You may have seen some TV ads talking about managing cholesterol with one or the other brand of cooking oil. Let's try and understand how cholesterol is important to us.
Cholesterol: the Nobel chemical
Cholesterol is a complicated molecule, part of a family of organic molecules called sterols. It was discovered by Michel Chevreul in 1812, and has been studied by many scientists since then. Thirteen scientists have received Nobel Prizes studying it, including Adolf Windaus.
Cholesterol is a very important part of the cell membrane. This membrane is necessary to keep our cells intact, and to regulate the to and fro flow of nutrients inside and outside the cell. The more cholesterol there is in a membrane, the stiffer it is. Nervous tissue in the brain and spinal cord, whose cells needs a lot of insulation, is rich in cholesterol.
Cholesterol is made by the liver. Much of it is used to make bile. Bile is a complex mixture including cholic acid, cholanic acid and desoxycholic acid. These acids are stored in the gall bladder, and released into the intestine during digestion. Bile emulsifies the fats we have eaten, allowing digestive enzymes to break them up.
Cholesterol is also used to make hormones that are important for normal body function. These include the corticosteroids, which are important for fighting off infections and allergies. Testosterone is made from cholesterol, and is responsible for the development of male characteristics in boys, like beards. Progesterone is a hormone found in women needed for maintaining pregnancy.
So why do people talk of good and bad cholesterol?
Cholesterol is used to make bile and also to make hormones that are important for normal body function.
Some of the cholesterol made by the liver is secreted into the blood to be transported to other tissues. In the blood, it is associated with another chemical called lipoprotein. If there's a lot of lipoprotein and less of cholesterol, this is known as high-density lipoprotein (HDL). HDL is used by the body to make other kinds of molecules, and is what is known as 'good' cholesterol.
If the reverse is true, it is known as low density lipoprotein (LDL). LDL is not transported easily in the blood, and gets deposited in the walls of arteries. These deposits are called plaques. If there are too many LDL plaques or if they are close to the heart, it can lead to a stroke or heart attack. That's why it is called 'bad' cholesterol.
Foods rich in cholesterol lead to an imbalance of lipoprotein, causing the body to make more LDL than HDL. That's why it's considered safer to buy cooking oil with less or no cholesterol. Foods rich in trans-fatty acids (like margarine and butter) promote LDL formation, while foods rich in fibre (root vegetables, fruits) and omega-3 fatty acids (fish, linseed oil) and Vitamin B3 promote good cholesterol. So let's go slow on the fries, and eat more carrots!
Foods rich in fibre (root vegetables, fruits) and omega-3 fatty acids (fish, linseed oil) and Vitamin B3 promote good cholesterol.
An ugly feature of cholesterol is steroid abuse or 'doping'. When there are high testosterone levels in the blood, the body gains more stamina. Many steroid molecules have been made from cholesterol that mimic the function of testosterone, like androstendione. These are called Performance Enhancing Drugs (PEDs) If an athlete inject a PED into his blood stream, he or she experiences a temporary increase in stamina, which may help beat the other athletes in a competition.
However, the dangers are many. PEDs are illegal in all sporting competition. Secondly, they can cause permanent damage to the body. They increase LDLs, reduce immunity to infectious diseases and create a high risk of getting cancer or a heart attack.
So now that you know the many aspects of cholesterol, here's to a long and healthy lifestyle with good cholesterol!