It's a popular image in media: someone settling down for bed with a nice warm glass of milk. But is this just an old wives' tale or are there actually benefits of drinking milk before bed?
The Problem with Restlessness
Approximately one-third of American adults aren't getting enough sleep. This isn't just unpleasant, leading to sleepy days and dragging feet. It can have more serious health consequences, such as high blood pressure, obesity, diabetes, and increased risk of heart attack. An increased risk of death is associated with severe sleep deprivation.
There are a lot of factors that lead to poor sleep, and a glass of milk can't counter them all. However, it might be one tool in your toolbox as part of an overall plan to better sleep habits.
But Does Warm Milk Help?
This is one of those cases where old wisdom actually rings true. In one study, researchers gave patients in a coronary care unit a mixture of milk and honey. By day three, the patients who had the milk and honey there was "a significant difference in sleep scores between the intervention and the control groups."
In fact, it may not be just milk that's warm or milk that helps with sleep. Sometimes the hardest part of getting good rest is falling asleep. One study looked at the consumption of milk and cheese alongside leisure-time physical activity. What researchers found was that those who engaged in leisure-time physical activity as well as consumed milk or cheese were less likely to complain of difficulty initiating sleep.
Another study went further and found that even yogurt may be helpful. They found that fermented dairy products can help by altering microbes in the gut that help favor production of serotonin, which can be converted to melatonin. (Read on for more about those two.)
Why Milk Aids in Sleep
The mechanisms behind why milk may help with sleep are surprisingly complex and multi-faceted. There are a few factors that play into it, including gut biome, proteins, tryptophan, melatonin, and the micronutrients zinc and magnesium.
Tryptophan
Tryptophan is an amino acid that can help improve sleep and mood. It also plays a role in the production of serotonin and melatonin. It turns out that the primary sources of protein in dairy, whey and casein, are rich in tryptophan.
Serotonin
Serotonin is a neurotransmitter that most people know affects mood. It also helps with cognitive function and memory. A group of researchers studied serotonin and found that serotonin itself can build up sleep pressure that may promote sleep.
Melatonin
Your body releases the hormone melatonin in response to low light and darkness to help you feel sleepy. It helps keep your natural sleepy rhythms in check. One study even discussed looking into melatonin as an early preventative to promote healthy aging and preventing Alzheimer's Disease.
Micronutrients: Zinc & Magnesium
Helping the role milk may have in sleeping is the micronutrients in milk. Particularly zinc and magnesium. These two nutrients have a lot of health benefits but they're also cofactors in the production of melatonin from serotonin.
Pre/Probiotics & Gut Health
Beneficial bacteria is well-known to be great for digestion, but did you know it can help with sleep? Researchers have found that fermented dairy products exert beneficial effects on sleep. This is because it alters the gut biome to further make it easier to produce serotonin, which we now know from above can convert to melatonin.
Busting Concerns
There could be some concerns about drinking milk before bed. Some are legitimate, such as those who are truly allergic to dairy or are lactose intolerant. (Though you may be surprised to find it's not lactose intolerance at all but a reaction to the beta casein…[Link to A2 Blog article])
However, we can put to bed a few common concerns.
Some might worry that it could cause weight gain. However, in conjunction with exorcise, drinking casein-containing milk 30 minutes before sleep can actually help with muscle recovery. Another study found that casein and whey proteins in milk before bed can help with your resting metabolic rate, or how fast one burns calories, the next day.
There's also the common belief that drinking milk increases mucus production and might make them snore. However, a study looking at the link between milk consumption and mucus production or asthma found there was no evidence of a correlation except for those individuals who were allergic to milk who had asthma-like symptoms.
Conclusion
Sleep can be hard to get with our busy lives, electronics, health conditions and other factors. However, there are some things that can help. Turns out grandma's advice of adding a warm glass of milk before bed is one way to promote healthy sleep. (That or a delicious, cheese-filled charcuterie for dinner!) And prioritizing good sleep habits is just one (large) part of great overall health.