Dr Rupy: Welcome to the Doctor's Kitchen podcast. The show about food, lifestyle, medicine and how to improve your health today. I'm Dr Rupy, your host. I'm a medical doctor, I study nutrition and I'm a firm believer in the power of food and lifestyle as medicine. Join me and my expert guests where we discuss the multiple determinants of what allows you to lead your best life.
Dr Rupy: Hey, it's Dr Rupy. I'm going to be doing another solo episode today talking about everything to do with mental health and wellbeing. This is really inspired by the sources information from the app. We've done extensive research looking at the dietary patterns and ingredients that align with mental wellbeing and we've instilled that in all the recipes that you can choose and filter through on the app using the mental health filter. Now, if you don't have the app or you're an Android for whatever reason, this doesn't mean that you don't have access to it, it just the app makes it easier. But I want to give you the, I want to be completely transparent about how we've come up with our health goal filters, the process of research and also transparent about how limited nutritional medicine can be despite the plethora of studies and information that we have out there. It's not an exact science and it won't be until we invest heavily in not only more research but a different type of research that's a lot more personalised and appreciative of how complicated these issues are. Not just to do with research but with the fact that mental health is just such a multifactorial issue as well.
Dr Rupy: Now, many of us saw our understanding of mental health evolve over the past couple of years, what with the pandemic and I think it's become a lot more acceptable than it was previously to talk about things like depression and anxiety. We've got a long way to go because within mental health, it's a very complicated umbrella term that includes everything from personality disorder, schizophrenia, bipolar. There are a lot of severe issues out there that I've been privy to working in medicine for over 10 years and speaking to my colleagues who are psychiatrists. But certainly, I think a lot more of us have been accepting of the term and have really been encouraged to look at our own mental wellbeing, which I think is always going to be a good thing. Whether that looks like making time for mindfulness, exercise, going out in nature, regular social catch-ups or even artistic activities, I think a lot more of us are putting in time for this.
Dr Rupy: One thing is is certain, we're all becoming more aware of the importance of caring for our mental health and mental health gyms as well as physical health and dietary health and all the other aspects of lifestyle medicine. And the emerging focus on mental health I think has given us a chance to experiment and change the way we think about and support mental health. So beyond the lockdowns, we can fully integrate mental health care into our daily lives and I think as one of the things I hasten to say the word post-pandemic, even though we're not really post-pandemic, but certainly in the aftermath of the more extreme lockdowns, we're more likely to instigate a lot of these practices into our daily lives as we return to quote unquote normal. And perhaps we can instill these habits in the same way we would instill our brushing our teeth. It's investing the same amount of time in mental health is should be the norm.
Dr Rupy: But before adding new habits to our days, whether that be a meditation practice or going for a walk or taking time to remove our screens or being a lot more intentional about our use of our digital devices, which is something that I'm always trying to hammer home to people that we have to curate your digital environment as much as your physical environment, considering how much more time we're spending on our devices. Why don't we look at something that we already do every day multiple times and that is eat. So in this episode, we're going to look at how food specifically influences our mental wellbeing and how we can use food to protect our brain, improve our mood and promote mental being, mental wellbeing in the long and short term. And the idea of this pod is to open up the discussion about nutritional research and better understanding of our biology. It's not, it's in no way meant to present the idea that you can fully modulate one's mental wellbeing using diet.
Dr Rupy: Anyone who's been an avid listener of mine for the last couple of years or has come across any of the content in the in the books and on social media will know that it's a blended approach that I'm a fan of rather than just looking at food as the only treatment. But certainly, a better understanding of how food interacts with our physiology and in particular has an impact on our mental wellbeing, I think is is a prerequisite for everyone. We should all really know about this stuff.
Dr Rupy: Before we get to the behind the scenes of our bodies and provide practical tips to start testing out what each of us can can use as unique individuals, I want to call out the podcast recipe of the week. You can find it on the app or the newsletter and we're going to share these on the website as well, the doctorskitchen.com. And I want to call out pit style beans and greens. I love this recipe. It's spicy, sweet, delicious, super easy to make, all in one pan. And if you have the app, you can see the step-by-step images as well. We've aligned this with multiple health goals actually because of its nutrient value. It's got kale in, it's got beans, it's got tomatoes, it's got three if not, actually it's got four portions of vegetables in. And if you've heard any of the talks that I've done recently, you'll realise that the main thing we need to really think about is a plant-forward approach that's encompassing of all the other nutrients that we need in our diet. So definitely go check that out if you've got the app, just look up pit style beans and greens and this is sort of setting the foundation of what I really want to see happen, which is essentially the ability to eat well every day easily and hopefully any user of the app will realise how easy it is to make the recipes and also build a week of healthy eating for yourself. So definitely go check that out. All right, but first, let's set the foundations. What do we mean by mental health?
Dr Rupy: Like I've already mentioned today, I think a lot of people think about mental health problems. They think about depression, anxiety, schizophrenia, some of these are more common than others. It's estimated that one in six people in the past week experienced a common mental health problem. That was from an adult psychiatric morbidity survey. So at least one in the six people that you made eye contact with on the tube this morning or at work have had a mental health problem in the last week. But what is what's important to remember I think is that mental health is not just the absence of illness, rather it is a state of emotional, psychological and social wellbeing that affects how we think, feel and act. So it's how we think, feel and act. And if you think about that, very similar to how I had conversations with other psychiatrists on the podcast, we're all having some perturbations of our mental wellbeing on a week by week basis. And we can further categorise those into subclinical and clinical. Subclinical being we experience it but it doesn't mean that we don't get out of bed in the morning and clinical which is where it's having a drastic impact on our day-to-day life.
