Everything You’ve Ever Wondered About Cholesterol, Finally Explained

We’ve all heard of ‘good’ and ‘bad’ cholesterol, and know that having high cholesterol can impact our health. But let’s face it: Many of us don’t know the full story on how cholesterol impacts our health.

Whether your doctor’s concerned about your cholesterol levels or you just want to understand the difference between ‘HDL’ and ‘LDL,’ we’ve gathered all the facts together.

Cholesterol Basics

Cholesterol is a waxy fat substance found in all of our cells that’s used to make hormones, vitamin D, and other compounds. Our liver produces most (about 80 percent) of the cholesterol we need, but we can make up the rest by eating foods that contain cholesterol, such as eggs, red meat, salmon, and shellfish.

Cholesterol is transported through our body by substances called lipoproteins. There are two types of lipoproteins: HDL (high-density lipoproteins), which are small and dense, and LDL (low-density lipoproteins), which are larger and less dense.

LDL is known as ‘bad cholesterol’ because it tends to stick to the walls of our blood vessels, explains Brittany Stucklen, R.D., dietitian at Medifast California. When LDL combines with other substances, like fat and calcium, it forms a substance called plaque and can contribute to a number of heart-related health issues.

There are actually two types of LDL: smaller LDLs (called ‘type B’), which get into arteries more easily, and bigger LDLs (called ‘type A’), which may be less harmful. Research published in Circulation suggests that people with more type B LDLs have greater risk of developing coronary heart disease compared to people with more type A LDLs. (Research suggests a diet high in refined carbs may be partially responsible for type B LDLs.)

Meanwhile, HDL, or ‘good’ cholesterol, helps scavenge LDL from the blood and transports it back to the liver, where it can be broken down and removed from the body. In this way, HDL helps support cardiovascular health—but it can only transport between a quarter to a third of LDL cholesterol.

Cholesterol And Your Health

Unhealthy body weight, poor nutrition, and lack of exercise are all key lifestyle contributors to high cholesterol, but the issue can also be genetic.

When you have too much LDL and/or not enough HDL in your blood, plaque builds up in your arteries and hardens over time, limiting blood flow to your heart. This forces your heart to work extra hard, and can cause chest pain or pressure called ‘angina,’ says Stucklen. At this point, your condition is considered ‘coronary artery disease.’ Then, when pieces of hardened plaque break off, blood clots can form and eventually grow large enough to completely block blood flow, putting you at risk for heart attack and stroke.

How To Keep Your Cholesterol In Check

Since high cholesterol typically doesn’t present warning signs or symptoms before a major health event like a heart attack or stroke occurs, get tested regularly after the age of 20—especially if you have a family history, recommends Paul Salter, R.D., M.S., founder of Fit In Your Dress.

Docs often first measure total cholesterol, which accounts for both the HDL and LDL in your blood, and should ideally be 200 or below. They then measure HDL, which should be above 60 to protect against heart disease, and LDL, which should be below 100 in low-risk people and 70 in higher-risk people. They’ll also test your triglycerides—a type of fat in your blood—since high levels can throw off cholesterol counts.

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From there, maintaining (or achieving) healthy cholesterol levels largely comes down to living a healthy lifestyle.

For years the USDA believed that the cholesterol in animal-based foods like eggs and shellfish significantly impacted our cholesterol levels, and recommended capping our dietary intake at 300 milligrams a day. (For reference, one large egg contains 182 milligrams.) Recently, though, the USDA removed this limit based on a lack of conclusive evidence that eating cholesterol raises our levels.

While eating eggs and shrimp is a-okay, there is another potential cholesterol-saboteur in your grub: saturated fat, which can contribute to elevated levels when consumed in excess, says Stucklen. To promote healthy cholesterol, the AHA recommends swapping processed and saturated fats for whole foods that contain unsaturated fats, such as nuts, chia seeds, olive oil, and avocados. Salter also recommends filling you diet with foods that contain soluble fiber—like nuts, seeds, lentils, and peas—which can help block cholesterol absorption and reduce LDL levels.

Upping your intake of omega-3 fatty acids, which are found in fish like salmon and may help thin the blood and reduce triglycerides which help protect your heart, according to the National Institute of Health.

Related: All The Things You Didn’t Know Omega-3s Could Do For Your Health

In addition to dietary tweaks, regular exercise also promotes healthy cholesterol levels, so Salter recommends an hour of cardio or resistance training at least three to five times per week.

If lifestyle changes aren’t enough to maintain or lower your levels, though, talk to your physician about medications—especially if you have a family history.

Keep your facts straight with this infographic: