Instant Genius - How to Hack Your Sleep: What to eat to get better sleep

Episode Date: October 28, 2024

We all know we should be eating a good diet to keep ourselves healthy, but did you know your diet can have a significant impact on how well you sleep? In this episode, we speak to Dr Piril Hepsomali, a psychologist and sleep researcher based at the University of Reading. She tells us how consuming caffeine affects our sleep, why we feel tired after eating a big Sunday lunch and what actually happens if you eat cheese before going to bed. This episode is presented in partnership with Lumie. https://www.lumie.com/ Learn more about your ad choices. Visit podcastchoices.com/adchoices

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delivering digital precision with analogue warmth. So you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to love. learn more. Hello and welcome to Instant Genius, a bite-sized masterclass in podcast form. Every Monday and Friday, you'll hear world-leading scientists and experts talking about the most fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor at BBC Science Focus. We all know we should be eating a good diet to keep ourselves healthy,

but did you know your diet can have a significant impact on how will you sleep? In this episode, presented in partnership with Loomie, we speak to Dr. Pyrill Hep's-Marl-Hepsaly, a site of psychologist and sleep researcher based at the University of Reading. She tells us how consuming caffeine affects our sleep, while we feel tired after eating a big Sunday lunch, and what actually happens if you eat cheese before going to bed? Hello, welcome to the podcast. Thanks very much for joining us. Yeah, thank you for inviting me. So we're talking about the effects of diet and sleep today, and you carried out a study based on this. So how did you go about that? So we pop up. We've We published this study a few years ago around, I think, 2021, and we examined the associations

between diet quality, intakes of specific food groups, namely fruits, vegetables, processed meat, unprocessed red meat, fish, fiber, as well as the intakes of milk, tea, coffee, water, and sleep quality in nearly half a million of participants in the UK. That was a big sample and we utilized the UK Biarrank data set. And we found in this study that participants with healthier diet scores reported to have better sleep quality. And this effect was probably driven by increased intakes of vegetables, fruits, as well as fiber, fish and water, moderate intakes of milk and lower intakes of processed meat, tea and coffee reported by these individuals. So if they had a better diet and if they consumed the better

foods and they had a good amount of water in their system, they reported to have better sleep quality. So in summary, a healthy diet of pattern and food groups that we know that are healthy, they were all associated with better sleep quality in our paper. Yeah, so before we get into that, so what is an ideal amount of sleep that we should be getting? Oh, so this depends on your age. So according to National Sleep Foundation, adults between the ages of 18 to 64 should aim for seven to nine hours, but adults older than 65, seven to eight hours is normally recommended. For babies, for instance, they need around 14 to 17 hours of sleep, so it's really dependent of your age. But here I would like to highlight one really important thing. Sleep is much more

bigger than duration only. Quality of sleep is very, very important. So you can get eight hours of sleep. But if you wake up 15 times a night and spend three hours to fall asleep, this should not be considered a good night's sleep. And again, National Sleep Foundation recommends what could be considered as a good quality sleep. And we need to be, for instance, fully into sleep in 15 minutes or less than 15 minutes. We should be waking up after sleeping just once or none at all. And If we do, it should be lasting for 20 minutes or less. So this applies to all ages, really. So we should also be taking into account of quality.

Yeah, that's horrible for me to hear because I'm such a bad sleeper. Yeah. I wake up at least 15 times. I'm the same. I'm the same. Four hours. I feel your pain. Yeah.

So let's look at the digestive system then. So what's going on there? And how does that affect our sleep? Yeah. So it is believed that dietary factors affect sleep via various biological pathways, via circulating hormones such as insulin, grilling, and by stimulating the synthesis of neurotransmitters of serotonin and melatonin, known as the neurotransmitter of happiness and the hormone of sleep respectively.

and also dietary factors could act on gamma aminobitric acid and serotonergic neurons. And again, we know that GABA, gamma aminovitric acid is a neurotransmitter that is mostly associated with relaxation and serotonin that I already mentioned and via other unidentified mechanisms. But here I would like to note that the microbiota gut-brain axis has been identified. identified as a primary diet or nutrient-mediated pathway that is involved in regulation of sleep health as well. So what you eat could affect your sleep via causing alterations in the gut brain system, acting through different biological mechanisms. So before we get into specific nutrients and things like that, how about the time we eat? So I know different people like to

eat at different times, you know, they had the dinner later, or they have it earlier. What effect does that have? So unfortunately, research is very, very limited in this area, but there are some studies, observational studies, reported poor sleep quality following late night eating. But if we look at experimental studies, they are inconsistent regarding the effect of late eating on sleep quality. but also there is a huge heterogeneity in research in terms of the timing of the late meals in these studies and nutrient content of these meals in these studies and the study populations. Some of them were conducted in healthy young adults. Some of them were conducted in individuals with sleeping disorder.