Dr Rupy: And that's not to say certainly one is worse than the other, but there isn't to say that we shouldn't ignore the subclinical stuff. We should really be looking at the subclinical signs as warning signs and trying to prevent it before it manifests into a clinical manifestation of a mental health illness. So caring for our mental health is not just about reducing the symptoms. It's not just about removing any sadness, stress or negative emotions because also the way we approach those stresses, those normal stresses of daily living can also be quite healthy as part of a very natural way of dealing with emotions. And I think again, the perspective that we take with regard to mental health is is very important as well. Looking at certain stresses as positive. When you get setbacks in your in your day-to-day life, you can approach those from the mindset of growth or the mindset of yet another thing that is bringing me down.
Dr Rupy: I guess what I'm trying to articulate is that what we're thriving for is a balanced mind that helps us make healthy choices, relate to others in a more positive manner and better cope with the normality of daily stresses. And good mental health is essential for not only our mood but cognitive function, our ability to think more clearly, learn, make decisions, but also that will encourage and have a knock-on effect on our ability to maintain physical health, lower the risk of other illnesses that also compound issues with mental wellbeing, cardiovascular disease, diabetes, metabolic issues. And our mental state influences our whole body and how we interact with the world around us as well. So it's a really, really important concept to to get right.
Dr Rupy: Our mind needs to be cared for every day in the same way our physical nourishment is, our exercise and everything else. And actually, they're all are very, very much intertwined as well. So hopefully by the end of this podcast, you'll have a grander appreciation for exactly why on a biological level and a physical level and how that all manifests as as better wellbeing.
Dr Rupy: So think of this episode like we're a bunch of detectives and we're going to look at clues and evidence to explore whether and how diet can impact mental wellbeing. Most of us here listening to this are probably already big believers in the power of food to promote health, but I think it's worth going back to the evidence base that explores these benefits so you can better understand and perhaps even articulate to your loved ones why food is so important. I think the science is is complex. The solutions are relatively simple but the implementation is hard. And I think when you have a better education and understanding around the science, that can help with the implementation, further motivate you to stick to a a healthier lifestyle.
Dr Rupy: So we're going to examine the suggested mechanisms and pathways linking diet to mental health. We're going to call out certain dietary patterns as well and looking at the associations between people who align with certain a certain way of eating and living and their risk of of mental health conditions. And then we'll also going to look at specific ingredients and nutrients as well and see what their relationship is to to better mental wellbeing too.
Dr Rupy: So let's start off there. Let's examine some suggested mechanisms and pathways linking diet and mental health. And I think the first step in our investigation is to look at the different routes to see whether the link is plausible biologically. And I think like I said, I think understanding our biology is essential to learn to pick up on not just the understanding of it and the ability to motivate oneself, but also to pick on pick up on your own body's signals and cues and become more intuitive about how your body is communicating to you on a daily basis and learning to speak its language to support it as best as as possible so you can have a better experience and and ensure that you're looking after your mental wellbeing and you're you're responding to those cues. And it's your choice as to whether you you respond to them or not. Sometimes we have to override certain elements to ensure that we're a working member of society, for example. You know, I don't always feel absolutely positive and always have a zest for life, but I do things because it's part of my routine and also because I have a duty to as well. But I think certainly being a lot more intuitive about how you're feeling in the moment is always going to help.
Dr Rupy: Most of the data come from observations in animal studies. And I think it's a really important first step in making sense of what we see in human studies, plus these pathways are super cool and they can help motivate all of us. So how could what we eat impact our minds?
Dr Rupy: The immune route. So the immune system is a pathway we've discussed many times on the podcast, but let's go through it in the context of the brain and mental health. So what we can eat influences the activation of our immune system. It can reduce inflammation, it can cause hyperactivation of the immune system. Processed foods as an example, low in fibre and nutrients and high in potentially trans fats, certainly sugar and salt can alter the community of our microorganisms, collectively known as the gut microbiota. And this can cause excessive secretion of things like pro-inflammatory chemical messages that puts the kilter, puts the balance of inflammatory versus pro-inflammatory messages out, so it's more pro-inflammatory. I've always, I always try and contextualise the the concept of inflammation because I think most people see inflammation as a bad thing, but that's not necessarily true. You do need certain elements of inflammation for a well-functioning body. It's how we respond to pathogens, it's how we signal, it's how your immune system essentially does its job by creating inflammation. It's a very necessary mechanism, but the imbalance of inflammation such that it is pro is a common root cause of a number of different issues, including potentially mental health issues as well.
Dr Rupy: So anything that can reduce the richness and diversity of your gut microbiota, i.e. a low fibre diet as an example, can promote more activation of the immune system and produce these pro-inflammatory chemicals. And mainly because of the decrease in the important molecules such as short chain fatty acids that have multiple roles. So acetate, butyrate, propionate, they all have an impact on nourishing your gut cells, ensuring that the gut barrier is is nice and and tight. These have a role in creating neurotransmitters, ensuring that your gut colonocytes are nourished effectively. And anything that puts your your gut environment out of balance in and even in combination with other things like stress, physical inactivity, smoking, these can all cause our immune system to be overly activated. And there's an ongoing increase in pro-inflammatory chemical messages that can last for an extended period of time. And over time, this can lead to chronic inflammation, which can affect the brain.
Dr Rupy: This chronic inflammation can impact the activity of chemical messengers and hormones in the brain and that causes changes in emotions and behaviour. And like I said, this has been shown in animal studies, but we can also see this in human trials as well. This culmination of excess inflammation can manifest in many ways physically, but also psychologically, low mood, fatigue, anxiety, sleep disturbances that can further exacerbate all the other things I just mentioned, cognitive dysfunction again, multifactorial. So chronic inflammation is something that could play a role in mental disorders. And ensuring that we feed our gut microbiota, a variety of nutrient rich whole foods, fruits, vegetables, nuts, seeds, oily fish, beans, lentils, we can promote that healthy environment such that your immune system is not overly activating, you don't have excess inflammation. That's essentially a very high level explanation of what's going on with your immune system and how that relates to your mental wellbeing.
