A commonly repeated claim is that cheese gives you nightmares. You've probably been advised not to tuck into a cheesy snack too late into the evening, lest it disrupt your night. The finger is often pointed at blue cheese as being the worst culprit, the theory being that the bacterial cultures cause vivid, weird or memorable dreams. But is there actually any science to back up these claims?
There are plenty of old wives' tales surrounding sleep, and just because something is repeated frequently doesn't mean it's accurate. For example, all evidence points to the idea that we eat eight spiders a year in our sleep being entirely made up. On the flip side, not all these claims can be discounted – there are plenty of studies that suggest that a full moon does indeed affect sleep quality, however unlikely that might sound.
To try and get to the bottom of the issue, sleep brand Emma (which makes one of our best mattress picks) conducted its own study. Read on for a look at why cheese might give you nightmares, as well as a look at the results of Emma's own study.
Is there any evidence that cheese gives you nightmares?
There's a surprising lack of research into the connection between dreams and cheese, given how widely accepted the claim is. There are plenty of theories as to why cheese could theoretically disrupt your sleep – and we'll get into those next – but little solid evidence either way as to whether it actually does.
Perhaps the most commonly cited research exploring potential links comes from 2005. The now-defunct British Cheese Board ran a 'Cheese & Dreams' study that asked 200 volunteers to eat 19g of cheese before bed, and make a record of how well they slept and what dreams they had. One thing that might have been instrumental in giving the myth momentum comes from 2005.
No participants experienced nightmares, but the results did suggest different types of cheese resulted in different kinds of dreams ("over 65% of participants eating Red Leicester revisited their schooldays, all female participants who ate British Brie had nice relaxing dreams whereas male participants had cryptic dreams," reads the British Cheese Board report).
Despite never being published in a peer-reviewed journal, the study was widely reported on in the media. And while its findings don't correlate with the nightmare theory, the study might have helped promote that idea that there's a link between cheese and dreams.
Another story that's cited fairly regularly was published in 1964 in the British Medical Journal, and concerns a patient who was having horrific dreams each night (including one where he was hanging from a meat-hook). Further digging revealed that he was eating 30-60g of cheese with his dinner each night. He cut out the cheese, and the dreams stopped. Again, it's far from conclusive proof of a link.
Moving to slightly more recent research, a 2015 study into the relationship between diet and dreams found that, of the people who perceived there to be a connection between the two, most picked out dairy products as being the food type that was to blame (39–44%). In particular, dairy products were linked to disturbing or bizarre dreams. All of the findings were to do with the participants' own perceptions, but the researchers do offer several theories as to why this could be the case, some of which we'll get into below.
Is there any evidence to the contrary?
There is some research supporting the idea that dairy products might actually make you sleep better. This 2020 review of various research undertaken between 1974 and 2019 concludes that, "Overall, these studies indicated that a well-balanced diet that includes milk and dairy products is effective in improving sleep quality".
Why might cheese affect your dreams?
One theory as to why cheese might cause vivid dreams or is because cheese is often rich in the amino acid tryptophan. "Tryptophan is a precursor to serotonin, which has been known to cause vivid dreaming when at higher levels in the body," explains psychologist and sleep scientist Theresa Schnorbach.
However, the same amino acid can also be a precursor to the neurotransmitter melatonin (a hormone associated with sleep), which means it's also relevant in the argument that cheese might improve sleep. "By helping your body to produce more melatonin, the tryptophan in cheese can help you better regulate your internal clock and doze off more easily," adds Theresa.
Another explanation as to why cheese might cause nightmares is because it's often rich in the amino acid tyramine, which induces the production of noradrenaline. This hormone is associated with your body's fight-or-flight response, which acts as a stimulant for our brain, impairing your sleep.
Theresa says that tyramine is used to produce dopamine, and according to research, higher levels of dopamine can impact dream activity. "Dopamine is involved in the regulation of the sleep-wake cycle and can influence the brain's ability to process sensory information during sleep," she explains.
Digestion in general
One popular explanation is that cheese is difficult to digest, which means your body is keeping you slightly awake while it's trying to process the cheese. "Our body remains in the REM sleeping phases for longer than usual, preventing us from fully resting during the night and potentially increasing the possibility of experiencing dreams as a result," says Theresa. REM sleep is the part of the sleep cycle in which most dreaming takes place.
The fact that cheese is often eaten at the end of a meal, closer to when you're heading off to bed, might be one reason why it's often identified as the cause of the nightmares. However, this explanation would apply to any hard-to-digest food, such as meat.
