Health
What to eat to reduce your risk of cancer
Can your diet really help prevent cancer? Here's what the latest research says – and the foods worth adding to your trolley.
By Sabrina Rogers-Anderson
From the classic heart-healthy Mediterranean diet to the DASH diet that controls blood pressure and the MIND diet designed to boost brain health, it seems that every chronic disease has its own evidence-based eating plan.
So, why doesn’t cancer have its own diet with a fancy-pants acronym?
“The evidence with cancer tends to be a lot weaker,” says Dr Nicola Bondonno, postdoctoral researcher at the Danish Cancer Institute. “And because there are so many different types of cancer, the way in which they develop and their risk factors are so different, which makes it a really complex disease to study, especially when it comes to diet.”
That said, there is a ton of evidence that some foods – including processed meats, red meat and alcohol – increase the risk of cancer.
“There are also around 13 cancers that are linked to obesity,” says Dr Bondonno. “So, limiting your consumption of fast foods, ultra-processed foods and sugary drinks can reduce your risk of developing obesity and its related cancers.”
But what about foods that help keep cancer at bay? Let’s dig in.
Are cancer-fighting “superfoods” a thing?
Many plant foods are packed with vitamins, minerals and phytochemicals that can help reduce cancer risk.
The American Institute for Cancer Research (AICR)'s Foods that Fight Cancer™ list includes:
But some experts warn that the idea of “superfoods” is a dangerous one because it can give us the impression we can prevent the Big C by chowing down on blueberries or having a kale smoothie every morning.
Instead, you should focus on eating a wide range of plant foods in a variety of colours to get as many of the more than 4000 known phytochemicals in your diet.
“Cancer develops through thousands of different pathways, so it doesn’t make sense to think that a specific food or nutrient can protect you against all those pathways,” says Dr Bondonno. “Choosing a wide variety of foods that work along all of those different pathways will provide you with much better protection.”
But despite this caveat, researchers continue to investigate how specific foods might reduce cancer risk and 3 recent studies have offered interesting new insights.
A glass of milk a day can reduce bowel cancer risk by 17%
A UK study of more than 540,000 women found that those who regularly consumed foods that were rich in calcium – including cow’s milk and yoghurt – had a lower risk of bowel cancer.
Those who consumed 300mg of calcium per day – about the amount found in 1 cup of whole milk – saw their bowel cancer risk reduced by 17%.
“This finding is consistent with findings in animal models, where dietary supplementation of calcium – along with vitamin D – can reverse the increased risk of colon tumours in mice fed a Western-style diet,” says Professor John Mariadason from the Olivia Newton-John Cancer Research Institute.
Dr Bondonno points out that the evidence from this study is particularly strong because the researchers used genetic data. “That means the results aren’t confounded by participants’ lifestyle factors,” she explains.
Siri, add milk and yoghurt to my shopping list.
Revealed: how fibre-rich foods protect against bowel cancer
It’s long been established that a diet high in fibre – including whole grains, fruits, vegetables and nuts – can decrease the risk of bowel cancer. But the reasons why have remained a mystery.
“Several mechanisms have been proposed, including increased transit times [the time it takes for food to travel through the digestive system], the dilution of carcinogens such as bile acids, and beneficial changes to the composition of the gut microbiome,” explains Professor Mariadason.
“The ‘butyrate hypothesis’ is also well-established, with [short-chain fatty acid] butyrate well-known to slow tumour growth by altering gene expression in tumour cells due to blocking enzymes called histone deacetylases.”
Until now, this mechanism was known to help control the growth of advanced bowel cancer tumours. But a new study shows that butyrate and another short-chain fatty acid called propionate also alter gene expression in healthy cells, which may prevent bowel cancer from developing in the first place.
“We also need to consider that whole grains, fruits, vegetables, nuts, seeds and legumes are rich in vitamins, minerals and other bioactive compounds like polyphenols that have anti-cancer properties,” adds Dr Bondonno. “As much as the fibre itself is important, these foods are full of other compounds that could also be protecting us.”
4 cups of coffee a day keep head and neck cancer away
Java lovers, rejoice! In a recent study published in the journal Cancer, drinking more than 4 cups of coffee a day was associated with a lower risk of head and neck cancer, oral cavity cancer and oropharyngeal (middle part of the throat) cancer.
“Coffee is full of polyphenols and diterpenes that can reduce your risk of cancer,” explains Dr Bondonno. “But how you consume your coffee is important. If you're having 5 teaspoons of sugar a day with your coffee, the risks might outweigh the benefits.”
Is 4 cups too much for you? Drinking 3 to 4 cups of joe reduces the risk of hypopharyngeal (bottom part of the throat) cancer and less than 1 cup of decaffeinated coffee is associated with a lower chance of oral cavity cancer.
If you’re more of a tea drinker, less than 1 cup of tea a day is associated with a decreased risk of hypopharyngeal cancer and head and neck cancer overall.
“The study authors didn’t highlight the beneficial effects of tea as much, but they were there,” says Dr Bondonno. “So, if you're after a warm caffeinated beverage, rather than having 4 cups of coffee, you're probably better off having a mix of tea and coffee throughout the day because you’ll get a wider variety of protective compounds. You'll be covering different mechanisms of disease development.”
Swap an apple a day for fruit salad
Nutritionists have been telling us for years that the secret to staying healthy is to eat a wide variety of foods from the 5 food groups – and preventing cancer is no different.
Why not challenge yourself to add 5 new foods from the table above to your menu this week? Try this delicious chickpea tagine or these 3 healthy longevity recipes from longevity expert Professor Luigi Fontana.
Feature image: iStock/fcafotodigital
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