Prostate cancer and the benefits of a plant-based diet
“I believe all men with prostate cancer should be referred to a dietitian and exercise physiologist. It frustrates me that men aren’t given good advice on diet – the danger is that they’ll try extreme diets that don’t provide adequate nutrition,” he says.
One in six Australian men will be diagnosed with prostate cancer by the age of 85 – so how strong is the evidence that more plant food might help prevent it?
In 2022, UK researchers reported a 43 per cent reduced incidence of prostate cancer in men eating a vegetarian or vegan diet, compared to meat eaters. A 2021 US study also linked a lower risk of fatal prostate cancer with eating more plant foods; another found that men with early prostate cancer who ate a Mediterranean diet had a reduced risk of their cancer progressing.
But there are still no specific recommendations on eating and prostate cancer from the World Cancer Research Fund, the peak body for assessing lifestyle factors and cancer prevention, says Clare Hughes, Chair of the Cancer Council Nutrition, Alcohol and Physical Activity Committee.
“We need more research to draw a conclusion. It can be difficult to compare studies of plant-based diets because there’s no one definition of ‘plant-based’ – it could mean a vegan, vegetarian or even a Mediterranean diet that’s mainly plants, but with some animal food,” she says.
“Some studies suggest a link between dairy products and a higher risk of prostate cancer too but again the evidence isn’t strong enough to recommend avoiding them. ”
Still, there’s no dismissing the link between being overweight and a greater risk of 13 cancers, including advanced prostate cancer – and diets big on plant foods like vegetables, fruit, legumes and wholegrains can help prevent weight gain, says the Cancer Council.
“Around 5300 new cancers in Australia each year are due to excess weight,” adds Hughes. “We need to improve people’s awareness – our 2019 Cancer Prevention Survey showed that although most people knew being overweight increased heart disease risk, only 45 per cent knew it was a risk factor for cancer.”
More plant food may also be a win for men’s sexual health. Two other studies this year found that men eating either a Mediterranean diet or another diet high in plants were less likely to have erection problems. That’s no surprise. Erections need healthy blood vessels to carry enough blood to the penis – and blood vessels can be compromised by poor diet and inactivity. That’s why flagging erections can warn of heart disease.
“Men tend to drop the ball with nutrition and miss out on a range of micronutrients in vegetables and fruit that promote good blood vessel health – 96 per cent of men don’t eat enough vegetables, and 59 per cent don’t eat enough fruit,” says Melbourne-based dietitian Joel Feren.
“A heart attack and erectile dysfunction are a double whammy but diet can help reduce the risk of both. I’m an advocate for a Mediterranean Diet – it emphasises vegetables, fruit, legumes, nuts, seeds and extra virgin olive oil, but allows for a little meat. Men can improve their diet with baby steps – fruit with breakfast or for dessert, some extra vegetables and one or two meatless meals each week.”
And speaking of blood vessels, that enemy of arteries, high cholesterol, is linked to an increased risk of prostate cancer too.
“The evidence is quite strong,” says Dr Andrew Hoy who heads the Lipid Metabolism Laboratory at the University of Sydney’s Charles Perkins Centre. His research has found that high cholesterol levels can help drive the growth of prostate cancer cells.
But it’s not working alone.
“High cholesterol, overweight and obesity, and raised blood sugar are all factors that can contribute to the development of some cancers, including prostate cancer,” he adds.
“Tackling all of them with diet and exercise will be more effective than just focusing on cholesterol levels.”
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