cholesterol
Enable an AI agent to recognise cholesterol, assess its chemical and contextual state, interpret observations about it, and identify justified handling or analytical actions.
Research draft, second pass
A second pass drafted this model: the structure a model of this thing needs, and what is known about it in the world. The line under this one says how the second half was obtained - researched against sources, or recalled without web access, in which case nothing here was read anywhere and every claim is a lead to verify. Unreviewed either way.
Researched by: Codex + Grok
Purpose and description
Enable an AI agent to recognise cholesterol, assess its chemical and contextual state, interpret observations about it, and identify justified handling or analytical actions.
Cholesterol is a sterol lipid (C27H46O) that is both synthesized endogenously and obtained from animal-derived foods, serving as a structural component of eukaryotic membranes and a biosynthetic precursor of steroid hormones, bile acids, and vitamin D.
It can be Verify a cholesterol identity claim against suitable structural or analytical evidence.; Quantify cholesterol on a declared free, esterified or total basis and compare compatible observations.; Locate cholesterol within a specified material, biological compartment or separated fraction.; Assess whether dissolution, extraction, separation or incorporation into a preparation is supported by the material state and intended use.; Select documented storage and handling conditions and flag evidence of chemical alteration.; Route clinical interpretations or decisions about associated particles to the relevant neighbouring model..
Distinguishing features
Identify cholesterol by its sterol structure, including the 3β-hydroxyl group and double bond between carbons 5 and 6; the molecular formula C27H46O alone does not establish identity against isomers.
Distinguish free cholesterol from cholesteryl esters by whether the hydroxyl group is esterified; an assay reporting total cholesterol may combine contributions from both.
Treat LDL cholesterol and HDL cholesterol as cholesterol measurements associated with specified lipoprotein fractions, rather than different molecular species of cholesterol.
Distinguish cholesterol from related sterols using analytical evidence capable of resolving the relevant structural differences, rather than appearance or a generic sterol-positive result.
Distinguish intact cholesterol from oxidised derivatives; a material derived from cholesterol is not automatically chemically unchanged cholesterol.
Scope
+ Molecular identity and discrimination from related sterols
+ Free cholesterol and explicitly distinguished cholesteryl ester contributions
+ Physical form, purity and chemical alteration of cholesterol-containing material
+ Cholesterol amount, concentration and distribution in a specified sample or compartment
+ Measurement interpretation, traceability and justified material-handling actions
- Lipoprotein particle identity, composition and transport behaviour as complete entities
- Patient cardiovascular risk, diagnosis and treatment decisions
- Whole-cell regulation, organ physiology and complete metabolic pathways
- Food composition, dietary planning and nutritional recommendations
- Other sterols, cholesteryl esters and cholesterol oxidation products as independently characterised substances
Characteristics
- Identity evidence
- Links to structural identification, reference material, analytical results or supplier documentation Determines whether the material is established as cholesterol or merely labelled or suspected to contain it.
- Chemical representation
- Free cholesterol; esterified cholesterol contribution; total cholesterol; unresolved Prevents chemically distinct forms and assay-defined totals from being treated as interchangeable.
- Material presentation
- Solid; dissolved; dispersed; membrane-associated; lipoprotein-associated; other specified presentation Controls what sampling, separation and handling operations are meaningful.
- Amount or concentration
- mol, g, mmol/L, mg/dL, mg/g or another explicitly defined basis Supports quantitative comparison only when the analyte definition, matrix and denominator are known.
- Purity or constituent fraction
- Mass fraction, mole fraction or method-defined purity with its basis stated Distinguishes a cholesterol reagent from a mixture containing cholesterol and constrains its suitability for use.
- Associated matrix or compartment
- Specified solvent, material, biological sample, membrane or lipoprotein fraction The same cholesterol amount can have different meanings and accessibility in different surroundings.
- Chemical integrity
- Integrity supported; alteration detected; alteration suspected; unassessed Determines whether observations and intended uses can still be attributed to intact cholesterol.
- Measurement qualification
- Method, calibration, uncertainty, reporting limit, sample preparation and observation time Establishes which conclusions a reported cholesterol result can support.
Also called
Where this came from
wikidata · CC0 1.0
Drafted structure
Bundle to layer to finding to question, as the second pass will find it: 6 bundles · 11 layers · 18 findings · 28 questions.
Cholesterol identity Establish what substance is present and what a cholesterol label actually denotes.
Cholesterol is easily conflated with related sterols, its esters and lipoprotein-associated measurements.
Molecular recognition
Record evidence that discriminates cholesterol from chemically similar substances.
