Food and Mood
As many know, there is a well-known and documented relationship between serotonin and food intake, as well as between nutrition and mood.
What is Serotonin
Serotonin is a neurotransmitter that acts on several receptor subtypes, thus exhibiting a wide range of functions that influence an "equally wide range of organic activities. Of all, serotonin is particularly known for its ability to promote good mood and tranquility, among other things by decreasing food intake. With reference to this last point, it is believed that serotonin:
- cause an "early onset of the satiety signal
- reduce the palatability of food and the total amount of food ingested
- reduce the ingestion of carbohydrates and increase the ingestion of proteins;
- does not affect fat intake and meal frequency
Medicines
Not surprisingly, the agonist drugs of the serotoninergic system - such as fluoxetine (prozac) - induce an immediate and significant decrease in food intake. These drugs are used in the therapy of depression, as - by increasing the levels of serotonin at the level of the nerve synapses - they improve the mood of the individual. They are also indicated in the treatment of bulimia nervosa, an eating disorder characterized by frequent binges, often compensated by self-induced vomiting or by the abuse of laxatives.
A serotonergic system agonist, fenfluramine, has long been used in the treatment of obesity, given its well-documented role in increasing serotonergic transmission and inducing satiety in both humans and animals. Unfortunately, the marketing authorization was withdrawn in 1997, driven by increasing reports of cases of pulmonary hypertension and valvulopathies.
Conversely, serotonin antagonists - with the opposite effect to the previous ones, and as such used in the treatment of migraine - cause an increase in appetite.
How it works
Serotonin suppresses food intake by interacting mainly with a particular type of post-synaptic receptors, concentrated in the lateral extremity of the ventro-medial hypothalamic nucleus. Its anorectic action can also be linked to the reduction of the synthesis and release of the neuropeptide Y, which increases the search for food, in particular for carbohydrates.
For the same reason, the cerebral concentration of serotonin can be modified with the choice of food; for example, foods rich in simple sugars and tryptophan, such as chocolate, increase serotonin levels. It is therefore completely physiological and natural to look for foods rich in sugars when the mood is low and you are looking for serenity and tranquility. However, the prolonged introduction of carbohydrates with a high glycemic index creates insulin resistance, a situation that predisposes to type II diabetes and more generally to a dysmetabolic picture referred to as the X or metabolic syndrome. Among the various consequences there is also an obsessive need to introduce sugars (carbohydrate craving), due to a transient increase in serotonin, determined precisely by insulin, which improves the mood.
Increase it with Food
To increase serotonin levels with food, without running the risk of gaining weight, it is necessary to eat low-calorie foods, rich in tryptophan but low in other amino acids such as leucine and phenylalanine. Unfortunately, this characteristic is only partially satisfied by some fruits, such as papaya, bananas and dates.
Another way to increase serotonin levels is to practice physical activity, since the muscles mainly use branched chain amino acids, saving more tryptophan (see article: branched chain amino acids and central fatigue).
These strategies are contraindicated in the presence of migraines, since in such circumstances raising the levels of serotonin would contribute to further aggravate the problem.
Supplements
In mild mood disorders it is also possible - with medical consent - to resort to the specific integration of tryptophan, or better still its derivative 5-hydroxytryptophan, present in food in negligible quantities. This amino acid derivative, capable of crossing the blood brain barrier, is proposed as an antidepressant, a valid aid against insomnia (serotonin can be converted into melatonin) and anorectic (inhibitor of appetite, especially the excessive need for sweet foods) .
