The Skinny on Cholesterol and Fat
By Kerry O’Brien. E-mail: kobrien@psy.otago.ac.nz
Everyday we are bombarded with facts and statistics concerning the dangers of excessive fat consumption in our diets. Excessive fat consumption is associated with obesity and high cholesterol levels, which in turn are responsible for the number one killers in our society, heart disease, diabetes, stroke and cancer. Despite the warnings on dietary fat the average person in western society still consumes approximately 60-70 lbs of fat per year. But both cholesterol and fat are required for the normal functioning of a number of important chemical and hormonal processes in the body.
Cholesterol
Cholesterol comes from the liver and dietary sources. It is important for the formation of cell membranes, transportation and manufacture of certain essential vitamins, and a number of hormones including testosterone and cortisone. We have all heard that high cholesterol levels are bad for us, but the story is not quite so simple.
There are 2 general forms of cholesterol in the body. LDL-cholesterol and HDL-cholesterol.
*LDL-cholesterol transports most of the cholesterol around the body, however, when there is too much LDL-cholesterol in the blood, it leads to a build-up of cholesterol (plaques) on the artery walls. These build-ups can eventually become blockages, which prevent blood from getting to the heart and this results in heart attacks. This is why LDL-cholesterol is referred to as BAD cholesterol.
*HDL-cholesterol removes excess cholesterol from the blood and prevents build-ups on the arteries. This is why HDL-cholesterol is referred to as GOOD cholesterol.
It has probably become apparent to you that it is not just the amount of cholesterol in the blood that is a problem but the type of cholesterol also. If we have high levels of HDL-cholesterol and low levels of LDL-cholesterol we are significantly less likely to suffer from heart disease and some cancers. So the ratio of HDL to LDL-cholesterol that is important as well, not the total levels of cholesterol in the blood. So how does fat come into all of this?
Fat
Much like the cholesterol story, the fat situation is not straight forward, as there are also what we call good and bad fat. It is worth noting that 1 gram of fat is equivalent to 9 calories, while 1 gram of protein or carbohydrate is equivalent to 4 calories.
*Saturated Fat (Bad Fat) is contained largely in animal product such as meat, lard, eggs, and in dairy products such as milk, cream, butter and cheese. Coconut oil is also high in saturated fats. These products are obviously abundant in pastries, cakes, ice cream and generally most of the foods we love. It just so happens that these are the same types of food that contain large amount of dietary cholesterol. Both saturated fat and dietary cholesterol lead to increases in the bad LDL-cholesterol. Saturated fat should make up less than 10% of your daily calorie intake.
*Polyunsaturated Fat (Good Fat) comes in the form of corn oil, soybean oil, sesame oil and sunflower cooking oils. These fats decrease overall blood cholesterol levels, and are associated with lower rats of heart disease.
*Monounsaturated Fat (Good Fat) is present in oils such as flaxseed, olive, and canola oils. It is also present in advacados and nuts such as pecans, cashews, almonds and walnuts. Monounsaturated fats have been shown to lower the bad LDL-cholesterol while maintaining good HDL-cholesterol in the blood.
Polyunsaturated and Monounsaturated fats should make less than 15% of your daily calorie intake. When combined with the saturated fats you should have a total fat intake that accounts for no more than 25-30% of your daily calories. The message here is to not necessarily eliminate fat from our diet but to be more selective in the types of fat we consume. It’s one way to have your cake and eat it too.