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For women’s sake, let’s screen for depression as part of the new heart health checks

Adrienne O'Neil

The latest government statistics, released last week, show that from 2001-2016, the rate of cardiac events (heart attacks or unstable angina) fell by more than half among Australian women.

That’s largely because of greater education about risk factors for heart disease (smoking rates continue to fall), and medical advances in prevention and treatment.

One thing that might reduce rates of heart disease even further is to make sure women, in particular, are asked about their current mental health. This can be a pointer to a hidden risk of developing heart disease in the future.

Mental illness can directly affect heart health by placing extra pressure on the cardiovascular system. Depression has been linked to inflammation, which can clog a person’s arteries. Depression also increases the presence of stress hormones in the body, which dull the response of the heart and arteries to demands for increased blood flow.

Less direct effects on heart health include the impact of depression on a person’s health behaviours, such as diet and exercise, and their connections with other people.

We’ve shown Australian middle-aged women with depression have double the risk of having a heart attack or stroke in the following 18 years compared to women without depression.

Preventing heart disease

Cardiovascular diseases including stroke, coronary heart disease, and heart failure remain the number one killer of Australian women. In 2016, three in ten deaths were due to heart disease. Indigenous women are twice as likely as non-Indigenous women to die from this cause.

While we’re seeing significant reductions in the number of people getting heart disease overall, the latest report shows the opposite is true in young women. The rate of cardiovascular events like stroke is increasing in women aged 35 to 54.

Drinking alcohol, smoking, high cholesterol, type 2 diabetes, overweight/obesity, and a family history of heart disease are some of the important predictors of a person developing heart disease over the next five years.

So if someone is considered to have high risk of a cardiovascular event, this risk can be managed with the help of a medical professional.

April 1 saw the introduction of two new Medicare item numbers allowing eligible patients (those aged 45 and over, or 35 and over for Aboriginal and Torres Strait Islander peoples) to be assessed for their risk of developing cardiovascular disease. This is known as a heart health check.

Using the Australian Risk Calculator, the doctor collects information to assess a patient’s risk of experiencing a cardiovascular event in the next five years.

If a person is identified as being sufficiently at risk, they will be targeted with preventative measures such as assistance with lifestyle modifications, and/or interventions like blood pressure or cholesterol medications.

Women have some unique risk factors

While many of the common risk factors for heart disease are shared between women and men, young and middle aged women have some that men don’t.

Polycystic ovary syndrome and complications during and after pregnancy (such as gestational diabetes and pre-eclampsia) are all important considerations.

We’re only beginning to understand how these factors affect a woman’s risk, but they are likely to be as important as traditional risk factors in the context of heart health checks.

Another common issue in young women that influences heart disease risk is poor mental health. Common mental disorders like depression are more common in women than men until age 75.

Both heart disease and depression are largely socially determined, especially for women and girls. Early life trauma, poverty, and gendered violence and discrimination can accumulate across a woman’s lifespan to shape her risk of heart disease and stroke.

Screening for mental health

We did some statistical modelling to see whether depression should be added to the risk equation that underpins the heart health checks.

For women who reported depression in this context, we were able to more accurately predict whether they’d go on to develop heart disease over the next ten years.

While more research is needed, asking about a woman’s mental health may help GPs better identify risk of heart disease in younger women.

Large population-based studies show reducing the prevalence of depression could have major implications for the prevention of heart disease and stroke. One study found having a poor psychosocial profile (depression, stress, isolation and anxiety) contributes 32% of the risk for heart attacks across the population.

In other words, if these psychosocial issues were eliminated, the incidence of heart attacks would be reduced by one-third.

Given the burden of these psychosocial issues is greater for women than men, women may have even more to gain if depression was targeted as part of preventing heart disease.

How can we address depression as a risk factor?

The heart health checks represent a significant step in the government’s investment in preventive medicine and public health.

While time poor clinicians can’t be expected to capture an infinite number of risk factors in a short consultation, these sessions may present a good opportunity for GPs to ask their patients about their mental health in the context of their heart disease risk. Equally, this may be a good time for patients to flag any concerns about their mental health with their GP.

