By Tilman Nathaniel, Founder of Superfood Box
How LNAAs and BCAAs Incluence Tryptophan Levels
Tryptophan, an essential amino acid, is converted in the brain to the neurotransmitter 5-hydroxytryptamine (5-HT), or serotonin, which boosts our mood and helps us sleep or relax. It is found naturally in many foods. One way of boosting serotonin with high tryptophan foods is consuming foods with a high tryptophan to LNAA ratio (large neutral amino acids). This is because the LNAAs compete with tryptophan to cross the blood-brain-barrier (Pardridge, Choi).
I couldn’t find any site that had these ratios so I did the math for many of the top sources of tryptophan to see which would be the most effective in boosting serotonin. The winner was Chia Seeds, by quite a bit!
These are all from the USDA’s Food Composition Database, which doesn’t include every single food in existence. The highest known source of Tryptophan is Griffonia Simplicifolia seeds, which is typically used for most 5-HTP supplements.
Branched-chain amino acids (BCAAs)- leucine, isoleucine, and valine- all three of which are also LNAAs, appear to play a role in serotonin release. They are used by the muscles during exercise, which increases the ratio of free tryptophan to LNAAs, releasing serotonin and signalling fatigue to the athlete. One study showed that having long-distance runners consume BCAAs during a race was able to delay the onset of physical and mental fatigue (Blomstrand). Another study found that BCAA supplementation offered positive results for anorexic cancer patients by manipulating plasma tryptophan levels to boost caloric intake, reducing incidence of anorexia.
How Free Fatty Acids and Vitamin B6 Influence Tryptophan Levels
Fatty acids can also be modulated to optimize free tryptophan levels in the blood. Tryptophan and fatty acids bind to albumin, the most abundant protein in our blood which is made by our liver.
The fraction of bound tryptophan varies inversely with the plasma fatty acid level and it is the free fraction that competes with branched chain amino acids for entry into the brain (Felipe, Grisolia).
In a study of rats fed a vitamin B6-deficient diet for 4 or 9 weeks, there was no significant difference in total serum tryptophan levels for either group, but the concentration of serum free tryptophan levels were significantly lower in the rats fed a vitamin B6 deficient diet for 9 weeks. The 9 week group also showed a significant decrease in free fatty acids correlated with the significant decrease in free tryptophan levels. The authors attribute the decrease in free serum tryptophan levels to the decrease in free fatty acid levels. Their data also showed that the B6 deficiency diet over 9 weeks led to a significant increase in the plasma levels of BCAAs (Allegri, Costa, Bertazzo).
Carbs and Tryptophan to LNAA Ratio
Another factor that affects the balance of plasma tryptophan to LNAA ratio, which has been established as an indicator of transport levels into the brain, is the makeup of carbohydrates in a meal. In one study, carbohydrate-rich meals resulted in a small increase in the ratio of tryptophan to LNAAs, while protein-rich meals corresponded with a decrease in the ratio of tryptophan to LNAAs.
Tryptophan Podcast with an Expert
This podcast covers some of the topics mentioned above and many more interesting questions, in an interview with professor Gilles Guillemin, who has been studying Tryptophan for 17+ years.
Show Notes - Courtesy of SmartDrugsSmart.com
Introduction to Professor Gilles Guillemin and L-tryptophan
This Week in Neuroscience: Long-Term Effects Of Alcohol Impair Brain's Pathways That Underlie Impulse Control
Thank-you to Jt Olsen
New writing on SmartDrugSmarts.com: Hypnagogic Harvests of a Sputtering Brain
The French Paradox
Mythology of L-tryptophan and Thanksgiving
What is L-tryptophan?
The effects of L-tryptophan and 5-HTP on our neurochemistry
Light exposure and its effects on Serotonin versus Melatonin production
Resveratrol, Nicotinamide adenine dinucleotide (NAD+) and anti-aging
Differences between consuming tryptophan as a supplement and as part of your diet
Why would one supplement with 5-HTP over L-tryptophan to regulate mood?
Difference between chemically synthesized and natural 5-HTP
Serotonin and quinolinic acid and their effects on depression and suicidal behavior
Ketamine used as an antidepressant (and Ketamine's physiological downsides)
L-tryptophan as a biomarker and its use with cancer patients
Tryptophan metabolites and their role in protecting fetuses from mothers' immune systems
Daily recommended amounts of tryptophan and how to get it in your diet
What does the "L" mean in "L-tryptophan"
Ruthless Listener-Retention Gimmick: What Do You Call A Group Of Turkeys?
Allegri, Graziella, Carlo VL Costa, and Antonella Bertazzo, eds. Recent advances in tryptophan research: tryptophan and serotonin pathways. Vol. 398. Springer Science & Business Media, 2012.
Blomstrand, E., et al. "Administration of branched-chain amino acids during sustained exercise—effects on performance and on plasma concentration of some amino acids." European journal of applied physiology and occupational physiology 63.2 (1991): 83-88.
Felipo, Vicente, and Santiago Grisolia. Hepatic Encephalopathy, Hyperammonemia, and Ammonia Toxicity. Springer Verlag, 2013.
Pardridge, W. M., and T. B. Choi. "Neutral amino acid transport at the human blood-brain barrier." *Federation proceedings*. Vol. 45. No. 7. 1986.
Schweiger, Ulrich, et al. "Effects of carbohydrate and protein meals on plasma large neutral amino acids, glucose, and insulin plasma levels of anorectic patients." Metabolism 35.10 (1986): 938-943.