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: Today I'm talking about SAD, also known as seasonal affective disorder because I was recently asked to explain it on BBC Morning TV. And it's surprisingly common and debilitating for millions of people in the UK alone and frustratingly, there's not too much known about the cause and a real lack of research. SAD, which is also referred to as winter depression, can have many similarities to depression in the way of symptoms, but it's hard to determine whether there are similarities in the mechanism that drives the symptoms themselves. So today, I'll talk about the proposed causes, evidence for diet and lifestyle interventions and what you can do today to help yourselves if you suffer with SAD. Remember, you can watch this podcast on YouTube, just click the link in the podcast bio and you can download the Doctor's Kitchen app for free and Android users, we have a release date which is going to be the 29th of January 2024. We can't wait for you guys to enjoy the benefits of having those hundreds of recipes, each with step-by-step images and lots more in the pipeline. You can also subscribe for free to our eat, listen, read newsletter and seasonal Sundays where we do a deep dive into a seasonal ingredient every Sunday and we look at the nutritional medicine research as well as its culinary uses and the historical aspects of how these ingredients that line our supermarket shelves came to be. It will give you a new appreciation for these humble heroes. For now, on to my podcast about SAD.
Dr Rupy: If you suffer with low mood, lack of motivation, a change in your sleeping patterns that tends to happen in the winter months, then you should definitely watch or listen to this podcast because it may be seasonal affective disorder, which is particularly common. It also is known as winter depression and you may have heard about this through the news or maybe something that you've read. And we're going to talk a bit about the causes of it and what you can potentially do using the evidence that we have available to us. Now, seasonal affective disorder, what is it? So essentially it's a biological and mood disorder with a seasonal pattern. Tends to be during the winter months when we have less light. And it is due potentially to a change in your hormones and potentially genetic expression as well as vitamin D status. We'll go into some of the causes a little bit later. The reason why I say that it could be SAD is because it is quite prevalent. So in the UK, around 2 million people are affected, which is quite a lot. And in the EU, it can be anywhere between three and eight per hundred people. So the prevalence does vary, but it is pretty prevalent. The symptoms, now these were first described in 1984 as hypersomnia, so hyper being lots of, somnia being sleepiness or sleep, overeating and symptoms that respond to changes in climate and you can definitely see an association with latitude as well, so where you are on the globe. What distinguishes it from depression is the seasonal pattern. So it's a regular progressive association between the onset of depression and a time of year with full diminution or full recovery of the symptoms during a certain point of the year. Now I say certain point of the year because this tends to be a winter based depression, but strangely enough, some people have at least identified that they have this seasonal depression during the summer, which I can't quite explain, but it does happen. So the key sort of differentiator for this is that it has a seasonal pattern, tends to be in the winter. And I can explain some of the reasons as to why that might be happening through some of the research that we have around why. Diagnosis. So the diagnosis really comes down to the pattern of symptoms that one has and the seasonality of them. That's the key differentiator between non-seasonal depression. Recording symptoms is really important for that reason. So figuring out what your symptoms are and when they occur and if they go away completely during different parts of the year. The commonest ones tend to be sleeping more and eating more that appear to be the main symptoms which is different from non-seasonal depression, although they can coexist. Some of those symptoms can include anhedonia, which is the fancy term for lack of interest or lack of enjoyment in doing things that would otherwise create that sense of enjoyment. It can be lack of interest in things like sex or other exercise. It could be lack of motivation as well. It can be overeating, particularly during later times in the day. That is a symptom that seems to be recognised as particularly common. And all the other features of depression. So a low grade anxiety, it can be also an idea that you have impending doom and unsettling physical symptom in your chest or your stomach. These are things that correlate and correspond quite closely with non-seasonal depression. It is, it does seem to be more common in women during the times when they can have children. It's three times more common in women than in men as well. So again, there are some similarities with non-seasonal depression. A lot of people ask me once we've identified that this could be SAD, what are the causes? Well, this is where it's quite hard to have this conversation because there are theories, but it is generally unknown as to why this occurs. Melatonin disruption is one of the main things that people point to. Now, melatonin, you might have heard described as the sleepy hormone, something that increases steadily during the