So it would create confounds and it prevents us to reach to a consensus on this matter. So I've read some papers and they talk about influence. inflammation and how that can have an impact. So what is that? What causes it and what effect does it have? Yeah. So systemic chronic inflammation, in relation to sleep, actually we studied this after publishing our first UK Biobank paper. We know from external researchers that systemic chronic inflammation, so increasing pro-inflammatory cytokines in the body, or other, inflammatory biomarkers, it could be modulated by diet. So if you eat high saturated fat foods or if you eat a lot of foods that are rich in sugar, it could increase this pro-implementary

cytokines and also increased systemic chronic inflammation is associated with poor sleep outcomes. And moving on to our study, we published two years ago, we have not only found some negative associations between inflammatory biomarkers and food groups that are abundant in healthy diets, as well as positive associations between inflammation and food groups that are abundant in unhealthy diets. We also showed that some of these biomarkers fully mediated the association between diet health and sleep health. So potentially by reducing systemic chronic inflammation via dietary interventions,

we could increase sleep quality. So diet could be an effective primary or complementary strategy in this case. So let's have a look at different foods then. So one big one I think is going to be caffeine. Like personally, I'm a two cups of coffee in the morning person. I can't really function without it. So what effect is that having on my sleep, you know, and when should we drink it? So I'm a three cups of coffee person. So caffeine promotes weightfulness by antagonizing specific receptors in the brain. And basically adenosin A1 and A2A receptors. And adenosin promotes sleep.

And caffeine blocked the sleep promoting effect of adonisin. And when we're talking about caffeine, it affects everyone differently based on various factors, including whether you are used to taking it, you're habitually taking it or not, whether you take other drugs around the same time you're consuming your caffeine, or whether you can metabolize caffeine faster or slower than the others. And in terms of when you should be drinking it or when you should be stopping drinking it, if we ingest caffeine orally, it's absorbed very, very rapidly. It reaches to a peak plasma concentration in half an hour to an hour.

And the half-life of single-dose caffeine is three to seven hours. But if you drink two cups, obviously the duration of action is extended. So there is no rule of thumb, as this depends on the many other factors that I've just discussed. but ideally individuals who would like to fall asleep around midnight should not consume caffeine after 4 or 5pm based on what we know about the half-life of a single-dose caffeine. If you're drinking two cups, it would change the timing. So another big one is alcohol. So lots of us drink alcohol.

I think anyone that drinks alcohol will know that maybe you don't get a great night's sleep after you've had a few drinks. So what happens there? So alcohol acts as a sedative and it interacts with various neurotransmitters that are involved in regulating sleep. And if you consume large amounts of alcohol just before going to sleep, it leads to decreased sleep onset latency. So you may fall asleep quicker, but it may create changes in your sleep architecture early in the night. with subsequent disrupted poor quality sleep later in the night. And it's important to note that it takes around one hour for your body to process one unit of alcohol. So a pint of lager or glass of wine or small glass of wine contain around just more than two units.

So it would just take over two hours to process one of these drinks. So this is how alcohol affects you. and the timing of what you're drinking also may play a role. Ambition comes in all shapes and sizes. At First Citizens Bank, we roll with your goals because we're built for what you're building. Fit for your ambition for Citizens Bank. You said this place was steps from the water.

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This is a tricky question because there is some research showing positive impact of some of the spices and herbs on sleep outcomes, like curcumin, like Valerian and things like that. But if you're referring to spicy takeaway foods, we know that they are rich in unhealthy fats, sodium, or some of these could be rich in sugar as well. and these would definitely impair sleep outcomes directly or indirectly via causing gastrointestinal issues like heartburn. So another thing is carbohydrates, another thing that I absolutely love. I love my mashed potatoes. So what effect does that have? Again, depends on the carbs.

So if you are referring to simple carbs, we know from research that simple carbs like table sugar, white bread, impair sleep outcomes, but complex carbs would not. And if we talk about like heavy meals, rich in simple carbs, high fats, high sugar and sodium, of course this would affect sleep badly, but carbs per se are not your enemy if we consume the right amount of carbs at the right time, I think. That's really good to hear. So say when we have a big Sunday lunch, why does that make us tired?

It depends what you include in that Sunday lunch. If we're talking about a roast dinner, then just because it doesn't really involve any complex carbs, unfortunately. It includes simple carbs. I think it's quite a fatty meal as well, and it's rich in sodium. it would affect our gastrointestinal system as well as actually mood and behaviour because we feel sluggish. It would definitely change our system right away. But initially it would make us happy. But a few minutes later, it would impair our mood as well.

