With unending options at the supermarket, and diet advice coming from all directions, filling your shopping trolley with the right things can seem an overwhelming task.
We're learning some of the best things to eat in this regard include vegetables, nuts and berries, foods containing "good fats" and, possibly, fermented foods.
As well as potentially improving our brain function, eating these sorts of foods could improve our mental well-being – and could even help the planet, too.
Diet and brain function
In the face of , over the past couple of decades, researchers have questioned whether increased weight or poor diet, could influence cognition. They have since looked at what sorts of diets might impair or improve the function of our brains.
Research has also shown short-term memory is poorer in people who report eating more saturated fat and sugar.
Long term follow-up studies show obesity is associated with in several domains of cognitive function, including short-term memory, attention and decision-making.
Research has also shown in people who report eating more saturated fat and sugar.
Conversely, the Mediterranean diet has been associated with and maintenance of cognitive abilities into older age. A Mediterranean diet is based on vegetables, whole grains, legumes and nuts, with healthy fats such as olive oil. Intake of red meat, saturated fats and sugar is limited.
A healthy diet has many elements, so let's look at what particular foods might explain these benefits.
Vegetables, nuts and berries
Evidence indicates eating more vegetables in cognitive abilities that occurs naturally as we age.
While all veggies are likely to contribute, those in the cruciferous (Brassicaceae) family through their high fibre, folate, potassium and vitamin content. Vegetables in this family include broccoli, cauliflower, brussels sprouts, and fad favourites kale and rocket.
Interestingly, while there's good evidence for the protective role of vegetables, there's less evidence when it comes to fruit.
Berries, though, contain high levels of antioxidants. These compounds protect the body by scavenging harmful free radicals and reducing inflammation. Together these functions are likely to protect our cognitive ability.
Studies in rats, and in older people with mild cognitive impairment, indicate supplementing diets with berries .
Nuts, meanwhile, are excellent sources of monounsaturated and polyunsaturated fats, minerals and vitamins. have shown the addition of nuts improves learning and memory. suggests consuming nuts within a Mediterranean-style diet improves measures of cognition, such as the capacity for verbal reasoning.
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Healthy fats
Healthy diets such as the Mediterranean diet are also characterised by foods such as oily fish, avocados, olive oil and small amounts of animal-derived fats (such as from red meat).
One of in rats showed diets high in saturated fat from lard or high in sugar led to memory impairments, whereas an oil-based diet high in polyunsaturated fats didn't.
Importantly, rats fed these different diets in their total energy intake – only the type of fat and sugar varied.
While we can't comment directly on the effects in humans, these findings suggest eating excess sugar, or animal-based fats may negatively impact cognition.
This is why some kids might not make friends with salad. Source: Getty Images
Fermented foods
For thousands of years, humans have prolonged the life of foods through fermentation, which increases the proportion of Lactobacillus and other healthy gut bacteria.
Kombucha and kefir are trendy right now, but other popular fermented foods include kimchi, miso, yoghurt and sauerkraut. Intake of these foods is thought to maintain the diversity of the gut microbiome.
GUT HEALTH
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Interest in the potential cognitive effects of fermented foods stems from for the importance of the gut microbiota in cognition and health.
It's well known that a poor diet can of the gut microbiome. Our work in rats has shown the cognitive impairments produced by exposure to an – a Western-style diet high in saturated fat and sugar – are linked to changes in the gut microbiome.
Beyond cognition
It's not possible to attribute "miracle" properties to one food group alone. We suggest a balanced, varied diet is the best approach to sustain not only brain health but heart health too.
It's not possible to attribute "miracle" properties to one food group alone. We suggest a balanced, varied diet is the best approach to sustain not only brain health, but heart health too.
And there may be other reasons to seek out these foods. A showed eating fruit and vegetables improved mental well-being. Subjects tended to feel happier, less worried and reported higher levels of overall life satisfaction.
The link between diet quality and better mental health is .
The recently published adds a further compelling reason to eat healthily: the environment. This commission argued for a – akin to the Mediterranean diet – consisting of whole grains, vegetables, fruits, nuts and dairy, healthy fats, with low animal protein and few processed foods.
Coconut amaranth & millet bowl with warm berries Source: Chris Middleton
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It is thought that shifting to such a diet, together with reducing food waste and adopting more sustainable food production systems, will minimise environmental damage and safeguard individual health.
The central message is the health of individuals and of the planet are inextricably linked, and this requires a rethink of global food systems.
is a Professor of Pharmacology and the Head of Pharmacology at UNSW. is a Postdoctoral Research Fellow at UNSW. This article is republished from under a Creative Commons license. Read the .
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