What type of unsaturated fatty acid is commonly found in fish and vegetable oils that helps lower cholesterol?

The common type of unsaturated fatty acid found in fish and vegetable oils that helps lower cholesterol is polyunsaturated fatty acids. These fatty acids, particularly omega-3 and omega-6 fatty acids, play an essential role in heart health. Omega-3 fatty acids, which are abundant in fatty fish like salmon and mackerel, have been shown to reduce triglyceride levels, lower blood pressure, and ultimately decrease the risk of cardiovascular disease.

Polyunsaturated fatty acids help improve the lipid profile by increasing high-density lipoprotein (HDL) cholesterol, which is known as the "good" cholesterol, while also reducing low-density lipoprotein (LDL) cholesterol, often referred to as "bad" cholesterol. This makes them a beneficial addition to a heart-healthy diet.

In contrast, the other types mentioned do not have the same beneficial effects on cholesterol levels. Monounsaturated fatty acids also contribute to cardiovascular health but are not as directly linked to lowering cholesterol as polyunsaturated fats. Saturated fats are generally associated with raising LDL cholesterol levels, while trans fats are known to negatively impact heart health and are discouraged in modern dietary guidelines.