The Food-Mood Connection

Lynne Malcolm: What kind of food makes you feel good? Cheese on toast, hot chips, gelato? I must admit, a little bit of smooth dark chocolate gives me an instant hit, but the effect tends to wear off quickly.

Well, how do you like the sound of purple risotto with goat's cheese, walnut and beetroot; miso broth with mushrooms and edamame beans; or saffron chicken with quinoa and cauliflower tabbouleh? Well, it turns out that these dishes may actually help to lift your mood.

Rachel Kelly: Actually I was just seeing my doctor for a regular check-up for my anxiety, because by that stage I was no longer suffering from depression but I still did have a whole lot of anxiety, and I saw my doctor and she said, 'Have you heard about happy foods?' And I said, 'No. Happy foods? Wow, tell me a little bit more.'

Lynne Malcolm: Rachel Kelly, mental health ambassador for Sane in the UK, and she's also the creator of those recipes I just mentioned.

Lynne Malcolm with you, and in today's All in the Mind, food and mood, the growing evidence that diet can directly affect your mental health.

Felice Jacka: What are we and others have shown now is that the quality of people's diets is related to their risk for depression in particular, and we see this across countries, different cultures, and really importantly we've also seen this very clearly across age groups. So understanding that half of all mental disorders start before the age of 14 and thinking what can we target to actually think about prevention for at least some people, understanding that diet is relevant to mental health in adolescents, which we've shown repeatedly, and even very young children.

So we published the first study looking at data from more than 23,000 mothers and their children over the first three years of life, and we showed that the quality of mothers' diets during pregnancy was related to the children's emotional regulation, which is a marker of vulnerability to mental health problems.

And then what the children ate in the first few years was also of relevance. And that has since been replicated in two other large European studies. And it's very concordant with what we see in animal studies where they can actually manipulate diet and have a look at the impact on the brain.

Lynne Malcolm: Professor Felice Jacka is research fellow at Deakin University and director of the Food and Mood Centre. She and her colleagues are at the forefront of this new field of nutritional psychiatry where there's now extensive evidence showing the link between the quality of people's diets and their risk of depression. That's independent of other factors such as socioeconomic status and education.

But what if you are already depressed? Can a change of diet help your mood? You'll hear about their recently published study looking at this question shortly.

Now though, here's Rachel Kelly about the depression she experienced earlier in her life.

Rachel Kelly: I have had two major depressive episodes and they have sort of become the defining episodes really of my life. The first was back in 1997. So I was in my early 30s and at that point I was a reporter at the Times newspaper in London. Life was good, it was the job I wanted, but I was an anxious person and I had taken on a lot, and I had two small children, and my husband also had a demanding job. And basically what happened was that one night I couldn't get to sleep, but with the insomnia came some quite alarming physical symptoms. My heart rate speeded up, I felt like I needed to vomit, my thoughts were racing in a way that I couldn't control them. And the thoughts went something like this; well, if I can't get to sleep, I won't get to work, if I won't get to work I won't be able to pay the bills, I won't pay the bills, I won't pay the mortgage, we'll lose the house, I'll lose the children…this kind of catastrophic thinking.

So it was a very alarming night. Unfortunately I had another night of this terrible insomnia and these very alarming symptoms, and then the third night I found myself in hospital. And that was the start of my first major depressive episode. It turned out it was a psychiatric hospital, even though I said, look, there's nothing wrong with me, I'm not depressed, I think maybe I'm having a heart attack.

Lynne Malcolm: Rachel Kelly was diagnosed with an anxiety driven major depressive episode. She was seriously ill for about six months. A few years later she had a second depressive episode which lasted for a year and a half. She was treated with anti-depressants and cognitive behavioural therapy. But she also developed her own ways of managing her depression.

