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What Is Night Milk?

Why milk taken from cows at night might be the answer to better shut-eye.

There is a sleep deprivation epidemic going on in the United States. According to the Center for Disease Control and Prevention, roughly one-third of the US adult population is sleep deprived.

While prescription sleep aids have been shown to be effective for helping people get a good night's rest, they also can come with a number of troubling side effects, which depending on the chemical composition of the sleep aid might range from dependency to sleep eating.


These unwanted side effects have led to increasing interest in natural sleep aids, one of the more bizarre of which is known as night milk.

"The epidemic of sleep deprivation has been going on for a long time," said Bryce Mander, a neuroscientist at UC Berkeley's Sleep and Neuroimaging Lab. "I think longer work hours and stagnant wages are major contributors, [and] chronic stress probably fuels increases in insomnia rates. Regardless, people are sleeping less, and this is fueling the need for anything that can help them manage their excessive daytime sleepiness."

This desperation for a good night's sleep is probably what led to increased interest in sleep aids such as night milk, which as its name suggests, is milk that is collected from cows at night.

More than just a superstition or a rehashing of the old home remedy of drinking a bowl of warm milk before bed, recent research has shown that milk taken from cows at night has significantly higher levels of tryptophan and melatonin, substances long known to promote and enhance sleep.

In a study published in December in the Journal of Medicinal Food, researchers from Sahmyook University in Seoul, South Korea dosed a group of mice and rats with night milk, and found that the effects of the night milk on the rodents was comparable to the effects of diazepam (first marketed as Valium), a drug known for its sedative effects. The researchers used four groups of rodents, one of which was given night milk, another given day milk, a group dosed with Diazepam, and a control group that just drank water.


Over the course of their experiments, the researchers had the rodents perform a number of tasks, such as running on a wheel and navigating a maze. Of course, the duration and quality of the rodents' sleep was also monitored.

According to the study, mice dosed with night milk were less inclined to explore during an open field test, which the team believes reflects reduced central nervous system activity and the sedative effect of the milk. Furthermore, when the mice dosed with night milk ran on a wheel, they demonstrated decreased motor balance and coordination. Both of these effects were similar to those exhibited by the rodents under the influence of diazepam.

"In the present study, we have found that Night milk, but not Day milk, produces sedative…effects in mice," the team wrote. "The effects of Night milk were comparable to that induced by the benzodiazepine, diazepam. These findings suggest that Night milk might be an effective natural sleep aid for managing sleep-related disturbances and a promising alternative for the treatment of anxiety disorders."

Night milk hasn't been tested much on humans (a 2005 study involved giving melatonin rich night-time milk to elderly patients with positive results, however), but this recent study with mice appears to bode well for a future in which natural sleep aids replace their pharmaceutical counterparts.

Others, such as Jennifer Martin, an associate professor at UCLA's School of Medicine and member of the American Academy of Sleep Medicine's board of directors, are less certain about its potential to replace pharmaceutical sleep aids.


"Night milk appears to have higher levels of tryptophan, [so] it theoretically could increase the levels of melatonin," said Martin. "However, melatonin is not an active ingredient in pharmacological sleep aids, and melatonin itself has not been shown to improve insomnia. Since the mechanism of action is not the same, it doesn't seem likely that night milk will replace pharmacological sleep aids."

Nevertheless, a few companies have apparently seen some promise latent in night milk and have begun marketing night milk powders as a sleep aid. The first such company was the German-based Nacht-Milchkristalle, which patented its night-milk crystals back in 2010.

In order to encourage the production of night milk that is high in tryptophan and melatonin, the farmers for Milchkristalle have taken to milking their cows between 2 and 4 AM, in addition to feeding the bovines a diet high in clover, which itself contains high levels of tryptophan. The tryptophan and melatonin rich milk produced by the cows is then dehydrated, resulting in night milk crystals which can be added to other drinks or foods such as yogurt to be consumed before hitting the hay.

The main problem faced by Milchkristalle is that milking the cows at night can lead to a stress response in the animals because they are not used to that milking schedule. This stress response can then lead to severely decreased levels of tryptophan and melatonin in the resulting milk, thereby undermining the entire process. In order to circumvent this dilemma, the dairy farmers at Milchkristalle alter the lighting for the cows at night, bathing them in soft warm lights, which relaxes the animals and allows them to produce milk with increased levels of tryptophan and melatonin.


Yet in defense of the practice of collecting night milk, Heiko Dustmann, an agricultural engineer involved in Milchkristalle's night milk research, told the Guardian,"The animals even benefit from the new product with light during the day, soft lighting at night, which helps them to sleep better and enables them to produce more milk."

When you buy milk at the store, there's a pretty good chance that it was collected from cows during the day, when most dairy farms operate. Although cows milked during the day may also be subjected to relaxation techniques such as listening to soothing music while they are milked, even in the off chance they get milked in the early evening their milk is still likely to contain less melatonin than that produced by Milchkristalle's cows.

According to Tony Gnann, Milchkristalle's company manager, this is both because the night milk is diluted with milk produced during the day and the confusion brought about by being milked at night will also lead the cows to produce milk that is unusually low in melatonin. In order to produce the melatonin and tryptophan rich milk marketed by Milchkristalle, it was necessary to switch the cows to an exclusively night milking schedule (to lower confusion/stress levels from the routine change) and adjust the lighting accordingly.

"Conditions for the cows have to be just right – light in the day and very low light conditions at night," said Gnann.


Unfortunately, night milk proves hard to find, at least for now. Since I am located abroad, I asked Motherboard contributor Rachel Pick to try her hand at finding night milk in the US.

"Aside from the Milchkristalle team, I couldn't find any solid leads to finding night milk either in the US or anywhere else," Pick told me. "A product called 'Goodnight Milk' was a false start—turns out it's just a baby formula that claims to have a naturally soporific effect on infants, but isn't actually made from milk produced at night. What I did find was a lot of news coverage and hype about the potential of night milk, without any suggested means to obtaining the product itself."

Pick's observation played out for me as well in my quest to find night milk outside of the US. Of the two vendors I found online, a UK vendor hadn't been producing the stuff since the mid aughts and the German vendor Milchkristalle GmBH didn't respond to my requests comments. Which is all to say that despite the hype, night milk might not even be available commercially at the moment.

Since it appears that night milk may not become the panacea for America's sleepless nights remains any time soon, most sleep researchers agree that rather than waiting for a better sleep aid, it's more important to change the behaviors that lead to sleep deprivation in the first place.

"There was a media blitz about melatonin in the 1990s that was completely unjustified scientifically," said Mander, who remains skeptical of any 'cure all' approaches to sleep. "There is a great body of work on multiple types of sleep drugs and there is starting to be some work on alternative sedatives that some consider more "natural,"[but] the truth is that it is much more difficult to find any aids that reproduce what your body does naturally."

This opinion is buoyed by Martin, who recommended cognitive behavioral therapy, which she claims is now considered the best available treatment for insomnia, treating the disorder as well as, if not better than, sleeping pills.

"Exploring new options and developing safe and effective ways to help people with insomnia to sleep better is always beneficial," said Martin. "Clearly research with humans is needed to determine whether Night Milk can be used in this way in humans. At this point, it's important that anyone who has insomnia lasting more than three months…seeks medical care either from a primary care provider or a sleep specialist [who] can help patients to identify what is causing their sleep problems and then can recommend the best options for improving sleep."