, but it is based on the most comprehensive review of the evidence to date.’

Professor Elliott, who carried out the UK Government’s inquiry into food safety after the horsemeat scandal, said the study brought more clarity to what has been a confusing area for the food industry and the public.

He explained: ‘Because there have been conflicting claims in the scientific community and the media about which types of meat may be carcinogenic, this study couldn’t have come at a better time.

‘It brings much-needed rigour and clarity and points the way for further research in this area.’

Lead author Dr Green added: ‘It’s important we eat a healthy, balanced diet in line with the government’s “Eatwell Guide”.

‘The current Department of Health guidance advises the public to consume no more than 70g of red or processed meat per day.

‘That remains the guidance, but we hope that future research investigating the link between diet and CRC will consider each type of meat individually rather than grouping them together.

‘Our findings clearly show that not all processed meats, for example, carry the same level of risk.’

The scientists say more research is needed before they can definitively prove causality regarding processed meat and cancer.

‘But based on our study, which we believe provides the most thorough review of the evidence on nitrites to date, what we can confidently say is that a strong link exists between nitrite-containing processed meat, such as frankfurters, and CRC,’ Dr Green concluded.

The research was published in the journal Nutrients.

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