BRS1(KC1) - Amino Acid Substrate Sufficiency
1. Definition
Availability of meaningful amino-acid substrate to support neurotransmitter precursor supply at the meal level.
2. Constraint Role
Provides dietary amino-acid substrate for brain transport of large neutral amino acids and downstream neurotransmitter precursor pathways [1]. Enables dependent PMs and FMs when protein and amino-acid intake at meals is sufficient to support normal precursor availability [2][3].
3. Supporting Inputs/Substrates
- Choline
- Complementary amino-acid combinations where single sources are limiting
- Dietary protein
- Tryptophan
- Tyrosine
- large neutral amino acids (LNAAs) at the meal level
4. Biological Importance
Brain neurochemistry depends on dietary supply of amino-acid precursors and their competitive transport across the blood–brain barrier [1]. Normal meals differing in protein and carbohydrate composition alter plasma tryptophan and tyrosine ratios, changing substrate availability for brain monoamine pathways [3]. Inadequate dietary protein and amino-acid patterns can leave precursor supply below levels needed to support linked transmitter systems [1][2].
5. Connected Mechanisms
- Functional Mechanisms
- Primary Mechanisms
6. Constraint Stressors / Burdens
- low-protein meals or inadequate protein distribution across the day [2]
- precursor-poor protein sources without compensating combinations
- meal compositions that unfavourably shift plasma tryptophan and tyrosine availability [3]
- chronic energy deficit reducing overall amino-acid intake
- erratic meal timing limiting consistent precursor supply
- LNAA imbalance at meals affecting competitive brain transport [1]