Structure-supported identity
Record the claimed identity, its supporting evidence and whether relevant sterol alternatives were resolved.
- What evidence establishes the cholesterol structure, including its stereochemistry, rather than only a compatible formula or sterol class? definition
- Which reference material, analytical record or supplier record supports this identity claim? provenance
Chemical form boundary
Separate free cholesterol from esterified contributions and other derivatives.
Free cholesterol versus derived forms
Record whether cholesterol denotes the unesterified substance, a cholesterol contribution within esters or an assay-defined total.
- Does this record refer to free cholesterol, esterified cholesterol contributions or total cholesterol? definition
- Which esters or oxidation products require linked substance records rather than being counted as intact free cholesterol? boundary
Material state and integrity Describe how cholesterol is physically presented and whether its chemical identity has been preserved.
A solid reagent, a solution and cholesterol incorporated into a membrane require different observations and operations.
Physical presentation
Characterise the phase and surroundings in which cholesterol is available.
Phase and dispersion
Record whether cholesterol is solid, dissolved, dispersed or incorporated into an organised lipid environment.
- Is cholesterol present as a solid, in solution, in a dispersion or associated with a membrane or particle? measurement
- What solvent, temperature and preparation history support that state, and is precipitation or phase separation evident? provenance
Purity and alteration
Assess non-cholesterol constituents and changes affecting intended use.
Intact cholesterol fraction
Record purity evidence and any detected or suspected conversion to other chemical species.
- What fraction of the material is intact cholesterol, and does the method distinguish relevant impurities or oxidation products? measurement
- What storage or exposure history could affect integrity, and what evidence confirms or leaves that effect unresolved? provenance
Amount and assay meaning Make cholesterol quantities interpretable and comparable.
A cholesterol number is incomplete without its analyte basis, sample matrix, denominator and measurement method.
Quantity definition
Specify exactly what each reported cholesterol quantity counts.
Declared cholesterol basis
Bind each quantity to a free, esterified or total basis and a specified sample denominator.
- What cholesterol quantity is reported, in which units, and relative to what sample volume, mass or amount? measurement
- If esters contribute, is the result expressed as cholesterol equivalents or as the mass of whole ester molecules? definition
Analytical validity
Capture the analytical operations and limitations behind a cholesterol result.
Method-qualified result
Record sample preparation, assay selectivity, calibration and uncertainty sufficient to assess the result.
- How was cholesterol measured, and did preparation include extraction, ester hydrolysis or fraction separation? provenance
- What uncertainty, recovery limitations or interferences constrain comparison with another cholesterol result? measurement
Biological and material location Locate cholesterol without confusing the molecule with its carrier or host system.
Cholesterol measurements in membranes, bulk materials and lipoprotein fractions describe different contextual populations.
Host and compartment
Identify the material or biological location to which an observation applies.
Located cholesterol population
Record the sample, compartment or material population represented by the cholesterol observation.
- Which material, specimen or biological compartment contains the cholesterol being described? definition
- Was that location directly sampled, experimentally separated or inferred from a broader measurement? provenance
Carrier association
Represent cholesterol association with lipoproteins or membranes as a contextual relation.
Fraction-associated cholesterol
Distinguish cholesterol content attributed to a fraction from properties of the particles or membranes themselves.
- If the observation is labelled LDL cholesterol or HDL cholesterol, how was the fraction association measured or calculated? measurement
- Which conclusions concern cholesterol content, and which require a separate lipoprotein, membrane or patient model? boundary
Supported operations Connect cholesterol state and evidence to justified analytical and material operations.
An agent must know which operations preserve the intended cholesterol identity and which deliberately change what is being measured or used.
Preparation and transformation
Specify prerequisites and consequences of preparing cholesterol-containing material.
Operation with a defined target
Record the target chemical form and material state for dissolution, extraction, separation or incorporation.
- What documented procedure supports the intended cholesterol preparation in this matrix and at this scale? action
- Will the operation preserve free cholesterol, release cholesterol from esters or otherwise change the analyte basis? boundary
Retention and use readiness
Assess whether the material remains fit for its stated analytical or experimental purpose.
Evidence-based use disposition
Connect documented storage requirements, current integrity evidence and intended use to a handling decision.
- Which storage and handling conditions apply to this specific cholesterol preparation according to its documentation? provenance
- Does the available identity, purity and integrity evidence support use, or is reanalysis or replacement needed? action
Evidence and external alignment What the world already says about this thing, gathered so the model can be checked against it.
A model that cannot be lined up against existing standards, identifiers and practice cannot be adopted by anyone who already uses them.
