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 different receptor subtypes, thus exhibiting a wide range of functions that influence an equally wide range of organic activities. Among all, serotonin is particularly known for its ability to promote good humor and tranquility, among other things reducing food intake. With reference to this last point, it is believed that serotonin:
- determines 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
drugs
Not surprisingly, the agonists of the serotoninergic system - such as fluoxetine (prozac) - induce an immediate and significant drop in food intake. These drugs are used in the therapy of depression, because - by increasing the levels of serotonin in the nervous synapses - they improve the mood of the individual. They are also indicated in the treatment of bulimia nervosa, a eating behavior disorder characterized by frequent binges, often compensated by self-induced vomiting or by the abuse of laxatives.
An agonist of the serotoninergic system, fenfluramine, has long been used in the treatment of obesity, given the well-documented role in increasing serotonergic transmission and inducing a sense of satiety, both in men and in animals. Unfortunately, the marketing authorization was withdrawn in 1997, driven by increasing reports of cases of pulmonary hypertension and valvulopathies.
Conversely, serotonergic antagonists - with the opposite effect compared 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 mainly interacting with a particular type of post-synaptic receptors, concentrated in the lateral end of the ventro-medial hypothalamic nucleus. Its anorectic action can also be linked to the reduction of the synthesis and release of neuropeptide Y, which increases the search for food, in particular 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 sugar when the mood is low and you are looking for serenity and tranquility. However, the prolonged introduction of high glycemic index carbohydrates creates insulin resistance, a situation that predisposes to type II diabetes and more generally to a dysmetabolic picture indicated by the name of syndrome X or metabolic. 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 the levels of serotonin with food, without running the risk of getting fat, it is necessary to take low-calorie foods, rich in tryptophan but poor in other amino acids such as leucine and phenylalanine. Unfortunately, this characteristic is partially satisfied only 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 the article: branched amino acids and central fatigue).
These strategies are contraindicated in the presence of migraine, given that in similar circumstances raising serotonin levels would further aggravate the problem.
Supplements
In mild mood disorders it is also possible - subject to medical consent - to resort to the specific supplementation of tryptophan, or better still of its 5-hydroxytryptophan derivative, present in food in paltry 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 of the immoderate need for sweet foods) .
