Meat-free benefits: Two vegetarian days a week slashes cancer risk

Saying goodbye to your breakfast bacon, lunchtime sausage butty and evening burger for at least two days a week is enough to reduce your chances of getting cancer, a new study by Oxford University suggests.

People who eat meat – including processed, red meat, or poultry – five times a week are 9% less likely to get colorectal cancer, also known as bowel cancer.

The study, published in BMC Medicine, analysed more than 470,000 Brits aged between 40 and 70 who were free from cancer at the the onset of the study, for more than a decade.

Researchers divided participants into regular meat eaters, low meat eaters, and vegetarians, based on their meat intake.

The findings found the risk of cancer was reduced further for pescatarians, vegetarians and vegans.

So why is cutting out beef, pork and lamb food products thought to be beneficial?

Meat, in particular red and processed, is thought to increase the risk of cancer due to the chemicals it contains, such as nitrosamines, as well as the chemicals formed while cooking, which can harm calls in the body on consumption.

An average of just under 43,000 new cases of bowel cancer each year occur in the UK, with more than 16,000 dying annually, according to Cancer Research UK.

Just over a half (53%) of cases are preventable.

Read more: Many chilled sliced meats sold in UK are saltier than Atlantic Ocean

While meat can be a good source of protein, vitamins and minerals – though these nutrients can also be found in other food groups – if you eat more than 90g of red or processed meat a day, the Department of Health and Social Care advices cutting down to 70g.

As some meats are high in saturated fat, this can raise blood cholesterol levels, putting health at risk, such as the risk of coronary heart disease, while red or processed meat is especially linked to bowel cancer.

In the study, more than half (52%) were regular meat-eaters, having it at least six times per week, 44% were low meat-eaters, defined as having meat five or less times per week, 2.3% were pescatarian, and 1.8% were vegetarian or vegan.

Read more: Eating lentils could add 10 years to your life, scientists say

Watch: Eating processed meat 'increases heart disease risk by a fifth'

When tracking the participants' NHS records for 11.4 years, they found that overall, nearly 55,000 developed some form of cancer.

Nearly 11.7% of people eating meat five times a week developed cancer, compared to 11.9% of those eating it nearly daily.

In comparison, 8.8% of pescatarians and just 7.7% of vegetarians were diagnosed with a type of the disease.

When honing in specifically on bowel cancer, the difference between the two levels of meat-eaters can be identified even more. Some 1.3% of those who ate meat at least six days were diagnosed with this cancer, compared to 1.2% of those who ate meat less regularly.

After adjusting for gender and age, the study unearthed that the chances of getting bowel cancer were 9% lower in the lower meat-eating group than in those eating it more often, while the risk was 16% lower in pescatarians, and 22% lower in veggies.

While there was no risk difference between high and low meat eating for prostate cancer, there was a slight reduction in risk of postmenopausal breast cancer in vegetarian women.

The risks were lower for pescatarians, vegetarians and vegans for bowel, breast and prostate cancer.

The study's author, Cody Z Watling, said on bowel cancer, "The intake of processed meat has been evaluated by the World Health Organization and World Cancer Research Fund to be a definite cause of colorectal cancer and red meat as a probable cause of colorectal cancer."

In terms of why, he added, "This is likely to at least in part explain the lower risk of colorectal cancer in low meat-eaters, and mechanisms suggested include chemicals in meat such as nitrosamines.

"Overweight and obesity also increase the risk of colorectal cancer, but in mediation analyses, BMI did not appear to mediate the difference observed between low meat-eaters and regular meat-eaters."

Read more: Lack of meat and cheese in women's diet could compromise health, says scientist

A study published in The Lancet, Carcinogenicity of consumption of red and processed meat, explains why red meat can have a negative impact on health further, echoing evidence that the type of meat product you choose and how you cook it matters.

It explains, "Meat processing, such as curing and smoking, can result in formation of carcinogenic chemicals, including N-nitroso-compounds (NOC) and polycyclic aromatic hydrocarbons (PAH).

"Cooking improves the digestibility and palatability of meat, but can also produce known or suspected carcinogens, including heterocyclic aromatic amines (HAA) and PAH. High-temperature cooking by pan-frying, grilling, or barbecuing generally produces the highest amounts of these chemicals."

In the study, researchers analysed the link between red meat and colorectal cancer, with the working group classifying "consumption of red meat as 'probably carcinogenic to humans', carcinogenic meaning capable of causing cancer in humans.

A carcinogen may be able to cause cancer due to its ability to damage cells or disrupt the set of chemical reactions that occur in living organisms to maintain life.

The NHS suggests, that if you do eat meat, you can make healthier choices while doing so, such as asking your butcher for a lean cut, checking nutrition labels to see fat contents, opting for turkey and chicken without the skin and limiting processed meats.

You can also cut down on fat while cooking by grilling instead of frying, avoid adding extra oil, roasting on a metal rack to allow the fat to run off and using smaller quantities of meat.