Reported evidence
Findings from the breadth pass, kept separate from the structural claims.
Kinds and varieties
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Endogenous cholesterol (hepatic and extrahepatic de novo synthesis)
- Dietary cholesterol (animal-source food cholesterol)
- Free (unesterified) cholesterol
- Cholesteryl esters
- LDL cholesterol (LDL-C)
- HDL cholesterol (HDL-C)
- Non-HDL cholesterol
- Remnant cholesterol
- Which of these kinds and varieties hold for the sense of cholesterol this model covers, and on what evidence? provenance
Identifiers and schemes
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Wikidata - Q43656 - Wikidata item for cholesterol (the chemical substance).
- CAS Registry Number - 57-88-5 - Chemical Abstracts Service registry number for cholesterol.
- ChEBI - CHEBI:16113 - ChEBI identifier for cholesterol.
- PubChem CID - 5997 - PubChem compound identifier.
- InChIKey - HVYWMOMLDIMFJA-DPRGBGLPSA-N - Standard InChIKey for cholesterol.
- ATC - C10A* - WHO ATC class C10A (lipid-modifying agents, plain) covers drugs that act on cholesterol metabolism, not the molecule itself.
- Which of these identifiers and schemes hold for the sense of cholesterol this model covers, and on what evidence? provenance
Standards and regulation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- IUPAC Gold Book: sterols (steroid alcohols) - International Union of Pure and Applied Chemistry
- NCEP ATP III / 2018 AHA/ACC Guideline on the Management of Blood Cholesterol - US National Heart, Lung, and Blood Institute and American Heart Association / American College of Cardiology
- ESC/EAS Guidelines for the management of dyslipidaemias - European Society of Cardiology / European Atherosclerosis Society
- WHO Global Hearts / CVD risk factor guidance treating raised blood cholesterol as a modifiable cardiovascular risk factor - World Health Organization
- EU Regulation (EC) No 1924/2006 on nutrition and health claims (cholesterol-related food claims) - European Commission
- FDA food labeling rules for cholesterol content and nutrient content claims (21 CFR 101) - US Food and Drug Administration
- Which of these standards and regulation hold for the sense of cholesterol this model covers, and on what evidence? provenance
Real-world use
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Measured on a fasting or non-fasting lipid panel (total cholesterol, LDL-C, HDL-C, non-HDL-C, triglycerides) in primary care and cardiology to estimate atherosclerotic cardiovascular risk and to guide statin and other lipid-lowering therapy.
- Used as a raw material and reference standard in pharmaceutical, diagnostic, and biochemical manufacturing (e.g. lipoprotein calibrators, cell-culture media supplements, steroid-hormone synthesis feedstock).
- Encountered in food composition tables and nutrition labels as milligrams of cholesterol per serving in animal-source foods (egg yolk, offal, shellfish, meat, dairy).
- Target of public-health screening programmes (workplace, national health checks) and of over-the-counter point-of-care cholesterol meters.
- Pharmacologic target of HMG-CoA reductase inhibitors (statins), ezetimibe, PCSK9 inhibitors, bempedoic acid, and bile-acid sequestrants.
- Which of these real-world use hold for the sense of cholesterol this model covers, and on what evidence? provenance
Typical measurements
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Total blood cholesterol (adult clinical) - about 3.0-6.5 (desirable often <5.2; high often ≥6.2) - mmol/L
- LDL cholesterol (LDL-C) - about 1.0-4.9 (many guidelines treat <2.6 as desirable in primary prevention; very-high-risk targets can be <1.4 or <1.8) - mmol/L
- HDL cholesterol (HDL-C) - about 0.8-2.2 (low often <1.0 in men, <1.3 in women in US cut-points) - mmol/L
- Dietary cholesterol intake (adults, mixed diets) - about 200-400 - mg/day
- Molecular mass - 386.65 - g/mol
- Melting point (anhydrous cholesterol) - about 147-150 - °C
- Which of these typical measurements hold for the sense of cholesterol this model covers, and on what evidence? provenance
Failure modes and hazards
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Elevated circulating LDL and non-HDL cholesterol drive atherosclerotic plaque formation and increase risk of coronary heart disease, ischaemic stroke, and peripheral artery disease.
- Genetic disorders of LDL-receptor pathway (familial hypercholesterolaemia) produce very high LDL-C from childhood and premature atherosclerotic disease if untreated.
- Very low circulating cholesterol can occur in malnutrition, malabsorption, hyperthyroidism, or severe liver disease and is a marker of poor prognosis rather than a primary toxin of the molecule.
