And what's the difference between good and bad cholesterol?
Cholesterol is essential for healthy cells and is a building block of hormones, but too much of it increases the risk of heart attack and stroke.
The Centers for Disease Control and Prevention (CDC) recommends adults have a cholesterol screening every four to six years. Most annual physicals at UCLA Health include this simple blood test and its resulting “lipid panel” that lays out cholesterol numbers.
Three separate figures comprise cholesterol levels: LDL (low-density lipoprotein), HDL (high-density lipoprotein) and triglycerides.
What is cholesterol?
Cholesterol is a waxy substance in the blood produced by the liver and also ingested through food. Diets high in animal sources — meat, poultry, full-fat dairy and eggs — can lead to higher blood cholesterol, says Elizabeth Ko, MD, assistant clinical professor of medicine at the David Geffen School of Medicine at UCLA.
“The liver produces more cholesterol when there’s a diet that’s high in these bad fats,” says Dr. Ko, who discussed the basics of cholesterol, medication and nutrition during a virtual lecture on July 14 as part of UCLA Health's monthly Wellbeing Webinar series.
About 38% of American adults have high cholesterol, according to the CDC.
Making sense of cholesterol numbers
There’s good cholesterol and bad cholesterol.
“LDL is bad cholesterol, and we want it to be low,” says Dr. Ko, noting that it can be helpful to consider the L in LDL to stand for “low.” HDL is good cholesterol “and we want it to be high,” Dr. Ko says. “H for high.”
Dr. Elizabeth Ko
UCLA Health labs target an LDL under 100 and HDL over 50. The number represents milligrams per deciliter in the blood.
Elevated LDL is a risk factor for atherosclerosis – plaque buildup in the arteries that can obstruct blood flow.
“We don't want plaque, because plaque is debris, and that can lead to a clot which can eventually cause a heart attack,” Dr. Ko says.
HDL, on the other hand, negates the effects of LDL.
“We know that an increase in HDL of one point decreases the risk of heart attack and cardiovascular death by 6%,” Dr. Ko says. “An HDL of greater than 60 is cardioprotective, so we want this to be as high as possible.”
The third number in the mix is triglycerides, or free-floating fat in the bloodstream, which should be as low as possible. The UCLA Health target for triglycerides is less than 150.
While the CDC considers a total cholesterol value of 200 or greater to be high, Dr. Ko says she doesn’t put too much stock in this catchall measurement when it comes to patient health.
“This is not a very important value,” she says, “because it doesn't differentiate between the good and the bad.”
Medication to lower cholesterol
The most common medications to lower cholesterol levels — and consistently some of the most prescribed drugs nationwide — are statins, with brand names such as Lipitor and Crestor. These drugs block an enzyme the liver needs to make cholesterol. A vast body of research shows these medications reduce LDL and the risk of related cardiovascular problems.
“There are jokes that statins should be in our water supply, because of the benefits that are there,” Dr. Ko says. “The literature is very strong.”
Statins have also been shown to raise HDL and lower triglycerides. “It has the triple effect of great news for all three parameters,” she says.
Other ways to reduce cholesterol include prescription-level fibrates, niacin and omega-3 fatty acids. Health care providers consider an individual’s age, overall health and cardiovascular risk factors when deciding whether to prescribe cholesterol-lowering drugs.
Lowering cholesterol naturally
However, medicine isn’t the only route to better cholesterol numbers. Dietary changes can have a marked impact on cholesterol levels, says Dr. Ko, medical director of the UCLA Health Integrative Medicine Collaborative.
“More and more patients want to be active participants in their health, not just taking a prescription or being the recipient of an intervention,” she says. “Patients want to be proactive in their care, with both managing disease and also health promotion.”
Reducing cholesterol is an area where lifestyle choices can make a significant difference.
“I have seen very favorable changes in cholesterol panels with nutrition,” Dr. Ko says.
Foods to minimize or avoid are those with saturated fat or trans fats, as reducing consumption of these foods can help lower cholesterol. Dr. Ko recommends eliminating trans fats, found in margarine and shortening, and using moderation with foods high in saturated fat, which is solid at room temperature and mainly derived from animals.
Foods high in saturated fat include:
- Red meat
- Dairy, including butter and ice cream
- Coconut milk
Polyunsaturated and monounsaturated fats are better choices, Dr. Ko says. “These are the good fats we hear about in the news,” she says. “They are generally liquid at room temperature and they are heart-healthy.”
These fats can be found in:
- Olive oil
- Canola oil
- Fatty fish such as salmon
- Flaxseed oil
- Soybean oil
“Flax oil can lower LDL and raise HDL,” Dr. Ko says. “These are the fats we want to focus on that can have a positive impact on our cholesterol.”
Saturated fats can raise both LDL and HDL, Dr. Ko says, so more study is needed.
Fiber is another dietary element that impacts cholesterol, particularly soluble fiber. “Soluble fiber is a great cure-all for blood pressure, cholesterol, constipation and sugar,” Dr. Ko says.
Look for soluble fiber in such foods as:
- Chia seeds
- Oats and oatmeal
- Dried figs
- Sweet potatoes
Data show that two to 10 grams of soluble fiber a day reduces LDL cholesterol by 22 points and total cholesterol as well.
Exercise is also helpful to reduce triglycerides and raise HDL levels, Dr. Ko says. Exercise and dietary changes that contribute to weight loss also lower LDL levels.
Says Dr. Ko: “Patients who lose weight, make changes to their diet, minimize saturated fat, go up on plant-based fats really can make a positive impact on their cholesterol panel.”
Learn more about cholesterol and the treatment options.