Dietary Fat and Cholesterol
The amount and kinds of food eaten can contribute to atherosclerosis and heart disease. The risk of atherosclerosis is proportional to the serum (blood) levels of total cholesterol and LDL cholesterol. It is now an accepted scientific fact that high cholesterol levels increase the risk of developing heart disease.
What is Cholesterol?
- It is a fatty, wax-like substance resembling soap.
- It circulates in the blood and is essential to life for the formation of cells, production of hormones, and protection of joints and nerves.
- The different components that make up the total cholesterol are attached to protein and are called lipoproteins or fat proteins. These components include HDL, LDL and triglycerides.
- Levels in the blood are determined by genetic make up and may or may not respond to dietary or lifestyle changes.
Where Does Cholesterol Come From?
- The liver has the ability to produce enough cholesterol to meet the body's needs, about l000 mg/day.
- Cholesterol and animal fat in the diet also contributes to the amount of cholesterol in the blood.
- Excessive amounts of cholesterol in the blood may be due to heredity, lifestyle, and/or excessive dietary intake of saturated fats.
Is There Good and Bad Cholesterol?
- LDL or low density lipoprotein is called the "BAD" cholesterol.
- High levels of LDL cholesterol are associated with greater risk for heart disease.
- LDL cholesterol is found in the atherosclerotic plaque which narrows the artery wall and restricts blood flow.
- Low LDL blood levels are desirable.
- LDL is decreased by:
- decreasing dietary intake of saturated fats
- decreasing high cholesterol foods
- substituting unsaturated fats
- increasing high fiber foods
- decreasing body weight, specifically fat weight
- stopping smoking
- medications
- exercise
- HDL or High density lipoprotein is called the "GOOD" cholesterol.
- High levels of HDL cholesterol are associated with a decreased risk of heart disease.
- It acts as a scavenger, collecting excess bad cholesterol and transporting it to the liver for disposal.
- HDL can be increased by:
- monounsaturated fats in the diet
- aerobic exercise
- a decrease in body fat and an increase in muscle mass
- being female (hormones)
- stopping smoking
What Are the Recommended Levels of Cholesterol?
- Ideal HDL cholesterol levels: 50 mg/dl or greater
- Ideal LDL cholesterol levels: l00 mg/dl or less
- Ideal triglycerides: 200 mg/dl or less
- Total cholesterol levels: 200 mg/dl or less
What Are Saturated Fats?
Saturated fats are found in animal products and are solid at room temperature. Saturated fat in the diet should be limited as they are known to raise serum cholesterol levels dramatically and is a more significant factor than foods high in cholesterol. The higher the saturation, the greater the effect of increasing blood cholesterol levels.
Examples of foods high in saturated fats include butter, lard, beef, hot dogs, luncheon meats, and full-fat dairy products. In addition to animal fats, there are some vegetable fats that are highly saturated, including coconut, palm oil, and chocolate. Coconut and palm oil are the most highly saturated fats and the most potent in elevating serum cholesterol. These two oils are added to many processed foods.
NOTE: Many products are labeled "No Cholesterol" but, in fact, are high in total fat and saturated and hydrogenated fats.
What Are Monounsaturated Fats?
Monosaturated fats are found in vegetable products and are liquid at room temperature. They are the more desirable fats as they may be as effective as polyunsaturated fats in lowering cholesterol levels but do not decrease HDL cholesterol. Example: olive, canola and peanut oil, avocados, nuts.
What Are Polyunsaturated Fats?
These fats are also found in vegetable products, are liquid at room temperature, and decrease LDL cholesterol levels. They may also slightly decrease HDL cholesterol. Corn, soybean, safflower and sunflower oils are examples of polyunsaturated fats.
What Are Hydrogenated Fats?
Hydrogenated fats are unsaturated fats that have been changed to saturated fats by a chemical process called hydrogenation. These fats should be limited as the process of hydrogenation changes more desirable fats to less desirable fats: oil to margarine. Most commercially prepared foods contain hydrogenated fats as they are cheap and extend the shelf life of food.
What Are Omega-3 Fatty Acids?
The fat in fish is rich in highly polyunsaturated omega-3-fatty acids and is considered to be very beneficial fat. This fatty acid decreases triglycerides and may increase HDL levels. It expands arteries, increasing blood flow and oxygen, and decreases the stickiness of the platelet. This decreases the chance of clots forming in an already narrowed artery. It may also decrease blood pressure. The use of fish oil capsules is not recommended unless prescribed by a physician.
What Are Triglycerides?
Triglycerides are blood fats and form part of the lipoprotein complex. They are elevated by certain foods in the diet: alcohol, fat and sugar. Triglycerides may be an independent risk factor for coronary artery disease. Diet and drug therapy are recommended to lower high levels of triglycerides.
What is the Effect of Fiber on Serum Cholesterol?
Fiber is effective in decreasing the absorption of cholesterol and fat in the intestinal tract, thereby decreasing blood cholesterol levels. There are two kinds of fiber, water soluble and water insoluble.
Water soluble fiber is most effective in decreasing cholesterol levels.
- oat bran
- fruit pectin (apples and citrus fruits)
- corn bran
- rice bran
- dried peas and beans
Water insoluble fiber is most effective in improving elimination or preventing constipation.
- wheat bran
- dried peas and beans
- whole grain breads
- fruits and vegetables
- whole grain cereals
What is the Treatment for Elevated Cholesterol Levels?
- A dietary change, if blood cholesterol levels are between 200-240 mg/dl (moderate risk).
- Increase fish meals to 3 times a week (especially salmon, mackerel, tuna, sardines, and herring).
- Increase dietary intake of water soluble *fiber, especially oat bran.
- Increase high *fiber foods (whole grain breads and cereals, vegetables, dried peas and beans).
- Decrease saturated fats (animal fats, palm and coconut oil).
- When using fats, use monounsaturated and polyunsaturated fats.
- Decrease high cholesterol foods (eggs, organ meats).
- Read labels to determine type and amount of fat.
- Start exercise program and lose weight if necessary.
- Stop smoking.
- Cholesterol lowering medications may be prescribed if the change in diet and lifestyle is not effective after 3 - 6 months.
*Fiber should be increased very slowly to avoid intestinal problems.