The knock-on effect on body temperature is also relevant. For good quality sleep, our bodies need to cool down by one degree. Eating late in the evening has been linked to a rise in core body temperature. Whatever the cause, most sleep coaches will suggest it's a good idea to stop eating a few hours before bedtime (as per the 10-3-2-1-0 sleep rule), in order to give your body a chance to fully digest everything before you go to bed.
Chances are, you're not just tucking into a big block of cheese on its own. (Although if that is what you're doing, no judgement here.) What you're eating with your cheese may well also have an impact on your sleep.
For example, crackers are many people's cheese-holder of choice. These are high in carbohydrates, which in large amounts causes your body to release extra insulin to balance your blood sugar levels. Theresa explains that this extra insulin boost causes an increased intake of most amino acids into your system, leaving you feeling lethargic.
If you're having your cheddar as part of a cheese and wine night, the alcohol can also disrupt sleep. Because alcohol is a depressant and sedative, it might make you drop off more quickly, but it's not key to a restful night's sleep. "[Alcohol] has been found to adversely affect sleep patterns and particularly REM sleep – the stage in which we dream," says Theresa.
Some believe that the disturbed sleep might be caused by an intolerance to lactose, with the resulting physical symptoms disrupting sleep patterns. It's explored in this study, referred to as the 'food distress hypothesis'. "It's entirely possible that [reports of cheese causing disturbing dreams] were due to people having lactose intolerances," study author Tore Nielsen told the BBC. "It's likely an indirect effect in that lactose produces symptoms like gas, bloating and diarrhoea and influences dreams, as dreams draw on somatic sources like this. And if you have certain kinds of intolerances, you still may be likely to eat those foods sometimes."
Disturbed sleep can also mean you're waking up more in the night, which might make you more likely to remember your dreams. In turn, this could create the impression that those dreams are more vivid.
You're probably familiar with that feeling of lethargy and sleepiness following a large meal. If you've overdone the cheese and put yourself into a 'food coma', that's going to disrupt your sleep too. Even if you drop off easily after your cheese binge, Theresa warns that you're unlikely to have a refreshing, good quality sleep.
"[Food comas] can actually be harmful to our health; impacting digestion, lowering blood pressure, causing issues such as heartburn and indigestion, and even leading to gastroesophageal reflux disease (GERD)," she explains.
The power of suggestion
One final, important possibility is that the very fact that people are so aware of the idea that cheese gives you vivd dreams that we've almost willed it into existence. People might be more focused on their dreams after cheese, and more likely to draw conclusions when in fact the dreams themselves are fairly standard.
Theresa Schnorbach is a psychologist and sleep scientist, specialized in Clinical Psychology and Cognitive Neuropsychology. She has completed post-graduate training in Cognitive Behavioural Therapy for Insomnia (CBT-I) with the German Sleep Society (DGSM), endorsed by the European Research Society. She works as a sleep specialist for bed brand Emma.
What did Emma's study find?
To assess if cheese might actually be affecting your sleep, bed brand Emma ran a study. It asked 30 participants to consume different types of cheese before going to bed. These were the types of cheese included in the trial:
- Quicke’s Mature Cheddar (a hard cheese, aged for 12 months)
- Baron Bigod (a soft cheese, aged for 8 weeks)
- Yorkshire Blue cheese (aged for 8 weeks)
Participants ate the cheese 20 mins before sleep, with the aim that digestion would match up with the last REM cycles. It's thought that the dreams that occur during the final REM cycles are easier to remember, which would make recording them easier. Here were some takeaways:
- Across all cheeses, participants gave an average dream vividness score of 6/10
- Participants reported worse sleep quality after blue cheese compared to the mature cheddar
- Participants slept better after the Baron Bigod or Cheddar (with 58% and 49% of participants rating it as 'great' or 'good' respectively), compared to the Yorkshire Blue (with 44% of participants reporting their sleep as just 'ok')
- After Yorkshire Blue, there was a slightly higher average number of wakeups during the night (1.8, compared to 1.67 for the other two cheeses)
So, does cheese actually give you nightmares?
While the results of Emma's study did suggest that different cheeses might have some kind of impact on sleep, it didn't offer any concrete conclusions on the relationship between dreams and cheese.
"There remains a lack of robust evidence that cheese can cause vivid dreams and nightmares or influence sleep, but there is also no evidence to prove otherwise," says Theresa. "Sleep, and dreaming in particular, are such personal experiences that can be impacted by a variety of external factors. It seems there is much more research still to be done in this area – but if that means more cheese for us, that's no bad thing!"
For more information and tips on how to improve your sleep, try the Emma Up app, available for free and on all app stores.