35th ECNP Congress 2022
ECNP Congress programme spotlight
Plenary Lecture — Nutritional psychiatry — where are we going?
Felice Jacka

Felice Jacka will present the Plenary Lecture ‘Nutritional psychiatry – where are we going?’ at the 35th ECNP Congress in Vienna in October. As well as being professor of nutritional psychiatry and director of the Food and Mood Centre at Deakin University in Victoria, Australia, she is founder and president of the International Society for Nutritional Psychiatry Research (ISNPR) and immediate past president of the Australian Alliance for the Prevention of Mental Disorders (APMD).

Professor Jacka has pioneered a highly innovative programme of research that examines how individuals’ diets interact with the risk of mental health problems. Her current work focuses closely on the links between diet, gut health, and mental and brain health. Here she talks with ECNP press officer Tom Parkhill.

TP: Thanks for talking to us. You’re coming to the ECNP meeting in Vienna in October.
FJ: Yes, we’re coming to Vienna, and we’re also doing an ECNP nutritional psychiatry workshop just after the ECNP meeting. The workshop is organised for 19 October, just after the conference finishes. We will also be doing a workshop in London, with Rupy Aujla and the Doctor’s Kitchen, which will aim to train GPs, psychiatrists, and other health practitioners on how to put nutrition knowledge into practice.

Your talk at the Vienna Congress is entitled ‘Nutritional Psychiatry – where are we going?’. It’s a very topical subject, how did you get involved?
I came into psychiatry research quite accidentally and when I did I was interested and surprised to realise that there was very little existing research on diet and mental health. There were a few studies on nutrient supplements, and there were a handful of epidemiological studies that looked at the intake of individual things like seafood or folate and depression. But, of course, we don’t just eat individual food components, we eat complex diets. The rest of medicine had long recognised that nutrition was fundamentally important for risk of chronic disease, such as heart disease or cancer, but this wasn’t true in psychiatry.

Around the same time – this is the early 2000s – there was an increasing recognition that our immune system was bi-directionally involved in our mental health. This was pointing to a shift away from thinking about psychiatry as things that happen above the neck, and moving towards mental and brain health as being part of a sophisticated whole-body system. Similarly, there were interesting animal studies showing that dietary manipulation could affect hippocampus plasticity. And, of course, the hippocampus is involved in learning and memory, as well as in mental health. It had been newly recognised as the one area of the brain that puts on new neurons throughout life. So, the fact that you could manipulate the size and function of the hippocampus using diet made me think that this research could be important. Nutrition influences your immune system, but perhaps also brain plasticity. So, I proposed to look mostly at complete diet and its association with mental health for my PhD. I took the new knowledge from nutritional epidemiology and applied it in psychiatry, looking at the link between what we eat and clinical and depressive anxiety disorders in a large cohort of women.

A lot of people thought I was a bit silly, although my supervisors were supportive. But the results ended up on the front cover of The American Journal of Psychiatry and that opened doors, so I was able to begin to develop the evidence base, looking at the link between diet quality and common mental disorders, right across the life course and across different countries. Of course, other people then started to do the same thing, and in the last few years the field has moved on to producing more randomised controlled trials. This evidence shows that it can be both efficacious and cost-effective to take a dietary approach to treating even severe clinical depression. Our centre – the Food and Mood Centre – has a whole comprehensive programme of research that spans basic science up to population-based trials. We’re starting to have an impact on policy and clinical practice guidelines; it’s a very exciting time.

