Can serotonin in food lower testosterone?

Serotonin (in excess) can lower testosterone.

Should we thus avoid food high in serotonin if our goal is to maximize testosterone?

Quick background on serotonin

Serotonin is produced from tryptophan via the enzymes tryptophan hydroxylase (TPH) 1 & 2. About 90-95% of all serotonin is produced in the gut and the remaining 5-10% is produced in the brain. Serotonin produced in the gut doesn’t cross the blood-brain barrier unless it’s leaky.

Only about 1% of tryptophan is used to create serotonin. Serotonin is broken down by monoamine oxidase A (MAO-A) into 5-HIAA, which is then excreted from the body.

Serotonin has a modulatory function like dopamine, which exerts its effect through several different brain areas. Therefore, it has no particular function but instead “adjusts,” the brain’s behavior via a wide spectrum of neurological, mental, biochemical, and metabolic processes to better control them. This encompasses mood, wakefulness and sleep, appetite, aggression frequency, circadian rhythms, body temperature, and neuroendocrine activity (R). 

Excess serotonin in the body contributes to cancer, vasoconstriction, diarrhea, vascular leakage, fibrosis, etc. So we definitely don’t want too much of it.

Serotonin’s effect on testosterone

Serotonin inhibits testosterone production in a variety of ways such as:

• Releasing CRF in the testes and brain, which inhibits the effect of LH as well as inhibits steroidogenic enzymes (R).
• Increasing cortisol.
• Increasing prolactin.
• Impaired LH response to GnRH (R).

SSRIs are known to induce hypogonadism (oftentimes with elevated estradiol) as a common side effect (R).

Water extract from banana peel lowered testosterone and increased estrogen (R).

However, another rat study found that plantain peel water extract (same doses as above) restored testosterone and erectile function that’s been reduced by paroxetine (R).

Foods high in serotonin

There are three chief sources of serotonin: fruits, vegetables, and seeds.

They include

• bananas
• cherries
• chicory
• cabbage
• coffee beans
• brinjal
• green grapes
• legumes
• onion
• hickory peanuts
• hot peppers
• kiwi
• green lettuce
• oats
• papaya
• green pears
• pineapples
• plums
• potatoes
• green spinach
• strawberries
• tomatoes
• walnuts

In terms of quantity, the top 3 highest in serotonin are plantain, pineapple and banana.

The following fruits have high serotonin concentrations (expressed in micrograms/g):

• plantain 30.3 +/- 7.5
• pineapple 17.0 +/- 5.1
• banana 15.0 +/- 2.4
• Kiwi fruit 5.8 +/- 0.9
• plums 4.7 +/- 0.8
• tomatoes 3.2 +/- 0.6.
• butternuts (the nut, not squash) 398 +/- 90
• black walnuts 304 +/- 46
• English walnuts 87 +/- 20
• shagbark hickory nuts 143 +/- 23
• mockernut hickory nuts 67 +/- 13
• pecans 29 +/- 4
• sweet pignuts 25 +/- 8

Pineapples and bananas are the highest serotonin-containing fruit that is likely the most commonly consumed.

Are these two fruits an issue?

This study looked at the urinary and blood levels of serotonin and 5-HIAA after people consumed 4 bananas. I don’t know about you, but I’m usually satisfied after the 2nd banana. Anyway, here’s what happened to their urinary 5-HIAA. It skyrocketed.

4 bananas were enough to increase 5-HIAA to the same level found in patients with serotonin-producing carcinoid tumors. Scary right? Nope.

That’s because serotonin itself (in the platelets or urine) didn’t increase, only 5-HIAA (R). Thus, all the serotonin is metabolized to 5-HIAA by MAO-A before being absorbed.

As an interesting aside, bananas are also one of the fruits with the highest dopamine content. Dopamine is a powerful antioxidant, similar to gallocatechin gallate and ascorbic acid (R).

According to this study, when seven volunteers ingested the pulp of four bananas, there was a 46% increase in their urinary excretion of homovanillic acid (the principal metabolite of dopamine) and a 293% increase in their urinary excretion of 5-HIAA (R).

Fruit on testosterone

Now that we know that food rich in serotonin likely doesn’t even get absorbed, let’s look at the effects of fruit on testosterone.

There aren’t any placebo-controlled studies looking at this, so we have to look at in vitro and animal studies for now.

In vitro studies

A few plant compounds have been shown to stimulate testosterone production.

Flavonoids having a 5,7-dihydroxychromen-4-one backbone tend to increase the expression of the steroidogenic acute regulatory protein (StAR), being critical for the entry of cholesterol into the mitochondria, leading to increased testosterone production from testis Leydig cells (R).

A few good flavonoids are:

• Baicalein (found in Chinese skullcap)
• Luteolin
• Apigenin (Article: how apigenin can increase testosterone and how much to take)
• Chrysin

Animal studies

Combining cocoa with pomegranate rind extract has been shown to increase testosterone (R).

Raspberry (R), date (R), Feijoa (R), and citrus (R) protect the testes against toxins.

Although fruit might not skyrocket testosterone, it protects the testes against toxins that can potentially lower testosterone production.

Fruit and erectile dysfunction

The last thing to look at is serotonin-rich food on erectile function.

Since fruit is the most commonly consumed serotonin-rich food, let’s look at fruit and erectile function.

As you can guess, fruit likely improves erectile function and reduce the risk of getting ED.

This study found that higher total intake of fruit, a major source of anthocyanins and flavanones, was associated with a 14% reduction in the risk of ED (R).

Another study found that the consumption of 50mg/day of flavonoids lowered the risk for ED by 32% (R).

Some of the benefits include a reduction in vascular inflammation, increased NO bioavailability, and reduced PDE5 expression.

Anthocyanidins (part of the flavonoid category) are particularly high in blackberries, blueberries, cranberries, cherries, and elderberries. All contain >80 mg/100 g. Elderberries are the highest at 749 mg/100g.

Other fruits are also rich in flavonoids, so don’t feel like you have to limit it to berries.

Summary

Food rich in serotonin doesn’t increase circulating serotonin as all of it is broken down in the gut. Since 95% of all serotonin is produced in the gut, the gut is also rich in MAO-A to metabolize it.

Fruit also has many other benefits, such as improving sleep quality, lowering inflammation, helping against constipation, improving gut health, protecting against neurodegeneration and much more.

Don’t be afraid of fruit, it’s more likely to increase your testosterone than anything else.

• The complete guide on how to boost your testosterone
• The complete guide on how to lower excess serotonin
• My favorite anti-serotonin stack
• How to lower serotonin and increase dopamine with this simple stack