Dr Rupy: We talk a lot about improving our overall eating pattern, that's an important strategy, but there are some also some specific foods and nutrients that we're going to talk about in relation to this episode and how that reduces chronic inflammation as well. So that's the immune system. Another route that you're going to be familiar with if you're an avid listener of the podcast is reducing oxidative stress. Now we've talked about oxidative stress many times in the podcast. As a refresher, it's basically what happens when our cells and tissues produce more reactive oxygen species than natural antioxidants. So your reactive oxygen species accumulate and overwhelm the body's natural ability to detoxify, which can damage cells as well. Again, very much related to inflammation.
Dr Rupy: In the case of mental health, because oxidative stress is implicated in several mental health problems including depression and schizophrenia, it would be pertinent to make sure that it's not overly stressed, i.e. we're not having that imbalance of oxidative stress versus natural antioxidants. It's seen in studies where patients with mental health disorders showed high levels of oxidative stress markers and lower levels of antioxidants such as vitamin E and vitamin C when compared with healthy controls. And we know that there is an abundance of antioxidant compounds in foods such as fruits and vegetables. It's not the only way in which fruits and vegetables confer their benefits to the human host. It's a very popular, very well sort of recognised feature of fruits and vegetables that most of the public can recite, but it's definitely not the overly the overarching way.
Dr Rupy: And it's my belief that not only plant chemicals and the direct effects of antioxidants are responsible for the health benefits, but it's also the indirect mechanisms by which are likely to be via the microbiota, so via ensuring a a healthy environment for microbes to flourish and do their important jobs. As well as having this indirect effect via the microbiota, it's also been suggested in studies that things like polyphenols, plant chemicals that you find in a variety of different colourful vegetables, increase the response of our own antioxidant defense systems. So the way they do this is by modulating pathways with funny names like Nrf2, NF-kappa B, there's a number of different pathways, but essentially what happens is those chemicals in fruits and vegetables are mild stressors that encourage our cells to activate certain pathways that reduce oxidative stress.
Dr Rupy: It's basically something called plant hormesis. It's something that turmeric does, quercetin does, resveratrol does, you find those in various compounds. You find, well, obviously turmeric, you find it in turmeric, but quercetin you find in onions and apple, resveratrol you find it in grapes, nuts, certain other types of berries as well. And there's an interesting mechanism whereby the overall the overarching effect and the overall effect is anti-inflammatory and reducing oxidative stress, but the short term is actually a mild noxious stressor. So it's a it's a really interesting paradoxical way of looking at fruits and vegetables.
Dr Rupy: So very much like inflammation, you can see it as a balance. There's a seesaw swinging from side to side. For health, we need relatively, we need enough reactive oxygen species because that's essential for normal biological processes, but not too much such that it causes damages, damage to our cells and and and tissues.
Dr Rupy: Okay, another interesting link, the third way is via the HPA axis involved in stress response. And just because I'm going through this in order one, two, three, doesn't signify any importance. It's it's multifactorial. Now, this link via the hormonal system that controls the body's stress response, something that we refer to as the HPA axis is because it involves three components, part of the brain called the hypothalamus and the two glands, the pituitary and the adrenal glands. And one of the main roles of this axis is to regulate the production of the hormone cortisol, often called the stress hormone. And again, you're going to get a very common theme throughout this podcast, which is all about balance.
Dr Rupy: In the same way we need inflammation and oxidative stress to be kept in balance, so does the HPA axis. When it comes when it becomes overly activated for long periods of time, it can impact our mental health and increase the risk of mental health disorders. But you certainly need cortisol, a normal diurnal variation, so one that goes up and down throughout the the time of day is something that is super important. And so it's again, it's not about reducing all all manner of cortisol, it's making sure it's in appropriate amounts. What's interesting is that eating more nutrients found in whole foods such as things with polyphenols in, vitamin C, omega-3 fatty acids from small fish has been shown to improve cortisol levels in healthy adults and people with depression.
Dr Rupy: So to recap, we've gone through how studies have shown food nutrients can improve mental health by reducing inflammation, oxidative stress, cortisol levels. These are pretty general mechanisms that apply to the brain as well as the whole body. But are there more specific brain routes? And there are. It turns out there are ways in which we can influence the formation of new neurons and brain plasticity. So the formation of new neurons in the brain is something called neurogenesis. It's an important process for learning, memory, mood regulation. The generation of new neurons is a relatively new concept. It's something that can be a bit of a misnomer as well because creating new neurons, once they're gone, they're gone.
Dr Rupy: But creating new connections and which is essentially the foundation behind how we learn, that's something that can be altered and that can have a role in mental health problems as well, improving the processes of learning, memory, mood regulation. Research has suggested that food nutrients such as omega-3 fatty acids, polyphenols and vitamin E can stimulate this process. The question is how? How can what we eat influence the formation of these new neurons in the brain? It sounds very impressive. Well, the process of neurogenesis is controlled by molecules in the brain such as brain-derived neurotrophic factor, so BDNF. We've come across a lot of these different abbreviations before, neurotrophins, these are other chemicals that are molecules in the brain. And although the evidence behind these is still limited, research suggests that diet can influence the levels of these molecules, especially BDNF. For example, there was a study where researchers assigned people with schizophrenia to increase their consumption of fruit and vegetables to and to reduce saturated fat and sugar intake. And after four weeks, they found increased levels of serum BDNF compared to controls. We're going to go into a bit more detail about specific nutrients later, but again, I think it's another interesting route that may link what we eat to our mental state as well.
