Abstract: Cholesterol is a key structural component of eukaryotic cell membranes. It maintains the stability and fluidity of the membrane by regulating packing density of lipid. It is also a core component of lipid raft microdomain，participating in cellular signal transduction. Physiologically，cholesterol is an essential precursor for many vital substances in human body，such as steroid hormones，vitamin D，and bile acids. Particularly in the nervous system，Cholesterol plays a critical role in neural insulation,synaptic plasticity，and neuro-development,as a major component of myelin. Cholesterol homeostasis relies on the precise regulation of multiple metabolic pathways，including synthesis，uptake，efflux，and esterification. Key genes such as HMGCR，NPC1L1，ABCA1，ABCG1，and LCAT play central roles. Cholesterol plays a dual role in maintaining health balance. Hypercholesterolemia increases the risk of atherosclerotic cardiovascular diseases，specific types of cancer，Alzheimer’s disease and some other disorders. However，cholesterol insufficiency can also disrupt cell membrane function，impair neural transmission，and lead to endocrine disorders. Given the complex regulatory mechanisms of cholesterol metabolism in human，recent nutritional perspectives no longer simply set an upper limit for dietary cholesterol intake，but emphasize its indispensability in physiological function，and advocate for balance in overall dietary patterns. Future research should focus on the balance between the nutritional value of cholesterol and individual metabolism to precisely prevent and treat related diseases.

Key words: cholesterol, neurodevelopment, cholesterol homeostasis, atherosclerosis, neurodegenerative diseases, nutrition

摘要： 胆固醇是真核细胞膜的关键结构组分，通过调节脂质堆积密度以维持膜的稳定性与流动性，更是脂筏微域的核心构成，参与细胞信号转导。在生理功能上，胆固醇是人体内许多重要物质诸如类固醇激素、维生素D及胆汁酸等生理活性物质的必需前体，尤其在神经系统，胆固醇作为髓鞘的主要成分，对神经绝缘、突触可塑性及神经发育至关重要。机体胆固醇稳态依赖于合成、摄取、外排与酯化等多条代谢途径的精密调控，其中HMGCR、NPC1L1、ABCA1、ABCG1及 LCAT等关键基因发挥重要作用。胆固醇在维持健康平衡中具有显著的双重性，高胆固醇血症会增加动脉粥样硬化性心血管疾病、特定类型癌症及阿尔茨海默病等疾病的发病风险。然而，胆固醇不足同样会破坏细胞膜功能、影响神经传导，并导致内分泌紊乱。鉴于人体对胆固醇代谢的复杂调控机制，新的营养学观点不再简单设定膳食胆固醇的摄入上限，而是强调胆固醇在生理过程中的不可或缺性，并倡导在整体膳食模式中寻求平衡。未来研究需重视胆固醇的营养价值与个体代谢平衡，精准防治相关疾病。

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