LDLs and HDLs are lipoproteins that transport triglycerides, which are fats, and cholesterol throughout your bloodstream to deliver nutrients to your cells and help maintain enzyme and cellular structures. They are made in the liver, and the liver regulates the level of lipoproteins in your body. According to registered dietitian Mary Grosvenor, who is a former nutrition researcher at UCLA, exercise frequency and intensity, and eating different types of fats--saturated or unsaturated--affects the amount of LDLs and HDLs in your body.
LDL
LDL--low-density lipoproteins--transport triglycerides and cholesterol into your arteries and other parts of your bloodstream. They deliver cholesterol to your cells to form or repair cell membranes. LDLs, like all other lipoproteins, resemble spheres with two layers. The inner layer contains vitamins, cholesterol and triglycerides, while the outer layer is made up of proteins and phospholipids that envelop the contents.
HDL
HDLs--high-density lipoproteins--transport cholesterol away from your bloodstream to your liver for reprocessing and storage, or to other glands that require high cholesterol levels to make hormones. They are the largest lipoproteins that are made in your intestinal tract and liver. Their structures are the same as those of the LDLs.
Sources
You can increase your LDL level by consuming foods that are high in cholesterol and saturated fats, such as red meats, liver, cakes, cookies, chips, french fries, fried foods and many processed foods.
George Mateljan, a biologist and author "World's Healthiest Foods," recommends that you consume more foods that raise your HDL level, such as cold-water fish, fruits, vegetables, vegetable oils and whole-grain foods. Foods high in fiber remove cholesterol in your intestinal tract, which also prevents constipation and colon cancer.
Effects
Too much LDL forms fatty deposits in your arteries. This causes plaque to form that clogs your blood vessels, reducing the blood flow. Many cardiovascular diseases occur from having a high level of LDL. This is why LDL is known as the "bad" cholesterol.
A high HDL level lowers your risk of cardiovascular diseases because it clears cholesterol from your bloodstream before they can form plaques. This cholesterol-clearing action earns HDL the "good" cholesterol designation.
Recommended Levels
The American Heart Association recommends that you maintain your HDL level between 40 and 60mg per deciliter of blood. For LDL level, keep the level below 100 mg per deciliter of blood. If your LDL level is above 160 mg per deciliter, then you have a very high chance of getting cardiovascular diseases, notes the heart association.
References
- "World's Healthiest Foods"; George Mateljan; 2006
- "Nutrition From Science to Life"; Mary Grosvenor; 2001
- American Heart Association: What Do My Cholesterol Levels Mean?