day, peaks at night, induces that drowsiness and then is inhibited by light. I think this is a naive way of looking at melatonin because melatonin has lots of other uses in the body. It can be a very powerful antioxidant, it has a role in your immune system, it has a role in lots of other things. I'll go into that in a second. It's produced in the epithalamus and a particular part of the epithalamus called the pineal gland. So you might have heard of the third eye, as it's colloquially known. This is essentially in the epithalamus, the seat of the brain, and it is inhibited by light. So one of the reasons why there is a sort of general trend and and actually advice and something that I always say to people as well is getting out outside of your house as soon as possible to experience some of that daylight, even if it is overcast or cloudy outside. That natural light is at a particular frequency and particular intensity that will inhibit melatonin and essentially take away the sleepiness effect of that hormone and get you to wake up and and and start your day. The dysfunction of the epithalamus has been associated with mood disorders including major depression, schizophrenia, sleeping disorders. Low level, low levels of melatonin will typically give rise to give rise to mood disorders as well. So this is why one of the reasons or one of the theories as to why people experience seasonal affective disorder is due to disruption to the melatonin hormone. Melatonin, like I said, has uses beyond sleep and I'm going to pull up a diagram here for those of you who are listening to this, I'll just describe the main features for melatonin and why it's such a powerful tool beyond just the sleepiness effect that it can have. When melatonin is released, it has multiple uses because there are receptors for melatonin at various points in the body, including the GI tract, your gastrointestinal tract. It regulates things like the motility of your gut, so how you are digesting food and how active the actual gut wall is, pushing food down the digestive tract so it can be properly digested. It can also have an impact on things like the digestive enzyme secretion from your pancreas. So again, impacting how you absorb nutrients from certain foods. It also has direct antioxidant properties. So these are things that can scavenge the natural production of reactive oxygen species, also known as ROS, in and around the body. It also has this activity inducing effect of superoxide dismutase, also known as SOD. And this is one of the most powerful antioxidant enzymes that we have. It's a, it's got a phenomenal impact on the antioxidant property and that's why it has a potential anti-cancer role as well. So one of the reasons that people have hypothesized for people who are stressed, depressed, or they have disruption to their sleeping rhythms and the association, and I want to just heighten the word association here, between those disruptions and cancer risk is potentially because of the lack of melatonin that is produced and the effect that that has on reducing the chances of certain types of cancer as well. So melatonin has a really, really important role. It also has a role in your mitochondria. So you will have heard mitochondria being sort of referred to as the the battery powerhouses of your cells. So this incredible organelle that lives in all cells and produces energy, produces the ATP that powers those cells in all different types of cells around your body. Mitochondria has an impact on the expression of certain complexes that are essentially the generators for that energy in these mitochondrial organelles. It is a really, really important hormone when it comes to that energy feeling. So if you're having disruption to that melatonin system, then it stands to reason that it can potentially have an impact on your energy levels around and and during your day. It also has an anti-inflammatory effect as well. The uses, I'm hoping as you're you're you're gathering from this description, is that there are multifactorial. It also has an impact on your immune system. So again, you can understand some of the reasons as to why disruption to sleep impacts your immune system and can render you more susceptible to things like common colds and viruses. This is all to say melatonin has a very, very important role and may have an impact on your propensity to seasonal affective disorder if that system is disrupted. Another system that is isolated as a potential cause as to why people experience SAD is serotonin disruption. So serotonin, again, being sort of labelled in a quite glib way as being the happy hormone. I think again, in the same way, melatonin has multiple uses in the body, serotonin has multiple uses in the body. I think we'll we'll save a description for that for that on another podcast episode. This can also have an impact on your likelihood of of SAD. Vitamin D. Now, it stands to, this is probably the most popular hypothesis as to why people experience seasonal affective disorder. The lack of vitamin D, which is synthesized via UVB exposure to your skin. What happens is that there is a conversion that is essentially instigated by UVB light exposing, going onto your skin, exposing to your skin, and it causes the production of vitamin D3 or cholecalciferol from something called 7-DHC. I'll put a diagram up here just to give you an idea of what happens at the skin level. It creates this enzymatic reaction that creates vitamin D3 via processing in the liver and then the kidney, and that vitamin D is distributed throughout the rest of the