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Date added:June 28 2023
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Read time:8 min
Like most things in life, our diets have changed over time. Much of what we now eat comes from a factory rather than a farm. And while the impact of that is clear on our physical health – with high rates of obesity, type 2 diabetes and heart disease – less is known about the impact of what we eat on our mental health.
But that is changing.
The Food & Mood Centre, a world-leading research hub in Victoria, is trying to understand how what we eat influences our brain, mood and mental health. Evidence consistently shows that people who eat a healthier diet have a lower risk of depression. And that trend is consistent across the lifespan, from early childhood to older adults, says Dr Hajara Aslam, one of the Centre’s researchers.
When it comes to mental health, there are many parts at play, but it is the role of the gut microbiota that has sparked the interest of the researchers.
Meet your microbiota
What is the gut microbiota? The gut is the home of the gut microbiome which is made up of trillions of microorganisms and their genetic material that live in your intestinal tract. The richer and more diverse these populations of ‘gut bugs’ are, the more benefit they seem to have on your health.
The Food & Mood Centre researchers are particularly interested in how our diets can affect the gut microbiota, and how that in turn influences our mental health. Previous research has shown that the gut microbiota changes in response to what we eat. And it can change fast.
Dr Samantha Dawson, a research fellow at the Centre, says several studies have looked at the impact of different diets. A diet rich in meat, cheese and eggs versus a plant-based diet had surprising results. “Within that first 24-hour period of starting a different diet, they could detect a change in the gut microbiota,” she says.
This discovery was heartening to the researchers because it suggests that changing your diet can rapidly change your gut bugs, and this may influence mental health. So how does your gut microbiota affect the brain, you might ask?
The gut-brain link
The relationship between your gut microbiota and your brain is complex. It is also bi-directional, which means the organs ‘talk’ to each other.
The gut microbiota is involved in pathways that produce serotonin and dopamine – the brain chemicals that are linked to mood, motivation and feelings of reward.
What’s more, Dr Dawson says, the gut microbiota of people with depression looks different to that of those without depression. “We recently reviewed over 40 studies comparing the gut microbiota of people with mental health conditions (such as depression) to people without mental health conditions, and we saw consistent differences between the two groups.”
There is still a lot to discover. But even so, the overall evidence suggests that a healthier diet is linked to better mental health and a healthier gut microbiota.
Foods of focus
To support your gut health and mental wellbeing through your diet, it’s best to focus on wholegrains, vegetables, fruits, legumes, nuts, lean protein and healthy fats. Good gut bacteria also thrive on fibre.
Jean Hailes naturopath Sandra Villella recommends the Mediterranean diet, as it is rich in plant foods and healthy fats from olive oil, fish, nuts (especially walnuts) and seeds. She says these foods fight inflammation through their antioxidant action, and this in turn may protect brain and nerve cells from damage.
Wholegrains like brown rice, oats and barley also form part of a brain-healthy diet, as they are rich sources of B vitamins “which play important roles in the making of neurotransmitters (brain chemicals) that affect mood”, explains Ms Villella.
Other cuisines also follow similar principles by being rich in whole foods, however the Mediterranean diet has a large amount of published scientific research behind it for promoting health and longevity.
Learn more about the Mediterranean diet.
Start simple
To embark on a new diet pattern, it’s best to start simple and small. “If you’re someone who doesn’t eat vegetables at all, start by including one serve a day, then gradually increase it,” says Dr Aslam. Aim for variety in your choice of vegies, and consider adding spices like cumin and turmeric to your cooking – both have anti-inflammatory and antioxidant properties.
The good news is, eating to support your mental health is within everyone’s reach. “It’s about what you do most of the time,” says Dr Dawson. “If you’re following a healthy diet pattern with good habits for most of the time, that is a good way forward.”
3 things to do
- Bring on the vegies, healthy fats and lean protein for a healthier gut and better mental health.
- Treats and take-away? Save these for sometimes or special occasions.
- The Mediterranean diet is all about good-mood food. Fill your plate with colourful plant foods.
Learn more about the evidence-based benefits of the Mediterranean diet.
Following a ‘good-mood diet’ is also about what we should eat less of, which is “less of the highly refined foods, the foods that don’t have fibre”, says Ms Dawson. “That’s the packaged highly processed foods [such as chips, biscuits and take-away foods] which are pretty common in people’s diets,” she says.
Ms Villella agrees, saying that the Mediterranean diet is low in refined carbohydrates and “unhealthy trans fats found in fast food and commercial bakery goods which have been associated with a higher depression risk”.
Knowing the why
A diet rich in whole and plant foods, such as the Mediterranean diet, may be supportive of mental health for various reasons. “We know the Mediterranean diet plays a role in reducing the risk of cardiovascular disease and metabolic syndrome, and in fact depression shares several mechanisms that are similar to these diseases,” says Ms Villella.
These foods fight inflammation and may help to protect brain and nerve cells from damage via their antioxidant action, says Ms Villella. Wholegrains such as brown rice, oats and wholemeal bread are rich in B vitamins, “which play important roles in the making of neurotransmitters (brain chemicals) that affect mood”, she says.
Dr Aslam says it is the important compounds in these whole foods that benefit our health beyond simple nutrition and fuel. “Vitamins, minerals, omega-3 fats, probiotics, prebiotics – these are all functionally-active ingredients and they can affect our physical and mental health overall,” she says.
“In particular, these foods have a beneficial impact on the gut microbiota as well.”
Start simple, start small
With less than 4% of people in Australia eating the recommended daily amounts of vegetables and legumes, and faring only slightly better in the fruit and grains department – around 30% of people meet the recommended daily serves for these food groups – many of us have a way to go in our journey toward healthy eating.
Both Ms Dawson and Dr Aslam agree that adapting to a new diet pattern can be challenging. “At the outset it might appear costly, and it might need a bit of dedication,” says Dr Aslam. But before you throw out all the food in your freezer, for best effect, it’s recommended to start simple and start small.
“[For example,] if you’re someone who doesn’t eat vegetables at all, start by including one serve a day then gradually increase it. That way you’ll start enjoying new things on your plate,” says Dr Aslam.
When it comes to feeding your gut microbiota, dietary variety is as important as diet quality, says Ms Dawson, who suggests you “aim for a wide range of colourful vegies” in your meal. Adding different spices to your cooking can also pay dividends in both flavour and benefit. “Certain spices such as cumin and turmeric have really good anti-inflammatory and antioxidant properties,” says Dr Aslam.
Impactful eating
Ms Dawson believes that being aware of the many health impacts of your diet is an all-important first step. “Making that connection between what you eat and your gut, and then in turn, your gut and your health, might help people to stop and think ‘Oh okay, I will have that high-fibre food instead of that processed food.’ It’s about seeing that link,” she says.
The good news? Eating to support your mental health is not out of reach for anybody. It doesn’t involve secret superfoods, strict rules or striving for perfection. As Ms Dawson says, “It’s about what you do most of the time. If you’re following a healthy diet pattern with good habits for most of the time, that is a good way forward.”
The Jean Hailes approach to food and eating is all about good nutrition, eating well, enjoyment and balance. Head to our recipes section for inspiration!