Dr Rupy: I want to talk about the fifth thing, mitochondrial dysfunction. So this last element that I want because we could spend all day talking about all these different hypotheses and stuff, but this last pathway that connects diet and mental health, although there there are probably many more, is linked to core symptoms of fatigue and cognitive complaints related to attention, memory, complex decision making, reasoning, judgment. This pathway involves tiny compartments present in almost every cell of the body called mitochondria. It's a very, very important organelle. And these generate most of the chemical energy needed to power the cells by chemical reactions and store energy into ATP. They're basically our cells power plant. And this power plant is thought to be dysfunctional in many mental health problems, other issues as well, not just mental health problems, causing symptoms such as fatigue and cognitive issues related to attention and memory. And this is because mitochondria in brain cells are not producing enough energy and it can cause issues with essential brain functions that we discussed earlier.
Dr Rupy: And this can also have a negative impact on the brain's ability to be plastic. So the plasticity of your brain is essentially measured by the ability of it to form new neural connections. What's really interesting is that considerable preclinical evidence suggests that an influence of the diet has an impact on the function of your mitochondria. There are some animal studies that found that phytonutrients such as quercetin and resveratrol could upregulate the production of new mitochondria. This is something called mitochondrial biogenesis.
Dr Rupy: Come to think of it, we should probably do an episode on mitochondria because it's such an important organelle. Its origins are actually foreign to human DNA. It's like a bacteria. It yeah, it's a fascinating subject actually and mitochondrial dysfunction has a role in a number of conditions, including long COVID, fibromyalgia, it's it's a very important subject. So we'll definitely do a deep dive. But just for the context of this podcast on mental health and diet, just so you can contextualise everything that we're going to talk about with regard to dietary patterns and lifestyle, those clues that we have on how diet and mental health can be linked are inflammation, oxidative stress, HPA axis, the formation of new neurons and the function of your mitochondria, which all of which are linked. You know, the microbiota is linked, the mitochondria is linked to the inflammation response. It's it's all very very interlinked. But those are the general things that you need to keep in mind.
Dr Rupy: Okay, so let's re-anchor ourselves. We've looked at evidence to support the link between diet and mental health and looked at the suggested mechanisms underlying this link. When we research the question around food, we can look at two different types of studies. So there are observational studies which look at whether or not there is an association between an activity and an outcome or interventions or experimental studies where we're actually delivering a specific type of intervention, be that a dietary pattern or a supplement, and then looking to see what happens using predefined markers of success or failure. So we can examine eating patterns, whole foods and specific nutrients.
Dr Rupy: Let's look at eating patterns. So many studies look at the Mediterranean diet and the anti-inflammatory diets in the context of mental health. We talk about eating patterns a lot, especially the Mediterranean diet. Now, I know it can sometimes seem vague and repetitive, but the reason why there's so much emphasis on it is because A, there are lots of studies using the Mediterranean diet as a as a firm intervention. And and B, it gives us some general good food categories that we can choose from. So it doesn't necessarily restrict us so much in terms of the the flavour of food or the cuisine of food. It's rather principles rather than a certain flavour of food. And it means it can be adapted to to many different people's heritage, which makes it a lot more accessible. I know that seems like a bit of a misnomer because it's Mediterranean, so you imagine it would only be Mediterranean flavoured, but no, it's it's more about the categories of food that you can pick and choose from.
Dr Rupy: These eating patterns provide principles for us to consistently come back to when we are shopping for food or cooking or arranging a meal. And at the core, we've got two main principles of the Mediterranean diet. We've talked about the Mediterranean diet before in previous episodes. So just looking at it from a top-down perspective, it's whole foods that are rich in a variety of nutrients. So think foods that are closest to their natural form, minimally processed and have minimal ingredients on their lists. And they're also high quality sources of protein such as legumes, nuts and fish. It's largely plant-based, although not plant exclusive.
Dr Rupy: There are lots of studies looking at the effects of the Mediterranean diet on mental health, specifically looking at the risk of symptoms of depression. There's little data on other mental health problems and promoting better mental health in people without diagnosed conditions, which is sort of one of the limitations. But for the Mediterranean diet, there were two systematic reviews and meta-analyses published in molecular psychiatry and the annals of neurology. They both found an association between high adherence to the Mediterranean diet and reduced risk of depression. So participants who had the closest diet to what we would regard as a Mediterranean diet, and we use a Mediterranean diet score typically in these studies, that's the inclusion of legumes, fish, largely vegetables, etc. Those people were less likely to become clinically depressed. Now, with all of these studies, as we've discussed before, the limitations of observational research is, well, it's there's a lot, there's a lot of limitations with observational research because it's very hard to separate out the healthy user effect. So if someone's going to have a diet that is closer to the Mediterranean diet, what other activities are they doing that are associated with someone who typically has that diet? Have they got better access to health care? Are they educated? Do they read up more about mental health material so they're able to utilize other lifestyle measures that might protect them or lead them to better manage a diagnosed mental health condition. There's so many other variables that's quite hard to capture in this research.
Dr Rupy: In addition, we don't really know how applicable these findings are to a wider population outside of the study participants. There are many methodological considerations that can affect the results and limit our interpretation of them. Two to keep in mind are A, how is depression assessed? In a lot of times you have different scoring systems for measuring depression, and also how diet was assessed for each participant in these studies. They included different methods to assess depression in these meta-analyses. And just as a refresher, systematic reviews and meta-analyses, they're studies where they pull lots of different research into one to try and draw stronger conclusions from. And whilst they are at the higher tier of evidence, they are limited by what you actually put into the meta-analysis. And I've seen papers where they've done a meta-analysis on less than five studies and you know, how much you can draw from that is is marginal.
