We might hear a lot about childhood obesity but another trend that's got health authorities jittery is the spreading waistlines of the over 50s. It's not just the rising risk of heart disease that goes with ageing and weight gain either – but the effect on the brain.
"By itself, ageing is a risk factor for cognitive decline but obesity is another - and around 70 per cent of 55- to 74-year-olds are overweight or obese. We now have both factors working together to increase problems with brain function," says Associate Professor Jon Buckley, Director of the Nutritional Physiology Research Centre at the University of South Australia.
But Buckley thinks ageing brains may have a new ally – foods like burritos, minestrone and dahl that are based on beans and lentils.
A preliminary study from Canadian researchers at the University of Manitoba has found that eating a serve of legumes daily for eight weeks improves the function of blood vessels, making them smoother and less rigid. Building on that evidence, Buckley is working on new research to see if eating legumes every day benefits the blood vessels supplying the brain.
Healthy blood vessels are more resistant to vascular dementia (the most common form of dementia after Alzheimer's) as well as heart disease and stroke.
"Supple arteries cope much better with the pressure of blood pumping around our body every day because they can expand to accommodate the volume," he explains. "But if they're like steel pipes they don't cope well and blood pressure increases."
Legumes are already linked to healthier cholesterol levels because of their high fibre content, but other positive effects on arteries may come from a range of bioactive compounds that are found in these foods – as well as the fact that they might displace other less healthy foods on the plate.
The real challenge though is getting us to eat more of them – only 22 per cent of Australians eat legumes once a week according to a study by the Grains and Legumes Nutrition Council – not knowing how to cook them was one of the main reasons people gave for not eating them.
Legumes are a quiet achiever, sustaining poorer people all over the planet, but in meat-loving Australia, their status is also-ran. It doesn't help that they're known as meat alternatives or meat substitutes either – yet they're not pretend meat any more than lamb chops are pretend lentils. With their earthy flavours, they're in a class of their own and are a versatile base for creating curries, casseroles, soups and salads – if only we knew how. We need need someone to do for legumes what Adriano Zumbo did for macarons.
The big hurdle for lots of us is the idea of pre-soaking beans before cooking, but you can skip this step by using canned legumes. Once you're an old hand you can work on soaking and cooking beans in bulk and storing in the freezer – but in the meantime, chickpeas, red kidney beans and cannellini beans are on every supermarket shelf. You'll find canned black beans and borlotti beans at delis or larger greengrocers. Lentils don't need pre-soaking. As for cooking, once you get started you soon realise that that making a pasta sauce or curry with beans or lentils is much the same as cooking with minced or chopped meat or poultry – you kick off with cooking some onions and then you toss in your legumes and flavours. Easy.
Including legumes in a dish doesn't mean it has to be a meatless meal either. You can just use less meat instead and pump up the volume with legumes. Good combinations are chicken with chick peas, and beef with black beans, red kidney beans, or borlotti beans.
Another great thing about legumes is that they make it easy to increase your vegetable intake, adds Buckley.
"A serve of meat gives you protein, but a serve of legumes gives you two for one – protein and vegetable - both at the same time."
What's your favourite legume dish?
* Steve Manfredi's lentil, carrot and turnip salad with hazelnut sauce recipe