- Laboratory misclassification: Friedewald-estimated LDL-C is unreliable at high triglycerides; direct LDL-C and apoB better separate particle number from cholesterol mass.
- Statin and other lipid-lowering adverse effects (myopathy, rare rhabdomyolysis, new-onset diabetes) are hazards of treating cholesterol, not of the sterol itself.
- Oxidized cholesterol species and cholesterol crystals in plaque contribute to inflammation and plaque instability.
- Which of these failure modes and hazards hold for the sense of cholesterol this model covers, and on what evidence? provenance
Regional variation
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- US practice still commonly reports cholesterol in mg/dL; most of the world, including Europe, uses mmol/L (conversion: mg/dL ÷ 38.67 ≈ mmol/L).
- US dietary guidance after 2015 no longer sets a numeric cap of 300 mg/day dietary cholesterol, while some national food-based dietary guidelines still advise limiting high-cholesterol foods.
- European ESC/EAS guidelines use risk-category LDL-C targets (including <1.4 mmol/L for very-high-risk) more aggressively than older US treat-to-target culture, which shifted toward risk-based statin intensity after 2013 and returned to explicit LDL-C thresholds in 2018 AHA/ACC.
- Japan and some East Asian populations have historically lower mean population LDL-C and different CHD event rates at a given cholesterol level, which affects local treatment thresholds.
- Food-label cholesterol claims and 'cholesterol-free' marketing are tightly regulated in the US and EU but loosely or differently defined in other markets.
- Which of these regional variation hold for the sense of cholesterol this model covers, and on what evidence? provenance
Neighbouring kinds and how to tell them apart
Reported by the breadth pass; each item needs checking against its source before it becomes normative.
- Plant sterols / phytosterols (e.g. sitosterol, campesterol) - Same tetracyclic sterol nucleus but extra alkylation on the side chain; humans absorb them poorly. Gas chromatography or mass spectrometry of the sterol profile, not a routine lipid panel, separates cholesterol from phytosterols. Sitosterolemia is the clinical exception.
- Cholesteryl esters - Fatty-acyl esters of cholesterol stored in lipid droplets and in the core of lipoproteins; distinguished from free cholesterol by saponification or enzymatic free-vs-total cholesterol assays.
- Triglycerides - Glycerol triesters, not sterols; reported on the same lipid panel but measured by a different enzymatic assay. High triglycerides invalidate Friedewald LDL-C and raise remnant cholesterol.
- Apolipoprotein B (apoB) - Protein cargo of atherogenic particles, not the sterol. ApoB immunoassay counts particle number; LDL-C measures cholesterol mass inside those particles. Discordance appears in hypertriglyceridaemia and diabetes.
- Vitamin D (cholecalciferol) and steroid hormones - Biosynthetic products of cholesterol, not cholesterol itself; distinguished by specific immunoassays or LC-MS/MS of 25-hydroxyvitamin D, cortisol, sex steroids, etc.
- Bile acids - Oxidized, side-chain-shortened cholesterol metabolites that act as detergents and FXR ligands; measured as bile-acid profiles, not as blood cholesterol.
- Which of these neighbouring kinds and how to tell them apart hold for the sense of cholesterol this model covers, and on what evidence? provenance
Sources
- sterols (steroid alcohols) - IUPAC Gold Book definition of sterols as naturally occurring steroids with a 3-hydroxy group, of which cholesterol is the principal animal example.
- Physiology, Cholesterol - Membrane role, de novo synthesis via HMG-CoA reductase, lipoprotein transport, steroid/bile-acid/vitamin D precursor functions, and clinical lipid-panel fractions.
- Blood Cholesterol - Clinical distinction of LDL, HDL, and triglycerides; atherosclerotic risk framing; and US public-health treatment of blood cholesterol as a measured quantity.
- Cardiovascular diseases (CVDs) - WHO attribution of raised blood cholesterol as a major modifiable risk factor for atherosclerotic cardiovascular disease globally.
What the second pass must settle
- Does the registry already contain authoritative models for sterols, cholesteryl esters, lipoproteins or clinical lipid observations that should own some of these boundaries?
- Which identity methods and reference materials provide sufficient discrimination from relevant sterol isomers and impurities for each intended use?
- Which assay conventions govern total and esterified cholesterol reporting in the target sample types, including cholesterol-equivalent calculations?
- What preparation-specific storage conditions, integrity criteria and reanalysis intervals are supported by authoritative documentation?
- Which physical-state details, such as solid form or membrane accessibility, materially change decisions in the intended applications and therefore warrant finer modelling?