Dr Rupy: As we've also discussed before in another podcast episode, a common limitation is a self-reported method for the diet questionnaire. It's something like a food frequency questionnaire. And if anyone has tried this with someone else or you know, been asked to report their diet, typically, as a general rule of thumb, people underestimate things like energy consumption, they underestimate how many snacks they have. So it might not be an accurate representation.
Dr Rupy: Having said that, there was a specific intervention study published in 2019 that is quite interesting because it looks at self-reported mental health issues rather than clinically diagnosed issues. And what they did is they randomly allocated 95 adults with self-reported depression to A, a Mediterranean diet group where they received cooking workshops and teaching Mediterranean style recipes, food hampers providing all the ingredients and omega-3 supplementation as well, or a control group attending only social group activities to control for the social interaction element of it. What they found was that participants in the in the Mediterranean diet intervention group showed improved adherence to the Mediterranean diet, obviously, improved their anxiety, depression and stress scores compared to the control group. The increased omega-3 intake didn't appear to have an effect on depressive symptoms. That suggests a greater influence of overall diet quality rather than single nutrient supplementation, which I inherently believe, but I think we need to see more studies that demonstrate that to be honest.
Dr Rupy: The authors also suggest that the importance of promoting cooking skills and seeing the Mediterranean diet as more of a lifestyle is something that needs attention as well. There is obviously the social element that they were trying to control for, but the actual practice of cooking, I think is a mindfulness routine that probably has some further benefits than just having a natter with a with a new group of friends. So, yeah, I think there's there's something something else going on there too.
Dr Rupy: Another way to improve our overall diet is actually looking at the anti-inflammatory diet score. So there is some research looking at the anti-inflammatory diet, the the the inflammatory potential of one's diet and the impact on a person's mental health. When we say the inflammatory potential of a diet, it's really whether a diet or food increases or decreases inflammatory chemical messengers. And the common method used to measure inflammatory potential is something called the dietary inflammatory index. It's based on a world standard reference values for 45 food parameters that were derived from reviewing and scoring over 2,000 articles on diet and inflammatory markers and 11 food consumption data sets from different countries. So pretty extensive.
Dr Rupy: And the dietary inflammatory index, something that we use within our simple but smart algorithm on the app, scores the inflammatory potential of food components and they they range from strongly pro-inflammatory indicated by positive values to strongly anti-inflammatory indicated by negative values. It's something that we're actually working on displaying on our recipes because at the moment everything is sort of hidden in the back end, but we have to work out a way to figure out a nice design on the app so we can actually show you without showing all these random gobbledegook numbers. And the last thing I want people to think about is, yes, even though something might be slightly pro-inflammatory using this isolated index, it doesn't necessarily mean that the entire recipe is bad for you. And I think we have to be quite mindful of that as well. You can't look at food through the lens of one particular element, whether that be glycemic load, whether it be the inclusion or exclusion of animal products, whether that be the fibre content, the saturated fat content, etc, etc. You have to look at food a lot more holistically. And I just worry sometimes if we we add certain elements to it, then it could detract from that. Plant points I think is a is an obvious one that most people hopefully appreciate that a Doctor's Kitchen recipe always has three or more plant points, probably more actually, it's more like eight to 10, but yeah.
Dr Rupy: There was a meta-analysis conducted in 2019 that combined and analysed studies looking at the link between the inflammatory potential of a diet and depression, including over 100 studies with over 100,000 participants aged between 16 and 74 years old. And what happened in these studies is that the researchers took a group of people and measured the inflammatory potential of their diet, usually by having each participant complete one of those famous food frequency questionnaires. And from there they calculated their individual dietary inflammatory index score. The other parameter measured for each participant was either a diagnosis of depression or depressive symptoms using a questionnaire or validated scale. So for each participant, you've got data on the inflammatory potential of their diet and their diagnosis of depression or depressive symptoms.
Dr Rupy: And these studies had five to 13 years follow-up, which means that after a number of years, the participants were asked to fill out the questionnaire again. Lo and behold, after combining all the results from all these studies, they found that the participants on the most pro-inflammatory diet had a 1.4 increased risk of being diagnosed with depression or presenting with depressive symptoms compared to those on an anti-inflammatory diet, which means adherence to a healthy diet with lower inflammatory potential could reduce the risk of developing depression or presenting with depressive symptoms. Now, I emphasize could because again, this is looking at a number of studies that have their own limitations and there's only so much that you can control for, one of which I've already mentioned, the lower the inflammatory score of your diet, what are the other co-founding issues, confounding issues that could create erroneous results. So is someone with a lower inflammatory diet score also going to be exercising more and how much is it the exercise versus the diet? It's very, very hard to pull out those two different things. But from what we know about those plausible biological mechanisms and what we know about an anti-inflammatory diet, it's a pretty pragmatic thing to think about with regards to mental health.
Dr Rupy: This particular paper which we will reference in the notes, also suggests how inflammatory diet can influence the function and plasticity of the brain that we talked about earlier with brain molecules like BDNF as well. And studies in mice have shown that nutrients from an anti-inflammatory diet could increase the expression of genes that have positive effects on neuronal function and plasticity. So when we say the expression of genes, what we're talking about is epigenetics. So not changing the sequence of genes or anything like that using CRISPR technology, which is not something that anyone really has access to. It's more the turning on and turning off of certain genes. So using methyl donors, there are four ways in which I believe you can change the expression of your genes. Methylation is the the the popular one. But this mechanism needs to be confirmed in in in humans. But there is a there is a promising link between an anti-inflammatory diet and mental state. That's that's definitely something that we can conclude needs further investigation.
