Cholesterol is not inherently harmful — the body makes and needs it. The risk lies in high circulating levels of LDL (low-density lipoprotein) particles, which can deposit in artery walls and drive atherosclerosis. HDL (high-density lipoprotein) helps transport cholesterol back to the liver for removal; higher HDL is generally associated with lower cardiovascular risk.
Diet influences LDL primarily through saturated fat and trans fat intake, which raise LDL, and through soluble fibre and plant sterols, which help lower it. Dietary cholesterol (from eggs and shellfish) has less impact on blood LDL for most people than saturated fat does — evidence here has shifted substantially over the past two decades.
Genetics, physical activity, body weight, and smoking all affect cholesterol levels. A full lipid panel and clinical assessment is needed to interpret your individual results.