The link between diet and cancer

20 Aug 2021

Over the past few years, scientists have explored the possibility of a link between what we eat and the occurrence of cancers in our society. And although specific dietary links have yet to be conclusively found, some promising results have begun to trickle through.

According to Associate Professor Judith Lacey, Head of Integrative Oncology and Supportive Care at Chris O’Brien Lifehouse, when it comes to breast cancer, research indicates that diet may indeed play a role.

“If you're looking at women with a high risk of breast cancer, there's no strong evidence about specific diets,” says Lacey, “but there's an indication that the Mediterranean diet may be associated with better outcomes in those who have had breast cancer and a reduced recurrence of breast cancer.”

What we should be eating
This isn’t the first time that the Mediterranean diet has made headlines. In fact, studies show that it may also reduce the risk of chronic diseases, such as cardiovascular and neurodegenerative disease and diabetes.

So what exactly is the Mediterranean diet and why is it so good for you?

What researchers talk about today as the Mediterranean diet is based on the diet of people who lived in and around the Mediterranean in post-War II Europe when food was relatively abundant but processed products were very scarce.

“Essentially, we’re talking about a fruit- and vegetable-rich diet,” explains Lacey, “with a lot of fish and plant-based proteins, as well as reduced sugar, reduced red meat, and reduced preservatives.”

The key to its healthy properties, however, doesn’t lie with what is included in the diet, but what is conspicuously absent from it. Generally, there isn’t much butter, only a moderate amount of bread, and almost no preservatives or additives. Arguably, the opposite to the diet of a lot of people living in Western cultures today.

Curbing our sweet tooth
One of the biggest concerns for researchers is the abundance of refined sugars in the average Western diet, and while there has been a popular trend in Australia to reduce our levels of sugar consumption, some researchers believe we are still consuming too much. However, Lacey says it’s important to keep it in perspective.

“Look, I don't say to people, if you eat sugar your cancer is going to come back or you're at high risk of developing cancer,” she says. “But we do know that there is a relationship between sugar and obesity, and that obesity is associated with cancer. So, if you reduce obesity, you reduce your risk of developing some cancers.”

As such, Lacey recommends reducing refined sugars as much as possible in your diet and replacing them with natural sugars from fruit and vegetables. She adds that another source of sugar that most people forget about is the sugar found in alcoholic drinks.

“We know that increased alcohol is associated with quite a few cancers, including breast cancer,” she explains. “So, we highly recommend minimal alcohol intake. No alcohol intake is fantastic, but that's not realistic in our society.”

She says if you can't reduce your alcohol intake to zero then try keeping it to one to two drinks a day, and if you’re a wine lover, stick to red wines.

“I think it is really hard to recommend zero alcohol,” she says, “because we know that in Western society, in particular, there's a relationship between stress management and alcohol. And so, until we change our ways of behaving, alcohol will continue to play an integral part in many people's stress management strategies.”

Lacey adds that this area of lifestyle choices and their relationships to occurrences of cancer is still being developed, with more evidence being recorded all the time.

“The questions remain; is there something in our environment that triggers the cancer? Is it stress? Is it diet? Is it environmental toxins?,” she explains. “We don't know the answer to that, but researchers are looking into that. In the meantime, we have research about how diet may affect this and we’re much better at detecting cancer early, which makes a huge difference.

Preparation is key
It’s not just the food we put in our mouths Lacey suggests we reconsider; it’s how we prepare our food as well.

“First of all, to get the best nutrition often it's slow cooking that keeps the nutrition and stops breaking down some of the fibres, so we do recommend that,” she explains. “But the evidence suggests avoiding barbecues and chard meat and vegetable because there is a relationship between that form of cooking and some cancers.”

While this all may seem a little overwhelming, Lacey says it’s a no-brainer from where she is sitting.

“The message I want to spread is that we don't know the extent of how much it’ll help, but there's no harm in changing your diet,” she says. “At a minimum, try to choose a healthy plant-based diet, with less oil, less toxic substances, and less alcohol.”

With everything else, she adds, it’s best to have a discussion with your doctor or nutritionist as the answers will be specific to your situation and overall health.