Rachel Kelly: So I started to look at what were the strategies I could use to improve my mental health, always looking for the evidence base. So I started introducing some elements of mindfulness, which I find helpful. You know, using the breath to stay grounded and in the moment. I introduced more physical exercise, obviously some very good evidence around that. Some different psychological approaches. I learned to develop a different narrative in my head, a gentler, more forgiving narrative, a sense that we have several selves. I could still have the very anxious self, which I still have, but I could grow another self alongside.

And then about five years ago I became very struck by the difference that nutrition could make. Actually I was just seeing my doctor for a regular check-up for my anxiety, because by that stage I was no longer suffering from depression but I still did have a whole lot of anxiety, and I saw my doctor and she said, 'Have you heard about happy foods?' And I said, 'No. Happy foods? Wow, tell me a little bit more.'

Lynne Malcolm: This idea about happy foods planted the seed for Rachel Kelly's recent book The Happy Kitchen: Good Mood Food.

Rachel Kelly: So I went to see a lady called Alice Macintosh and I said, 'Look, I'd like to know a little bit more about this and be evidence-based.' So she's a nutritional therapist. She also has a degree in biomedical science. And we started to work together. She started to help me with my symptoms. We then worked together for five years and we put together 70 recipes based on 150 different nutritional studies, all of which are looking at the particular effects of particular foods, particular combinations, diets and what affects our mental health.

If I had to mention two of the biggest areas of research with the best evidence and the most compelling studies that we looked at, probably the first area would be around healthy fats, the omega threes, and I'd say the second area would be the evidence around a healthy microbiome or our gut flora, so the links between our brain and our stomach and how those two are connected.

But I think as a backdrop to all this evidence is a really frontal shift in how I understood my brain really and how it operated. But I think this would be reflecting what scientists are now looking at. So when someone was suffering from anxiety and depression like me, people felt, okay, it's just about the brain, whereas I think now the shift is that we are looking at the whole system and the way that the brain links with other parts of our physical being.

Lynne Malcolm: Rachel Kelly.

Felice Jacka and colleagues at Deakin University and the University of Melbourne have recently published a study. It investigated whether changing to a healthy diet could help people with depression. It was funded by the NH&MRC, and it's called the Smiles Trial.

Felice Jacka: What we did was we recruited adults who had a major depressive episode. So they were currently suffering from clinical depression. They were randomised to go into one of two groups. One group received social support, and we already know that this is very helpful to people with depression. The other group saw a clinical dietician, and both groups saw somebody to the same schedule, over a 12-week period. The dietary group received guidance from the clinical dietician to make improvements to their diet. So that meant to reduce the intake of the unhealthy and extras foods that we know are noxious to health, and to increase the consumption of vegetables, legumes, good quality lean fish and meat, olive oil, nuts, seeds, those sorts of foods that we know are healthful.

And what we saw was that the group who received the dietary support had a bigger reduction in their mental health symptoms, their depressive symptoms, and that the level of the dietary change correlated with their level of depression improvements. So that the people who change their diet the most were the ones that experienced the greatest benefit to their depressive symptoms.

Lynne Malcolm: The Smiles Trial used a modified Mediterranean diet, but it's not the only form of diet that's potentially helpful for mental health.

Felice Jacka: In all the work that we've done we see that a healthy diet can take many different forms, depending on the country that it comes from. But at their heart what they have is a higher intake of nutrient and fibre dense foods. So vegetables, fruits, often legumes, not always though, nuts, good-quality forms of protein from fish and lean red meats, but also very importantly a low intake of the junk and processed foods that we are increasingly recognising as being particularly noxious to health.

And we are understanding from our point of view the impact of these particular dietary components on the brain and the gut, both of which are linked. For example, there is new evidence to suggest that the common emulsifiers that are in many processed foods have a very noxious impact on the gut, the gut lining. Artificial sugars seem to change gut microbiota in a way that is detrimental and that promotes glucose dysregulation, so altered glucose metabolism in a way in turn that may put on weight in people. So even though they don't have calories per say they seem to potentially induce weight gain. And of course there is a very extensive data from animal studies showing that unhealthy food components, and here we are talking about high fat, trans fats, high sugar foods, they affect areas of the brain particularly in the hippocampus, which is a region of the brain that really is important for learning and memory, and also mood regulation.

