Cholesterol is a fatlike substance which is found in the tissue of humans and other animals. It plays important roles in cell membrane structure, certain hormones, and manufacturing vitamin D. Our livers procude all of the cholesterol that we need for these important functions. Excess cholesterol can contribute to antherosclerosis or clogging of the arteries. Cholesterol is found in all food from animal sources: meat, eggs, fish, poultry, and dairy products. Some animal foods contribute substantial amounts of cholesterol, while others contribute only small amounts. There is no cholesterol in any plant-derived foods. Excess dietary cholesterol can increase blood cholesterol, which can increase the risk of coronary heart disease. You'll often hear cholesterol referred to as either good cholesterol or bad cholesterol. To help in our understanding of the two and their differences, we first need to define the word "lipoproteins." These are packets of proteins, cholesterol, and triglycerides that are assembled by the liver and circulated in the blood. When we talk about LDL cholesterol, we're referring to low density lipoprotein cholesterol. And when we refer to HDL cholesterol, we're referring to high density lipoprotein cholesterol. LDL cholesterol, often referred to as "bad cholesterol," carried cholesterol through the bloodstream, dropping it off where it's needed for cell building and leaving behind any unused residue of cholesterol as plague on the walls of the arteries. HDL cholesterol, often referred to as "good cholesterol," picks up the cholesterol which has been deposited in the arteries and brings it back to the liver for reprocessing or excretion. You can easily understand why there's a distinction between good and bad cholesterol now that you understand the unique functions of each. Saturated fats are usually from animal products such as lard, fats in meat and chicken skin, butter, ice cream, milk fat, cheese, etc. Tropical oils such as coconut oil and palm oil are also highly saturated. These fats are usually solid at room temperature. You've undoubtedly heard from somewhere that you should keep your saturated fats to a minimum, but do you know why? Because these fats tend to increase your blood cholesterol levels, which in turn increases your risk of coronary heart disease. Hydrogenated fats are those liquid vegetable oils than have been turned into solid saturated fats through a chemical process. These fats also contribute to your blood cholesterol levels. Polyunsaturated fats are liquid at room temperature and derived from plants. Examples: safflower, corn, soybean, cottenseed and sunflower oils. Polyunsaturated fats tend to lower LDL (your bad cholesterol), but in excess can also lower your HDL (good cholesterol). Monounsaturated fats are also derived from plants. These include olive oils and canola oil. Replacing the saturated fats in your diet with monounsaturated fats can help to lower your LDL (again, bad cholesterol) without lowering your HDL (good cholesterol). This is why monounsaturated fats are a healthy choice for your heart. However, keep in mind that too much of any form of fat can contribute to obesity. The bottomline: whenever you're making a choice about the fats you use, keep in mind that good heart health depends on keeping your LDL cholesterol low while maintaining your HDL cholesterol.