body. Vitamin D is seen a lot as an important factor in bone health, in the calcium cycle, the calcium regulation within your within your body. But it is so much more than just related to calcium. Vitamin D can be seen more like a steroid hormone. It is a master gene regulator. It acts more like a hormone than it does a a singular vitamin that you can get from food. In fact, it's quite hard to get vitamin D strictly from food. It's mainly from the conversion from your skin via sunlight. It has a role, yes, in calcium metabolism. It is very important for bone health. It's also really important for your immune system. It's has a role potentially in other mood disorders. It is related or associated, a deficiency of vitamin D is related and associated with autoimmune conditions. So there are a number of different conditions that have been associated with vitamin D deficiency. And I'm just going to pull up a graphic now that looks at vitamin D deficiency and the potential consequences. And you can see they are vast. There's viral illnesses or or susceptibility to viral illnesses. There's malabsorption, so lots of different gut related issues. There are, there's potentially a relationship with dementia and other neurocognitive dysfunction. There's also a relationship, of course, with osteomalacia, which is the adult version of rickets. Lots of different associations there with vitamin D. And yes, there is a potential reasonable explanation as to why this is related to seasonal affective disorder. It does stand to reason because if you're not getting the exposure to sunlight that we're used to during the summer months because of the shortening days, we tend to spend a lot more time indoors rather than outdoors, even in low levels of light, we're going to have less vitamin D. And actually, that's why it is recommended to replace vitamin D3 that I always recommend with K2. We'll get into that a little bit later, during the winter months and getting your vitamin D levels checked anyway. There is a bit of controversy around vitamin D supplementation. Some people believe that it's purely an association that can be explained via other means, like the quality of your diet. But I think there is enough evidence to suggest that it is a reasonable thing to do to to replace vitamin D3 above the national levels that are seen as deficiency. So within the NHS, the ranges of deficiency of anything lower than 25 to 30 nanomoles per litre are seen as a deficiency. I think we need to be aiming for a lot higher than that. So around 50 appears to be the sweet spot, but again, I appreciate there is controversy around that.
Dr Rupy: Treatment. So we've isolated that this is a difficult topic because we don't strictly know what the causes are. So how do you address the root cause if you don't really have a full grasp on what could be driving these these symptoms? The treatment that appears to work best includes cognitive behavioural therapy, artificial light, so these are some some light lamps you can get. There is potentially a role for antidepressants, although there was a big review that came out very recently that showed that it wasn't really that effective. But I think in certain circumstances, particularly if we believe that there is a role for serotonin, it could have a, it could have a beneficial effect. And then vitamin D3 as well. So there are some cases of vitamin D supplementation creating sufficiency in a in an individual leading to resolution of of the symptoms. Let's go through those in turn. So CBT, cognitive behavioural therapy, otherwise known as talking therapies. You can imagine that if you are having lack of motivation, you're not stimulated, you are having anhedonia, lack of interest in things that usually create enjoyment, talking therapies is a great way of creating habits that can counter those negative thoughts. So CBT does appear to be one of the best things that people can do. Again, it really comes down to what is driving this condition. So CBT, I would say is relatively harmless and may be helpful. Morning light. Now there is an argument that we should just be having artificial lamps because going outside doesn't actually give you that much light. I would actually disagree. So looking at the number of lux that you tend to get from natural outdoor light, even in overcast days, you can get up to 10,000 lux of light. And that that ranges between 10 and 25,000 lux. In direct sunlight, you get 30,000 to 100,000 of of lux. When you're inside, you're getting less than 1,000. So even if you go outside, despite the fact that it is overcast, despite that the fact that it is grayer or darker, you're still going to be getting a lot of lux out there. And the longer you leave yourself exposed is great. And just to explain what lux actually means, because I think there's a bit of confusion. One lux of light is the measure of light density equivalent to one meter squared. So one meter square, if you imagine a candle and a meter of light that that candle is exposing onto a white wall, that is one lux. So the intensity of light that you're getting from direct sunlight is 100,000 that. In ambient daylight, it is anywhere between 10 and 20,000. Overcast is around something anywhere between 5 and and 20,000. Inside you're getting less than 1,000. So it does stand to reason that getting that morning light, even when it is overcast outside, is a worthwhile activity. Plus you have the stimulation of being outdoors and the natural energy that you'll get from being outside and the fresh air and maybe even exposure to nature as