Australian-first research has found eating a diet higher in omega-6 fats to be associated with better cognition in older Australians.
According to Dr Amanda Patterson, who is presenting her research at the Dietitians Association of Australia's National Conference in Sydney this week, older adults with higher intakes of omega-6 fatty acids, but not other types of fatty acids, scored better across five cognitive domains, including language and attention – measured by the Audio Recorded Cognitive Screen (ARCS) tool.
Dr Patterson's research involved 2,750 adults, aged 55-86 years, from the Hunter region of New South Wales.
"Our findings suggest that a higher intake of omega-6 fatty acids, found in a range of plant-based foods including nuts and seeds, and polyunsaturated oils like canola and sunflower oil, might be protective against cognitive decline in older Australians.
"Given that age-related cognitive impairment is a fast-growing problem in Australia and across the globe, finding ways to prevent or decrease it is a public health imperative," said Dr Patterson, from the University of Newcastle.
She said linoleic acid and other omega-6 polyunsaturated fatty acids are key components of cell membranes, with an important role in the development, maintenance, function and integrity of cells.
Dr Patterson, an Accredited Practising Dietitian, said specific dietary patterns can influence a person's cognitive performance throughout their life.
"The Mediterranean diet is the most studied dietary pattern to date, being convincingly linked with lower rates of cognitive decline, and also better cognitive function and reduced risk of Alzheimer's disease," said Dr Patterson.
She said the Mediterranean diet is characterized by a high intake of healthy oils, fish, vegetables, fruits, nuts, seeds, legumes, and cereals – a dietary pattern she recommends, including for older Australians.
And because it includes a wide range of foods and food groups, it also incorporates a range of fatty acids, including monounsaturated fatty acids, both omega-3 and omega-6 polyunsaturated fatty acids, and small amounts of saturated fatty acids.
"When we think of the Mediterranean diet, we often think of fish and the beneficial omega-3s it offers, and also olive oil as a source of healthy monounsaturated fats. But the cognitive benefits of the Mediterranean diet might be due to many different components of the diet, and the combinations of these – including all the fatty acids it contains, with plant-based omega-6 fats a key part of this," said Dr Patterson.
She recommends older Australians eat nutrient-dense foods, including vegetables, legumes, fruit, good quality grain (cereal) foods, nuts and seeds, lean meat and fish, dairy foods, and plant-based oils which contain predominantly polyunsaturated and monounsaturated fats.
In 2015, around 1.3 per cent of the Australian population were estimated to have dementia, with this expected to rise to four per cent by 2050. And according to Alzheimer's Australia, dementia cost Australia around $14 billion in 2016, up from an earlier estimate of around $6.6 billion in 2002.
Dr Patterson said further research is needed into the effect of omega-6 fatty acids on cognitive ageing.