So, many studies have shown that in animals at least you can alter the proteins and the action and activity of the hippocampus by introducing dietary change, and we published a study in 2015 showing that in older adults the quality of their diet were very clearly linked to the size of their hippocampus.

Now, this doesn't have implications only for older people, although certainly as we age we want to protect our hippocampus. But it has implications for brain health across the lifespan. So there are many ways in which unhealthy dietary components can have an influence on mental health and where healthy ones can be protective.

Lynne Malcolm: Felice Jacka explains that they're now understanding that diet can also affect the immune system and in turn influence mental health.

Felice Jacka: Unhealthy diets are linked to high levels of what we call inflammatory markers, markers of sort of a low-grade chronic inflammation which we know in turn is a risk factor for all sorts of diseases. But this is also apparently a risk factor for depression, according to most of the data looking at this in some detail. And of course this also works through the gut because the diet is the most important variable that influences the composition of the gut microbiome, and the gut is now seen to be really the heart of immune function in the body.

So the gut microbiota, they ferment dietary fibre, and the fermentation products, they're called short chain fatty acids, they play a very important role in modulating the immune system and immune function. So of course this means that the gut really needs dietary fibre to be able to act to promote health. But of course in the West and in many countries across the globe now, because our intake of plant foods is so much lower than it should be, we are not having the amount of dietary fibre that we should be having. And this of course means that the gut can't do its stuff, which has a noxious impact on the immune system. And we believe that this then in turn influences the risk for depression, as well as being linked to the risk for heart disease and a range of other physical conditions.

Lynne Malcolm: And there are dietary ways of rebalancing that gut biota aren't there.

Felice Jacka: That's right. So if you increase your plant fibre, so again it comes down to your vegetables, your legumes, your fruits, your whole grains, good-quality foods. This provides the food that the gut microbiota need and can improve the health of the gut. Certainly studies that have increased fruit and vegetable consumption in people have shown benefits to the immune system, and it's likely to be working at least in part through the gut. So really what we are saying to people is concentrate on feeding your gut bugs and you will probably receive a benefit. And it's also about what you don't eat, so not having the refined sugars and the processed foods that we think have a noxious and detrimental impact on the gut.

Lynne Malcolm: And some fermented foods as well, like kefir and those sorts of fermented foods can be helpful?

Felice Jacka: Well, we think so. We have very little evidence so far because the studies just haven't been done, although this is something that we hope to do next year in fact. But what we know is that fermented foods have been part of traditional diets for millennia, and of course people relied on fermentation when they didn't have access to refrigeration. So in every culture you will have fermented foods as part of their traditional diet. For example, in Europe it would be sauerkraut, in Asia you have kimchi and tempeh and nato and those sorts of foods. And these are a very good source of bacterial diversity. One of the things we are pretty sure of, even though it's still a very early and young field and we are lacking many human data, we are pretty sure that more bacterial diversity in the gut is a marker of gut health. So replenishing that diversity by exposure to fermented foods, and even things such as avoiding too much of the detergents and the antiseptics, for example, and of course avoiding antibiotics wherever possible unless they are strictly necessary, the sorts of things are all likely to help with the health of the gut.

Lynne Malcolm: Felice Jacka from Deakin University.

It's All in the Mind on RN, I'm Lynne Malcolm with the latest on how your diet can impact your mood and wellbeing.

In their book The Happy Kitchen: Good Mood Food, Rachel Kelly, along with dietician and co-author Alice Mackintosh came up with some golden rules for good mental health.

Rachel Kelly: Our 10 rules are basically eat mostly plants, use herbs and spices, particularly turmeric and saffron. We found good evidence around both of those for mood boosting spices. Go nuts, so eating more nuts. Again, some nice studies around how nuts can help our mental health. Eating for your gut, the second brain. Fats are my friend, so there's omega threes, the healthy fats. Getting the right balance of protein. Avoiding sweeteners and additives. Keeping an eye on blood sugar levels, to keep them steady.