There are few studies yet that definitively show treating depression will prevent a first heart attack or a recurrent event.

This is especially true for women, who are under-represented in this type of research. One study, where participants were given psychological therapy after a cardiac event like a heart attack, found the intervention benefited future heart health outcomes for “white men, but not other subgroups”.

We need more research to tell us if and how treating depression might prevent heart disease and stroke, especially for women. In the meantime, there are many free or subsidised options for the management of depression available either via your GP (psychologists and counsellors) or online.

Associate Professor O’Neil is Deputy Director of The Food & Mood Centre and Director of the Heart and Mind research program.  She is also a National Heart Foundation Future Leader Fellow.

This article was first published in The Conversation at https://theconversation.com/for-womens-sake-lets-screen-for-depression-as-part-of-the-new-heart-health-checks-118910 on June 24th, 2019

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Fueling the fire: diet, depression and inflammation

Sarah Dash

By Dr Sarah R Dash

You likely know inflammation as the redness and swelling that appears after you cut your finger – it’s painful, but its job is to help us heal. Systemic (or chronic) inflammation is different. We can’t see this low-level autoimmune response, and it’s usually a prolonged reaction to a persistent problem, like chronic disease or environmental stressors (think pollution or smoking). Instead of a quick response to an obvious injury or illness, systemic inflammation is a slower, continuous burn, like a cindering fire. Chronic inflammation can damage and disrupt biological systems and tissues, and this increases risk of illness in both the body and brain. While we cannot control all factors that influence our health, there are several lifestyle behaviours over which we have a bit more say, such as our diets, that influence levels of inflammation. 

 

There are many foods and nutrients that are particularly good at ‘tidying up’ the inflammation in our bodies – you’ve perhaps heard them advertised as antioxidants or ‘super foods’. While there’s no quick fix as promised on a punnet of blueberries, there are many foods that can and should be incorporated as part of a healthy overall diet. For example, fish, rich in omega 3s, and vegetables and whole grain cereals, packed with fibre, are known for their anti-inflammatory properties. When it comes to inflammation, it’s best to choose foods that come from a farm rather than a package.  

 

On the other hand, unhealthy foods (ie fast foods or lollies) can increase inflammation, possibly through influencing the health of our gut. The gut is an important interface between what we eat and our other biological systems. A junk food diet can contribute to a weakening of the gut barrier lining that prevents food particles from leaking out into the bloodstream where they do not belong. Because these food particles are out of place in the bloodstream, off go the alarm bells of our inflammatory response. When poor quality foods are a part of our daily diet, the body maintains this low level of alarm, and we believe this to be a risk factor for mental health problems such as depression. 

 

Chronic inflammation is linked to brain function and mood. In animals and humans, injection of ‘pro-inflammatory’ molecules gives rise to symptoms and behaviours like fatigue, withdrawal, and  depression itself. Further, people with higher levels of inflammatory markers in their blood have been shown to be more likely to develop depression in the future.  

 

We are learning more each day about the connection between the gut, inflammation and brain health. What goes on in the gut, as well as the inflammatory response that might follow, can disrupt the processes in the brain that help regulate our mood. For the health of your belly, body and brain, aim to avoid heavily processed foods, and instead rely on a range of colourful, fibre rich foods in your daily diets. 

Bugs for your brain? The effect of prebiotics, probiotics and fermented foods on cognition

MEGHAN HOCKEY, Wolf Marx and MELISSA LANE

When it comes to health, we’re all after a quick fix, but new research shows neither popping a prebiotic or probiotic pill, or consuming fermented foods, has an effect on boosting our brain power. So, does this mean you should throw out those pills and kefir for good? Not quite.

Cognition – the scientific term for brain power – refers to the mental processes of gaining knowledge and understanding, including thinking, knowing, remembering, judging and problem solving. Research into the role of diet on cognition is rapidly growing with studies showing that certain diets (i.e. the Mediterranean diet) could have positive benefits for cognition, in particular for the elderly. Although it’s unclear how foods may benefit cognition, researchers have a gut feeling the answer may lie in the microbiota-gut-brain axis – the communication pathway between the bacteria (or bugs) that live within our gut and the brain.