Thinking about RCTs, perhaps we could talk about the SMILES trial? Can you tell me a bit about the background to that, but also about the effect it had. You said that you met some initial resistance, did SMILES change that?
The SMILES trial was the first randomised controlled trial to test the hypothesis that, if you took people who already had an established clinical depression and supported them to improve their diet quality, it would have an impact on their mental health. We needed to move on from observational studies; we know that correlation doesn’t equal causation. So, I was in the first year of my post-doc and I had never done any nutrition interventions before. Basically, we recruited people with moderate to severe clinical depression. They were then randomly assigned to receive either social support, through a befriending protocol (which is often used as a control in psychotherapy trials) or dietary support with a clinical dietician. It ran for a period of 12 weeks, with depressive symptoms as the outcome measure. We aimed for a sample size of roughly 160, and after three hard years of blood, sweat and tears we had achieved 67. It was an impossible trial to recruit for. We had no support from clinicians, because no one believed that this would have any impact on such a serious mental health condition. There’s also a sort of clinical nihilism, which still persists in psychiatry, that people with a mental disorder will not change their diet, like it’s too hard, they are too fatigued, they are too unwell. Everything that we know now tells us that this is not the case at all. People themselves, I think, didn’t think it would be of any use to them, so they didn’t enrol. But we did manage to get 67 people, and at the end of the trial we crunched the numbers and we thought, “There’s no way we are going to see a separation between the groups”, and we all nearly fell off our chairs when we saw the really major difference. Of course, the trial was still blinded, so we were worried until the blinds came off. But in fact about a third of those who got the dietary support went on to have remission of their depression. The degree of change of diet correlated closely to the degree to which their depression improved.

We also did an economic evaluation and found that there was around a AU$2,500 cost saving per participant in the dietary support group, because they lost less time out of role and they saw other health professionals less often. We also did a very detailed cost analysis and found that the diet we were advocating was less expensive than the junk food heavy diet that people were eating when they came into the study. And of course we weren’t advocating hand-picked organic berries from the top of a mountain in Peru. The food we were advocating was normal food, the sort of stuff I eat every day: frozen vegetables, tinned fish, tinned beans and legumes, foods that are very affordable and accessible. And people loved it. People who had been very sick, often for a long time, loved it because it was putting power back into their hands.

Diet of course is a gateway behaviour. If people improve their diet, they start to feel better. They are prompted to get up off the couch and move a bit more, to give up cigarettes, to reduce alcohol. We had so much feedback after the study where people reported more and more improvements to their health. Since I wrote my book, Brain Changer, there have been so many people who have contacted me from all over the world reporting similar things. Almost immediately after this another group did a similar trial – but in a group setting with a larger sample size – and found the same thing. There have been another two studies done recently with young adults, which showed that even in a short space of time, three weeks, people improved their diet and they reported improvement in mental health.

We also did a large meta-analysis in which we looked at all the studies where they hadn’t necessarily set out to improve depression or anxiety with a dietary approach but where they happened to have measured depression and anxiety, and when we crunched the numbers we found that dietary change improved depressive symptoms. So, whilst we can say that there is still much work to be done, we are highly encouraged by the consistent results.

This research is starting to filter down into the mainstream. It has been cited in more than 80 different policy documents around the world, including by the UN, WHO, etc. In Australia, for the first time, the Royal Australian and New Zealand College of Clinical Psychiatrists has updated their clinical guidelines for the treatment of mood disorders to include what is essentially lifestyle medicine – addressing diet, physical activity, substance use, including cigarettes, and sleep – as the foundation of treatment. They call it ‘essentially non-negotiable’. So we are seeing a fundamental shift in the way psychiatrists conceptualise mood disorders, from thinking about everything happening only in the head and the brain, to this recognition of us as highly integrated complex systems, where food is the petrol that drives all the fundamental processes in our body and brain. Of course, we are increasingly understanding that there are other pathways. There are lots of different ways in which diet can influence mental and brain health. It’s a very exciting time, because we are also now starting to move towards more sophisticated ways of testing hypotheses. We’ve just finished a large-scale effectiveness trial and we will be doing a big national trial next year. We also may be able to personalise dietary advice a bit.

I’m really impressed at how enthusiastic patients seem – studies in obesity and nutrition show it’s notoriously difficult to get people to change their diet. I suppose it’s because they can see change quickly?
Yes, I think that this shows some of the limitations of our previous public health and clinical approaches. If you look at messaging around food and diet over the last 20 or 30 years, it has very much been aimed at body weight. But body weight is really difficult to shift. There’s a huge genetic component, but we are also in an environment where we have unlimited access to food. Once you are a certain body weight size, without bariatric surgery it is really challenging for people to lose weight and, more importantly, to keep it off. There are all sorts of complex systems that lead us to regain weight. And what happens is that people give up because they think “I can’t lose weight and keep it off, so I’m just going to keep eating the fries”. It’s really quite counter-productive.

