Phosphatidylcholine

evidence_span

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experimental_model

Protein processing, localization, transport and cell-growth experiments

exposure

PARL processing and compartment-specific STARD7 expression

limitations

Purified-protein binding with a CoQ variant; not demonstrated dietary choline competition with CoQ10 absorption.

nutrient_topic

Coenzyme Q10 research collection; topical membership is not evidence of a direct dietary effect. · Coenzyme Q10 / CoQ10 redox system

organism

Mammalian cell models

plain_language

Choline-containing membrane lipid and a CoQ analogue shared access to a transport protein.

primary_references

[coq10-p36658222] Mitochondria regulate intracellular coenzyme Q transport and ferroptotic resistance via STARD7. (2023). https://pubmed.ncbi.nlm.nih.gov/36658222/ DOI: 10.1038/s41556-022-01071-y

tissue_or_cell_type

Mitochondria and plasma membrane

Coenzyme Q10: biosynthesis, electron transfer, antioxidant recycling and nutrient interactions (2026-09-17) · lines 502–513

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Protein processing, localization, transport and cell-growth experiments · source_derived_draft · unverified_draft

### coq10-stard7-pc A CoQ variant competed with phosphatidylcholine for binding to purified STARD7. Condition category: normal nutrient_topic: Coenzyme Q10 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Choline-containing membrane lipid and a CoQ analogue shared access to a transport protein. organism: Mammalian cell models tissue_or_cell_type: Mitochondria and plasma membrane experimental_model: Protein processing, localization, transport and cell-growth experiments limitations: Purified-protein binding with a CoQ variant; not demonstrated dietary choline competition with CoQ10 absorption. exposure: PARL processing and compartment-specific STARD7 expression evidence_span: {"source_cache": "artifacts/coq10-research/36658222.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "8cd5c486ecb31ad03ea06a817eb5bc56e60abdfa8ae8d50a46502974be2898ce", "start_char": 0, "end_char": 1410, "text_sha256": "8cd5c486ecb31ad03ea06a817eb5bc56e60abdfa8ae8d50a46502974be2898ce"} [coq10-p36658222] Mitochondria regulate intracellular coenzyme Q transport and ferroptotic resistance via STARD7. (2023). https://pubmed.ncbi.nlm.nih.gov/36658222/ DOI: 10.1038/s41556-022-01071-y

evidence_access

Primary abstract

experimental_model

Primary human-heart enzyme cloning and characterization.

limitations

Does not establish that supplemental choline increases ketone use.

nutrient_topic

Fasting physiological-state collection; human protocols, cellular deprivation and refeeding are distinguished. · Fasting / abstention from energy intake

plain_language

A membrane lipid linked to choline supports a ketone enzyme.

primary_references

Molecular cloning and characterization of (R)-3-hydroxybutyrate dehydrogenase from human heart. · 1992 · https://pubmed.ncbi.nlm.nih.gov/1639787/

Fasting: fuel switching, nutrient sensing, ketone signaling, nutrient dependencies and refeeding (2026-09-18) · lines 136–142

AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Primary human-heart enzyme cloning and characterization. · source_derived_draft · unverified_draft

## fast-bdh-choline A membrane lipid linked to choline supports a ketone enzyme. Human-heart mitochondrial BDH1 was described as specifically requiring phosphatidylcholine for enzymic activity. Model: Primary human-heart enzyme cloning and characterization. Limitations: Does not establish that supplemental choline increases ketone use. Evidence access: Primary abstract Molecular cloning and characterization of (R)-3-hydroxybutyrate dehydrogenase from human heart. · 1992 · https://pubmed.ncbi.nlm.nih.gov/1639787/

cross_nutrient

Phosphatidylcholine-dependent retinol storage links retinoid metabolism to choline-containing phospholipid availability.

evidence_location

Abstract

experimental_model

Human and rat liver microsomes supplied phosphatidylcholine and CRBP-bound retinol.

exposure

Exogenous phosphatidylcholine plus CRBP-bound retinol.

limitations

Biochemical donor requirement; dietary choline deficiency was not tested.

nutrient_topic

Vitamin A research collection; topical membership is not evidence of a direct dietary effect. · Vitamin A

organism

Homo sapiens and Rattus norvegicus

outcome

Human and rat liver LRAT activity transferred the sn-1 acyl group of phosphatidylcholine to CRBP-bound retinol.

plain_language

A membrane choline phospholipid supplies the fatty-acid group used to store vitamin A.

primary_references

[va-macdonald-1988] A lecithin:retinol acyltransferase activity in human and rat liver (1988). https://pubmed.ncbi.nlm.nih.gov/3178828/ DOI: 10.1016/S0006-291X(88)80818-0

tissue_or_cell_type

Liver microsomes

Vitamin A: forms, mechanisms, deficiency and excess (2026-09-17) · lines 317–330

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human and rat liver microsomes supplied phosphatidylcholine and CRBP-bound retinol. · source_derived_draft · unverified_draft

### va-lrat-phosphatidylcholine-donor Human and rat liver LRAT activity transferred the sn-1 acyl group of phosphatidylcholine to CRBP-bound retinol. Condition category: normal nutrient_topic: Vitamin A research collection; topical membership is not evidence of a direct dietary effect. plain_language: A membrane choline phospholipid supplies the fatty-acid group used to store vitamin A. organism: Homo sapiens and Rattus norvegicus tissue_or_cell_type: Liver microsomes experimental_model: Human and rat liver microsomes supplied phosphatidylcholine and CRBP-bound retinol. limitations: Biochemical donor requirement; dietary choline deficiency was not tested. exposure: Exogenous phosphatidylcholine plus CRBP-bound retinol. outcome: Human and rat liver LRAT activity transferred the sn-1 acyl group of phosphatidylcholine to CRBP-bound retinol. evidence_location: Abstract cross_nutrient: Phosphatidylcholine-dependent retinol storage links retinoid metabolism to choline-containing phospholipid availability. [va-macdonald-1988] A lecithin:retinol acyltransferase activity in human and rat liver (1988). https://pubmed.ncbi.nlm.nih.gov/3178828/ DOI: 10.1016/S0006-291X(88)80818-0

evidence_span

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experimental_model

Human CHPT1 cryo-EM, sequence analysis and biochemical characterization

exposure

CDP-choline/CDP-ethanolamine substrate selectivity

limitations

Human CHPT1 and CEPT1 remain separate. Evolutionary suggestions about oviparous species are not asserted as human bifunctionality.

