28/06/2016 8:03 PM AEST | Updated 15/07/2016 12:56 PM AEST

The Truth Behind Red Meat And Bowel Cancer Risk

It's not just a theory anymore.

Jon Feingersh
Eating more than two fist-size amounts of red meat per week increases the risk.

It's no longer a 'maybe' -- high consumption of red meat is linked to an increased risk of bowel cancer.

Bowel cancer is Australia's second biggest cancer killer and affects 15,000 Australians each year. According to Bowel Cancer Australia, it affects men and women almost equally, and despite declining rates in the over 50s there is an upward trend in younger people.

A diet high in red meat -- which includes beef, veal, pork, lamb, mutton, goat and horse -- is shown to increase the risk of bowel cancer, yet this risk declines when the protein is primarily from plant-based foods.

According to Bowel Cancer Australia Nutritionist Teresa Mitchell-Paterson, it all comes down the amount of red meat we're consuming.

"It's about how much red meat you're consuming," Mitchell-Paterson told The Huffington Post Australia. "If you're consuming 500 grams of red meat or 500 grams of red meat combined with processed meat (bacon, salami, sausages, etc.) per week, that's the amount we try to stay below.

If you're looking at your palm, take it as a measurement of how much red meat you can have. You can have two palms' worth a week of 3-4cm thickness.

"That's two steaks, or one steak and some ham, so you can see how quickly you would get to 500 grams."

In order to make sure you're not going over 500 grams, Mitchell-Paterson recommends using your hands as a guide.

"If you're looking at your palm, take it as a measurement of how much red meat you can have. You can have two palms' worth a week of 3-4cm thickness," she said.

Red meat should be a 'once or twice a week' occurrence, not a 'once a day'.

"The World Health Organisation seems to be decreasing their amounts of what you can safely eat. It was 500 grams and in their last iteration is was 300 grams. It is looking as though the amount of red meat is definitely going down in the quantity of consumption."

The main reason why red meat consumption is linked to bowel cancer is due to the way it "sits" in the bowel wall.

"There is a transit time in the bowel that's quite slow," Mitchell-Paterson told HuffPost Australia. "These chemicals sit against the bowel wall and, in a way, they irritate it. This can cause an increase in inflammation, a quicker turnover of cells and the potential for cancer to become evident in that area.

Bowel Cancer Australia facts

Bowel cancer (also known as colorectal cancer) is the third most common type of newly diagnosed cancer in Australia.

14,958 Australians are told they have bowel cancer each year, including 1,115 people under the age of 50.

Bowel cancer claims the lives of 4,162 Australians every year, including 217 people under the age of 50.

Bowel cancer patients currently have a 5-year survival rate of 66 percent which lags well behind other patients with common cancers such as breast, melanoma and prostate with survival rates of around 90 percent.

The way the red meat is cooked is another potential cause for concern.

"If you're burning the meat -- for example charring a sausage on the barbecue -- you get some chemical changes to the meat in regards to fat and iron," Mitchell-Paterson said.

"You get three rather nasty compounds which become quite toxic in the bowel itself: polycyclic aromatic, hydrocarbons, heterocyclic aromatic amines and N-nitroso compounds."

According to Mitchell-Paterson there are a few ways to help decrease the risk of bowel cancer (aside from the obvious -- to not eat red meat).


Eat more resistant starches

Research suggests that if we combine resistant starch with meat consumption we may lower the cancer risk.

"What they have found is if you add resistant starch to the diet -- such as beans, legumes, cold potato, banana, whole grains and seeds -- and eat this with the meat, the contact time against the bowel wall is actually less and reduces the risk," Mitchell-Paterson told HuffPost Australia.

"For example, if you look at chilli con carne, it's got red meat with kidney beans."

It is the bacterial fermentation of resistant starch in the bowel produces short-chain fatty acids including butyrate which has a protective effect, Mitchell-Paterson added.

"This fatty acid prevents the build-up of polyamines, which are cancer promoting chemicals from meat, and encourages their breakdown thereby reducing time to contact on the bowel wall."

Cold potato salad is a winner for high resistant starches.

Marinate your meat

Love marinated meat? Good news: soaking red meat may help reduce some of the risks.

"Another thing that helps is if you marinate the meat," Mitchell-Paterson said. "If you put it in some olive oil, herbs and spices and you marinate it, it causes a chemical change in the outside of the meat which makes it less likely to create those toxic compounds."

Eat more vegetables

Like legumes, vegetables are high in fibre and can help protect against bowel cancer.

"Without a doubt, we've got to increase the amount of vegetables we eat," Mitchell-Paterson said. "Only around six percent of Australians are getting their five serves of vegetables a day. It's scary.

"It's only 400 grams of veggies a day -- you can do that in a soup or a salad."

Including a tofu and veggie salad is a great way to increase gut-friendly fibre while still getting enough protein.

Try plant-based proteins

If it's something available to you, consider a plant-based diet -- or at least substitute red meat for plant proteins for some meals.

"There are a lot of proponents for vegetarian diets reducing the risk of bowel cancer," Mitchell-Paterson told HuffPost Australia.

"There's quite a few other choices for protein. Tofu and tempeh are fantastic -- they're a perfect and 'complete' source of protein, containing all the amino acids found in meat. Certainly you can also have egg, cheese, fish and chicken.

"A quiche or frittata are great, and don't forget the lentil burgers."

Staying active and eating a healthy diet can help reduce the risk of cancers.

According to Mitchell-Paterson, the other ways to help reduce the risk of bowel cancer include:

Eating garlic -- Garlic wards off potential pathogens in the gut but doesn't kill off your good bacteria, which is very important in protecting the bowel against possible toxins.

Having milk and/or calcium -- Calcium has a protective effect. Obviously some people can't have milk but they can use fortified soy milk and other milk alternatives.

Reducing alcohol -- No one wants to hear that one, however alcohol increases the risk without a doubt.

Increasing physical activity -- If you can stand up at your desk a couple of times an hour that's going to be a great thing.

Keeping your weight down -- It's more about the weight around your tummy, that abdominal fat. Aim for a waistline that's under 80cm for a female and under 94cm for a male.

"And don't smoke," Mitchell-Paterson said.