Dr Rupy: You're probably asking yourself, okay, what are the anti-inflammatory ingredients I should be including? Well, if you look at the dietary inflammatory index, you'll see nutrients like fibre, beta carotene, magnesium, omega-3 fatty acids. These are all highly anti-inflammatory. So foods that that include those types of nutrients are leafy green vegetables, spinach, kale, oily fatty fish, salmon, mackerel, tree nuts, like almonds, walnuts. We'll have a podcast quick card that will be coming up on the newsletter at some point in the next couple of weeks that the research team are helping us out with, where we're going to present all this information so you can save or download. There's also as part of the doctorskitchen.com newsletter, every week we always have an attachment at the bottom which is all about inflammation and the different types of foods. It's basically the same principles that I always talk about, colourful foods, nuts and seeds, cold pressed oils, as well as judicious amounts of oily fish as well as an anti-inflammatory lifestyle. And you'll find you'll find lots of information in that PDF that is for free at the bottom of the newsletter every single week.
Dr Rupy: On the other side of the scale, you're going to find foods that have high pro-inflammatory scores. And these are things like trans fats, fats found in processed meats, for example, pastries, creams, cheese. You know, these are things that yes, will readdress the balance in the other way, but it doesn't mean that if you're going to eat a pastry, your body's going to catch on fire. It doesn't doesn't work like that. So it's it's a bit overwhelming when you see these lists of foods and nutrients and actually hard to translate into meals. And that's why we created the app because when we're developing the recipes, we're adapting it to the that dietary inflammatory index with added scores to each of our recipes in the back end to make it as anti-inflammatory as possible and to ensure that it's along it's aligning with the guidelines so you can eat according to those different health goals that we have. And you don't necessarily have to have health goals. Even the general wellbeing category has all of these things in mind as well.
Dr Rupy: Just to give you a little insight into what we've got in the anti-inflammatory health goal, I'm just going through it now. There's freekeh and hazelnut salad. There's a jalfrezi, there's the lemon and garlic white bean salad, masala kashu colour. You'll find loads. You'll find loads in there. And you know, we've spent so much time creating the images to make it easy so you can cook well every day. But anyway, there's a show you'll find all the recipes there. And there's loads on the website as well if you're waiting for the Android version. I'm sorry, I keep on getting messages about that.
Dr Rupy: So the idea is to focus on eating patterns rather than individual nutrients. And it's important in research because it's really the effects of the overall diet that have much more of an effect than assuming single foods or nutrients will have the same magnitude. And looking at these studies that focus on eating patterns captures the interactions between nutrients and foods. So the synergism between those foods as well, which we all know can play a really important role in the benefits of what we eat to nurture our health. It's very hard to study because there's so many nutrient interactions and it's not as if we're we're having each nutrient in isolation. So there's there's definitely a an interaction going on there. And then when you combine that with the magnitude of differences between one's microbiota and one's genetic predispositions, it becomes even even harder to to make very, very specific suggestions.
Dr Rupy: All that being said, we can stick to some general principles and hopefully the recipes that I put out there will help you stay on the the straight and narrow and and certainly have been demonstrated in research studies to have a beneficial effect on preventing the risk of mental health and even being part of treatment alongside all the other treatment tools that we have too.
Dr Rupy: If we just turn our attention to specific whole foods and nutrients, I think it is interesting to to learn a bit more about because it gives us a bit more context as to why a certain eating pattern can have beneficial effects on a wide range of issues. So fruits and vegetables, you know, containing lots of vitamins, minerals, plant compounds, lots of protective effects against mental health problems, potentially because of vitamin C, vitamin E, carotenoids, compounds that we get from carrots, spinach, oranges, plantains and many more. Again, it might be because of antioxidants, might not be, might not be as grand as we we used to think in terms of oxidative stress. It's certainly something that plants have been demonstrated to be able to mitigate against and as we already discussed, high oxidative stress levels can contribute to mental health problems.
Dr Rupy: There are other ways in which fruits and vegetables may help protect our brain and mental health. Another study published in 2018 in the British Journal of Nutrition looked at fruit and vegetable consumption and the risk of depression. But what was interesting about this is that again, same limitations of using a food frequency questionnaire, etc, etc. And the questionnaire they used is the Center for Epidemiological Studies Depression scale that you can find online if you're curious about it. After the analysis, the results showed that participants with the highest intake of fruit and or vegetables had a lower risk of depression compared to participants with a lower fruit vegetable intake as well. But what's interesting is that every 100 gram increase in fruit or vegetable intake was associated with a 3 to 5% reduction in the risk of depression. So what we find and this is where you have a dose effect, it it it provides a bit more evidence as to there being a causative element to to the findings.
Dr Rupy: They discussed a bunch of reasons as to why this might be the case, but the authors talk about potential biological mechanisms being related to things like folate and other B vitamins on the activity of brain chemical messages. For example, increasing your levels of vitamin B6 can regulate the production of brain chemical messages like serotonin, which is involved in mood elevation. And that's found in things like dark green leafy vegetables, bananas, oranges, papaya, cantaloupe. So fruits and vegetables may have protective effects not just because of the antioxidant and the anti-inflammatory potential, but also from those specific nutrients that they contain as well.
Dr Rupy: So we know fruits and vegetables, we've got to get those in. Fish, fish consumption, especially oily fish like sardines, mackerel and salmon, they're all also linked to better mental health. And this most people believe is due to the high content of long chain fatty acid, omega-3 fatty acids, so EPA and DHA. You can still benefit from this molecule by having plant-based sources of them. So traditionally we used to think that nuts, especially walnuts and flax seeds and pumpkin, they all also have omega-3, but they're the short chain, so they need to be converted into the long chain. And the conversion varies from person to person. So some people, particularly if you're from Asian background, have a particular snip, a particular gene that accelerates the conversion from short chain to long chain fatty acids. It's something called the FADS2 gene. And that may be beneficial and that that might protect you against deficiency if you're on a purely plant-based diet.
