Types of cholesterol
- Saturated fats: Saturated fats are solid at room temperature, Foods that contain a high proportion of saturated fat are butter, lard, coconut oil, cottonseed oil and palm oil, dairy products (such as cream and cheese), meat, skin, and some prepared foods. People with diets high in saturated fat are reported to have an increased incidence of atherosclerosis (hardening of the arteries) and coronary heart disease. Saturated fats are popular with manufacturers of processed foods because they are less vulnerable to rancidity and are generally more solid at room temperature than unsaturated fats.
- Unsaturated fats: Unsaturated fats are liquid at room temperature. Unsaturated fats include monounsaturated and polyunsaturated fats. Monounsaturated fat remains liquid at room temperature but may start to solidify in the refrigerator. Foods high in monounsaturated fat include olive, peanut, and canola oils. Avocados and most nuts also have high amounts of monounsaturated fat. Polyunsaturated fat is usually liquid at room temperature and in the refrigerator. Foods high in polyunsaturated fats include vegetable oils, such as safflower, corn, sunflower, soy, and cottonseed oils. The use of monounsaturated and polyunsaturated fats instead of saturated fat can help to lower blood cholesterol levels.
- Trans fats: Trans-fatty acids (trans fats) are a type of unsaturated fat. Trans fat is formed when liquid vegetable oils go through a chemical process called hydrogenation, in which hydrogen is added to make the oils more solid. Hydrogenated vegetable fats are utilized in food production because they allow longer shelf life and give food desirable taste, shape and texture. Trans fat can be found in shortenings (e.g., Crisco®), margarine, cookies, crackers, snack foods, fried foods (including fried fast food), doughnuts, pastries, baked goods, and other foods processed with partially hydrogenated oils. Some trans fat is found naturally in small amounts in dairy products and some meats. The primary health risk associated with trans fat consumption is an increased risk of coronary heart disease (CHD). Effective January 1, 2006, the U.S. Food and Drug Administration (FDA) requires food companies to list trans fat content separately on the nutrition facts panel of all packaged foods.
- Lipoproteins: Cholesterol and other fats cannot dissolve in the blood. They have to be transported to and from the cells by special carriers called lipoproteins. There are two main types of lipoproteins, including low-density lipoprotein (LDL, or "bad") cholesterol and high-density lipoprotein (HDL, or "good") cholesterol. Another type, very-low-density lipoprotein (VLDL) is converted to LDL in the bloodstream. Each form of lipoprotein contains a specific combination of cholesterol, protein, and triglyceride (a blood fat). VLDL cholesterol contains the highest amount of triglyceride.
- Too much LDL cholesterol can block the arteries, increasing the risk of heart attack and stroke. LDL takes cholesterol into the bloodstream, and HDL takes it back to the liver for storage. It is also believed that HDL removes excess cholesterol from plaque in arteries, thus slowing the buildup. Studies suggest that high levels of HDL cholesterol reduce the risk of heart attack.
- Lipoprotein (a) (Lp(a)) cholesterol: Lp(a) is a lipoprotein (fat-protein molecule) found in the body that is a genetic variation of LDL cholesterol. A high level of Lp(a) is an important risk factor for developing fatty deposits in arteries. The way increased Lp(a) contributes to disease is not understood, but Lp(a) may attract substances that increase inflammation, such as interleukins (IL-1, IL-6, TNF-alpha) and prostaglandins (PG2), leading to the buildup of fatty deposits.
- Triglycerides: Triglycerides are the body's storage form for fat. Most triglycerides are found in adipose (fat) tissue. Some triglycerides circulate in the blood to provide fuel for muscles to work. Extra triglycerides are found in the blood after eating a meal, when fat is being sent from the intestines to fat tissue for storage. People with high triglyceride levels often have high LDL cholesterol and low HDL cholesterol levels. Many people with heart disease also have high triglyceride levels. People with diabetes or who are overweight are also likely to have high triglyceride levels.
Diagnosis and screening
- Recommendations for cholesterol screening and treatment have been provided by the National Institutes of Health (NIH) and are summarized in the National Cholesterol Education Program (NCEP). The guidelines recommend that all adults have their cholesterol levels checked at least once every five years. Patients with coronary heart disease or other forms of atherosclerosis are at the highest risk for heart attack and stroke (lack of blood and oxygen to the brain). These patients may benefit the most from cholesterol-reduction therapy and should have a full lipid profile (lipid panel) performed annually. This includes measuring total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides. Very-low-density lipoproteins (VLDL) and lipoprotein (a) (Lp(a)) levels can also be taken. For the most accurate measurements, there is no eating or drinking anything (other than water) for 9-12 hours before the blood sample is taken.
- There is no formula to determine what cholesterol level is considered "safe" and what cholesterol level requires treatment for each individual. General recommendations are based on ongoing research regarding future risk for heart attack. In a person with established coronary heart disease, the risk for heart attack (or subsequent heart attack) and death is much higher, so even mildly elevated cholesterol levels must be treated aggressively.
- Total cholesterol levels: The total blood cholesterol will fall into one of three categories, including desirable (less than 200mg/dL, or milligrams per deciliter), borderline high-risk (200-239mg/dL), and high-risk (240mg/dL and above).
- If the total cholesterol is less than 200mg/dL, the risk of heart attack risk is relatively low, unless there are other risk factors, such as smoking, a previous heart attack, or high blood pressure.
- If the total cholesterol level is 200-239mg/dL, individuals are classified as borderline high-risk. About one-third of American adults are in this group, whereas almost one-half of adults have total cholesterol levels below 200mg/dL. Not every person whose cholesterol level is in the 200-239mg/dL range is at increased risk.
- If the total cholesterol level is 240mg/dL or more, an individual is at high risk of heart attack and stroke. In general, people who have a total cholesterol level of 240mg/dL have twice the risk of coronary heart disease as people whose cholesterol level is 200mg/dL. About 20% of the U.S. population has high blood cholesterol levels.
- Lipoprotein levels: LDL, or "bad" cholesterol, is a major risk factor for developing atherosclerosis (hardening of the arteries) and coronary artery disease (CAD). LDL levels are reported in several categories. An LDL level below 100mg/dL is best for people at risk for heart disease. If an individual is at very high risk for heart disease, such as having had a previous heart attack, an LDL level less than 70mg/dL is optimal. LDL levels can also be near optimal (100-129mg/dlL, borderline high (130-159mg/dL), high (160-189mg/dlL, or very high (190mg/dL and above).
- HDL ("good") cholesterol protects against heart disease, so for HDL, higher numbers are better. A level less than 40mg/dL is low and is considered a major risk factor for developing heart disease. HDL levels of 60mg/dL or more help to lower the risk for developing heart disease.
- Triglyceride levels: High levels of triglycerides can increase heart disease risk. Levels that are borderline high (150-199mg/dL) or high (200mg/dL or more) may need treatment.
- Children: Total cholesterol levels in children and adolescents (2-19 years old) are classified as acceptable (less than 170mg/dL), borderline (170-199mg/dL), and high (200mg/dL and greater). LDL cholesterol levels for children are classified as acceptable (less than 110mg/dL, borderline (110-129mg/dL), and high (130mg/dL or greater).
Copyright © 2011 Natural Standard (www.naturalstandard.com)
The information in this monograph is intended for informational purposes only, and is meant to help users better understand health concerns. Information is based on review of scientific research data, historical practice patterns, and clinical experience. This information should not be interpreted as specific medical advice. Users should consult with a qualified healthcare provider for specific questions regarding therapies, diagnosis and/or health conditions, prior to making therapeutic decisions.