Which foods lower serotonin?
One more reason to avoid excess fructose – it can prevent you from absorbing tryptophan. As many as 1/3 of us are prone to fructose malabsorption with even the smallest amounts of fructose. If you are among the sensitive, even small amounts of it can be an issue. Even if you’re not sensitive to fructose, too much can block tryptophan for most anyone.11
About one-third of the Western European population has fructose malabsorption – the inability to absorb fructose efficiently.12 This problem can affect women even more strongly than men. The researchers in this particular study pointed to estrogen as the reason, since estrogen activates an enzyme that alters the metabolism of tryptophan from serotonin (happy) to kynurenic (not happy). It doesn’t help that women have less tryptophan in their bodies than men to begin with, so anything that further decreases the amount of it or alters its metabolism is going to adversely affect their serotonin levels, leading to low serotonin symptoms.13
Alcohol is a psychoactive agent that depresses the central nervous system. Small to moderate amounts of alcohol can increase the amount of serotonin in the body temporarily, which can be a problem for those taking an SSRI, since an additional increase in serotonin puts them at risk of serotonin toxicity syndrome.
Regular use of alcohol causes major disturbances in the metabolism of brain serotonin, decreasing the amount of it in the brain. It also makes the cells respond more poorly to the serotonin that is present. This would explain the link between excessive alcohol use and aggressive behavior, as well as depression and anxiety (or a worsening of those symptoms).14
3. Diet soda (aspartame)
Diet sodas aren’t an improvement, though. Aspartame’s content is about 50% phenylalanine, which has been shown to deplete serotonin to such an extent, it has been known to trigger manic depression, hallucinations, panic attacks, paranoia, and even suicidal tendencies, as well as other symptoms of low serotonin listed above. The amino acid tyrosine, a product of phenylalanine, “reduces the amount of tryptophan that can cross the blood-brain barrier for utilization in serotonin production.”15
Dopamine is a metabolite of phenylalanine, and altered brain dopamine concentrations have been linked to mental illness, particularly schizophrenia. The direct injection of dopamine into the brain ventricles of humans can induce hallucinations and psychotic episodes.16
Besides phenylalanine, aspartame also contains 40% aspartic acid and 10% methanol. It comes from genetically modified E. coli bacteria. Aspartic acid is an excitotoxin, meaning it goes right to the brain and starts poking it with tiny cattle prods. Methanol is wood alcohol used in antifreeze.17
Considering the bounty of healthier alternatives available, there’s no reason for us to continue poisoning our bodies with chemicals that alter our brain chemistry (for the worse). A fermented drink like kombucha – available in a variety of flavors – will not only refresh you in ways that chemical-laden soft drinks can’t, it will also add beneficial flora to your gut, which in turn can raise serotonin production and help your body heal itself.
I’m wincing as I write this, but even caffeine doesn’t come out squeaky clean under close examination. North Americans who drink caffeinated beverages tend not to stop at the recommended daily limits, and while drinking caffeinated beverages can increase serotonin, excessive caffeine consumption increases the body’s need for the neurotransmitter.
Caffeine increases cortisol levels, in proportion to the amount of caffeine consumed, so while a moderate amount can raise serotonin levels, more than that will raise cortisol levels to the point where your body needs more serotonin to balance the cortisol, since these two neurotransmitters need to remain in balance with each other.18
Your brain adapts to the amount of caffeine you habitually drink, so when you cut back or miss a cup or two one day, the absence or shortfall of caffeine results in a drop in your serotonin levels, which can cause irritability, headache, feelings of anxiousness, and an inability to concentrate.19
According to Medicine Plus, drinking two to four cups of coffee a day isn’t likely to be harmful, but everybody is different, and if you’re experiencing frequent headaches, rapid or irregular heartbeat, and difficulty sleeping, you should probably cut back on the caffeine. Too much is unlikely to improve your performance if it sends you to bed with a headache or puts your heart at risk. 20
Coffee can also inhibit your body’s absorption of iron, which is a key mineral in the synthesis of both serotonin and dopamine. It can also decrease the circulating amounts of B vitamins, and since we need the activated form of B6 to synthesize serotonin, this can decrease the amount of serotonin produced, while simultaneously creating a greater need for it.21