by Jamie Liu
During an annual checkup with your doctor, they may have talked to you about cholesterol, how too much is bad for you, and eating healthily. Cholesterol isn’t all bad, but what is it exactly and how does it affect our health?
What is cholesterol?
Cholesterol is a waxy, fat-like substance that is found all throughout our bodies. Cholesterol is made of four hydrocarbon rings with a hydroxyl group and a hydrocarbon tail. We use cholesterol to make cells, hormones (including estrogen and testosterone), and vitamin D.
Image created by author using BioRender
Where does cholesterol come from?
Cholesterol is produced in the liver or can come from foods that we eat. About 80% of the cholesterol you need is made by the liver, with the remaining 20% coming from food. Examples of food that contain cholesterol include red meat, eggs, full-fat dairy products like ice cream or butter, nuts, avocados, and fried foods.
How does cholesterol impact our health?
Since cholesterol is a hydrophobic molecule, it can’t enter our water-based blood and travel around the body. Therefore, the liver packages cholesterol with other fats, like triglycerides, into round particles called lipoproteins. These packages have a hydrophilic shell, allowing easy travel around in the bloodstream. There are two types of lipoproteins, low density lipoproteins (LDLs) and high density lipoproteins (HDLs). LDLs are considered the “bad” type of cholesterol. This is because LDLs carry cholesterol to your arteries where too much can cause plaque build up. Plaque can stick to the inner lining of the arteries restricting blood flow, increasing blood clot formation, and ultimately creating risk of heart disease and stroke.
Image created by author using BioRender
On the other hand, HDLs are considered the “good” type of cholesterol. Compared to LDLs, HDLs have more proteins, which make them more dense. The extra proteins and increased density of the HDLs equip them to collect cholesterol from the bloodstream. HDLs are decorated with apolipoproteins, a family of proteins that are capable of binding to cholesterol and phospholipids. As HDLs circulate in the blood, the apolipoproteins help HDLs collect free cholesterol and phospholipids. Some apolipoproteins are capable of turning the biologically active, free cholesterol into storage and transport-friendly cholesterol ester. HDLs can then transport cholesterol back to the liver, where the excess is then broken down and excreted from the body. Therefore, HDLs are considered the “protective” type of cholesterol.
Image created by author using BioRender
How can we keep track of cholesterol levels?
Blood work at a doctor’s appointment can give us an idea as to how much cholesterol is circulating in the bloodstream. Cholesterol in the blood is measured by devices called chemistry analyzers. Chemicals are mixed with blood, causing emission of light. The chemistry analyzer then determines the color of light coming from the chemical reaction between the chemicals and cholesterol, allowing cholesterol quantitation. Those with higher levels of LDLs are more at risk for heart disease. LDL levels <100 mg/dL, HDL levels > 60 mg/dL, and total cholesterol (LDL and HDL) <200 mg/dL are considered heart-healthy.
If your cholesterol is a little high, no need to panic! Having a balanced diet and regular exercise can be helpful in reducing and maintaining healthy cholesterol levels. Also, eating unsaturated fats like avocados, nuts, and seeds can boost good cholesterol HDL levels!
