Cholesterol has a bad rap as yet another health evil we all need to be monitoring. But just like most things related to our bodies, it’s more complicated than writing off all forms of cholesterol as the villain. There are actually two types of cholesterol, and while one deserves its bad reputation as a risk for your health, the other does a lot of important jobs to keep you running right. Meet cholesterol’s good and bad sides, and find out how you can find the balance.

Sliced and whole avocados

“Good” versus “bad” cholesterol

Cholesterol is a type of waxy fat that gets “packaged” up with a type of protein so it can travel around in your blood. This new molecule is called a lipoprotein. The right kind of cholesterol is essential for your body: “We need cholesterol to create cells in our brain and also to create hormones,” says Brittany L. Jones, MS, RD, owner of Blush Nutrition in Greenville, SC. The “good” kind of cholesterol is called high-density lipoprotein (HDL) and the “bad” kind is low-density lipoprotein (LDL): Jones recommends thinking of the “H” in HDL as “happy,” and the “L” in LDL as “lousy.”

LDL has earned the ire of doctors because it is rich in pure cholesterol, which tends to build up in your arteries and lead to the plaque formations that cause narrowing and blockage, says Robert Greenfield, MD, a cardiologist and lipidologist, and Medical Director of Non-Invasive Cardiology & Cardiac Rehabilitation at MemorialCare Heart & Vascular Institute at Orange Coast Medical Center. “It is also inflammatory, so it can cause plaque buildup in our arteries that become unstable and rupture, or erode to cause heart attacks and strokes.”

HDL, on the other hand, is seen as the body’s superhero because it clears up the bad cholesterol. Dr. Greenfield compares it to garbage disposal: “HDL is the sanitation truck that picks up the garbage, and the garbage is the LDL.” To extend the metaphor further, HDL is more like a dedicated recycler who picks up discarded junk and transports it to someone who can turn it into treasure: “It can pick up cholesterol from the blood and blood vessels and carry it to the liver so the liver can use that cholesterol to make bile, vitamin D, and other necessary products that we need to live,” Dr. Greenfield says. “It also carries cholesterol to the gonads and adrenal glands so they can synthesize hormones. And if that wasn’t enough, HDL may help with our immunity and help us to fight infections.”

Another type of fat that affects your cholesterol levels are triglycerides; Dr. Greenfield explains that these come from saturated fats and simple carbohydrates and sweets in the diet. Like cholesterol, they are both necessary and potentially bad for you. “Triglycerides have energy that is stored for later use,” Jones clarifies. “Your body releases triglycerides from your fat cells between meals to use for energy.” The problem comes, Dr. Greenfield says, when your triglyceride levels rise too high: “Excess triglycerides are stored for later use in fat cells. As we become more sedentary and tend to eat too much, we have an overabundance of triglycerides and our fat cells get fatter!” High triglycerides can be a particular problem for people with type 2 diabetes, he says, and, “They also “play dirty tricks on their neighbors, HDL and LDL, as they decrease HDL in the blood and they make the LDL particles smaller and more dense, so they can more easily penetrate the blood vessel wall and accelerate atherosclerosis, or ‘hardening’ of the arteries.”

How to keep your cholesterol in check

As you can tell, ideally you want to keep your LDL levels low, your HDL levels high, and your triglycerides just right. Let’s start with HDL. “Having low levels of HDL can increase your risk of having a heart attack or stroke,” cautions Martha Gulati, MD, Physician Executive Director for Banner—University Medicine Heart Institute. “Your HDL level should be at least 40mg/dL [milligrams per deciliter] for people assigned male at birth, or 50mg/dL for people assigned female at birth — but higher is better.” Dr. Greenfield agrees: “The ‘sweet spot’ for HDL is between 60 and 80 mg/dl, and levels below 40 or above 100 can be problematic,” he adds.

So how do you up those HDL levels? You can’t find LDL or HDL in a store, Dr. Greenfield points out, and nutrition labels don’t go into that much detail. That being said, certain foods and diets can influence their levels in your body. And that’s good news for avocado lovers: “Foods that help increase your HDL cholesterol include what you may have heard of as ‘good’ fats such as olives and olive oil, avocados and avocado oil, fatty fish like salmon, and nuts and natural nut butters,” Jones says.

In addition to eating more of those, you have to also eat less of the foods that can increase LDL. Namely, says Dr. Greenfield, saturated fats and trans fats. Trans fats (including hydrogenated oils) both raise LDL and lower HDL, and “can typically be found in processed foods with shortening like cakes, cookies, donuts, and also in coffee creamer, especially the powdered kind,” Jones advises. “The American Heart Association recommends that 10 percent of our calories or fewer should come from saturated fat to keep our LDL cholesterol low; this can be found in meat, dairy, and coconut products.” Dr. Greenfield also recommends you keep an eye on your carbohydrate intake (although you should never cut them out completely, unless you’ve spoken to your doctor about it first), since these can lead to excess triglycerides, which in turn raise LDL and lower HDL. “Exercise can also increase HDL,” he adds. “And even more interesting, alcohol increases HDL as well — however, we don’t recommend people start drinking!”

Unfortunately, your LDL levels can be down to more than just your diet. Some people are genetically predisposed to high LDL or low HDL. “You can get an ApoE genotype test to see if you have a predisposition to high cholesterol,” Jones says. “You can also get tested to see if you have familial hypercholesterolemia (FH) through a genetic test and working with a genetic counselor.” FH, explains Dr. Gulati, “is a condition where excess LDL is made and not cleared from the body.” It’s surprisingly common: Dr. Greenfield estimates that about one in 200 patients with high cholesterol have this condition.

Other factors that can increase your risk from cholesterol, Dr. Gulati adds, include smoking, which lowers HDL; certain drugs — including thiazide diuretics (for hypertension), steroids, amiodarone, and cyclosporin — which can raise LDL; and the combined birth control pill, which might actually raise HDL and lower LDL, but can also raise triglycerides.

The myths and rumors around cholesterol show just how important it is to find out the details before cutting things out of your diet in the name of health. With a better understanding of the nuances, you can keep the lousy low and the happy high.

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