For this reason, it’s thought that supplements and foods that have the potential to change the composition of the gut microbiota, may in-turn have benefits for cognition. This includes probiotics, which deliver beneficial strains of bacteria to influence the gut microbiota composition and activity, and prebiotics, which can be thought of as food or substrates used by the microbiota to grow. Both prebiotics and probiotics can be consumed in supplement form or via foods such as fermented foods (i.e. probiotic milks, kefir and kimchi). As suggested, the consumption of these products can alter the composition and function of the gut microbiota. In turn, this can lead to changes in how the gut interacts with the brain – via the immune system, vagus nerve and neurotransmitters – which could lead to potential changes in how we think and feel.

But findings from our new meta-analysis, suggest there was no significant effect for prebiotic, probiotic or fermented food interventions for global cognition. The meta-analysis published in Neuroscience and Biobehavioural Reviews included 22 randomised controlled trials that investigated probiotic (11 studies), prebiotic (5 studies) and fermented foods (6 studies) interventions. Fourteen (64%) of the included studies within this meta-analysis reported that a prebiotic, probiotic or fermented food intervention improved at least one cognitive measure. But when the results of the included studies were pooled (or combined), these findings were no longer significant which meant there was no apparent evidence of an effect of prebiotics, probiotics or fermented foods on overall cognition.

So why were the overall results no longer significant? Many of the included studies were in healthy populations where cognitive changes may be unlikely to be seen: Put simply, if your petrol tank is already full, adding in more petrol is not going to make your car travel any further.  For probiotic interventions, studies also varied in the strain and dose of bacteria used (known as colony forming units). Different strains have different properties and we don’t yet know what the optimal strain for cognition is (if indeed these probiotics are able to colonise the gut in the first place – but that’s for another time!). Studies were also relatively small in sample size, which means there may not have been enough participants to detect a statistically significant difference, if one existed. And lastly, adding to the complexity, studies were also relatively short in duration which begs the question: Does it just take time for prebiotics, probiotics or fermented foods to work their magic?

In short, these results may not reflect a lack of an effect, but rather a lack of robustly designed studies investigating the effects of prebiotics, probiotics or fermented foods on cognition. Before we write them off as a health fad, there are many more areas of research we need to explore including what strains are best, what dose may be optimal and who (or which populations) may benefit from these interventions. Interestingly, other meta-analyses do show promise for other brain outcomes like depression. But from what we currently know, feeding your gut bugs through prebiotics, probiotics and fermented foods, is unlikely to be a magic fix to boost your cognition.

Lactobacillus and anxiety: what’s the link?

Amy Loughman and MARY NEYLAN

How our gut microbiome could help reduce anxiety and its potential effects on the most common antidepressant and anti-anxiety medication.

Interactions between the gut and anxiety

Oftentimes, when we’re nervous or worried we feel it in our belly. We may feel nauseous or need to run for the bathroom. Am I right in thinking you’ve felt something like this before?

There’s a growing body of evidence out there about a bidirectional connection between the gut and the brain, the gut-brain axis. Gastrointestinal disorders and mental illness often occur hand in hand. It has been found that the rate of irritable bowel syndrome (IBS) and other functional gastrointestinal disorders was four times higher in people with anxiety than those who don’t have anxiety. The rate of anxiety was also five times higher in people with IBS than without.

The reason for this bidirectional relationship may lie within the microorganisms populating our gut, an important aspect of the gut-brain axis. Termed the microbiome, our gastrointestinal system houses thousands of bacterial, fungal, and protozoan species, as well as viruses. Currently, the majority of research involving the brain-gut axis is focused on cell lines and animal models. In mice, it’s been found that some bacterial species living in the gut are associated with poor social behaviour and social avoidance. These species include Lachnospiraceae and Ruminnococcaceae, two pro-inflammatory bacteria from the Clostridiales class.

Supplements comprising other bacterial species have been found to reduce these behaviours in both mice and humans. There’s growing evidence that particular gut bacteria including Lactobacillus, Bifidobacterium, andBacteroides may be related to anxiety symptoms.

