Fats – The Good, the Bad, and the Ugly

Fats do form an essential part of our diet. They help in various essential bodily functions, such as nutrient absorption, nerve transmission, maintenance of cell membrane integrity, etc.

Fats & Cholesterol ctd

However, when consumed in excess amount, fats contribute to weight gain, heart disease and certain types of cancer. Another important fact is that some fats promote health positively while some increase the risk of heart disease. The solution lies in replacing bad fats with good fats in the diet.

All fats are mainly composed of triglycerides, which are in turn, composed of fatty acids. These fatty acids are categorized as saturated, trans fatty acids, and unsaturated (which include monounsaturated and polyunsaturated). A brief overview of different types of fats is given below.

1. Saturated Fatty Acids
Saturated fats (or fatty acids) are usually solid at room temperature and they are more stable - that is, they do not combine readily with oxygen. Saturated fats are found mainly in animal products and tropical oils. These include:

* Animal-based foods containing high amounts of saturated fatty acids include beef, beef fat, veal, lamb, pork, and lard
* Poultry skin, chicken wings, and dark meat chicken
* Plant-based oils containing saturated fatty acids include coconut oil, palm oil and palm kernel oil and cocoa butter.
* High fat dairy products, such as cheese, butter, whole milk, cream, cream cheese, sour cream, and ice cream

2. Trans-fatty Acids (Trans Fats/Hydrogenated Fats)
Trans fats were invented as scientists began to ‘hydrogenate’ liquid oils so that they could withstand better in food production process and provide a better shelf life.

These are found in the following:
* Stick margarine and some tub margarines
* Vegetable shortening
* Fried foods: doughnuts, french fries, other deep fried fast food items
* Commercially prepared foods containing partially hydrogenated oils: crackers, cookies, cakes, pastries, microwave popcorn and other snack foods

3. Unsaturated Fats
Polyunsaturated and monounsaturated fatty acids together form unsaturated fatty acids.

i) Polyunsaturated fatty acids
Polyunsaturated oils are liquid at room temperature and in the refrigerator. They easily combine with oxygen in the air to become rancid. Polyunsaturated fatty acids tend to help the body get rid of newly formed cholesterol. Thus, they keep the blood cholesterol level down and reduce cholesterol deposits in artery walls. Common sources of polyunsaturated fatty acids are safflower, sesame and sunflower seeds, corn and soybeans, many nuts and seeds and their oils.

a) Omega-3 fatty acids
Research has shown that they reduce the risk of sudden cardiac death, help keep blood vessels flexible and reduce excess blood clotting. Common sources include:
* Fatty fish such as salmon, herring, sardines and trout
* Flaxseed, walnuts and canola oil (all contain a less active form of omega-3)

b) Other Polyunsaturated Fats (Omega-6 Fatty Acids)
Common sources include:
* Vegetable oils: corn oil, safflower oil, sesame oil, soybean oil, and sunflower oil
* Soft (liquid or tub) margarine, ideally one that is trans fat free
* Walnuts
* Sunflower seeds, pumpkin seeds, and sesame seeds
* Soy ‘nuts’ (roasted soy beans), soy nut butter, and tofu

ii) Monounsaturated fatty acids
Monounsaturated oils are liquid at room temperature but start to solidify at refrigerator temperatures. Monounsaturated fats also lower total cholesterol and LDL (bad) cholesterol and increase the HDL (good) cholesterol.

Sources of monounsaturated fatty acids include:
* Vegetable oils: olive oil, canola oil, and peanut oil
* Nuts: almonds, cashews, peanuts, pecans, and pistachios
* Avocado
* Peanut butter and almond butter

All fats, even if they are monounsaturated and polyunsaturated, are high in calories. Fat contains nine calories per gram. In comparison, protein and carbohydrates only contain four calories per gram. Using a large amount of monounsaturated or polyunsaturated fats to lower cholesterol is not advisable as the extra calories will lead to excess weight, which will further push up cholesterol levels.

Other Causes

There is an unambiguous link between high cholesterol levels and a diet high in dietary cholesterol and saturated fat, although genetic factors also play an important role.

The causes can be dichotomized into those that can be controlled (secondary factors), and others that cannot be (primary factors).

Primary Factors

1. Genetics
Some people are genetically prone to having high levels of cholesterol. A variety of minor genetic defects can lead to the excessive production of LDLs or a decreased capacity for their removal. This tendency towards high cholesterol levels is often passed on from parents to their children. Familial hypercholesterolemia (FH), which affects 1 in 500 individuals, is a common inherited disorder whose victims have a diminished number or nonexistent LDL receptors on the surface of their liver cells. People with this disorder also tend to develop atherosclerosis and heart attacks during early adulthood.

2. Age and Sex
The risk of high cholesterol increases as one gets older. Starting at puberty, men have lower levels of HDL than women. However, younger women have lower LDL cholesterol levels than men, but after age 55 they have higher levels than men.

Secondary Sources

1. Diet
Diet is one of the most important of the secondary causes of high cholesterol. Foods that are high in cholesterol, saturated fat, and trans fat increase cholesterol levels and the risk of developing heart disease. It is important to remember that the liver produces all the necessary cholesterol needed by the body and as such, it is not necessary to get additional cholesterol from food. Fruits and vegetables can be consumed without fear, whereas consumption of animal and dairy products should be restricted.

2. Weight
Excess weight tends to increase LDL (bad) cholesterol and triglyceride levels, and reduce the HDL level. Weight loss helps to lower triglyceride levels, as well as raise HDL (good) cholesterol levels.

3. Alcohol
Alcohol intake increases HDL (good) cholesterol but does not decrease the bad or LDL cholesterol level. In addition, drinking too much alcohol damages the liver and heart muscles, leads to high blood pressure, and raises triglyceride levels. Doctors are not certain whether alcohol also reduces the risk of heart disease. Hence, the risks overweigh the uncertainty and alcoholic beverages should not be used as a means to prevent heart disease.

4. Smoking
Smoking reduces the HDL cholesterol and is linked to about 20% of deaths from heart disease.

5. Stress
Although stress does not directly increase cholesterol levels, it affects an individual’s mood and eating habits. For example, when some people are under stress, they comfort themselves by eating fatty foods. Apparently, stress causes the speedy burning of calories and sugars are a quick calorie builder. The saturated fat and cholesterol in these foods contribute to higher levels of blood cholesterol.