Final answer:
HDLs and the liver are key regulators of blood cholesterol levels through cholesterol transportation and synthesis control.
Explanation:
High-density lipoproteins (HDLs) play a crucial role in regulating blood cholesterol levels by carrying cholesterol out of the bloodstream and into the liver for reuse or removal.
The liver is the main regulator of blood cholesterol levels as it controls the synthesis of cholesterol in response to the cholesterol level in the blood.
Dietary modifications like substituting unsaturated fats for saturated fats and reducing trans fatty acid consumption can help lower total cholesterol and improve the LDL:HDL ratio, thus reducing the risk of heart disease.
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