A common anxiety drug and the gut-brain axis

Fluoxetine, also known as Prozac, is a drug most commonly used as an antidepressant. It can also be used to reduce anxiety symptoms and is one of the first drugs prescribed to treat the condition.

A common side effect – weight gain

Like all medications, fluoxetine may cause unwanted side effects, such as weight-gain. In fact, weight gain is one of the most common reasons for choosing to stop the drug or not taking it properly. Amongst others, one possible mechanism by which fluoxetine causes weight gain may be related to its antimicrobial effect on one particular bacterial strain, Lactobacillus.

Lactobacillus is a group of bacterial species commonly populating our gut that is thought to work in harmony with our digestive system. It has been found to be relevant to many health factors including the regulation of body weight. Numerous studies in both animals and humans have determined a close relationship between abundant Lactobacillus species, including Lactobacillus casei, Lactobacillus fermentum, and Lactobacillus johnsonii, and healthy weight maintenance.

Can Lactobacillus control fluoxetine’s common side effect?

In one study the body weights of two groups of mice were monitored over a 29-day period. One group was given fluoxetine dissolved in a saline solution, and the other given an equal volume of the saline solution alone. As well as gaining more weight on average than the control mice, the mice given fluoxetine were also found to have lower populations of Lactobacillus in their gut microbiome. Could there be a connection here? Could the depletion of Lactobacillus have something to do with the weight gain of fluoxetine-treated mice?

The proposed ability of Lactobacillus species to help modulate body weight might be useful to control the unwanted side effects experienced by people taking fluoxetine.

The data from a meta-analysis of intervention studies in humans and animals, as well as two observational human studies, suggests that taking Lactobacillus probiotics may help moderate weight. In the meta-analysis, particular species of Lactobacillus, including casei, plantarum, and gasseri, were found to reduce obesity.

Although these studies suggest a connection between particular Lactobacillus populations and weight regulation, clinical trials re required to establish effects in the context of treatment for anxiety with Fluoxetine. Clinical trials are so important because they could help confirm the therapeutic effects of Lactobacilli in humans that have so far predominantly been observed in mice.

Lactobacillus and serotonin

There is another tantalizing reason to be interested in Lactobacillus: it may actually improve the effectiveness of fluoxetine. Fluoxetine works primarily by increasing the availability of serotonin in the brain, which you might know as the “happiness hormone”. Serotonin has other important functions, including regulating circadian rhythms and helping with sleep, improving memory, and influencing digestion.

At least one in-vitro study has examined the possibility that the species Lactobacillus salivarius possesses the same transporter found in neuronal cells associated with serotonin uptake. This investigation focused on the uptake of serotonin-like fluorescent molecules into Lactobacilli salivarius cell cultures. The results indicated that such transporters do exist, but more research using real serotonin in animals and humans is needed. Studies show that fluoxetine and other SSRIs have antimicrobial effects, demonstrating that there are interactions between the gut microbiome and antidepressants in both directions.

Anxiety-modulating properties of Lactobacillus

There are also studies suggesting that Lactobacillus could have its own anxiety-reducing properties. A common theme amongst stressed, anxiety-ridden mice is that they were found to have low Lactobacilluspopulations, and that their symptoms improved with administration of the bacterium.

So at least we know how to deal with mouse anxiety! What about humans? The administration of a Lactobacillus helveticus and Bacteroides longum combination probiotic saw improved psychological symptoms in humans and a decrease in the stress-related hormone, cortisol.

A recent meta-analysis cusing on human studies between 2017 and 2019 examined the potential anxiety-modulating effects of multiple probiotics. Of 24 trials examining Lactobacillus’ effect on anxiety, 22 saw reduced anxiety symptoms at the end of treatment compared to placebo controls.

A randomised, placebo-controlled human trial saw a reduction in stress-related symptoms after the daily consumption of Lactobacillus plantarum for 8 weeks. Another study determined that Lactobacillus rhamnosus significantly reduced depression and anxiety symptoms in women who had recently given birth. In a similar study, anxiety symptoms were alleviated in 39 chronic fatigue patients receiving Lactobacillus casei.

