Soy
Overview
Soy provides complete plant protein (DIAAS 92-96), isoflavones (genistein), and choline, supporting neurotransmitter synthesis and neuroprotection. Soy protein isolate has a DIAAS score of 92-96, indicating high protein quality, though it is methionine-limited and should be paired with grains. Genistein, a soy-derived isoflavonoid, has shown potential as a modulator of several biochemical pathways, including the endocannabinoid system and neuroinflammation. Soy is listed as a source for choline, tryptophan, tyrosine, and B6.
Recipes
Substances
8 substances in this food
Choline
Acetylcholine precursor; methyl donor; phospholipid synthesis for membranes
Genistein
Soy isoflavone; ECS modulation via FAAH inhibition; anti-inflammatory/neuroprotective
Iron
Oxygen transport; dopamine synthesis (tyrosine hydroxylase cofactor)
Quercetin (and Isoquercetin)
Polyphenol; antioxidant; mitochondrial support; bioavailability improved with vitamin C
Tryptophan
Serotonin/melatonin precursor; NAD+ pathway substrate; LAT1 transport dynamics
Tyrosine
Dopamine and norepinephrine precursor; LAT1 competition with LNAAs
Vitamin B6 (Pyridoxine → PLP)
PLP cofactor for neurotransmitter synthesis; relies on brain PDXK activation
Vitamin B9 (Folate; 5-MTHF)
One-carbon metabolism; methylation; homocysteine recycling
Preparation Notes
- Fermented forms (tempeh, miso, natto) may have additional benefits including probiotics and improved digestibility
- Pair with grains for complete amino acid profile; grain-legume complementarity improves essential amino-acid coverage
- Part of diverse plant protein strategy
- Supports choline and neurotransmitter synthesis
- Vegans should ensure adequate choline intake (e.g., soy or sunflower lecithin, soy foods, quinoa, broccoli) to support phosphatidylcholine synthesis
Biological Target Matrix
| Biological Target | Substance | Therapeutic Areas | Mechanism of Action |
|---|---|---|---|
| Endocannabinoid System (ECS) | Choline | Precursor for phosphatidylcholine (PC) synthesis; PE can be converted into PC or N-acyl phosphatidylethanolamines (NAPEs); NAPEs are precursors to N-acyl ethanolamines (NAEs) like palmitoylethanolamide (PEA), oleoylethanolamide (OEA), and anandamide (AEA), bioactive lipids which act as neuromodulators with anti-inflammatory, neuroprotective, and mood-regulating effects | |
| Endocannabinoid System (ECS) | Genistein | Inhibits fatty acid amide hydrolase (FAAH), preserving anandamide levels and enhancing ECS tone; modulates dopamine, glutamate, and GABA signaling | |
| Hormonal Response | Quercetin (and Isoquercetin) | Flavonoid support for calcium modulation and insulin sensitivity | |
| Inflammation | Genistein | Anti-inflammatory and anti-neuroinflammatory properties; reduces neuroinflammation | |
| Inflammation | Quercetin (and Isoquercetin) | Anti-inflammatory, anti-neuroinflammatory, and neuroprotective properties; supports gut barrier integrity and TLR4 suppression | |
| Methylation | Choline | Precursor to trimethylglycine (TMG/betaine), a dietary methyl donor that helps recycle homocysteine to methionine via an alternative pathway; supports one-carbon metabolism alongside folate, riboflavin, and B12; influences methylation dynamics relevant to MTHFR and COMT activity | |
| Methylation | Vitamin B6 (Pyridoxine → PLP) | Essential cofactor in remethylation of homocysteine to methionine, which is converted to S-adenosylmethionine (SAMe); works with B2, folate, and B12 | |
| Methylation | Vitamin B9 (Folate; 5-MTHF) | Essential cofactor in remethylation of homocysteine to methionine, which is converted to S-adenosylmethionine (SAMe); SAMe fuels synthesis of dopamine, norepinephrine, and serotonin and drives phospholipid methylation in neuronal membranes | |