Our rule number nine is vary your diet. So it turns out that the average Western diet consists of around 20 ingredients, whereas ancestral man probably ate more like 150. So we need much more variety in our diet. And finally, relax and enjoy. So these were our broad golden rules and then we looked at symptom by symptom of my symptoms. And so when I first saw Alice, my first thing really was a lack of energy. Very, very common with people with low mood and anxieties, you don't have much energy.

And what was so exciting about some of these nutritional interventions is that the effects are very quick. So when I first saw Alice, I think the first thing she said was avoid CRAP. I'm sorry about the acronym on air, but carbonated drinks, refined sugars, aspartame additives and some of the processed meats and processed foods. When I cut those out of my diet, I really began to see quite a change very quickly, like even within a few days. And certainly my energy started to increase. She helped with keeping my blood sugar steady, because that was the best way to get steady energy.

We then worked through all my symptoms, we started with energy, then we worked on to staying nice and calm, beating the blues, working on what to eat for mental clarity, hormonal peace. Sweet dreams, because I still had patches of insomnia. And then also comfort. But as I say, what was amazing was that these nutritional interventions were making a difference to my mood really very quickly. And I now run Good Mood Food workshops for some of the charities I'm involved with in the UK. And what's amazing is that some of the people I work with, they have really amazingly quick responses to some of these dietary interventions.

Lynne Malcolm: So being careful about what you eat and even following recipes requires discipline, and this is often difficult when you may be struggling with low mood. What do you suggest to people who do have that difficulty?

Rachel Kelly: Yes, it's such a good point and it was difficult for me. And I know from the people I work with that it is really hard because if you're not feeling great, you're feeling a bit flat and low mood, what do you do to cheer yourself up? You have a sugary snack.

So there's a few devices that I used and I would really recommend. So one of the things that I did was I drew up a timetable. So it wasn't just Monday to Friday, it was Monday to Sunday, because one of the patterns often is that we have a routine Monday to Friday, and we have a different routine at the weekends. And actually Alice taught me that actually our body loves routine all the time. So don't suddenly switch and eat differently or have a different timetable at the weekends.

So she helped me set up a timetable. You know, when was I planning to eat, when was I going to exercise, when was I working, when was I going to take some time out, because all these things link together. So nutrition doesn't work in isolation. Exercise feeds into a healthy digestive system. And obviously by getting my energy up, by eating better, I was exercising more, which in turn meant that I slept better. And of course when you sleep better your digestive system works better. So that was one key strategy to enforce a kind of discipline.

Another really helpful strategy that Alice recommended was to keep a food diary and just note down exactly what you are eating. And that was really helpful because I think the thing that it was most helpful for me was this business about variety. Because I didn't really realise I was just pretty much eating the same things again and again and again. Also you can note the different effects of food. So I had…as I say, I had a reasonably healthy diet, but I did have a fondness for Diet Coke, and I just began to watch what happened to my anxiety levels when I had a Diet Coke. So little devices like that were very helpful.

The third thing I'd say on psychological approaches to change is this sense that you have a choice. And I think that feeling of agency, that you have a choice to make these decisions, no one's forcing you to do this, but you can make choices. You know, the great thing with nutrition, you can make choices six or seven times a day, and you can always make a choice…you know, we always talk about…in our book we talk about healthy foods and less healthy foods, we don't demonise things, good and bad. And allied to having a choice is always to feel, you know, is it worth it? So sometimes if it's a wedding anniversary or birthday, it may be worth having that sugary or less healthy thing. But do it with mindfulness and focus and deliberation and choice. You know, you made a choice to do that. I think the difference for me was shifting from the fridge gaping and mindlessly knocking back my Diet Coke, whereas now…and I'm not always perfect, you know, I still need to focus on this, but to do things because I've decided to do them.

Lynne Malcolm: Rachel Kelly. And keep an eye out on the All in the Mind website and our Facebook page over the next few days for more information and some recipe ideas from her book.