nutrient_topic

Choline research collection; topical membership is not evidence of a direct dietary effect. · Choline

organism

Human proteins; evolutionary comparisons explicitly separate

plain_language

A separate terminal enzyme can serve both headgroup pathways.

primary_references

[choline-p40435706] Structural basis for substrate selectivity and evolutionary insights into human choline phosphotransferase 1. (2025). https://pubmed.ncbi.nlm.nih.gov/40435706/ DOI: 10.1016/j.bbrc.2025.152082

tissue_or_cell_type

Membrane phospholipid synthesis

Choline: metabolism, signaling and nutrient connections (2026-09-17) · lines 776–787

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human CHPT1 cryo-EM, sequence analysis and biochemical characterization · source_derived_draft · unverified_draft

### choline-cept1-pc CEPT1 can catalyze PC production as well as PE production. Condition category: normal nutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect. plain_language: A separate terminal enzyme can serve both headgroup pathways. organism: Human proteins; evolutionary comparisons explicitly separate tissue_or_cell_type: Membrane phospholipid synthesis experimental_model: Human CHPT1 cryo-EM, sequence analysis and biochemical characterization limitations: Human CHPT1 and CEPT1 remain separate. Evolutionary suggestions about oviparous species are not asserted as human bifunctionality. exposure: CDP-choline/CDP-ethanolamine substrate selectivity evidence_span: {"source_cache": "artifacts/choline-research/40435706.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351", "start_char": 0, "end_char": 1339, "text_sha256": "d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351"} [choline-p40435706] Structural basis for substrate selectivity and evolutionary insights into human choline phosphotransferase 1. (2025). https://pubmed.ncbi.nlm.nih.gov/40435706/ DOI: 10.1016/j.bbrc.2025.152082

evidence_span

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experimental_model

Human CHPT1 cryo-EM, sequence analysis and biochemical characterization

exposure

CDP-choline/CDP-ethanolamine substrate selectivity

limitations

Human CHPT1 and CEPT1 remain separate. Evolutionary suggestions about oviparous species are not asserted as human bifunctionality.

nutrient_topic

Choline research collection; topical membership is not evidence of a direct dietary effect. · Choline

organism

Human proteins; evolutionary comparisons explicitly separate

plain_language

One terminal enzyme specializes in making phosphatidylcholine.

primary_references

[choline-p40435706] Structural basis for substrate selectivity and evolutionary insights into human choline phosphotransferase 1. (2025). https://pubmed.ncbi.nlm.nih.gov/40435706/ DOI: 10.1016/j.bbrc.2025.152082

tissue_or_cell_type

Membrane phospholipid synthesis

Choline: metabolism, signaling and nutrient connections (2026-09-17) · lines 763–774

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human CHPT1 cryo-EM, sequence analysis and biochemical characterization · source_derived_draft · unverified_draft

### choline-chpt1-pc Human CHPT1 catalyzes the PC-producing final step of the Kennedy pathway with choline-headgroup substrate selectivity. Condition category: normal nutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect. plain_language: One terminal enzyme specializes in making phosphatidylcholine. organism: Human proteins; evolutionary comparisons explicitly separate tissue_or_cell_type: Membrane phospholipid synthesis experimental_model: Human CHPT1 cryo-EM, sequence analysis and biochemical characterization limitations: Human CHPT1 and CEPT1 remain separate. Evolutionary suggestions about oviparous species are not asserted as human bifunctionality. exposure: CDP-choline/CDP-ethanolamine substrate selectivity evidence_span: {"source_cache": "artifacts/choline-research/40435706.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351", "start_char": 0, "end_char": 1339, "text_sha256": "d08b2ce68e8731e88e1204dc1b09d1301020452752a630a880ec3a2cdb0f2351"} [choline-p40435706] Structural basis for substrate selectivity and evolutionary insights into human choline phosphotransferase 1. (2025). https://pubmed.ncbi.nlm.nih.gov/40435706/ DOI: 10.1016/j.bbrc.2025.152082

evidence_access

Primary full text

experimental_model

Model membranes and computational recognition analysis.

limitations

Membrane interaction is not evidence that choline intake increases silica injury or protects against it.

nutrient_topic

Silica collection; molecular form, preparation, species, exposure and manipulation remain explicit. · Silica and soluble silicon

plain_language

The phosphocholine headgroup creates a molecular link to membrane composition.

primary_references

Molecular recognition between membrane epitopes and nearly free surface silanols explains silica membranolytic activity. · 2022 · https://pubmed.ncbi.nlm.nih.gov/35738078/ · DOI 10.1016/j.colsurfb.2022.112625

Silica: soluble silicon, cellular transport and particle-specific mechanisms (2026-09-19) · lines 400–406

AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Model membranes and computational recognition analysis. · source_derived_draft · unverified_draft

