Understanding Fat and Cholesterol

1. An explanation of fats and cholesterol:

Blood Lipid Parameters:

The National Cholesterol Education program recommends that everyone over the age of 20 be tested for cholesterol at least once every 5 years.

Blood Lipid	Desirable	Borderline	High
Total Cholesterol	< 200 mg/dL	200-239 mg/dL	>= 240 mg/dL
Low-Density Lipoproteins (LDL)	< 130 mg/dL	130-159 mg/dL	>= 160 mg/dL
High-Density Lipoproteins (HDL)	> 35 mg/dL (values >60 mg/dL are considered a negative risk factor)
Triglycerides	< 200 mg/dL

Lipids (Fats) Explained:

Fats, or lipids, can be divided into three general categories: Triglycerides, Phospholipids and Sterols.

Triglycerides - (fats and oils) This is the main form of fat in the diet. Triglycerides provide us with energy, insulates, cushions and protects internal organs and helps our bodies use carbohydrates and proteins more efficiently. Triglycerides can be further divided into the following categories:

Saturated fats - Usually solid at room temperature, saturated fats contain the maximum number of hydrogen atoms (saturated with hydrogen). Saturated fats are considered the most detrimental to health.

Monounsaturated fats - Liquid at room temperature, monounsaturated fats include olive and canola oils. This type of fat tends to lower "bad" LDL cholesterol while leaving the "good" HDL cholesterol unchanged.

Polyunsaturated fats - Liquid at room temperature, polyunsaturated fats include corn oil, safflower oil and sunflower oil. This type of fat tends to lower both "bad" LDL and "good" HDL cholesterol.

Hydrogenated fats - This fat results from a process where hydrogen atoms are added back to polyunsaturated or monounsaturated fats to protect against rancidity . This procedure effectively causes hydrogenated fats to become saturated fats. Thus, if a food lists partially hydrogenated oils among its first three ingredients, it usually contains alot of trans-fatty acids and saturated fats.

Trans-fatty acids - In nature, most unsaturated fats are cis-fatty acids. During hydrogenation, the molecular structure changes from cis- to trans-fatty acids. Trans-fatty acids increase "bad" LDL cholesterol and lower "good" HDL cholesterol, which may increase heart disease risk.

Essential fatty acids - Essential fatty acids must be supplied by the diet. The body uses essential fatty acids to maintain the structural parts of cell membranes. They are also used as a component in the production of hormone-like substances (eicosanoids) that help regulate blood pressure, clot formation, and maintain the immune response.

Linoleic Acid - The Omega-6 family. Common sources for these essential fatty acids are vegetable oils and meats. Most individuals can ensure an adequate intake of Omega-6 fatty acids by including grains, seeds, leafy vegetables, and small amounts of vegetable oils and meats in the diet.

Linolenic Acid - The Omega-3 family. Linolenic acid is a major component of the communicating membranes of the brain, and is active in the eye's retina. It is essential for growth and development. Fish, in particular, is abundant in both Omega-3 and Omega-6 fatty acids.

Phospholipids - (eg. lecithin) Phospholipids help transport fat-soluble vitamins, hormones and other substances through cell membranes. Because they can dissolve in both water and fat, they act as an emulsifier, helping to keep fats suspended in body fluids and blood. The liver can produce all the body's phospholipids from scratch, therefore it is not an essential nutrient.

Sterols - Sterols include cholesterol, vitamin D and sex hormones. The are a component of bile, sex hormones (testosterone), adrenal hormones (cortisol) and are a structural component of cell membranes. 9/10 of the body's cholesterol is stored in cells.

Cholesterol - The liver manufacturers about 800-1500 mg. of cholesterol per day, which contributes much more to total body cholesterol than does diet. The liver can also make cholesterol from carbohydrates, proteins or fat. Only animal foods contain cholesterol. Excess cholesterol harms the body when it forms deposits on artery walls, leading to atherosclerosis and heart disease. Cholesterol can be further divided into HDLs and LDLs:

Low-Density Lipoproteins (LDL) - Considered "bad" cholesterol. It is produced in the liver and circulates through the body, transporting fat to the muscles, heart, fat stores and other tissues.

High-Density Lipoproteins (HDL) - Considered "good" cholesterol. It is produced by the liver to carry cholesterol and phospholipids from the cells back to the liver for recycling and/or excretion. Because HDLs represent cholesterol removal from arteries and blood to the liver for breakdown and disposal, it is considered "good" cholesterol. Therefore, high levels of HDL cholesterol is considered a negative risk factor for heart disease.

2. Cholesterol in Foods:

Approximate Cholesterol Amounts in Foods:

Food	mg/chol
Grains, vegetables, fruits	0
Whole Milk, 1 cup	30-35
Nonfat Milk, 1 cup	5-10
Cheese, 1 ounce	25-30
Butter, 1 tablespoon	10
Beef, chicken, or pork, 3 ounces	70-85
Liver, 3 ounces	410
Egg yolk	213
Egg white	0
Shrimp, 3 ounces	165
Fish, lobster, clams,    3 ounces	50-60

The table above shows the approximate amounts of cholesterol that can be found in common foods.

Note that current research indicates that food cholesterol does not appear to increase blood cholesterol as dramatically as does saturated fats. So while it is wise to watch your cholesterol intake, be sure to decrease your consumption of saturated fats as well.

3. How you can improve your cholesterol Levels:

• Reduce or maintain a desirable weight Exercise. Aerobic exercise four days per week for 30 minutes or more can increase the level of ("good") HDL cholesterol in your body
• Choose monounsaturated or polyunsaturated fats in small amounts in place of saturated fats
• Avoid saturated fats.
• Eat fish once or twice per week
• Avoid hydrogenated or trans-fatty acids
• Reduce consumption of high-cholesterol foods
• Consume more soluble fiber (see our Amazing Grains article)
• Graze. Eating 5 or more meals per day keeps insulin concentrations low and slows down the liver's synthesis of cholesterol