well. That being said, sometimes it is really hard to get up in the mornings, particularly when it doesn't actually get light until 8 a.m. in some cases, depending on where you are in terms of the latitude. There is potentially a role for artificial lamps. So these are, they're called SAD lamps. You can find them online. Lots of them are being advertised. They range in cost from anywhere between 40 pounds and 400 pounds. It is a bit of a minefield. If you are going to invest in one, I would always say, A, use them properly and B, make sure you're getting one of the correct intensity. And the intensity sweet spot that you want to go for is 10,000 lux. Now, these aren't like tanning booths. You're not going to get the radiation from them. So it's not going to be harmful to your skin, but you are going to get that stimulation. So you want to be looking for 10,000 lux at least, and you want to be using that first thing in the morning for at least 10 to 15 minutes. Ideally, when you're doing your makeup in the morning or you're brushing your teeth or you're doing some activity first thing after getting out of bed, getting that exposure to that artificial SAD lamp for at least 10 to 15 minutes, that's where you're going to get the sweet spot. Conversely, you don't want to be using that at the end of the day. The reason why is because you're inhibiting that melatonin. So you're trying to get rid of that melatonin first thing in the morning so you wake up and you have that motivation. But the last thing at night, you don't want to be using that lamp. You don't want to have it anywhere near you because you don't want your melatonin inhibited before you're going to be going to sleep because you want that melatonin hit overnight where it's going to have all those different activities on your immune system, your antioxidant systems, your gut systems, etc. So, so really, really important. Vitamin D3, the doses that are recommended in the UK are 400 IU, so that's 400 international units. I always say 1,000 international units plus vitamin K2. If you look on the back of your vitamin packet, it should say menaquinone 7 or MK7. And the reason why you want to be having a vitamin D3 plus K2 is because K2 is very important for the recycling of calcium. So vitamin D3 will increase the calcium level in your bloodstream, but that's not a good thing if it is isolated. You want to ensure that your calcium is not going to be hanging around in your bloodstream for too long, where it could potentially end up where it doesn't belong or you don't want too much of it, which is your arteries. So there is some evidence that high levels of vitamin D3 and high levels of calcium in your bloodstream can lead to an association with cardiovascular disease and and clogging up of your your coronary arteries. So it's very important to supplement vitamin D3 with K2 as well, if you are going to try vitamin D3 supplementation, which I do recommend. I would love to say diet has a role in seasonal affective disorder. Looking at a lot of the different studies and looking at some systematic reviews, meta-analyses, it does not appear that improving one's diet, and I want to say that sensibly, it does not appear that improving one's diet has an impact on SAD. What they do say is people who experience seasonal affective disorder exhibit distinctive diet preferences and eating behaviours. And these include eating later at night and eating generally more carbohydrates. So those are the two sort of eating patterns that seasonal affective disorder patients tend to exhibit. There doesn't appear to be any resolution of symptoms by simply improving one's diet. However, big however here, I don't think it would be unreasonable to think that supplementation and improving one's diet could potentially have an impact on one's mood as an individual. The studies don't tend to say to to suggest this, but nutritional science studies are quite hard to interpret and it is very hard to it is very hard to make the case that these particular vitamins or this particular eating pattern can improve something that is quite transient, i.e. it comes and goes depending on the season. So having said that, I don't think it's unreasonable to at least experiment with certain additions or supplements that may have a link with non-seasonal depression. And these include B vitamins, omega-3 fatty acids, vitamin D3 and K2 like we've just mentioned, as well as a diverse diet and unprocessing your diet as well. So removing things that can be depressive. And these include hyper-processed foods and known depressants like alcohol. And it is a bit of a catch-22 situation because you do find yourself drinking more, particularly during the winter months where you have festive activities and there's lots of celebrations and all that kind of jazz. But if you do find yourself someone experiencing winter depression or SAD, then these are things that I would think about as well. Specifically for B vitamins, if you are going to think about B vitamin rich foods, there are plenty of different foods that you can eat, but I would say a B vitamin complex, one that contains all B vitamins including vitamin B12, may be something to supplement with to see if that helps. It's one of those vitamins that I think are fairly harmless because they are water soluble, you essentially pee out most of the B vitamins if you don't utilize them, and a lot of people are vitamin B12 in particular deficient. Omega-3 fatty acids, so these are the fatty acids that you get from wild fish or from algae supplementation, although algae