The body of knowledge surrounding anxiety, fluoxetine, and Lactobacillus suggests that a close connection exists and that Lactobacillus could help people taking fluoxetine in more ways than one. The bacteria could help reduce anxiety symptoms, reduce the weight-gain side effect, and maybe even increase the absorption of serotonin! More research is still needed to properly understand the bacterium’s potential, as many of the studies thus far have focused on mice.

While we obviously need more human clinical trials of lactobacillus and SSRIs combined, it’s possible that probiotics will one day be recommended alongside medications to better treat disease and to decrease potential side effects. 

 

Image by: Bob Blaylock / CC BY-SA

Dr Amy Loughman is a Postdoctoral Research Fellow at The Food & Mood Centre and leads the microbiome research stream. Her research aims to uncover the role of the human microbiome in brain function and mental health across the lifespan.

Mary Neylan is on an internship with The Food & Mood Centre whilst completing a degree in biomedical science at Deakin University. Mary’s research interests include neurology and found working on this article to be fascinating and worthwhile.

Healthy diets to healthy minds:  Join with us to transform mental and brain health

CLAIRE YOUNG

“Our research aims to identify nutrition-based approaches that can both prevent and treat mental and brain health conditions, thus improving lives across the world.”

– Professor Felice Jacka

Poor diet is now the leading cause of illness and early death across the globe. At the same time, mental disorders account for the leading cause of global disability. Mental illness stops people from participating fully in life, and it affects individuals, families and communities alike. The social and economic toll in Australia and elsewhere is enormous, and rapidly increasing.

We’re leading the way, internationally, in understanding how what we eat can influence our mental health and wellbeing, as well as brain health, from birth through to old age. We’re showing that the quality of our daily diets is inextricably linked to the risk of depression and anxiety throughout our lives, and that by improving our diets, we can effectively treat these conditions. We’re also demonstrating that our diets are closely tied to the health of our brains and our cognitive abilities –from childhood through to old age. Our work has enormous implications for the prevention and treatment of mental illnesses, for brain health and function, and for the general wellbeing of people everywhere.

But we’re impatient to drive new breakthrough discoveries and innovation. We know that there is so much more to do!

Philanthropic partnerships sit at the core of what we’re able to achieve – they are absolutely essential for us to continue ground-breaking research that has a bigger impact on more people’s quality of life.

If you share our passion for preventing mental and brain health conditions across the lifespan, and improving the lives of those already affected, please consider joining us in our mission!

  • Make an online gift today to support our work
  • Learn more about our transformational plans for the future – and how you can be a part of the change
  • Or connect with us to have a conversation about how a gift in your Will can make a lasting change for generations to come

I look forward to hearing from you.

-Professor Felice Jacka

Should I test my gut microbes to improve my health?

Heidi Staudacher and Amy Loughman

People are paying hundreds of dollars to have their gut microbes analysed, hoping the insights will allow them to adjust their diet and improve their health.

But these testing services are based on science that’s still in its infancy, as we explain in our recent paper.

So while there may be great promise for analysing our gut microbiome to help diagnose and treat people in the future, for the moment knowing what’s in your gut is mostly a curiosity.

But aren’t these tests based on science?

The idea of your gut microbiome – the whole community of gut microbes and their products – influencing your health is gaining momentum.

Over about the past two decades, the gut microbiome has been linked to everything from inflammatory bowel disease to depression.

So it’s been appealing to think if you just knew what was in your gut microbiome, you could tweak your diet and create a “designer microbiome” to improve your health.

There’s preliminary evidence analysing the gut microbiome in a stool sample can help predict who will do well on a certain diet.

There’s also some evidence it can help predict which people with inflammatory bowel disease respond to medical treatments.

But these findings are far from being applied more generally and for routine health care.

One day, we may understand how combining information about your microbiome with other test results, such as genomic tests (sequencing your human genes) might help.

The idea is that this would help people prevent disease and medication side-effects, predict their future risk of disease, and help choose a personalised diet for optimal health.

For instance, information about someone’s microbiome, when combined with blood tests and their diet, can predict how someone’s blood glucose levels respond to specific meals.

This 2015 study also showed that by analysing someone’s gut microbes you could tailor their diet to keep their blood glucose under control.