## silica-phosphocholine-recognition The phosphocholine headgroup creates a molecular link to membrane composition. NFS-rich silica strongly adsorbed zwitterionic phospholipid assemblies and disrupted their order more than negatively charged liposomes. Model: Model membranes and computational recognition analysis. Limitations: Membrane interaction is not evidence that choline intake increases silica injury or protects against it. Evidence access: Primary full text Molecular recognition between membrane epitopes and nearly free surface silanols explains silica membranolytic activity. · 2022 · https://pubmed.ncbi.nlm.nih.gov/35738078/ · DOI 10.1016/j.colsurfb.2022.112625

availability_state

nutrient_deficiency Imported condition classification; unverified.

cross_nutrient

Folate/choline restriction affects circulating phospholipid.

experimental_model

Metabolic-unit depletion/repletion: 11 men, 10 women.

limitations

Male cohort; concentration does not identify biosynthetic flux.

nutrient_topic

Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect. · Folate (vitamin B9)

organism

Homo sapiens

plain_language

A choline-containing lipid also declined.

primary_references

[jacob-1999] Folate nutriture alters choline status of women and men fed low choline diets (1999). https://pubmed.ncbi.nlm.nih.gov/10082779/ DOI: 10.1093/jn/129.3.712

tissue_or_cell_type

Plasma

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Folate and folic acid: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 706–716

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Metabolic-unit depletion/repletion: 11 men, 10 women. · source_derived_draft · unverified_draft

### folate-methyl-low-folate-pc Men on the combined low-folate/low-choline diet showed 26% lower plasma phosphatidylcholine. Condition category: nutrient_deficiency nutrient_topic: Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect. plain_language: A choline-containing lipid also declined. organism: Homo sapiens tissue_or_cell_type: Plasma experimental_model: Metabolic-unit depletion/repletion: 11 men, 10 women. limitations: Male cohort; concentration does not identify biosynthetic flux. cross_nutrient: Folate/choline restriction affects circulating phospholipid. [jacob-1999] Folate nutriture alters choline status of women and men fed low choline diets (1999). https://pubmed.ncbi.nlm.nih.gov/10082779/ DOI: 10.1093/jn/129.3.712

evidence_span

{"source_cache": "artifacts/phosphorus-research/9593753.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45", "start_char": 0, "end_char": 1766, "text_sha256": "6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45"}

experimental_model

Human isoform cloning and COS-7 expression studies

exposure

CCTbeta transfection and catalytic assays with lipid regulators

limitations

Expression-system findings; maximum activity required lipid regulators. Do not generalize the early clone to every subsequently described splice variant.

nutrient_topic

Phosphorus research collection; topical membership is not evidence of a direct dietary effect. · Phosphorus

organism

Human PCYT1B expressed in African-green-monkey-derived COS-7 cells

plain_language

The pathway feeds a phosphorus-containing membrane lipid; it is distinct from free phosphate transport.

primary_references

[phosphorus-p9593753] Cloning and characterization of a second human CTP:phosphocholine cytidylyltransferase. (1998). https://pubmed.ncbi.nlm.nih.gov/9593753/ DOI: 10.1074/jbc.273.22.14022

tissue_or_cell_type

Cytoplasm and phospholipid biosynthesis

Phosphorus: metabolism, signaling and nutrient connections (2026-09-17) · lines 711–722

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human isoform cloning and COS-7 expression studies · source_derived_draft · unverified_draft

### phosphorus-pcyt-lipid Human CCTbeta expression enhanced radiolabeling of phosphatidylcholine in COS-7 cells. Condition category: normal nutrient_topic: Phosphorus research collection; topical membership is not evidence of a direct dietary effect. plain_language: The pathway feeds a phosphorus-containing membrane lipid; it is distinct from free phosphate transport. organism: Human PCYT1B expressed in African-green-monkey-derived COS-7 cells tissue_or_cell_type: Cytoplasm and phospholipid biosynthesis experimental_model: Human isoform cloning and COS-7 expression studies limitations: Expression-system findings; maximum activity required lipid regulators. Do not generalize the early clone to every subsequently described splice variant. exposure: CCTbeta transfection and catalytic assays with lipid regulators evidence_span: {"source_cache": "artifacts/phosphorus-research/9593753.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45", "start_char": 0, "end_char": 1766, "text_sha256": "6ed2c0c0ceaa7eb2efb90c66565bae51b71023f77cdd0224159fd9814e3b7d45"} [phosphorus-p9593753] Cloning and characterization of a second human CTP:phosphocholine cytidylyltransferase. (1998). https://pubmed.ncbi.nlm.nih.gov/9593753/ DOI: 10.1074/jbc.273.22.14022

availability_state

nutrient_deficiency Imported condition classification; unverified.

evidence_span

{"source_cache": "artifacts/choline-research/16679290.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "656910ebe959c2867cac5d7cb75341ba3974ff922e584274829161326f10cf4d", "start_char": 0, "end_char": 1016, "text_sha256": "656910ebe959c2867cac5d7cb75341ba3974ff922e584274829161326f10cf4d"}

experimental_model

Dietary depletion and Pemt/Mdr2 mouse genetics

exposure

Choline-deficient feeding in Pemt-null and double-null mice

limitations

A combined diet/genotype model; total PC amount, PC/PE ratio and membrane damage are not interchangeable measurements.

nutrient_topic

Choline research collection; topical membership is not evidence of a direct dietary effect. · Choline

organism

Mouse, with separate human tissue comparison in the paper

plain_language

The balance between two membrane lipids mattered, not just one concentration.

primary_references

[choline-p16679290] The ratio of phosphatidylcholine to phosphatidylethanolamine influences membrane integrity and steatohepatitis. (2006). https://pubmed.ncbi.nlm.nih.gov/16679290/ DOI: 10.1016/j.cmet.2006.03.007

tissue_or_cell_type

Hepatic membranes

trigger_kind

nutrient_deficiency Imported condition classification; unverified.

