Sweet dreams are made of cheese

You’re running down a hallway; running away from someone? Running towards something? Your feet start to lift off the ground and the ceiling opens up. You float higher and higher, and you get the feeling you’re not alone. You turn to your left and it’s Bob Dylan, laughing and calling you “Mr. Tambourine Man”. Suddenly the balloon you were holding onto, carrying you up into the sky, turns into a tangerine and you start to plummet back to earth. Just before you slam into the ground you awaken; sweaty, sheets twisted, wondering what the hell that was all about.

Dreams are weird. Especially if you’ve eaten a lot of cheese the night before.

Or so says the common myth. From Charles Dickens to Arab Strap, cheese dreams have been a part of our popular culture for over the last 150 years. But is there actually any truth in this old wives’ tale?

A study conducted in 2005 by the British Cheese Board attempted to debunk this claim by giving 200 participants 20 grams (roughly 0.7 ounces) of cheese 30 minutes before they went to bed and asking them to record their dreams and quality of sleep. In the study, 67% of participants recalled their dreams, and none reported the presence of any nightmares, something the Cheese Board is calling a win.

Instead of night terrors, the researchers report that the cheese resulted in pleasant nighttime fantasies in most individuals. They even went so far as to test the varying effects different types of fromage had on an individual’s dream-state. From their conclusions, blue Stilton resulted in the most bizarre trips, affecting about 80% of participants and resulting in visions of talking animals, vegetarian crocodiles and warrior kittens. On the other end of the spectrum, Cheshire cheese produced the least memorable nights, with less than half of the participants being able to recall their dreams.

The study (again, initiated by the cheese industry) also claimed that eating cheese before bed actually helped people fall asleep. This is supposedly due to the relatively high tryptophan content in cheese, an amino acid involved in the production of melatonin (and serotonin), which plays an important role in our sleep-wake cycle.

However, it should be noted that there was no report of a control or placebo group in this experiment, such as participants who ate nothing or consumed a soy cheese sample (yum!) before bed. Thus, there’s no empirical evidence that it was actually the cheese causing these effects and that it was not just the natural sleep state for these individuals.

As for the dream link, there is only one academic paper that mentions the cheese-dream phenomenon, and that is only anecdotally. However, one Internet theory I found (I know, I’m reaching here) proposed that the bacteria and fungal content in cheese, and in potent blue cheeses in particular, might be at the root of the increase in dream vividness. This is due to the potential psychoactive effects different compounds found in fungi, like tryptamine or tyramine, might have, influencing our brains’ chemical systems and thus our state of mind.

Tryptamine is a common chemical precursor for serotonin and other related alkaloids, some of which are involved in the hallucinogenic effects of psilocybin (“magic” mushrooms) and DMT. However, there’s no hard evidence that tryptamine is actually present in the Stiltons and Gorgonzolas of the world, and even if it was, it would be in extremely low doses. After all, when was the last time you felt high after eating cheese?

Conversely, tyramine is a monoamine that works by releasing other neurotransmitters like adrenaline, noradrenaline and dopamine into the body. Another theory is that tyramine’s effect on noradrenaline release in an area of the brain called the locus coereleus, a region important in our sleep-wake cycle, is altering our dream patterns.

Some antidepressants work by inhibiting the breakdown of monoamines (monoamine oxidase inhibitors – MAOIs), and it can be potentially dangerous to eat foods high in tyramine when on this medication as it can result in an excess of these chemicals in your brain and body. The medication mentioned in the old academic paper, pargyline hydrochloride, actually works as an MAOI, potentially explaining the bizarre effect eating cheese had on the patient. There are also reports of foods high in tyramine causing migraines in some individuals, particularly those on MAOIs; however, another study found no evidence of this link.

Finally, there are numerous other types of foods that contain chemical compounds like tyramine and tryptophan affecting our neurotransmitter systems. This includes cured meats, egg whites and soybeans, none of which have the dream-producing reputation of cheese. So for now, it appears to be an untenable link between cheese specifically and these nighttime apparitions.

Then again, I did eat some cheddar last night, which might just explain Bob Dylan’s appearance in my nocturnal activities. According to the Cheese Board, cheddar was linked to visions of celebrities dancing in your head.

(Thanks to Sam Greenbury for the inspiration for this post.)

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What’s keeping you awake at night?

There’s nothing worse than not being able to fall asleep at night. You toss and turn, fluffing one pillow and then another. Blankets on, blankets off. Window open, window closed. Nothing seems to be right. Thoughts about the previous day and the impending dawn tumble through your head, swirling around, popping up, flitting away – teasing you and flirting with your subconscious.

Exasperated, you give up on sleep and open your laptop to check Facebook, or pull up the latest round of Candy Crush on your phone, hoping the mind-numbing scrolling will finally hypnotize you into sleep.

But what if these LED screens are exactly what’s keeping you awake?

