Learn how dietary choices and nutrient intake, such as tryptophan, can influence brain chemistry and mood.
Depression is on the rise globally, but an overlooked solution may be as simple as what we eat.
Nutrition plays a crucial role in brain health and mood regulation, with key nutrients like tryptophan serving as the building blocks for feel-good neurotransmitters.
“The brain is a high-performance machine“ that requires the right ”premium-grade fuel” to function optimally, Chantelle van der Merwe, a registered dietitian, told The Epoch Times. People struggling with depression often lack these essential nutrients, putting them at a significant disadvantage.
This overlooked factor in mental health may hold the key to a more holistic approach to managing depression.
Tryptophan Deficiency Can Worsen Depression Symptoms
A meta-analysis
published in Neuropsychopharmacology investigated the effects of tryptophan deprivation on humans.
The study found that when people who had previously recovered from depression were deprived of tryptophan, it triggered a significant recurrence of depressive symptoms in around 50 percent of them. Also, 20 percent experienced a complete relapse back into a “full blown” depressive episode, according to the authors.
The researchers concluded that acute tryptophan depletion (ATD) causes a near or complete return of depression, described as “depressive exacerbation” or a “partial relapse.” One possible reason, as suggested by
previous research, is that lowering dietary tryptophan levels can reduce brain serotonin levels.
One strategy to enhance serotonin synthesis is to take in optimal amounts of the precursor nutrients. Tryptophan is the precursor to 5-hydroxytryptophan—5-HTP for short—which is the precursor to serotonin.
Patrick Holford, a British author and nutrition expert, told the Epoch Times that “a year or so on antidepressants really drives serotonin low and may account for the severity of withdrawal effects.” According to a
systematic review done by University College London scientists, people who use antidepressants have lower levels of serotonin in their blood, suggesting that long-term antidepressant use reduces serotonin concentrations. Mr. Holford said that in these cases, supplementing the most potent form of tryptophan, 5-HTP, from 100 to 300 milligrams, could be effective in relieving depression.
In a study published in a
Japanese Society of Psychiatry and Neurology journal, participants took a daily dose of 150 to 300 milligrams of 5-HTP for three weeks. Researchers found that almost 68 percent of the participants experienced mood improvement.
Pairing Carbs With Protein May Increase Tryptophan Levels
Increasing tryptophan levels in the brain may not be as straightforward as simply including more tryptophan-rich foods in your diet. This may have to do with how tryptophan gains access to the brain at the level of the blood-brain barrier.
Large amino acids like valine, isoleucine, leucine, tyrosine, phenylalanine, and methionine are prioritized at the blood-brain barrier. Tryptophan, on the other hand, is not favored, as it is not an abundant amino acid. This means that when we consume a protein-rich meal, the high plasma levels of the large amino acids will compete with tryptophan,
preventing a rise in brain tryptophan levels.
This may be mitigated by including a carbohydrate-rich food alongside the protein. Carbohydrates trigger the release of insulin, which stimulates the uptake of the large and abundant amino acids into the muscles rather than into the brain. This
allows tryptophan to pass through the blood-brain barrier with less competition from the other large amino acids.
Optimal absorption and conversion of tryptophan into serotonin require the presence of certain enzymes and nutrients. “For tryptophan to become serotonin, it needs the help of several nutrients, including vitamin B6 (found in foods like tuna, chicken, papayas, oranges, and cantaloupe),” Ms. van der Merwe said.
Main Problems for Tryptophan to Serotonin Conversion
When considering optimal serotonin production, the health of the digestive system is crucial.The gut-brain axis is a bidirectional communication system that links the gut’s functioning with the brain’s cognitive and emotional centers. While neurons located in the central nervous system account for only 5 percent of total serotonin synthesis, a staggering 90 percent of serotonin is produced in the periphery, with the gut’s lining being the most prominent source.
Evidence suggests that people suffering from irritable bowel syndrome (IBS) experience changes in the balance of their gut bacteria, and this is associated with alterations in both brain and gut serotonin levels. A 2014 study review published in the
Journal of Neuroscience found that the metabolic activity and composition of the gut microbiome play a role in brain disorders such as depression, anxiety, and autism.
Stress levels are another factor that must be considered in the conversion of tryptophan to serotonin.
Long-term stress may decrease brain tryptophan availability. This is because chronic stress tends to
divert available tryptophan metabolism away from the 5-HTP and serotonin production pathway and toward the kynurenic pathway, a major route for the breakdown of tryptophan.
Tips to Optimize Brain Tryptophan Levels
To support optimal serotonin production, be sure to:
- Include tryptophan-rich foods in your diet, such as chicken, turkey, nuts, and seeds.
- Add a carbohydrate source to enhance tryptophan absorption at the blood-brain barrier level.
- Eat a varied, nutrient-dense diet because different nutrients are required to convert tryptophan to serotonin.
- Get enough vitamin B6, which is found in foods like beef liver, salmon, chickpeas, dark leafy greens, and bananas (and the foods mentioned earlier).
- Maintain a healthy digestive system, as the gut is a significant producer of serotonin through the gut-brain axis.
- Manage stress levels effectively, as chronic stress can divert tryptophan metabolism away from serotonin production.