Choline: metabolism, signaling and nutrient connections (2026-09-17) · lines 906–917

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Dietary depletion and Pemt/Mdr2 mouse genetics · source_derived_draft · unverified_draft

### choline-pc-pe-membrane Experimental manipulation supported a causal role for the lowered PC/PE ratio in loss of hepatocyte membrane integrity. Condition category: nutrient_deficiency nutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect. plain_language: The balance between two membrane lipids mattered, not just one concentration. organism: Mouse, with separate human tissue comparison in the paper tissue_or_cell_type: Hepatic membranes experimental_model: Dietary depletion and Pemt/Mdr2 mouse genetics limitations: A combined diet/genotype model; total PC amount, PC/PE ratio and membrane damage are not interchangeable measurements. exposure: Choline-deficient feeding in Pemt-null and double-null mice evidence_span: {"source_cache": "artifacts/choline-research/16679290.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "656910ebe959c2867cac5d7cb75341ba3974ff922e584274829161326f10cf4d", "start_char": 0, "end_char": 1016, "text_sha256": "656910ebe959c2867cac5d7cb75341ba3974ff922e584274829161326f10cf4d"} [choline-p16679290] The ratio of phosphatidylcholine to phosphatidylethanolamine influences membrane integrity and steatohepatitis. (2006). https://pubmed.ncbi.nlm.nih.gov/16679290/ DOI: 10.1016/j.cmet.2006.03.007

evidence_span

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experimental_model

Human isotope challenge with antibiotics plus a separate observational cohort

exposure

Two eggs plus d9-PC before/after antibiotics; three-year event follow-up

limitations

The challenge establishes microbiota involvement; the outcome cohort establishes association, not that avoiding choline or eggs prevents events.

nutrient_topic

Choline research collection; topical membership is not evidence of a direct dietary effect. · Choline

organism

Human

plain_language

A label on dietary PC appeared in the downstream microbial-host product.

primary_references

[choline-p23614584] Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. (2013). https://pubmed.ncbi.nlm.nih.gov/23614584/ DOI: 10.1056/nejmoa1109400

tissue_or_cell_type

Healthy challenge participants; 4007 angiography patients in the outcome cohort

Choline: metabolism, signaling and nutrient connections (2026-09-17) · lines 1140–1151

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human isotope challenge with antibiotics plus a separate observational cohort · source_derived_draft · unverified_draft

### choline-pc-tmao-tracing The challenge produced time-dependent increases in TMAO and its d9-labeled isotopologue. Condition category: normal nutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect. plain_language: A label on dietary PC appeared in the downstream microbial-host product. organism: Human tissue_or_cell_type: Healthy challenge participants; 4007 angiography patients in the outcome cohort experimental_model: Human isotope challenge with antibiotics plus a separate observational cohort limitations: The challenge establishes microbiota involvement; the outcome cohort establishes association, not that avoiding choline or eggs prevents events. exposure: Two eggs plus d9-PC before/after antibiotics; three-year event follow-up evidence_span: {"source_cache": "artifacts/choline-research/23614584.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "9de33f54f0fce1c470cc96c18163574d26fc5c56802e60771c75fdacc5804e0a", "start_char": 0, "end_char": 2119, "text_sha256": "9de33f54f0fce1c470cc96c18163574d26fc5c56802e60771c75fdacc5804e0a"} [choline-p23614584] Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk. (2013). https://pubmed.ncbi.nlm.nih.gov/23614584/ DOI: 10.1056/nejmoa1109400

evidence_span

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experimental_model

Human liver fractionation and recombinant PEMT membrane-topology experiments

exposure

Protein cleavage mapping and methyltransferase localization

limitations

Three methyl transfers make a choline-containing phospholipid; PEMT does not directly synthesize free choline from nothing.

nutrient_topic

Choline research collection; topical membership is not evidence of a direct dietary effect. · Choline

organism

Human enzyme

plain_language

The body can build a choline headgroup in a membrane lipid by spending methyl groups.

primary_references

[choline-p12431977] Membrane topography of human phosphatidylethanolamine N-methyltransferase. (2003). https://pubmed.ncbi.nlm.nih.gov/12431977/ DOI: 10.1074/jbc.m210904200

tissue_or_cell_type

ER and mitochondria-associated membranes

Choline: metabolism, signaling and nutrient connections (2026-09-17) · lines 802–813

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human liver fractionation and recombinant PEMT membrane-topology experiments · source_derived_draft · unverified_draft

### choline-pemt-pc PEMT converts PE to PC through three sequential SAM-dependent methylation reactions. Condition category: normal nutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect. plain_language: The body can build a choline headgroup in a membrane lipid by spending methyl groups. organism: Human enzyme tissue_or_cell_type: ER and mitochondria-associated membranes experimental_model: Human liver fractionation and recombinant PEMT membrane-topology experiments limitations: Three methyl transfers make a choline-containing phospholipid; PEMT does not directly synthesize free choline from nothing. exposure: Protein cleavage mapping and methyltransferase localization evidence_span: {"source_cache": "artifacts/choline-research/12431977.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7c299a547408772f2f24bdd77f2f22dc8ea9e5aaf8179150f2d8b59c9713306a", "start_char": 0, "end_char": 1380, "text_sha256": "7c299a547408772f2f24bdd77f2f22dc8ea9e5aaf8179150f2d8b59c9713306a"} [choline-p12431977] Membrane topography of human phosphatidylethanolamine N-methyltransferase. (2003). https://pubmed.ncbi.nlm.nih.gov/12431977/ DOI: 10.1074/jbc.m210904200

evidence_span

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experimental_model

Human liver fractionation and recombinant PEMT membrane-topology experiments

exposure

Protein cleavage mapping and methyltransferase localization

limitations

Three methyl transfers make a choline-containing phospholipid; PEMT does not directly synthesize free choline from nothing.

nutrient_topic

Choline research collection; topical membership is not evidence of a direct dietary effect. · Choline

organism

Human enzyme

plain_language

Membrane PC synthesis and the methyl-donor pool are connected.