Several articles have reported on the effects of LED backlit screens and their emission of a certain blue-light wavelength on melatonin levels, an essential hormone that makes you drowsy and kicks in your sleep cycle. Melatonin is released naturally at the onset of darkness, preparing your body for rest, and then continuously throughout the night as part of your natural circadian rhythm – your body’s daily biological clock. However, melatonin can be partially curbed by exposure to light, and the abnormally bright glow of backlit computer screens seems to be especially disruptive to its release. Suppression of melatonin then has the opposite effects, increasing alertness and arousal, and even altering REM sleep patterns when you finally do nod off.

To test this phenomenon, researchers measured melatonin levels in college students after having them sit in front of either an LED backlit or non-LED computer screen at night for several hours. Although melatonin did rise naturally over the course of the experiment in all participants, it rose much less steeply and with a delay in those exposed to the LED screens. EEG recordings of brain activity in the frontal cortex indicating slow-wave sleep patterns were also suppressed in the LED-viewing participants. Curiously though, self-reports of sleepiness increased throughout the night in both groups (not surprising), but did not differ between the two screen groups. Thus, even though the LED group had lower melatonin levels, indicating they might have more difficulty falling asleep, they did not feel any more awake. However, researchers also had participants complete a series of attention and memory tasks during the study on their respective computers, on which the LED group performed significantly better, presumably reflecting their increased alertness and arousal, despite not objectively experiencing it.

In a similar study, a separate group of researchers sat students down in front of an LED screen from the hours of 11pm-1am (not too unusual an occurrence), but this time they also equipped them with specialized goggles that either ramped up or down the amount of blue light they received. Melatonin levels were reduced by almost 50% in the blue goggle condition, which amplified the target blue-light wavelength, but were down only 7% in the pure LED condition after two hours of exposure, and not at all after one hour. Thus, it seems the brightness of the light and the length of time spent staring at it significantly affects the impact on melatonin levels.

But maybe it’s not the screen you’re looking at itself; maybe it’s what’s on the screen that’s the problem. Several studies have reported an increase in stress levels induced by late-night texting, which can trigger insomnia and disrupt sleep patterns. A preliminary study from University of Texas Pan-American reported higher stress levels and poorer sleep in students who texted or went online within two hours before going to bed. Another report stated similar findings when it came to active screen behaviors, like emailing or playing a video game, but no difficulties in those who just watched a movie on their laptops. Thus, the problem may be more linked to the type of activity you use your computer for, with active screen behaviors causing higher arousal rates before bed.

Either way, when it comes to your night-time routine, you might do better with the age-old adage of reading a boring book or counting sheep to help you fall asleep instead of checking your email one last time.

(Originally posted on Mind Read)

A Thanksgiving ode to tryptophan

My favorite holiday is on Thursday. And while I can’t be at home in the States to celebrate, being an ex-pat at Thanksgiving does have its perks, as I get to attend multiple alternate feasts over the weekend. That means twice the stuffing, twice the cranberries, twice the turkey, twice the tryptophan.

Yes, tryptophan. That infamous amino acid we use to justify dozing off during our aunt’s vacation slideshow after the big meal. Tryptophan is an essential amino acid, a protein precursor that the body uses to build various chemical structures. This includes serotonin, one of the primary neurotransmitters in the brain that is involved in everything from decision-making to depression. Serotonin is also a precursor to melatonin, which is important in sleep and wakefulness and is where the tryptophan-tiredness link comes in. However, despite the popular neuro-myth, turkey is actually no higher in tryptophan concentration than other types of poultry. Numerous different plant and animal proteins provide us with our daily doses of tryptophan, with sunflower seeds, egg whites and soy beans having some of the highest concentrations of the amino acid. In fact, turkey comes in at a measly 10th on the list of tryptophan sources.

Instead, the relation between eating and sleeping seems to be more dependent on the amount of food consumed, rather than the type we eat. Insulin is released after every meal, particularly ones high in carbohydrates, and the more carbs consumed, the more insulin is produced. This increase then changes the chemical levels in our bloodstream, affecting the re-uptake and release of various amino acids. Ultimately these changes result in greater amounts of tryptophan crossing the blood-brain-barrier and being taken up into the brain. There the tryptophan is converted to serotonin, some of which is also metabolized into melatonin, causing our postprandial nap.

Tryptophan’s influence on serotonin levels doesn’t just affect sleep cycles. The link between depression and low serotonin levels is well established, and tryptophan supplements have been suggested as less invasive treatments for the disorder. Unfortunately these studies have been mostly unsuccessful to date, as mild modifications of tryptophan seem to have little to no effect on mood in most individuals. However, it is possible that people with low endogenous levels of tryptophan due to specific genetic profiles may be more susceptible to the chemical’s effect on mood, and current research is still ongoing in the matter.

So regardless of whether it’s turkey, stuffing or sweet potatoes you prefer, remember to load up your plate during Thanksgiving to get those happy drowsy effects later. It may just help you feel a little bit calmer, and prevent some of the Black Friday mayhem the next day.