Dr Rupy: However, the conversion is still fairly low, so I think it's actually pertinent to think about omega-3 fatty acid supplementation regardless. I mean, I take omega-3 fatty acids myself despite having oily fish in my diet every every week, because I think it's quite hard to get the amount that you need. There is some debate about omega-3 in its entirety actually. There are some academics that believe that the research just certainly isn't strong enough from the perspective of cardio protective effects, from anti-dementia effects. On the whole, I think it's largely innocuous in terms of the risk. So if you can afford it, you might as well.
Dr Rupy: I would just be careful about the source of omega-3 fatty acids that you get because as a recent newspaper article found, but it's pretty well known actually, a lot of the companies that sell omega-3 don't really store it properly, so the oils can become rancid. So I'd always go for a reputable company and I know that there is an American company called Labdoor that will independently test all different types of supplements. So you can look to see the purity of your ingredients and it's something that we discussed with the co-founder of examine.com, which is a website that I use for looking at studies on supplements. It's it's pretty robust and they are they're really trustworthy. They don't take any dollars or pounds from supplement companies. So I think they're pretty robust.
Dr Rupy: Back to omega-3 and the anti-inflammatory and antioxidant properties, eating enough could potentially reduce inflammation and oxidative stress that can have a knock-on effect on protecting brain cells and help prevent mental health problems. The omega-3 fatty acids themselves could also influence the activity of potential of of important brain chemical messengers such as serotonin and dopamine. There was also a systematic review and meta-analysis that was published in 2018 in Asia Pacific Psychiatry where they combined results from 10 prospective cohort studies. They had a total of over 100,000 participants and what they found was similar to the study on fruit and vegetables. So people with the highest fish consumption were less likely to develop depression compared to those with the lowest fish consumption.
Dr Rupy: Now, to recap, you know, protective effect of fish is thought to be omega-3 fatty acids. It might be a step too far to completely intertwine the two because what you also get in fish are adequate amounts of protein, for example. You you'll get different types of choline, you'll have lots of different elements in fish is not just protein and omega-3 mixed up together. There are a whole bunch of other attributes that could be protective, they could also be damaging as well. So it it it there's only so much you can you can take away from these studies. But the one thing that I've come to the conclusion of after looking at a lot of studies on omega-3 is an omega-3 supplement is probably going to be a good thing.
Dr Rupy: Moving on from omega-3, there are other nutrients that have garnered some attention, magnesium, zinc and iron. These are thought to help protect mental health. I should state, I'm not suggesting that you take isolated supplements of any of these things, apart from maybe omega-3, but that's, you know, it has to be your personal choice. But there are some studies looking at these individual nutrients. So in 2017, there was a meta-analysis published in the Australian and New Zealand Journal of Psychiatry that found an association between dietary magnesium intake and decreased risk of depression. Remember, magnesium comes in all those wonderful foods that we've already mentioned, things like nuts and seeds, dark green leafy vegetables where it's attached to the chlorophyll molecule. So there are potentially benefits of magnesium in isolation, but also in the foods that we take.
Dr Rupy: Aside from that, there was an intervention study, a randomized clinical trial, randomized control clinical trial in stressed adults with low blood magnesium levels. And the researchers found that increasing magnesium intake to around 75-100% of the recommended daily intake rapidly reduced stress levels in the trial population. And there was a reduction in perceived stress scores of about 30% over after about four weeks of magnesium intake and 40% after eight weeks. So that is quite interesting. Again, all these things need to be repeated again and again. And I'm sure there's a plethora of negative studies that didn't show that, but they just don't make it into the journals because there is a a positive bias by journals whereby we we only get to see the nice sexy positive results rather than the negative ones that don't garner as many views or garner as much attention because no one wants to read a whole study and get to the conclusion that there was no effect. So that's just something to bear in mind when whenever reading any headline.
Dr Rupy: An interesting aside to this study is that the benefits of increased magnesium intake were actually greater when combined with vitamin B6. So this reinforces what we were talking about earlier about the idea that nutrients work synergistically, i.e. together to provide benefits. So the sum of those synergistic benefits might be more than those individual nutrients taken on their on their own, which is why I'm such a fan of a food focused approach, a food first approach because you're going to get that natural synergism when you consume them on your on your plate. We definitely need more placebo controlled studies to confirm these results, but they are pretty suggestive of the important role of meeting our daily needs for a number of different nutrients, magnesium being being one of them.
Dr Rupy: Why would magnesium have a role in depression? What is the the plausible biological mechanism? Well, the researchers from from these studies suggested a couple. For example, there are studies in animal models of disease that show the positive role of magnesium in reducing brain inflammation, also called neuroinflammation. So another way by which magnesium could be promoting mental health. Another is by blocking dysfunctional receptors involved in mental health conditions such as depression. So an example of a receptor is the NMDA receptor of which magnesium is a natural blocker and this could help protect neurons against cell death, i.e. improving the the viability and the function of your neuronal cells.
Dr Rupy: And as I've said the abbreviation, I won't I won't go into the minutiae of details, but NMDA stands for N-methyl-D-aspartate receptor. It's a family of glutamate receptors and they have a a really important role in in memory and and and critical for for learning and stuff like that. So very important when it comes to the role of stress and protecting one's brain. Magnesium can also regulate your stress response and your resistance to stress as well. So you see an increase in stress-associated hormones when serum magnesium is low as well. So lots of associations, potential biological mechanisms.
Dr Rupy: Let's move on to zinc and iron. So there are other nutrients that are consistently linked to a reduced risk of mental health. These essential minerals are found in similar foods, so nuts, seeds, beans, lentils, certain animal products. There was a meta-analysis published in psychiatry research that found an inverse association between dietary zinc and iron intake and the risk of depression. You're probably seeing or listening to a bit of a recurring theme here where you've got dietary elements of zinc and iron, but those dietary elements are basically fruits and vegetables. And they go there's also like an argument, okay, but are there specific vegetables that have greater impact? And the answer honestly, I I think it's very, very hard to answer that truthfully because whole foods in their natural form have wonderful sources of a mixture of different micronutrients, essential micronutrients like minerals such as magnesium, zinc and and iron, but also those phytonutrients as well.