Again, while the prospect might sound appealing – and the potential impact huge – we don’t yet have the evidence to implement this more widely.

There’s also much we don’t know about the microbiome itself. For instance, scientists don’t agree what a healthy microbiome looks like, we haven’t sequenced all of the bacterial genes, and we don’t know what they do or how they interact.

So while we are starting to understand the ideal microbiome for health, it is still more of a rough sketch than a blueprint.

But I’m curious anyway

Most companies ask you to send in a stool sample, which you take yourself and post in a secure package to a laboratory to analyse the results.

Each company is different

Different companies analyse your stool sample in different ways.

For instance, some tell you the relative abundance of bacteria down to the genus level (but not the species level). Some tell you which strains of microbe are present (not just bacteria, but viruses and fungi too) and their function. Some tell you which of the microbe genes are expressed and active.

All of these are legitimate approaches to analysing your gut microbiome, and you could expect a reasonable degree of accuracy.

How do you interpret the results?

The companies also differ in how they supply and interpret the results. The company may compare your results with others they’ve analysed. But they can’t compare them with an “average” or “healthy” microbiome because an individual company doesn’t sample the whole population, and scientists haven’t yet defined a “healthy” microbiome.

Some companies advise the types of foods you could eat to boost levels of particular bacteria. You might also be told that a certain bacteria can be associated with some health condition, like obesity or constipation.

Ideally, alongside your results would be an explanation about the types of research the insights are based on, limitations of the evidence, and a caution the results cannot be considered medical advice.

Unfortunately, consumers don’t always receive this information, and it can be hard to know what to do with the test results.

What about privacy?

Another important issue to consider is who has access to your test results and under what circumstances. This has been a concern with take-home genetic tests in the United States.

Although data about your microbial genes may not seem sensitive and private as your own genes, ensuring you know who might have access to your stool testing data is an important consideration.

There’s research to see whether the microbiome could may one day be used in forensics, demonstrating the very personal nature of these data.

In a nutshell

Given the complexity of the gut microbiome and its interaction with us, its host, we still need large research trials replicated across different centres to make sense of the data.

So-called microbiome diagnostics could become central to optimising health and improving care of people with chronic disease in the future.

But, for the moment, knowing the specific community of your gut microbes will only serve to satisfy your curiosity, not improve your health.

Dr Amy Loughman is a Postdoctoral Research Fellow at The Food & Mood Centre and leads the microbiome research stream. Her research aims to uncover the role of the human microbiome in brain function and mental health across the lifespan.

Dr Heidi Staudacher is a Postdoctoral Research Fellow, Food & Mood Centre, and accredited practising dietitian. Her research program investigates the role of diet in people with both mental illness and gut problems, as well as the importance of diet-driven microbiome changes in these conditions.


This article was first published in The Conversation at https://theconversation.com/should-i-test-my-gut-microbes-to-improve-my-health-131216 on March 16th, 2020

The SMILEs Trial

Claire Young

Many aspects of lifestyle, such as keeping active, being a non-smoker and maintaining a balanced diet are important factors in keeping physically and mentally healthy. There have been many studies that have demonstrated that a good quality diet is important to the risk of or prevention of mental disorders. However, the idea of diet as a part of the treatment of mental disorders has not yet been studied. The SMILES (Supporting the Modification of lifestyle in Lowered Emotional States) trial is the first of it’s kind to investigate the questions ‘if I improve my diet, will my mood improve?’ The study commenced in 2012 and recruitment was completed in 2015. The results of this study are now published and can be read HERE. The development of the dietary intervention and feasibility data can be read HERE.

Who participated in the trial?

Participants in the SMILES trial were recruited from the community and reported experiencing depression symptoms. Individuals who were interested in participating in the trial completed a comprehensive screening process. Briefly, this process allowed researchers to ensure that participants were experiencing current depression, did not have any comorbid physical/mental conditions that would inhibit their participation or make it difficult to assess their mood, and that they were able to follow a prescribed diet. Full details of the screening process can be found here.

How did the study work?