primary_references

[choline-p12431977] Membrane topography of human phosphatidylethanolamine N-methyltransferase. (2003). https://pubmed.ncbi.nlm.nih.gov/12431977/ DOI: 10.1074/jbc.m210904200

tissue_or_cell_type

ER and mitochondria-associated membranes

Choline: metabolism, signaling and nutrient connections (2026-09-17) · lines 815–826

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Human liver fractionation and recombinant PEMT membrane-topology experiments · source_derived_draft · unverified_draft

### choline-pemt-sam SAM supplies the methyl groups for each of the three PEMT-catalyzed transfers. Condition category: normal nutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect. plain_language: Membrane PC synthesis and the methyl-donor pool are connected. organism: Human enzyme tissue_or_cell_type: ER and mitochondria-associated membranes experimental_model: Human liver fractionation and recombinant PEMT membrane-topology experiments limitations: Three methyl transfers make a choline-containing phospholipid; PEMT does not directly synthesize free choline from nothing. exposure: Protein cleavage mapping and methyltransferase localization evidence_span: {"source_cache": "artifacts/choline-research/12431977.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "7c299a547408772f2f24bdd77f2f22dc8ea9e5aaf8179150f2d8b59c9713306a", "start_char": 0, "end_char": 1380, "text_sha256": "7c299a547408772f2f24bdd77f2f22dc8ea9e5aaf8179150f2d8b59c9713306a"} [choline-p12431977] Membrane topography of human phosphatidylethanolamine N-methyltransferase. (2003). https://pubmed.ncbi.nlm.nih.gov/12431977/ DOI: 10.1074/jbc.m210904200

evidence_span

{"source_cache": "artifacts/choline-research/19520976.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "57c952bdb4e387632c90b6dcc00ab5f0c600047b7e78bb179c08f6ccd62704d0", "start_char": 0, "end_char": 1537, "text_sha256": "57c952bdb4e387632c90b6dcc00ab5f0c600047b7e78bb179c08f6ccd62704d0"}

experimental_model

Pemt/Ldlr mouse knockout under a high-fat/high-cholesterol diet

exposure

Sixteen weeks of the specified diet; Pemt-null/Ldlr-null versus Pemt-intact/Ldlr-null

limitations

A lipid-export mechanism in a specific genetic model; lower plasma lipids do not establish healthier liver tissue or dietary benefit.

nutrient_topic

Choline research collection; topical membership is not evidence of a direct dietary effect. · Choline

organism

Mouse

plain_language

PC synthesis is connected to how the liver exports lipid.

primary_references

[choline-p19520976] Lack of phosphatidylethanolamine N-methyltransferase alters plasma VLDL phospholipids and attenuates atherosclerosis in mice. (2009). https://pubmed.ncbi.nlm.nih.gov/19520976/ DOI: 10.1161/atvbaha.109.188672

tissue_or_cell_type

Liver and circulating VLDL

Choline: metabolism, signaling and nutrient connections (2026-09-17) · lines 932–943

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Pemt/Ldlr mouse knockout under a high-fat/high-cholesterol diet · source_derived_draft · unverified_draft

### choline-pemt-vldl Pemt deletion modestly reduced hepatic VLDL secretion in Ldlr-null mice. Condition category: normal nutrient_topic: Choline research collection; topical membership is not evidence of a direct dietary effect. plain_language: PC synthesis is connected to how the liver exports lipid. organism: Mouse tissue_or_cell_type: Liver and circulating VLDL experimental_model: Pemt/Ldlr mouse knockout under a high-fat/high-cholesterol diet limitations: A lipid-export mechanism in a specific genetic model; lower plasma lipids do not establish healthier liver tissue or dietary benefit. exposure: Sixteen weeks of the specified diet; Pemt-null/Ldlr-null versus Pemt-intact/Ldlr-null evidence_span: {"source_cache": "artifacts/choline-research/19520976.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "57c952bdb4e387632c90b6dcc00ab5f0c600047b7e78bb179c08f6ccd62704d0", "start_char": 0, "end_char": 1537, "text_sha256": "57c952bdb4e387632c90b6dcc00ab5f0c600047b7e78bb179c08f6ccd62704d0"} [choline-p19520976] Lack of phosphatidylethanolamine N-methyltransferase alters plasma VLDL phospholipids and attenuates atherosclerosis in mice. (2009). https://pubmed.ncbi.nlm.nih.gov/19520976/ DOI: 10.1161/atvbaha.109.188672

compartment_description

Phospholipid surface

experimental_model

Kinetic reconstitution with defined phospholipids

limitations

Low residual Xa activity exists without the complete complex; this establishes biochemical assistance, not that extra dietary calcium accelerates clotting.

nutrient_topic

Calcium research collection; topical membership is not evidence of a direct dietary effect. · Calcium

organism

Bos taurus

plain_language

Calcium helps the membrane-associated clotting machinery generate thrombin.

primary_references

[rosing1980] The role of phospholipids and factor Va in the prothrombinase complex (1980). https://pubmed.ncbi.nlm.nih.gov/7350159/ DOI: 10.1016/S0021-9258(19)86294-4

tissue_or_cell_type

Purified blood proteins

Calcium: mechanism-first literature curation (2026-09-17) · lines 1116–1126

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Kinetic reconstitution with defined phospholipids · source_derived_draft · unverified_draft

