Serotonin is a neurotransmitter often connected to mood. While serotonin deficiency is linked to depression, it has an important role in a host of other conditions such as irritable bowel syndrome, sleep disturbances, migraines, fatigue, carbohydrate cravings, and obesity.
Recognizing serotonin role in brain chemistry, pharmaceutical companies have developed a class of drugs called Selective Serotonin Reuptake Inhibitors (SSRI). Drugs in this class include, (trade names in parentheses):
- Citalopram (Celexa, Cipramil, Cipram, Dalsan, Recital, Emocal, Sepram, Seropram, Citox, Cital)
- Dapoxetine (Priligy)
- Escitalopram (Lexapro, Cipralex, Seroplex, Esertia)
- Fluoxetine (Depex, Prozac, Fontex, Seromex, Seronil, Sarafem, Ladose, Motivest, Flutop, Fluctin (EUR), Fluox (NZ), Lovan (AUS), Prodep (IND))
- Paroxetine (Paxil, Paxil CR, Pexeva, Seroxat, Sereupin, Aropax, Deroxat, Divarius, Rexetin, Xetanor, Paroxat, Loxamine, Deparoc)
- Sertraline (Zoloft, Lustral, Serlain, Asentra)
- Fluoxetine combined with the atypical antipsychotic olanzapine (Symbyax)
SSRIs were originally developed for treating depression but are now taken for treating related disorders of serotonin deficit such as insomnia, migraine, fibromyalgia, and IBS.
Most do not know that about 90% of the serotonin produced in the body is made in the gastrointestinal tract and some is even produced by our heart. It is now known to influence bowel function. A deficiency increases vulnerability to digestive stress, constipation, and irritable bowel syndrome (IBS). Low serotonin levels are often seen in chronic pain syndromes and chronic fatigue syndrome.
Serotonin is known to affect appetite, especially for carbohydrates. Low levels of the amino acid tryptophan, a precursor to serotonin in the body, have been linked to binge eating and carbohydrate cravings. When carbohydrates are consumed, insulin is released and shuttles competing amino acids from the blood into muscle. This allows tryptophan to enter the brain more easily and increase brain serotonin levels. As a result, people frequently consume carbohydrates over other foods to overcome low tryptophan into the brain and get that “carb high” or a feeling of well-being and calmness.
Exercise, by increasing uptake of competing amino acids by the muscles, has a similar action and helps elevate mood temporarily.
Our diet (caffeine, alcohol and artificial sweeteners), stress, lack of natural light and lack of exercise compromise our production and levels of serotonin.
Elevating Serotonin Levels
Serotonin cannot cross the blood-brain barrier and must be synthesized in the brain itself from the amino acids tryptophan. Here how it works:
Tryptophan => 5-Hydroxytryptophan (5-HTP) => Serotonin //=> Melatonin
Tryptophan is an essential amino acid found in protein containing foods. Modern-day diets, with fast foods and carbohydrates and even a “healthy” diet often does not provide the quantities of tryptophan required since it is the least abundant amino acid found in food.
Good sources like: chicken, soybeans, tuna, turkey, venison, salmon, cheese, lamb, halibut, shrimp and cod, should be purposefully added to our diet.
Exposure to bright light (with adequate level of vitamin D) is an effective approach that increases serotonin significantly without drugs. Bright light (Light-box therapy) is a standard treatment for seasonal depression, but evidences suggest that it is also effective for nonseasonal depression.
In order for tryptophan to be transformed into serotonin, the following co-factors are necessary; magnesium, zinc, vitamin B-6 and vitamin C. An anti-inflammatory diet, with a balance of Omega-3 and Omega-6 is also good for overall health and particularly good for the brain.
In some cases, when additional support is needed, the intake of serotonin direct precursor 5-HTP, could help. Unlike tryptophan, 5-HTP absorption is less affected by other amino acids. 5-HTP synthesizes new serotonin to refill depleted levels in the central nervous system.
Serotonin deficiency seems to be epidemic, if the numbers of prescribed SSRI are any indication. Serotonin is our primary defense against anxiety and depression but is now link with seemingly unrelated conditions like panic, irritability, IBS, PMS, OCD/perfectionism and general pain. Some small tweaks in our routine in order to make sure we get an adequate tryptophan intake and serotonin levels, can have a huge impact on our (our friends and family too!) quality of life.