It's easy to become confused by the terms "good cholesterol," "bad cholesterol," and "dietary cholesterol." This is particularly true because there are ways to affect both good and bad cholesterol through the food you eat. To keep cholesterol in check and be as heart-healthy as possible, it's important to pay careful attention to diet.
Types of Cholesterol
Even though in common parlance there are two types of cholesterol -- good and bad -- in reality, there's only one kind of cholesterol. The cholesterol molecule is an important biomolecule that cells need in the correct proportions in order to maintain function. There are two types of cholesterol transporters, however, called HDL and LDL. These stand for high-density lipoprotein and low-density lipoprotein respectively, and ideally, you should have high HDL and low LDL.
Role of HDL
When you eat cholesterol in food, or when you eat food that contains the precursor molecules for making cholesterol, you pack cholesterol into LDL transporters, which carry it from the liver to the body cells. This increases the total cholesterol in your body. Your cells use HDL transporters as a mechanism for eliminating extra cholesterol from the body, explains Dr. Lauralee Sherwood in her book "Human Physiology." Cells pack excess cholesterol into HDL transporters, which carry it to the liver for excretion.
Cholesterol in Diet
There are two ways to increase the cholesterol in your body: You can eat cholesterol-containing foods, or you can eat foods that contain saturated and trans fats, from which your cells make cholesterol. Dietary cholesterol raises LDL, however, not HDL. There are a few ways to increase your HDL, but they largely don't depend upon diet. In addition to raising LDL, saturated and trans fats can also lower LDL, making them very heart-unhealthy fats, notes the American Heart Association.
HDL Recommendations
Because HDL helps clear cholesterol out of the body, the American Heart Association recommends that your HDL levels be as high as possible -- ideally greater than 60 mg/dL. With high levels of HDL, you can clear cholesterol from your diet and cholesterol that you make when you eat saturated and trans fats out of your bloodstream more efficiently, preventing the cholesterol from building up in your arteries.
Increasing HDL
While cholesterol in the diet doesn't increase HDL, there are a few ways you can increase your HDL and have a healthier blood cholesterol profile, notes MayoClinic.com. Regular exercise helps increase HDL -- ideally, you need at least 30 minutes of exercise three or more times per week. Smoking decreases HDL, but quitting smoking helps to increase your levels. Finally, maintaining a healthy weight helps to boost your HDL.
References
- "Human Physiology"; Lauralee Sherwood, Ph.D.; 2004
- American Heart Association: Fats
- American Heart Association: HDL Levels
- MayoClinic.com: Raising HDL