### calcium-phospholipid-prothrombinase Factor Xa activated bovine prothrombin efficiently when factor Va, Ca2+ and phosphatidylserine-containing phospholipids assembled the complete prothrombinase system. Condition category: normal nutrient_topic: Calcium research collection; topical membership is not evidence of a direct dietary effect. plain_language: Calcium helps the membrane-associated clotting machinery generate thrombin. organism: Bos taurus tissue_or_cell_type: Purified blood proteins experimental_model: Kinetic reconstitution with defined phospholipids limitations: Low residual Xa activity exists without the complete complex; this establishes biochemical assistance, not that extra dietary calcium accelerates clotting. compartment_description: Phospholipid surface [rosing1980] The role of phospholipids and factor Va in the prothrombinase complex (1980). https://pubmed.ncbi.nlm.nih.gov/7350159/ DOI: 10.1016/S0021-9258(19)86294-4

evidence_access

Primary full text

experimental_model

Human PSS1 proteoliposomes with POPC and radioactive serine assays.

limitations

The bound endogenous lipid density could not conclusively distinguish PC from PE; no universal exclusion of PE is asserted.

nutrient_topic

L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Serine

plain_language

Serine can replace a phospholipid headgroup to make a different membrane lipid.

primary_references

Structural basis for catalytic mechanism of human phosphatidylserine synthase 1. · 2025 · https://pubmed.ncbi.nlm.nih.gov/40044636/ · DOI 10.1038/s41421-025-00775-3

L-Serine: synthesis, one-carbon metabolism, lipids and cross-nutrient mechanisms (2026-09-19) · lines 246–252

AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Human PSS1 proteoliposomes with POPC and radioactive serine assays. · source_derived_draft · unverified_draft

## l-serine-pss1-exchange Serine can replace a phospholipid headgroup to make a different membrane lipid. Purified human PSS1 reconstituted with phosphatidylcholine showed serine base-exchange activity producing phosphatidylserine. Model: Human PSS1 proteoliposomes with POPC and radioactive serine assays. Limitations: The bound endogenous lipid density could not conclusively distinguish PC from PE; no universal exclusion of PE is asserted. Evidence access: Primary full text Structural basis for catalytic mechanism of human phosphatidylserine synthase 1. · 2025 · https://pubmed.ncbi.nlm.nih.gov/40044636/ · DOI 10.1038/s41421-025-00775-3

evidence_access

Primary abstract

experimental_model

Purified epitope-tagged human PSS1/PSS2 substrate and feedback assays.

limitations

In this preparation PSS1 used both PC and PE and was not inhibited by added PS; purified-enzyme feedback cannot be assumed identical across preparations or intact cells.

nutrient_topic

L-Serine collection; species, compartment, exposure, co-substrates and manipulation remain explicit. · L-Serine

plain_language

A second enzyme uses a different membrane-lipid starting material.

primary_references

Purification and characterization of human phosphatidylserine synthases 1 and 2. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19014349/ · DOI 10.1042/BJ20081597

L-Serine: synthesis, one-carbon metabolism, lipids and cross-nutrient mechanisms (2026-09-19) · lines 414–420

AI-assisted research curation; primary references, access levels and experimental limitations individually identified. Not publisher full text. · supports · Purified epitope-tagged human PSS1/PSS2 substrate and feedback assays. · source_derived_draft · unverified_draft

## l-serine-pss2-exchange A second enzyme uses a different membrane-lipid starting material. Purified human PSS2 converted phosphatidylethanolamine, but not phosphatidylcholine, into phosphatidylserine; added phosphatidylserine inhibited purified PSS2. Model: Purified epitope-tagged human PSS1/PSS2 substrate and feedback assays. Limitations: In this preparation PSS1 used both PC and PE and was not inhibited by added PS; purified-enzyme feedback cannot be assumed identical across preparations or intact cells. Evidence access: Primary abstract Purification and characterization of human phosphatidylserine synthases 1 and 2. · 2009 · https://pubmed.ncbi.nlm.nih.gov/19014349/ · DOI 10.1042/BJ20081597

cross_nutrient

true

evidence_location

Primary abstract radical accessibility and kinetic result

experimental_model

Soybean L-alpha-phosphatidylcholine liposomes undergoing Fe(III)-triethylenetetramine-initiated peroxidation; EPR, optical and polarographic measurements

exposure

Aqueous ascorbic acid described as physiological concentration in abstract (exact dose unavailable); bilayer alpha-tocopheroxyl radical detected at 10^-8–10^-7 M.

limitations

Membrane composition, radical initiator and assay conditions determine kinetics; no human clinical benefit or universal membrane rate is established.

nutrient_topic

Vitamin C research collection; topical membership is not evidence of a direct dietary effect. · Vitamin C

organism

Glycine max lipid preparation; cell-free

plain_language

Vitamin C recycled the vitamin E radical back into vitamin E across this artificial membrane-water interface.

primary_references

[c-reg-scarpa] Formation of alpha-tocopherol radical and recycling of alpha-tocopherol by ascorbate during peroxidation of phosphatidylcholine liposomes. An electron paramagnetic resonance study. (1984). https://pubmed.ncbi.nlm.nih.gov/6089911/ DOI: 10.1016/0304-4165(84)90070-9

tissue_or_cell_type

Artificial liposomes

Vitamin C: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 1201–1213

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Soybean L-alpha-phosphatidylcholine liposomes undergoing Fe(III)-triethylenetetramine-initiated peroxidation; EPR, optical and polarographic measurements · source_derived_draft · unverified_draft

