cholesterol: The project

by: Oizamsi Adeleke

Background

Cholesterol is both our friend and foe - at normal levels, it is an essential substance for the body's normal functioning, but if levels in the blood get too high, it becomes a silent danger that puts us at risk of a heart attack.
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LDL and HDL

Cholesterol is needed by all cells in the body. One type of lipoprotein (a combination of lipid and protein), LDL, is responsible for transporting cholesterol to the cells. Another type of lipoprotein, HDL, is responsible for removing excess cholesterol from the blood stream and transporting it to the liver. Too much cholesterol in the blood can cause a build-up inside the arteries. Therefore, a balance of these two molecules keeps circulating lipids from becoming trapped inside arteries.


All types of lipoproteins contain both lipids and proteins, but the relative composition of each lipoprotein varies. The main structural difference between LDL and HDL is their compositions. Approximately 50 percent of the weight of an LDL particle is cholesterol and only 25 percent is protein. High-density lipoprotein particles, on the other hand, consist of 20 percent cholesterol by weight and 50 percent protein. Since protein is more dense than fat, HDL particles are more dense than LDL particles, hence the names "high-density" and "low-density" lipoproteins. The other major structural difference between LDL and HDL relates to the types of protein they contain. Low-density lipoproteins contain proteins called B-100 proteins, while HDL particles contain mostly A-I and A-II proteins. The type of protein is significant because it determines the function of the lipoprotein particle.

Function

Low-density lipoproteins and high-density lipoproteins both transport cholesterol in the blood, but the main functional difference between the two is they deliver cholesterol to different parts of your body. Low-density lipoproteins -- the primary carriers of cholesterol -- bring cholesterol to cells throughout your body and can cause cholesterol to buildup within your arteries. This buildup can eventually lead to arterial blockage and an increased risk for heart disease and stroke. High-density lipoproteins, on the other hand, can benefit your health because these particles carry cholesterol away from your heart and other organs and deliver it back to your liver, where it is passed from your body.

why is LDL and HDL monitored

During a blood test, LDL and HDL are both monitored along with other things because they are used to help evaluate the patient's risk of heart disease. Whether more cholesterol is being taken to or from cells can be determined during a blood test. HDL levels should be at least 40mg/dL or closer to 60mg/dL. LDL should be lower than 129mg/dL or even lower for people that are at higher risks for heart disease.

Heart risk

An excess of LDL can result in plaque buildup on arterial walls which can ultimately result in atheroscerlosis. That is the hardening of the arteries and can lead to heart diseases like a heart attack or stroke. Unlike LDL, higher HDL levels can actually lower the risk of heart disease.

How can you change

Several things can be done to change the levels of both LDL and HDL in your blood. A healthy diet with reduced fat and cholesterol will increase HDL levels and decrease LDL levels. Saturated fat intake should be limited 7% or less of total calories, cholesterol should be 200mg per day or less, and Omega 3 fatty acids will increase HDL levels. It has been found that physical activity can raise HDL levels 5%. The activity needs to be consistent with at least 30 minutes a day for 5 days a week. An estimated every six pounds that are lost can increase HDL by one and lower LDL by one. Medication can also be used with the other things above.

Others

- triglycerides
- blood sugar level
- total cholesterol

Monounsaturated and polyunsaturated are the healthy types of fa that can improve cholesterol levels, decreasing your risk for cardiovascular disease according to MayoClinic.com. Monounsaturated fats -- found in nuts, avocados and olive oil -- promote better sugar control and insulin levels. Polyunsaturated fats include omega-3 and omega-6 fatty acids, which are essential fats your body needs. Eating a diet that includes good sources of polyunsaturated fat can lower your blood pressure, protect against irregular heartbeats and lower your risk for Type 2 diabetes, according to the Harvard School of Public Health. Additionally, your body relies on omega-3 and omega-6 fatty acids for proper brain development and function.


Saturated fat is a type of fat that comes mainly from animal products, such as meat and dairy products, as well as coconut and palm oils. This type of fat is unhealthy for your body and may increase your risk of Type 2 diabetes, according to MayoClinic.com. It may also increase your risk of heart disease by increasing your LDL, or "bad," cholesterol. The National Institutes of Health reports that saturated fat is the main dietary cause of high LDL cholesterol. Decreasing your risk of heart disease is not as simple as cutting back on the saturated fat in your diet. The Harvard School of Public Heath states individuals can decrease their risk of heart disease by replacing the saturated fat in their diet with healthy unsaturated fat but not by replacing the saturated fat with other unhealthy nutrients, such as refined carbohydrates.


Trans fat is the most unhealthful type of fat, according to the Center for Young Women's Health. MayoClinic.com states that trans fat can both increase your LDL cholesterol and decrease your HDL, or "good," cholesterol, thus increasing your risk of heart disease. Additionally, consuming trans fat can increase the inflammation in your body, which may increase your risk of cardiovascular disease and Type 2 diabetes, and it can lead to insulin resistance, according to the Harvard School of Public Health. Harvard also reports that for every 2-percent increase in daily calories from trans fat, risk of coronary heart disease increases by 23 percent. Most trans fat in the average American's diet comes from commercially baked goods, margarine, snack foods, fried foods and other processed foods.