It’s a ritual that we have all experienced at some point: enjoying a glass of milk before sinking into the arms of Morpheus. A “pleasure” gesture but which also, according to some, has incredible virtues. Julie Boët, dietitian-nutritionist, disentangles the truth from the false on this subject.
Milk, a superfood that could soothe
Sleep is a complex biological process, regulated by our nervous and hormonal systems. It depends in particular on serotonin and melatonin, two hormones derived from a well-known amino acid: tryptophan.
“However, milk naturally contains it. So this is where the idea that it could help you sleep better comes from. Tryptophan, once absorbed, is used to produce serotonin, the relaxation neurotransmitter, then melatonin, the sleep hormone.“, specifies Julie Boët.
Some studies have actually shown that foods rich in tryptophan can help you fall asleep and improve sleep quality, “especially when consumed in the evening, in a soothing context”, continues the expert. But these are not the only good points of milk! It also contains calcium, magnesium and zinc, three minerals which contribute to the proper functioning of the nervous and muscular system.
“Drinking a lukewarm drink, such as heated milk, often plays an important psychological role: it is a comforting ritual, associated with calm and security. This relaxing effect therefore comes not only from the composition of the milk, but also from the gesture itself and the moment of relaxation that it represents”, underlines the dietician.
A recipe that may not suit you
However, not everyone gets the same benefits from that nighttime glass of milk. Milk contains lactose, a natural sugar that requires an enzyme to be digested: lactase. However, many people produce this enzyme… in insufficient quantities, especially in adulthood. “We then speak of lactose intolerance. When lactose is not well digested, it ferments in the colon, causing bloating, abdominal pain, gas or digestive discomfort. These disorders can disrupt falling asleep or cause nighttime awakenings, the opposite effect to that sought. For these people, drinking milk before sleeping therefore does not promote sleep, but on the contrary can weaken”, warns the nutritionist.
Several studies have also revealed that the consumption of milk or dairy products can improve certain aspects of sleep, but the results remain variable depending on the individual. “Other work has shown that milk consumed in the evening can prolong total sleep time and improve the feeling of rest, without the effect being spectacular,” admits the expert.
Surprising fact: milk from cows milked at night naturally contains more melatonin. An “enriched” milk, which appears to reduce the time it takes to fall asleep and increase the duration of sleep. In humans, a modest improvement in sleep quality is also observed.although these results need to be confirmed”, nuances the specialist. Now it remains to be seen which type of milk to choose!
What type of milk to consume?
Whole milk, richer in fat, is often more nourishing and smoother, but it digests more slowly.
“In some people, especially those suffering from reflux or slow/difficult digestion, it can therefore interfere with sleep. A lighter, semi-skimmed or skimmed milk is therefore preferable. On the other hand, for those who tend to be hungry during the night, a slightly fattier milk can help avoid awakenings linked to a drop in blood sugar, even if it is more interesting to balance your diet to regulate your cravings. she assures.
For people with intolerance, lactose-free milk is an interesting alternative. It contains the same nutrients and the same tryptophan, but without the digestive discomfort. “Certain plant milks enriched with calcium can also be considered, even if their natural tryptophan and melatonin content is lower. specifies Julie Boët.
Then, be careful not to neglect the (right) time and the quantity ingested. Drinking a large glass of milk just before bed can make digestion difficult, especially if it is very cold or taken in excess. “On the other hand, a small warm cup, about an hour before bedtime, is more easily integrated into the process of falling asleep. Hot milk, through its soothing and symbolic effect, then acts more as a signal to the body that the day is ending, than as a natural sleeping pill.” underlines the nutrition specialist.
Of course, a simple occasional glass of milk will not have an impact on your sleep: it remains multifactorial (and depends on your stress level, your exposure to light, your eating habits and your pace of life…).
“If sleep is regularly disrupted, drinking milk will not be enough to solve the problem. You must also ensure that you maintain good sleep hygiene: light dinner, limit caffeine, avoid screens in the evening and adopt calming routines,” concludes the nutritionist.