Well, I won't stop eating them. So currently there's a lot of talk about processed food. So I was wondering, does that have any? effect on the sleep? Yeah. So it's this similar situation with spicy foods and heavy meals or your like Sunday lunch. When we look at research, processed meats and ultra-processed foods generally contain high amounts of saturated fats, sodium, and or sugar, and they are generally very, very low in fiber. And these nutrients are known to elicit. pro-inflammatory responses and via inflammatory pathways, it may impact sleep outcomes, unfortunately.

But research is in its infancy for us to be able to say it's bad. But when we're talking about processed meats and ultra-processed foods, we should definitely be looking at the specific nutrients we are talking about here. Yeah. So you've mentioned sodium a couple of times. So that's obviously in table salt, etc. Yeah. Why is that such a problem? Because it would create some issues within the circulatory system, and it's normally not recommended in individuals who have, for instance,

cardiovascular diseases because it may change blood flow, not in a good way. Yeah, got you. So let's have a look at dairy then. So this is a big thing. People say, like, you shouldn't eat cheese before you go to bed because it's going to give you funky dreams. Yeah, yeah. Is there any truth in that? Funky dreams. So again, this is another three-key question to answer. So milk contains a lot of essential nutrients like vitamin D, calcium, various group B vitamins that are really, really important for sleep. So it's

clear why possibly moderate amounts of milk might be associated with better sleep outcomes. But it also is a main dietary source of degalactose and chronic exposure, so sustained consumption of dairy milk, could cause inflammation in animal studies. So it hasn't been shown in humans yet. Also, dietary saturated fatty acid content of milk and dairy products is known to modulate gut microbiotic composition and low-grade systemic inflammation. so higher intakes could be associated with worse sleep outcomes. And in our study that I mentioned during the beginning of the podcast,

we also specifically looked at how milk intake could be associated with sleep quality. And we found an inverted U-like relationship where both participants in the lowest and highest milk intake groups had the lowest sleep quality scores. So clearly, moderate and moderate and measurement. of their intake is beneficial for sleep. Yeah, so that's like when I was doing it, we used to have a warm glass of milk before we went to bed. Yeah, yeah, yeah. I remember those days.

So long ago. Coming off the back of that, I'm a middle-aged man. So how about fluids? I often wake up with needing to use the toilet. Yeah, yeah. It's an important one to mention, I think. In our study, we observed that increased healthy sleep scores were associated with increased water intake, but this wasn't the case for other liquids that we assessed like tea and coffee.

And there are other studies showing associations between short sleep duration and higher odds of inadequate hydration. hydration is very, very important indeed, but perhaps for middle-aged individuals, timing should be adjusted depending on the age to prevent nighttime awakenings because then it would have an impact on sleep quality. So how about micronutrients? So everyone talks about these at the moment. You know, what does that mean and does that have an effect? Yeah.

So these are vitamins and minerals that are needed. by the body in very, very tiny amounts. And the deficiency in any of these could cause severe conditions because they are involved in a range of functions, such as enabling the body to produce enzymes, hormones, or other substances that are needed for normal growth or development. And they all have different mechanisms of action by which they could affect sleep outcomes. and looking at the literature, the most promising micronutrients for sleep are vitamin D and magnesium. But again, because of the heterogeneity of the research in this area, we can't really say,

these are going to save your life, these are going to improve your sleep 100%. For instance, there is a systematic review, a meta-analysis, across 13 clinical trials. and there was a strong evidence regarding the benefits of vitamin D supplementation on sleep quality. And another review, for instance, examined the impact of magnesium on sleep in healthy individuals and the results were promising, but they were mixed because two studies showed no significant effects of magnesium supplementation, whereas three studies showed that magnesium supplementation improved some sleep outcomes. So it really depends on the populations, the amount of supplementation, and the duration of supplementation as well. Right. Got you. So in summary, we've spoken about

a lot of different things now. So say someone listening is perhaps not sleeping too well and they want to do something to sleep better. So what can they do with their diet? So a healthy diet of pattern and food groups, including vegetables, fruits, seafood, water, and nutrients such as fiber that are consumed as a part of healthy dieted pattern could help your listeners to improve their sleep outcomes. But I would also like to highlight other lifestyle factors that may have an impact on sleep outcomes here, such as not smoking or not being sedentary and controlling stress, they are all equally important to have a impact on your sleep quality and duration and overall sleep outcomes as well. Thank you for listening to this episode of Instant Genius brought to you from the team behind BBC Science Focus.

That was Dr Pyrill Hipsomarling. If you liked to what you just heard, then please do consider subscribing to Insid Genius on your preferred podcast platform. The current issue of BBC Science Focus magazine is out now. Pick up a copy wherever you buy your favourite magazines or download us on your app store of choice. You can also find us online at sciencefocus.com. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name Audio believes you can have digital precision with analogue warmth.

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