Participants who met eligibility criteria were invited to a Baseline Assessment. During this appointment, a research assistant collected a range of information on physical health, lifestyle (physical activity, smoking, alcohol use, diet), mental health, as well as personal details such as education level, occupation, and income. At this time, participants also provided a blood sample that would allow the researchers to investigate their current health. Overall, the baseline assessment provides a detailed snapshot of a participant’s current environment, as well as their physical and mental health. This information serves as a basis of comparison, and allows researchers to compare a participant’s status to before the intervention began.

Intervention and control conditions

Participants were randomly assigned to one of two groups. This process was done electronically, so that the study researchers had no input into what group a participant is placed in. The randomisation process helps us to control for factors that might make the two groups in different in some way. For example, randomisation aims to create two equal groups, so that if you do see a change in one or both of your groups, it’s not because one group had a higher level of education, or was made up of only women.

In this study, the control condition was called ‘the befriending group’. Befriending is a tool used in psychology studies, and it is a ‘neutral’, social support process. Participants in this group met with a member of the research team and discussed subjects they enjoyed, but were not emotional or related to their mental health. A control group aims to keep as many details and experiences of the trial the same as the group who is receiving treatment, and the ‘Befriending group’ met with a researcher the same number of times and for the same amount of time as those in the ‘Diet Group”. This was done so that if there was an effect of the treatment being studied, it is more likely that the treatment was truly effective, and that one group didn’t do better than the other because they spent more time with a clinician.

The second group received a dietary intervention, which involved meeting with  an Accredited Practicing Dietitian for dietary education, support and nutritional counselling.  Participants were encouraged to follow a Modified Mediterranean Diet, which was constructed using existing dietary guidelines from Greece and Australia, traditional Mediterranean diet principles, and scientific evidence from the emerging field of Nutritional Psychiatric Epidemiology.

There is a good body of evidence to suggest that a healthy dietary pattern, such as the Mediterranean diet, promotes brain and mental health, and it is made up of fresh fruits, vegetables, whole grains, legumes, nuts, extra virgin olive oil, and fish. Participants worked in collaboration with the dietitian to make improvements to their overall diet quality. For example, increasing their weekly fish consumption, or swapping the occasional chocolate ice-cream for  natural  yoghurt with walnuts and a drizzle of honey.

After three months, participants attended a Follow Up Appointment where they completed all of the same measures they had completed at Baseline. Once again, participant’s provided a blood sample and were assessed on their physical health, diet and mood. By comparing to Baseline results, the research team can make comparisons on whether the befriending or diet group had greater improvements to their depression symptoms. Lastly, participants were followed up via telephone calls six months after their Baseline appointment to once again assess their diet and mental health.

WHAT DID WE FIND?

The results of the study, published in the international journal BMC Medicine, showed that participants in the dietary intervention group had a much greater reduction in their depressive symptoms over the three-month period, compared to those in the social support group.

At the end of the trial, a third of those in the dietary support group met criteria for remission of major depression, compared to 8 percent of those in the social support group.

These results were not explained by changes in physical activity or body weight, but were closely related to the extent of dietary change. In other words, those who improved their diet the most experienced the greatest benefit to their depression.

Why is this study important?

Although many people intuitively understand that diet is important to mental health, it’s important to develop high quality scientific evidence in this area. A randomised controlled trial is considered the ‘gold standard’ of research methods, and it helps researchers begin to understand treatment strategies that may be effective for depression. The results of this trial are  very important in directing future research, as well as informing how we manage or treat some common mental disorders such as depression.

Professor Jacka, who is director of the Food and Mood Centre and president of the International Society for Nutritional Psychiatry Research, said the findings offered an important new strategy for the treatment of depression.

“Mental disorders account for the leading cause of disability worldwide, with depression accounting for the large proportion of that burden,” she said.

“While approximately half of sufferers are helped by currently available medical and psychological therapies, new treatment options for depression are urgently needed.

“Importantly, depression also increases the risk of and, in turn, is also increased by common physical illnesses such as obesity, type 2 diabetes and heart disease. Successfully improving the quality of patients’ diets would also benefit these illnesses.”

The study suggests the new possibility of adding clinical dieticians to mental health care teams and making dietitian support available to those experiencing depression.