Most people understand that “your cholesterol” isn’t just a single number, and that instead there are such things as “good” cholesterol and “bad” cholesterol. You may even know that one type of cholesterol is called “HDL” and the other “LDL.” You may have sat nodding with understanding while a doctor explained the difference, or read and understood about the two types of cholesterol several times now…only to forget later which was which. That kind of thing happens to the best of us.

A simple memory hack

Here’s a quick trick that should help you avoid ever again forgetting which is the good cholesterol and which the bad. As a reminder, bad cholesterol is called LDL (for low-density lipoprotein) and good cholesterol is called HDL (for high-density lipoprotein). For the purposes of this memory hack, go ahead and forget about the “density lipoprotein” parts of those names, and focus instead on the “high” and the “low.”

Here’s the hack:

  • You want your HDL to be “High” (which is right in its name)
  • You want your LDL to be “Low” (which is right in its name)

To really drive this home, make a thumbs-up gesture when you say or imagine “HDL/High,” and do a thumbs-down when you say or imagine “LDL/Low.”

Beyond the names

Now that the identities of the “good” and “bad” cholesterols are forever fixed in your memory, there’s much to learn about these two substances and their role in health.

Cholesterol is a waxy substance produced by the liver that is necessary for proper cell functioning all throughout the body. It is one of several lipids, or fatty substances, that we need to survive.

Both HDL and LDL are lipoproteins, tiny particles that circulate in our bloodstreams and transport cholesterol and other fats to cells throughout the body. Remember, although too much fat is bad for our health, our cells need a certain amount of it in order to survive. But pure fats don’t mix well with blood, so our bodies bundle them into lipoprotein particles for ease of transport.

In a technical sense, the terms “HDL cholesterol” and “LDL cholesterol” are slight misnomers, since lipoproteins themselves are not pure cholesterols. The word “lipoprotein” consists of two parts, “lipo” referring to fat, and “protein” referring (of course) to protein, or in this case a specific type of protein called an apolipoprotein. Once these two substances have combined, you may picture the resulting lipoprotein as a tiny sphere or disc of protein in which a certain amount of cholesterol lipid is bound up. If you wanted to be pedantic, you’d refer to this as a “lipid-protein complex” rather than just as a type of cholesterol. But in the vernacular, we all use “HDL cholesterol and LDL cholesterol” as convenient shorthand.

The reason LDL particles get their “bad” name is that they are very rich in pure cholesterol. It’s this cholesterol, riding along on low-density lipoproteins, that collects on artery walls and causes health problems.

HDL particles, on the other hand, are “good” because as they travel throughout the body, they gather up between 25% and 30% of circulating LDL particles and carry them back to the liver to be eliminated. That beneficial function of HDL cholesterol is why you want your HDL to be high.

LDL and HDL are not the only lipoproteins. Others include:

  • Chlyomicrons: Large particles that transport triglycerides, a type of fat into which the body converts excess calories. Chlyomicrons are produced by the intestines.
  • VLDL (very low-density lipoprotein): Also a carrier of triglycerides, but produced by the liver, not the intestines.
  • IDL (intermediate-density lipoprotein): After VLDLs reach cells and have their triglycerides removed, they become IDL particles, and will then either be removed by the liver or converted into LDL.

Ratios matter

As a general rule for staying healthy, you can scarcely go wrong by striving to achieve higher levels of HDL and lower levels of LDL. The medical community has various sets of guidelines for what targets you should aim for regarding both HDL and LDL. The simplest and most commonly shared is the CDC guideline that suggests an optimal LDL reading of 100 mg/dL or less and an HDL 40 mg/dL or higher.

It’s easy to get hyper-focused on LDL, since we know it’s the culprit when it comes to atherosclerosis. But often what precipitates cardiovascular problems is not a steep rise in LDL but rather a drop in HDL and an increase in triglyceride levels. That’s why doctors tend to look closely at the mix and ratios of lipids in your body, rather than just purely at LDL, when determining whether you need drug therapy. When the proportions of HDL, LDL, triglycerides and other lipids are unfavorable, you’re said to have “dyslipidemia.” Granted, once your lipid profile has become problematic, the primary treatment goal will be to reduce your LDL.

HDL: The more the better?

So if HDL is good for you because it removes LDL, is there such a thing as a dangerously high HDL level? As it turns out, there may be. A 2022 study published in JAMA Cardiology found that, among nearly 15,000 patients with cardiovascular disease who were studied for about nine years, both very low HDL levels and very high HDL levels were associated with greater risk of death from cardiovascular disease or any other cause. In other words, for that study population there appeared to be a sweet spot for the protective effects of HDL. In the study, that sweet spot appeared to fall in the middle range of 40-60 mg/dL.

The negative effects of very high HDL were more strongly observed in menwo than in men. In a separate paper, the same team found that among patients without cardiovascular disease, only men, not women, faced increased risk due to very high HDL.

For most people, though, the prospect of excessive HDL is the last thing they need to worry about. Most of us would be hard put just to get our levels up into that Goldilocks zone of 40-60 and keep it there. So do what you can to increase your HDL and lower your LDL.

How to raise HDL and lower LDL naturally

Most people can give their HDL a significant boost while bringing down their LDL through diet and exercise. Try to get 2.5 to five hours per week of medium-intensity physical activity, and change your eating habits to more closely resemble the Mediterranean diet—cut down on fats from animal sources and refined carbohydrates and sugars, while consuming more whole grains, fruits, vegetables, and fats from plant sources.

A few elements of the Mediterranean diet have a direct effect on HDL and LDL:

Consuming fiber (from whole grains, fruits, and vegetables)Removes LDL
Consuming plant fats (from avocadoes, nuts, and seeds)Raises HDL
Cutting down on refined carbs and added sugarsReduces signaling to the liver to produce more LDL
Cutting down on animal fatsReduces signaling to the liver to produce more LDL

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