The critical thing to know is that in all the data we have generated – the epidemiological data from across the world and in clinical trials – shows that body weight doesn’t seem to come into it. It doesn’t explain the link between diet quality and the increased risk for depression. And certainly in the clinical trial, body weight is not shifted. The SMILES trial was not a weight-loss trial in any way. The average BMI for people in the trial was roughly 30, and that didn’t change, and yet it had this very profound improvement in their symptoms. Also, it’s not just a case of “well, you’ve got to eat healthy food otherwise you’ll get cancer or heart disease in the future”. That sort of messaging doesn’t work very well because it’s not proximal. But if you say “what you put in your mouth travels down to your gut, and within hours your microbiota produces thousands of different molecules that influence every system in your body, and it can affect how you feel and think as quickly as tomorrow”, that has an impact. It’s concrete, it’s something that people can see and understand and do for themselves, and if you think about so many of the risk factors for mental disorders, they are things that people don’t have much control over very often. You know, early life trauma, poverty, life stress, genetics. But this is something that people can control.

You largely work on depression and anxiety, but have you found that diet is involved in other things, bipolar disorder for example?
Good question. Nutritional psychiatry as a field is only around 12 years old, and to date we have focussed on depression and anxiety, which represents the largest burden of disability globally, and of course it’s very common. But we are very interested in doing work on bipolar disorder and schizophrenia, as well as other disorders (PTSD and eating disorders, for example). We’re trying to get funding but that’s very challenging. In general, funding for medical research is hard to come by. We’ve been supported by philanthropic donations, but these trials often take a lot of money. We just don’t have the funds at the moment, but we are certainly wanting to look at these conditions. We’ve got a trial underway on depression related to multiple sclerosis. We have a pilot of dietary intervention for people with comorbid depression and anxiety and IBS – of course, these often go together. We’re very interested in dementia and cognitive decline.

Your approach to treating depression involves handing back control to patients, which means communicating with them. You have written a book (Brain Changer), as well as another book for kids (There’s a Zoo in My Poo). This wider communication seems to be an integral part of what you do.
I think that the most effective researchers are those who are driven by a passion for something; they really want to solve a problem or answer a question. For me, I’m concerned about the pernicious influence of the industrialised food system, which is the leading cause of illness and early death across the globe, costing close to the GDP of China every year. Of course there are virtually no effective food policies anywhere in the world because the industrialised food system is larger than most nation states and governments. So, giving people concrete information they can use to improve the health of their friends and families is really critical to me. I wrote Brain Changer to give people evidence-based information, because there’s also a problem with misinformation put forward often by nutritionists and medical practitioners. Sometimes this is quite dangerous and not evidence-based. It’s important that information is available and accessible. There’s a Zoo in My Poo is the book my husband and I wrote. It’s directed at kids, but of course it’s also a sneaky way of reaching their parents and grandparents. Kids are super bright. If you tell them to eat their broccoli, that won’t cut it with them. But if you say “you have a whole zoo in your gut, and you are in charge of it. This zoo does all sorts of stuff, and if you feed it the right stuff, these are the good things it does, and if you feed it the wrong stuff, these are the bad things”, then they will see if differently. My husband did lots of great illustrations – the book is full of bacteria and poo. The whole point is to get meaningful concrete information to people. At the back of the book we have recipes for kids, like “zoo poo stew”. We’ve had great feedback from families. That’s why we want to communicate directly, and we’ve had great coverage. Everyone eats, everyone has a brain, everyone is affected by their mental health – people are really interested!

Thank you for being here today and talking to us.

Plenary Lecture
PL02 – Nutritional psychiatry – where are we going?
Sunday 16 October, 17.00-17.45

Campfire Session
CA15 – A personal glimpse of Felice Jacka
Monday 17 October, 13.20-14.05

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