### c-reg-tocopherol-radical-recycling Aqueous ascorbate reduced bilayer alpha-tocopheroxyl radical back to alpha-tocopherol in oxidizing soybean phosphatidylcholine liposomes; the reported apparent bimolecular rate constant was about 2 × 10^5 M^-1 s^-1 under those conditions. Condition category: normal nutrient_topic: Vitamin C research collection; topical membership is not evidence of a direct dietary effect. plain_language: Vitamin C recycled the vitamin E radical back into vitamin E across this artificial membrane-water interface. organism: Glycine max lipid preparation; cell-free tissue_or_cell_type: Artificial liposomes experimental_model: Soybean L-alpha-phosphatidylcholine liposomes undergoing Fe(III)-triethylenetetramine-initiated peroxidation; EPR, optical and polarographic measurements limitations: Membrane composition, radical initiator and assay conditions determine kinetics; no human clinical benefit or universal membrane rate is established. exposure: Aqueous ascorbic acid described as physiological concentration in abstract (exact dose unavailable); bilayer alpha-tocopheroxyl radical detected at 10^-8–10^-7 M. cross_nutrient: true evidence_location: Primary abstract radical accessibility and kinetic result [c-reg-scarpa] Formation of alpha-tocopherol radical and recycling of alpha-tocopherol by ascorbate during peroxidation of phosphatidylcholine liposomes. An electron paramagnetic resonance study. (1984). https://pubmed.ncbi.nlm.nih.gov/6089911/ DOI: 10.1016/0304-4165(84)90070-9

evidence_span

{"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"}

experimental_model

Lipid-peroxyl radical challenge in liposomes

exposure

AAPH or AMVN challenge; dietary and meso zeaxanthin

limitations

Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination.

nutrient_topic

Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. · Dietary (3R,3-prime-R)-zeaxanthin

organism

Cell-free system with human GSTP1

plain_language

This binding-related effect persisted without glutathione.

primary_references

[zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

tissue_or_cell_type

Egg-yolk phosphatidylcholine liposomes

Zeaxanthin: metabolism, signaling and nutrient connections (2026-09-17) · lines 288–299

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Lipid-peroxyl radical challenge in liposomes · source_derived_draft · unverified_draft

### zeaxanthin-gsh-independent The GSTP1–zeaxanthin protective effect did not require glutathione in this liposome experiment. Condition category: normal nutrient_topic: Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. plain_language: This binding-related effect persisted without glutathione. organism: Cell-free system with human GSTP1 tissue_or_cell_type: Egg-yolk phosphatidylcholine liposomes experimental_model: Lipid-peroxyl radical challenge in liposomes limitations: Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination. exposure: AAPH or AMVN challenge; dietary and meso zeaxanthin evidence_span: {"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"} [zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

evidence_span

{"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"}

experimental_model

Lipid-peroxyl radical challenge in liposomes

exposure

AAPH or AMVN challenge; dietary and meso zeaxanthin

limitations

Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination.

nutrient_topic

Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. · Dietary (3R,3-prime-R)-zeaxanthin

organism

Cell-free system with human GSTP1

plain_language

The protein helped preserve the pigments during oxidation.

primary_references

[zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

tissue_or_cell_type

Egg-yolk phosphatidylcholine liposomes

Zeaxanthin: metabolism, signaling and nutrient connections (2026-09-17) · lines 275–286

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Lipid-peroxyl radical challenge in liposomes · source_derived_draft · unverified_draft

### zeaxanthin-gstp1-stability GSTP1 association increased resistance of zeaxanthin diastereomers to chemical degradation. Condition category: normal nutrient_topic: Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The protein helped preserve the pigments during oxidation. organism: Cell-free system with human GSTP1 tissue_or_cell_type: Egg-yolk phosphatidylcholine liposomes experimental_model: Lipid-peroxyl radical challenge in liposomes limitations: Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination. exposure: AAPH or AMVN challenge; dietary and meso zeaxanthin evidence_span: {"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"} [zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

evidence_span

{"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"}

experimental_model

Lipid-peroxyl radical challenge in liposomes

exposure

AAPH or AMVN challenge; dietary and meso zeaxanthin

limitations

Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination.

nutrient_topic

Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. · Dietary (3R,3-prime-R)-zeaxanthin

organism

Cell-free system with human GSTP1

plain_language

Binding enhanced protection of the test membrane.

primary_references

[zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

tissue_or_cell_type

Egg-yolk phosphatidylcholine liposomes

Zeaxanthin: metabolism, signaling and nutrient connections (2026-09-17) · lines 262–273

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Lipid-peroxyl radical challenge in liposomes · source_derived_draft · unverified_draft

### zeaxanthin-gstp1-synergy GSTP1-bound dietary zeaxanthin synergistically inhibited peroxidation induced by either radical generator. Condition category: normal nutrient_topic: Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. plain_language: Binding enhanced protection of the test membrane. organism: Cell-free system with human GSTP1 tissue_or_cell_type: Egg-yolk phosphatidylcholine liposomes experimental_model: Lipid-peroxyl radical challenge in liposomes limitations: Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination. exposure: AAPH or AMVN challenge; dietary and meso zeaxanthin evidence_span: {"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"} [zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

evidence_span

{"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"}

experimental_model

Lipid-peroxyl radical challenge in liposomes

exposure

AAPH or AMVN challenge; dietary and meso zeaxanthin

limitations

Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination.

nutrient_topic

Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. · Dietary (3R,3-prime-R)-zeaxanthin

organism

Cell-free system with human GSTP1

plain_language

The two stereoisomers were not identical in this comparison.

primary_references

[zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

tissue_or_cell_type

Egg-yolk phosphatidylcholine liposomes

Zeaxanthin: metabolism, signaling and nutrient connections (2026-09-17) · lines 301–312

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Lipid-peroxyl radical challenge in liposomes · source_derived_draft · unverified_draft