| Mitochondrial Support | Iron | Critical for oxygen delivery to the brain via hemoglobin; supports mitochondrial function and energy production | |
| Mitochondrial Support | Quercetin (and Isoquercetin) | Enhances mitochondrial baseline activity and energy production; supports mitochondrial function | |
| Neurochemical Balance | Choline | Essential precursor for acetylcholine synthesis, supporting memory, learning, and neuroplasticity; supports membrane phospholipid biosynthesis (PC) which is critical for membrane fluidity and neurotransmitter receptor function; phospholipid methylation (PLM) alters membrane structure, facilitating faster neuronal recovery and influencing ion channel behavior in gamma oscillations linked to attention and cognition | |
| Neurochemical Balance | Genistein | Enhances endocannabinoid activity; modulates dopamine, glutamate, and GABA signaling pathways | |
| Neurochemical Balance | Iron | Essential cofactor for tyrosine hydroxylase, the rate-limiting enzyme in the conversion of tyrosine to dopamine; critical for catecholamine synthesis | |
| Neurochemical Balance | Tryptophan | Precursor for serotonin and melatonin; brain entry competes at LAT1 with other large neutral amino acids (LNAAs); carbohydrate-rich, low-protein meals raise the plasma tryptophan:LNAA ratio because insulin pushes competing LNAAs out to muscles; can feed NAD+ synthesis via the kynurenine pathway | |
| Neurochemical Balance | Tyrosine | Catecholamine precursor (dopamine, norepinephrine); brain transport via LAT1 competes with other LNAAs; iron is an essential cofactor for tyrosine hydroxylase, the rate-limiting enzyme in conversion of tyrosine to dopamine; cofactors include iron, B6, folate, omega-3s, and BH₄ (tetrahydrobiopterin) to support rate-limiting steps in catecholamine synthesis | |
| Neurochemical Balance | Vitamin B6 (Pyridoxine → PLP) | Cofactor for synthesis of dopamine, serotonin, GABA, and glutamate; supports rate-limiting steps in catecholamine synthesis; requires PDXK activation with magnesium and ATP support | |
| Neurochemical Balance | Vitamin B9 (Folate; 5-MTHF) | Supports neurotransmitter synthesis through methylation; cofactor for dopamine synthesis alongside iron, B6, and omega-3s | |
| Oxidative Stress | Genistein | Prevents neuronal death; increases hippocampal glutathione (GSH) and superoxide dismutase (SOD); lowers lipid peroxidation, ROS, and nitric oxide production | |
| Oxidative Stress | Quercetin (and Isoquercetin) | Effective antioxidant agent that scavenges reactive oxygen species; supports antioxidant defenses | |
| Stress Response | Quercetin (and Isoquercetin) | Contributes to LPS and immune defense; supports stress response modulation |
References
- Soy protein isolate: DIAAS 92-96, Methionine-limited; supports neurotransmitter synthesis; contains isoflavones with neuroprotective potential
- Genistein, a soy-derived isoflavonoid, has shown potential as a modulator of several biochemical pathways, including the endocannabinoid system and neuroinflammation
- Polyphenols such as genistein may further enhance ECS tone by inhibiting fatty acid amide hydrolase (FAAH), the enzyme responsible for anandamide degradation Gibellini and Smith 2010
- Quercetin is abundant in capers, apples, onions, berries, kale and soybeans
- Acetylcholine and choline: Memory, learning, neuroplasticity; food sources include egg yolks, fish roe, soy, wheat germ, liver
- B6 (chickpeas, potatoes, bananas, whole grains, soy) is a cofactor in the development of all key neurotransmitters
- Serotonin: Mood regulation, emotional control, impulse moderation; food sources include turkey, eggs, dairy, soy, seeds, oats, bananas
- Dopamine: Attention, motivation, executive function; food sources include lean poultry, beef, fish, dairy, soy, pumpkin seeds; omega-3 rich fish