Felice Jacka from the Food and Mood Centre explains the significance of brain plasticity to the field of nutritional psychiatry.

Felice Jacka: Well, I think that this is one of the most interesting aspects, and it's certainly why I first decided to actually investigate this. When I did my psychology degree and then I came into psychiatric research there was some really interesting work coming out of UCLA where they were looking at the impact of all sorts of food components on these particular proteins in the brain called neurotrophins. And these neurotrophins really act like manure to the brain in terms of protecting brain cells that are already there, but also promoting the growth of new brain cells in the two parts of the brain that do put on new brain cells over the life course. And one of those is the hippocampus.

And what they were showing is that many environmental exposures influence level of these neurotrophins, and then of course influence the size and function of the hippocampus. So exercise is one. Exercise has a wonderful beneficial impact on these neurotrophins, making more of them. But of course healthy dietary components, they've tested things such as berries and foods that have high levels of polyphenols, omega three fatty acids, healthful components of food seem to have a beneficial impact on these brain proteins, whereas high fat or high sugar type dietary factors have a negative impact, driving down the production of these neurotrophins and then having an impact on hippocampal function.

So this really, along with the emerging knowledge around the importance of the immune system in mental and brain health, pointed to diet as being a key factor that we should be investigating. But it's only been in the last two or three years that we've had the new information about the gut microbiome and how central that is to both immune function and the neurotrophins and the hippocampus in the brain, and glucose regulation and a whole range of other biological processes that would influence mental and brain health.

Lynne Malcolm: So how soon in the future do you see that we will be using diet and perhaps probiotics as a way of effectively treating depression and other mental health conditions?

Felice Jacka: Well, as far as diet goes and dietary improvement, I don't think you can go wrong. Even though at this point we only have one randomised control trial, which is tested, dietary improvement as a treatment strategy for major depressive disorder, obviously any studies need to be replicated, and our study wasn't anywhere near as large as we would have liked. So there is much work to be done, but in the meantime I would say that you are not going to lose by recommending that patients, for example, who come in with depression or related disorders address their diet quality. And this is because we know that depression is highly co-morbid. That means it's very often goes along with diabetes, increased risk for heart disease, obesity, all of these physical factors are very common in those with depression. So addressing diet would have a benefit to all of those things as well.

So what we would say is that from the point of view of all the evidence we have so far from the observational literature, from the animal studies and now from the emerging clinical studies, the precautionary principle would suggest that you are certainly not going to lose and very likely will experience benefit from taking a dietary approach to treatment. And this is not an either/or equation. So we are certainly not advocating that people, for example, adopt a particular diet instead of having anti-depressant treatment or psychotherapy already if there are other treatments.

And similarly we're certainly not saying that an unhealthy diet in and of itself could give somebody depression. There are many things and many factors that influence the risk for common mental disorders. The main one is genetics. All the other things such as early life stress and life stress and poverty, all of these factors all confer a small risk. And we think that the quality of people's diets is another one of these risk levers, if you like, that may be of relevance in the face of other stressors.

So we think that there is a real benefit in suggesting that patients who are suffering from depression in particular might see a dietician or another form of support to help improve their diet, but it doesn't necessarily need to be instead of any other sort of treatment.

Lynne Malcolm: Professor Felice Jacka from the Food and Mood Centre, led by Deakin University.

Check out the All in the Mind website for more details from the show today.

Production by Diane Dean and sound engineer Judy Rapley.

Subscribe to the All in the Mind podcast too, if you haven't done it already, and rate and review us as well, it's a good way to spread the word.

I'm Lynne Malcolm, thanks for joining me.

Rachel Kelly: For those people who do not respond to medication, some of these other holistic approaches and using nutrition is just so exciting. This is going to be a huge area of growth in mental health in the next decade.

Felice Jacka: We need to make healthy food choices, the easiest, the most accessible, the most socially acceptable and certainly the cheapest option. And that's our challenge now.


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