The sleep
Sleep is an ACTIVE CYCLICAL brain process (REM phase and NREM phase) which is absolutely essential for maintaining the general state of health.
Broadly speaking, it is possible to define that sleep reduces cerebral metabolism during the NREM phase and increases it during the REM phase; this alternation of the two phases determines a hyper and low central activation oscillation in constant evolution and influenced by numerous neuro-endocrine factors. The hormonal axis that regulates sleep-wake is also determined by: general stress, activities carried out in the evening hours, evening nutrition and other components of a psychological nature.
Influence of evening feeding on sleep
Evening feeding, both in quantitative and qualitative terms, can favor or make it difficult to start and maintain sleep.
The foods, and the nutrients they contain, interfere (more or less importantly) in hormone production and in endocrine regulation; moreover, the excessive commitment of the digestive system severely penalizes the activation and quality of sleep itself. From the biochemical point of view, it has been amply demonstrated that some nutritional molecules determine the secretion of sleep-favorable mediators, while others perform the opposite function; Among the sleep-promoting hormones we mention:
- Melatonin
- Serotonin
on the contrary, among the molecules that make it more difficult we remember:
- Dopamine
- Adrenaline
- Norepinephrine
Having said that, it is obvious that pro-hypnic foods (that is, those that promote sleep) supply above all precursor molecules and / or favor the synthesis of melatonin and serotonin. Basic groups:
- Foods containing tryptophan, an essential amino acid which in turn stimulates the production of melatonin and serotonin; it is contained in:
- Milk and cheese
- Meat and fish
- eggs
- Beans, chickpeas, broad beans, lentils, peas, peanuts
- Hazelnuts, almonds
- Whole wheat
- Banana, avocado, pineapple
- spinach
- Foods containing complex carbohydrates, polymeric macronutrients that cause the pancreas to produce insulin, a hormone that promotes the availability of tryptophan; complex carbohydrates are found mainly in cereals and derivatives, potatoes and chestnuts.
- Foods that contain good amounts of Thiamine (vit B1, contained mainly in cereals and legumes) and Pyridoxine (vit B6, almost ubiquitous) as essential components for the biosynthesis of serotonin. NB: SIMPLE carbohydrates have a negative effect on the bioavailability of pyridoxine.
- Foods that contain calcium and magnesium are also INDIRECTLY involved, whose deficiency negatively affects sleep cycles.
Milk before sleep
Having a rough view of the interaction between feeding and triggering and / or maintaining sleep, it is now possible to assess the hypnic potential of the milk consumed in the evening hours with greater objectivity.
Let's start by specifying that:
- tryptophan, pyridoxine and calcium, although present in cow's milk (the one most consumed) could also be consumed through the consumption of numerous foods; among other things, wanting to be precise, drinking cow's milk in the evening hours DO NOT introduce significant amounts of thiamine, magnesium and complex carbohydrates, which are useful for promoting better sleep quality.
That said, it seems obvious that the habit of taking milk in the evening hours in order to improve sleep quality (or even prevent insomnia) has NO biochemical basis; in simple terms, from a nutritional point of view, a glass of milk before bed has a hypnotic efficacy similar or even lower than that of a plate of "beans in the bird". It is true that psychology probably plays a decisive role; some specialists attribute to the warm milk before sleep a regressive potential that evokes infantile sensations and emotions responsible for a deep psychic relaxation ... which has nothing to do with tryptophan.
In conclusion, drinking milk in the evening hours does NOT directly improve the quality of sleep, or rather, no more than other foods; an obvious objection could be that: drinking hot milk, as opposed to eating many other foods, does not over-commit digestion ... False! Cow's milk, although a liquid food, certainly does not stand out for its easy digestibility. In fact, taking lactose tolerance for granted (and avoiding the formation of lactulose with heat), the protein content of cow's milk determines a sort of REBOUND effect on the acidity of the stomach. It favors a transitory increase in gastric pH consequent to the DILUTION of the digestive juices but later, thanks to the proteins contained in it, it stimulates in a decisive manner the production of pepsinogen and hydrochloric acid; obviously, all this happens during sleep, when both the acidity of the stomach and the tendency to gastro-esophageal reflux (facilitated by the supine position) are not perceived. Therefore, although it may represent an indispensable habit, it is possible to say with certainty that drinking milk before sleep is completely DISCOALED for gastro-sensitive subjects or those suffering from other disorders of the upper digestive tract.
A matter of taste or drug addiction?
According to some research, the poor digestion of the proteins contained in cow's milk would be responsible for maintaining numerous diseases of the central nervous system; the partial degradation of the aforesaid proteins would determine the entry (via the intestinal mucosa) of peptides composed of 7-15 amino acids defined as "opioids" or "caseo-morphine". It seems that these macromolecules (if present in significant quantities) are able to ALSO pass the blood-brain barrier to interact with some opioid receptors in the central nervous system; through this mechanism, caseo-morphine would hinder the processes of uptake of melatonin and serotonin, and would lead to neuro-psychiatric changes such as addiction and behavioral alterations. Based on these results [Ledochowski 1998 - Lecks 1986 - Kaplan 1989 - Kahn 1985 - Kahn 1988 - Kahn 1989 - Hanninen 1999], it would be possible to define that drinking milk before sleep, in addition to conferring no benefit, could lead to disorders sleep-wake cycles.
Readers do not take this research as "pure gold" or the discovery of the century; remember that the amino acids contained in milk proteins are the same nutrients contained in all foods; moreover, how is it possible to determine whether these caseo-morphines actually derive from the intestinal lumen and were not intermediate metabolites of some other physical or pathological process? Was the intestinal mucosa of the research samples intact? What is the age of the group studied (it is known that the intestinal permeability of children is much higher than in adults)? What basic neuro-psychiatric conditions related to the subjects? These are all questions whose answers would determine the reliability or otherwise of the results mentioned above; personally, I suggest the accurate reading of the works and the independent evaluation of the conclusions reported by the authors.
