Health
Can what we eat put the brakes on biological ageing?
In a nutshell: it’s likely. The right foods can help power up your body, slow ageing and protect your health.
By Paula Goodyer
If you’re wondering what makes us age, it’s the accumulation of damage to our body’s cells and tissues over time.
“We can’t stop this but we can help reduce the damage – and research into the biology of ageing underscores the importance of a mostly plant-based diet,” says Professor Luigi Fontana, Director of the Health for Life Program at the University of Sydney’s Charles Perkins Centre.
His new book, Plant Power, shows how to put the science of food and longevity into practice. His advice? Give highly processed food the flick and stick with a diverse range of vegetables, fruit and minimally processed whole grains.
“Eat mostly protein from plants like legumes, wholegrains and nuts and make fish and low-fat dairy your secondary protein foods,” he says. “If you eat meat or poultry, eat lean cuts sparingly but avoid processed meat.”
Try some of Dr Fontana’s Plant Power recipes:
So how can plants promote longevity?
The right food does more than provide nutrients – it can also influence processes in the body that minimise damage to cells and tissues, helping to slow ageing and defend against diseases like type 2 diabetes, heart disease, cancer and dementia, Professor Fontana says.
The science is complex but here’s a taste of the benefits of plant food, especially as we age.
Antioxidant armour
Picture a cluster of dishes with multi-coloured vegetables dressed with extra virgin olive oil, a grain-based salad of barley, nuts and fresh herbs, a rich red soup with ripe tomatoes and chick peas, and a bowl of fresh berries. This isn’t just great food but an abundance of antioxidants working against 2 factors promoting ageing and disease – oxidative stress and chronic inflammation. Animal studies have found that compounds called monoterpenes in citrus fruit, for instance, can have an anti-cancer effect by helping to kill off damaged cells.
Conquering cholesterol
Legumes, nuts and seeds have their own cholesterol-lowering magic – they deliver soluble fibre and compounds called sterols and stanols which all work to block cholesterol from going into our bloodstream and damaging arteries. “For example, studies have shown that eating nuts regularly can decrease the risk of heart disease by up to 60 per cent,” Professor Fontana says. More whole plant foods also means less room for meat and dairy foods high in saturated fat.
Healthier hormones
Healthy plant-based diets can also lead to fat loss. Besides trimming waistlines, this helps keep levels of hormones like oestrogen and testosterone healthy, along with other growth factors that, like high levels of some hormones, can promote cancer. More fibre can also help us excrete excess oestrogen, helping protect against hormone-related cancers like breast and ovarian cancer.
How protein affects ageing – for better or worse
You’ve probably heard you need more protein now that you’re getting older – but how does that fit with research linking lower protein diets to longevity?
“Over the last 20 years studies have linked high protein diets to higher mortality and a higher risk of cancer,” says Dr Rosilene Ribeiro, senior research fellow at the Charles Perkins Centre. “Now, the evidence shows that a low protein intake through most of our adult lives is best in terms of health and longevity but that after the age of 65, we might need to increase our intake to 1g of protein per kilo of body weight – more than the 0.75g per kilo for women and 0.85g per kilo for men recommended for younger adults.
“But the average Australian eats too much protein. It’s frail older people who’ve lost muscle who need it most.
“The problem with overdoing protein is that your body has to work faster to process it – and the faster your body works, the more likely it is for mutations to occur, raising the risk of diseases including cancer. Another issue is that if much of your diet is high in fatty cuts of meat, it comes with too much saturated fat which can increase heart disease risk. “
More protein from plants may be healthier
“It may be that the type of protein is important,” explains Fontana, adding that a study following 50 to 65 year-olds over 18 years found that those eating the most protein had a 75 per cent higher mortality rate and were 4 times more likely to die of cancer. “But these risks were reduced or eliminated when the protein came from plants.”
The reason may be that the levels of essential amino acids – the building blocks of protein – are different in plant sources of protein, he explains.
“For instance, the intake of one essential amino acid called methionine is about 40 per cent lower in a healthy plant-based diet – and animal studies have found that restricting methionine extends lifespan and protects against chronic disease.”
But before you reach for that plant-based sausage…
“We’ve seen a rise in plant-based products like burgers, nuggets and schnitzels but these aren’t necessarily better for you. They’re often highly processed and not always good sources of protein,” Dr Ribeiro stresses. “Much better are whole plant protein foods like chickpeas, lentils, adzuki beans, black beans, cannellini or soy beans, nuts and seeds.”
Feature image: iStock/DekiArt
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