### zeaxanthin-meso-bound-protection GSTP1-bound meso-zeaxanthin was more protective than bound dietary zeaxanthin in this assay. Condition category: normal nutrient_topic: Zeaxanthin research collection; topical membership is not evidence of a direct dietary effect. plain_language: The two stereoisomers were not identical in this comparison. organism: Cell-free system with human GSTP1 tissue_or_cell_type: Egg-yolk phosphatidylcholine liposomes experimental_model: Lipid-peroxyl radical challenge in liposomes limitations: Protein-associated antioxidant synergy is demonstrated in this assay, not a clinical supplement combination. exposure: AAPH or AMVN challenge; dietary and meso zeaxanthin evidence_span: {"source_cache": "artifacts/zeaxanthin-research/15949677.abstract.txt", "locator": "Primary indexed abstract; zero-based, end-exclusive Unicode character offsets", "file_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194", "start_char": 0, "end_char": 1404, "text_sha256": "4ed175c0b5cf937df5a37c94739b40d713261c3a99e2bebc02b3b6a37ea3f194"} [zeaxanthin-p15949677] Synergistic effects of zeaxanthin and its binding protein in the prevention of lipid membrane oxidation. (2005). https://pubmed.ncbi.nlm.nih.gov/15949677/ DOI: 10.1016/j.bbadis.2005.02.002

availability_state

machinery_impairment Imported condition classification; unverified.

cross_nutrient

Folate-pathway genotype relates to choline allocation.

experimental_model

Choline feeding and isotope tracing in women across reproductive states.

limitations

Genotypes not randomized; ratio is a pathway proxy.

nutrient_topic

Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect. · Folate (vitamin B9)

organism

Homo sapiens

plain_language

Relative choline allocation shifted toward phosphatidylcholine.

primary_references

[ganz-2016] Genetic impairments in folate enzymes increase dependence on dietary choline for phosphatidylcholine production at the expense of betaine synthesis (2016). https://pubmed.ncbi.nlm.nih.gov/27342765/ DOI: 10.1096/fj.201500138rr

tissue_or_cell_type

Plasma tracer metabolites

trigger_kind

machinery_impairment Imported condition classification; unverified.

Folate and folic acid: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 731–741

AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Choline feeding and isotope tracing in women across reproductive states. · source_derived_draft · unverified_draft

### folate-methyl-variant-choline-allocation Nonpregnant MTHFR rs1801133 carriers had lower labeled betaine:phosphatidylcholine enrichment ratios than noncarriers (0.8 versus 0.9). Condition category: machinery_impairment nutrient_topic: Folate and folic acid research collection; topical membership is not evidence of a direct dietary effect. plain_language: Relative choline allocation shifted toward phosphatidylcholine. organism: Homo sapiens tissue_or_cell_type: Plasma tracer metabolites experimental_model: Choline feeding and isotope tracing in women across reproductive states. limitations: Genotypes not randomized; ratio is a pathway proxy. cross_nutrient: Folate-pathway genotype relates to choline allocation. [ganz-2016] Genetic impairments in folate enzymes increase dependence on dietary choline for phosphatidylcholine production at the expense of betaine synthesis (2016). https://pubmed.ncbi.nlm.nih.gov/27342765/ DOI: 10.1096/fj.201500138rr

evidence_access

Primary abstract

experimental_model

Human endothelial radiotracer experiment.

limitations

Does not show that extra choline reproduces the effect.

nutrient_topic

CLA collection; isomer, preparation, species, exposure and manipulation remain explicit. · Conjugated linoleic acid / CLA isomer family

plain_language

A fatty acid was redistributed between membrane lipid pools.

primary_references

The effect of conjugated linoleic acid on arachidonic acid metabolism and eicosanoid production in human saphenous vein endothelial cells. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11880240/ · DOI 10.1016/s1388-1981(01)00198-6

Conjugated linoleic acid: isomers, signaling, nutrient interactions and discovery (2026-09-19) · lines 302–308

AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Human endothelial radiotracer experiment. · source_derived_draft · unverified_draft

## cla-aa-pc A fatty acid was redistributed between membrane lipid pools. c9,t11 increased arachidonate incorporation into phosphatidylcholine despite lower overall incorporation into membrane phospholipids. Model: Human endothelial radiotracer experiment. Limitations: Does not show that extra choline reproduces the effect. Evidence access: Primary abstract The effect of conjugated linoleic acid on arachidonic acid metabolism and eicosanoid production in human saphenous vein endothelial cells. · 2002 · https://pubmed.ncbi.nlm.nih.gov/11880240/ · DOI 10.1016/s1388-1981(01)00198-6

evidence_access

Primary abstract

experimental_model

Double-blind crossover in healthy men; enriched products supplied both CLA and vaccenic acid for six weeks.

limitations

Cannot separate direct CLA intake from precursor conversion or infer health benefit.

nutrient_topic

CLA collection; isomer, preparation, species, exposure and manipulation remain explicit. · Conjugated linoleic acid / CLA isomer family

plain_language

CLA reached several lipid compartments.

primary_references

Incorporation of cis-9, trans-11 conjugated linoleic acid and vaccenic acid (trans-11 18 : 1) into plasma and leucocyte lipids in healthy men consuming dairy products naturally enriched in these fatty acids. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16115358/ · DOI 10.1079/bjn20051506

Conjugated linoleic acid: isomers, signaling, nutrient interactions and discovery (2026-09-19) · lines 38–44

AI-assisted research curation; primary-abstract references and experimental limitations individually identified. Not publisher full text. · supports · Double-blind crossover in healthy men; enriched products supplied both CLA and vaccenic acid for six weeks. · source_derived_draft · unverified_draft

## cla-incorporation CLA reached several lipid compartments. Enriched dairy increased c9,t11 CLA in plasma phosphatidylcholine, triglycerides, cholesteryl esters and peripheral blood mononuclear cells. Model: Double-blind crossover in healthy men; enriched products supplied both CLA and vaccenic acid for six weeks. Limitations: Cannot separate direct CLA intake from precursor conversion or infer health benefit. Evidence access: Primary abstract Incorporation of cis-9, trans-11 conjugated linoleic acid and vaccenic acid (trans-11 18 : 1) into plasma and leucocyte lipids in healthy men consuming dairy products naturally enriched in these fatty acids. · 2005 · https://pubmed.ncbi.nlm.nih.gov/16115358/ · DOI 10.1079/bjn20051506