supplementation does appear to be more expensive. And you want to be looking at getting EPA and DHA as well. These are the long chain fatty acids. A lot of other supplements that are vegan based include flaxseed and walnuts. Those don't contain the long chain omega-3 fatty acids, they contain the short chain omega-3 fatty acids that whilst they are healthful, don't appear to have the same effect on brain health and mental health. So those are the two things I would think about or three things if you include vitamin D3 about supplementing, unprocessing one's diet and thinking about things that would certainly help mental wellbeing as well. So colourful diet, high fibre, things that improve your gut microbiota, prebiotics and probiotic rich foods. These have relationships with memory function, cognitive impairment and staving off things like dementia. It may have an impact on SAD, but none of the studies that have currently been done on diet and SAD show that association, just those eating patterns that I talked about a little bit earlier. So the main takeaway is that I want you to have around SAD are that A, the causes are unknown, but they may include disruption to melatonin and serotonin. Essentially that disrupts your internal circadian rhythm. And it stands to reason that that is probably going to be the most likely cause because you're not having as much inhibition of that melatonin and that can lead to apathy, lack of motivation, it can lead to disruptions to the beneficial effects of your sleep. There's so many different reasons as to why this web of interconnected hormones and the disruption of those can be limiting your your mood and your ability to to maintain a sense of um uh positive state. And again, throwing vitamin D into that equation of the the hormone disruption because I see vitamin D as more of a hormone than a vitamin, or most people do now as well. Morning light is really, really important and if you can't get that exposure to morning light, then experimenting with artificial SAD lamps. And I would say the third thing is that this is more than just mood. This is more a case of how seasonal affective disorder can disrupt your motivation. And it's a bit of a an ugly truth that during this time in winter is when we tend to try and establish new habits. And if you really think about when you try to establish new habits, you want to be in the best positive mental state as possible. You want to be in the best receptive mindset to try and and to to have that motivation that will push you through starting those new habits. So maybe the new year in the middle of winter, if you're listening to this in the UK or anywhere in the northern hemisphere, is perhaps not the best time to actually start new habits. Maybe those new habits should be done a little bit later on because I think everyone can everyone can reason with that apathy and that lack of motivation around the winter months because of some disruption to their circadian rhythm and their vitamin D synthesis. It might not be clinical to the point where you feel impending doom, the the lack of enjoyment, the things that will prevent you from getting out of bed. It may be subclinical, i.e. you feel a general sort of cloud of mood and that lack of motivation. So perhaps that being said, it may not be the best time to actually start those new year habits. Maybe it's something that you want to push back until March or or April. The way I actually changed my daily routines to lose weight, tone up, reduce belly fat, all those different things that I used to have issues with, is actually habit stacking. And I remember just doing the smallest thing possible, just to sort of figure out what what had the path of least resistance. And for me from a nutrition point of view, it was changing up my breakfast. It was simply swapping out my cereal and increasing my amount of fibre, increasing the diversity of my meals, sprinkling a bit of pumpkin seeds or walnuts or whatever it might be on my overnight oats or porridge, rather than trying to overhaul my entire diet, which is a common, common pitfall that a lot of people fall into, particularly around this time of year. So think about habit stacking, sticking to that commitment, and then adding another stack to it at a reasonable enough distance, so four to six weeks. Once you've established said habit, you've made it small enough, that's the best time to then add another habit stack to your your full stack of habits. And think about when the best time of year to do that is. So I hope you've enjoyed this mini episode on seasonal affective disorder. I really hope you understand a bit more about this winter depression, as it's colloquially referred to, the potential causes, the importance of melatonin, the circadian rhythm, and some of those supplements that you might want to experiment with as well.
Dr Rupy: Thanks so much for listening to this episode of The Doctor's Kitchen podcast. Remember, you can support the pod by rating on Apple, follow along by hitting the subscribe button on Spotify, and you can catch all of our podcasts on YouTube if you enjoy seeing our smiley faces. Review show notes on the doctorskitchen.com website and sign up to our free weekly newsletters where we do deep dives into ingredients, the latest nutrition news, and of course, lots of recipes by subscribing to the Eat, Listen, Read newsletter by going to the doctorskitchen.com/newsletter. And if you're looking to take your health further, why not download the Doctor's Kitchen app for free from the App Store. I will see you here next time.