Dr Rupy: One of the reasons why zinc is an example of a nutrient thought to have influence on brain plasticity is because it can influence the levels of brain-derived neurotrophic factor, BDNF, which if you remember is a key molecule in the brain that plays an important role in the development and survival of neurons, the plasticity of the brain and cognitive functions such as learning and memory. So it's seen in animal studies that zinc can increase the expression of the gene coding for BDNF in the brain. So there's there's all these other mechanisms by which the ingredients and food can can help with this as well, bar the antioxidant effect and the anti-inflammatory effect and the effect on one's microbes as well.
Dr Rupy: One of the ways in which iron can support mental health is by playing a role in brain oxygenation and influencing the production of essential brain chemical messengers like dopamine and serotonin. And there are many potential mechanisms that link iron and zinc intake to mental health and wellbeing. So the takeaway is you want to have good levels of all these different things. The best way is to have a plethora of different foods, a plant focused approach and having whole foods where possible. So you can understand where there is an association between ultra high processed foods, not only are you getting the double whammy of the high amounts of sugar and salt that can be detrimental to your cardiovascular system that can affect the the flow of of oxygen and blood going to your brain, but also you're not getting the fibre that you want to support your microbes action at having that reduced inflammation and all the other activities they do in maintaining the gut barrier. You're also having that overly activation of the immune system and you're not getting the full plethora of nutrients that you find in whole foods because they've all been refined or processed out. A good example of this is white bread, for example. If you have a loaf of white bread, there is now legislation that mandates millers add essentially a a multivitamin to the flour because you've taken everything out in the husks. And that that rich outer fibre has all the B vitamins which are naturally brain healthy. And unfortunately, we've got used to the the flavour and the palate of the texture of of refined food. So we're having to artificially add it back, which I don't think is adequate because you're missing all the other phytonutrients and plant chemicals that you find in in whole grains. So that as an aside, that's that's another reason why ultra high processed foods might be detrimental in the fact that they're just not giving you what you could potentially have for the same amount of money in a lot of cases.
Dr Rupy: So on the subject actually of foods to reduce or avoid to protect mental wellbeing, we should probably talk a little bit more about that. I mean, my approach to that I take when it comes to food is looking at what we need to increase of and actually eat more of and add to our diets to protect our health instead of demonizing certain foods. But it it it wouldn't be a full discussion if we didn't think about the foods that we need to reduce. Um, certainly on special occasions, you know, I'm having cakes, I'm having desserts, I'm having sweets, etc. I'm having those refined foods that don't really have much in them. Um, but we we should really look into, you know, how this can turn into a habitual issues that can be at the detriment of of our mental wellbeing. So not all bad, not all carbs are bad and not all fats should be banned from our diets. And rather, I always talk about quality fats from nuts, seeds and cold pressed oils rather than fats per se. And so it just it just goes to to demonstrate that it's it's more about the quality and the holistic aspect of your food rather than individual elements like, oh, you shouldn't have any saturated fats. Well, that needs to be it needs to be in context.
Dr Rupy: One of the things that I spoke about on the podcast is it's creating a culture around healthy eating, growing one's food. I'm not much of a grower, I'm trying to get into it, but having that intimate relationship with how our food is grown, how we use local seasonal ingredients and how we develop an affinity for the fun of cooking at home. You know, it's it's the best way to provide our body with and our brain with the nutrients it needs without all the added low quality fats and sugars and salts. And it doesn't have to be an activity that is particularly time consuming either. One of the goals that I do here with the cookbooks and the new app is to make cooking easy and fun so we can all benefit from not only the protective effects of food, but also the impact on our performance and our general wellbeing.
Dr Rupy: So I'm going to pause there. Hopefully we've given you an idea of how we've created the mental health goal filter on the app, but also how interrelated all of the different health goals are. And in future iterations of the app that we're trying to do, we want to make it that more personalized to you. So it becomes more about, yes, making sure that you have a good collection of ingredients that are protective for your brain, your heart, your mental wellbeing, maintaining appropriate inflammation, but also it's more intuitive for you because it's culturally relevant, it's according to your taste buds. And that's the degree of personalization that I really want to get into as well further down the line. It's quite an expensive activity running the app, which is why we haven't launched with the Android just yet, but we will be doing at some point in the future. But also utilizing different clues and cues from one's body, whether it be from wearables or whether it be by teaching you to be a lot more intuitive about how you individually respond to food, which is essentially how we should all really be working towards in terms of that that intuitive aspect because we're not all all going to be able to have access to bloods every single day or tracking monitors and that kind of stuff.
Dr Rupy: The next podcast episode that I want to do on the subject of mental health is going to be on this. It's going to be on interception, this this learning to respond and listen to one's own body cues. This is a really interesting section that I want to to cover. And I'm also going to be putting the the mic and the spotlight on some of our wonderful newsletter subscribers. It's a free newsletter on the doctorskitchen.com/newsletter, who have given us their tips on how they look after their mental wellbeing, including how they overcome any potential barriers, as well as their sort of tips and tricks that have helped them along their journey, whether it's been over the 10 years, 20 years or the last year. So I'm really excited to feature some of our lovely subscribers who have who have given some of their time and recorded some audio clips for for them to share with all of us. And we're going to be talking about a few more studies in the next episode as well, looking at the joy of food, the positive roots to wellbeing and the pleasure of eating obviously as well. So thanks so much for listening. I really appreciate it and I will see you here next time.
