What does high cholesterol mean?
Cholesterol is an artery clogging substance that is made by your liver. It’s really important to understand what does high cholesterol mean, because this is at the very heart (see what I did there?) of developing cardiovascular disease. A certain amount of cholesterol is super important because your body uses it to make hormones, vitamin D, and digest certain foods. However, too much cholesterol is not good because, particularly in the setting of inflammation, it can build up in your arteries to form blockages (called plaque), which can lead to heart attacks, strokes, and other complications.
Cholesterol blood test
Cholesterol levels can be checked with a blood test by your doctor.
A standard lipid panel, which is what the vast majority of people will get checked, tells you your total cholesterol, low density lipoprotein cholesterol (LDL-c), high density lipoprotein cholesterol (HDL-c), and triglycerides.
When your doctor tells you that you have high cholesterol, or hyperlipidemia, they are typically referring to an elevated low density lipoprotein cholesterol (LDL-c), commonly referred to as the “bad” cholesterol. This is because the cholesterol contained within the LDL particle is the cholesterol that deposits in your arteries leading to atherosclerosis (blocked arteries). While other particles can carry cholesterol in the bloodstream, under most circumstances, the LDL particles carry the majority of this artery clogging substance. HDL is known as the “good” cholesterol, because the HDL particle is responsible for returning cholesterol from the body’s blood vessels to the liver to get excreted. Thus, an elevated HDL appears to be “protective” for heart disease, although it’s much more nuanced than that.
What is a good cholesterol level?
While the acceptable ranges for cholesterol vary based on your other risk factors, typically we like to see the LDL-c below 100 mg/dL.
In individuals who have had a heart attack or stroke, the LDL-c should be below 70 mg/dL.
The higher the LDL-c, the higher your risk of heart attack and stroke, so the lower we can suppress it, the better. In fact, contrary to what you may have read, there is no known adverse effects seen from very, very low LDL-c (there are some individuals walking around who have very low or barely detectable levels of LDL-c lifelong due to genetic variation with no apparent issues!).
Triglycerides, a type of fat that your body uses for energy, can also increase your risk of heart disease if it’s too high, and so this should be kept below 150 mg/dL.
However, LDL-c is the primary focus for lipid lowering, as decreasing it has been consistently demonstrated to dramatically lower risk for cardiovascular disease in multiple randomized controlled trials (the gold standard for scientific research).
Advanced cholesterol tests
A few additional points about how to measure it and what this panel means.
1. First, in a standard panel, LDL-c is estimated from a formula using total cholesterol, HDL-c, and triglycerides - this becomes unreliable under certain conditions (mostly elevated triglycerides), and so can and should be measured directly in that setting.
2. Secondly, you may have noticed the “-c” after both LDL and HDL, which you aren’t used to seeing. This denotes the fact that in the standard lipid panel, what we are measuring is the cholesterol contained within an LDL or HDL particle. This distinction is important because, it is actually the number of LDL particles (or lipoproteins, the vehicles for cholesterol) that most accurately predicts cardiovascular risk. Sometimes, the LDL particle number is discordant from the LDL-c (ie, the LDL-c is low, but LDL particle number is high). This occurs because LDL particles can range in size, and so two people can have the same LDL-c but very different particle numbers, particularly when they have a lot of small, dense LDL. As a result, most people should also get an assessment of the number of atherogenic particles with either LDL particle number or apoB. This is particularly important for those with cardiometablic disease or insulin resistance.
3. Lastly, there are also atherogenic particles called Lp(a) that are very important to check and not available in the standard lipid panel. More on that at a later date, as this is a topic I am passionate about (nerd alert).
These advanced lipid tests can be particularly useful in individuals with a strong family history of heart disease, personal history of premature (early) heart disease, cardiometablic disorders like diabetes, and in anyone who we need to further fine-tune their cardiovascular risk.
What does high cholesterol mean for the body
Much like high blood pressure, elevated cholesterol doesn’t typically cause any symptoms until it leads to a heart attack or stroke - this means it’s super important to get it checked at somewhat regular intervals in adulthood. You should get it checked more frequently if you have any major risk factors for heart disease.
Hyperlipidemia, or high cholesterol, is very commonly lifestyle related. It is closely linked to the standard American diet, which is high in saturated fat, trans fat (thankfully being phased out), and refined grains/processed foods while being deficient in fiber. High cholesterol is also commonly associated with above ideal body weight, hypertension, insulin resistance/diabetes, and kidney disease. Secondary causes of elevated cholesterol, such as hypothyrodism and medications, should be ruled out by your doctor. There are also genetic causes of dyslipidemia, which are highly variable in responsiveness to diet - the most common of these is called familial hyperlipidemia.
Lifestyle changes to lower cholesterol
Depending on how high your cholesterol levels are and your overall risk for cardiovascular disease, often the first line of treatment is to lower cholesterol with lifestyle changes. Dietary treatment for dyslipidemias have the most potential for cholesterol lowering effects (unfortunately, exercise, while very important for your overall cardiovascular risk, can only modestly lower your LDL-c if at all). Adopting a plant-based (or plant predominant diet such as a true Mediterranean or DASH-style diet), can lower LDL cholesterol significantly (by as much as 30% in some studies).
Food that lower cholesterol
While I typically like to talk about using nutrition to modify risk in terms of dietary patterns rather than specific macros or nutrients, it can be a somewhat useful framework when specifically trying to harness the power of diet to lower cholesterol.
Quite simply, fiber is your friend here.
Dietary fiber, particularly soluble fiber, lowers LDL cholesterol likely via multiple pathways including slower gastric emptying and increased satiety, inhibiting cholesterol synthesis in the liver, and increased excretion. It’s also great fuel for your friendly gut microbiome. Soluble fiber can be found in psyllium, lentils, oats, nuts, and many beans. Many consider adding flax seed or chia seeds to their diet. Plant stanols and sterols, found in nuts, legumes, whole grains, fruits, vegetables, plant oils, and supplements, are chemically similar to cholesterol and compete for absorption in the small intestine - this can also help lower cholesterol as well. Lastly, increased consumption of black or green tea, nuts, soy products, and polyphenols (found in many plants including coffee, cocoa, red wine, olive oil, and blueberries to name a few) may also have a role in decreasing cholesterol levels. Read more about the power of certain foods to lower cholesterol here.
Does saturated fat raise cholesterol?
Saturated fat (predominantly found in meat, eggs, and dairy products - with dairy the main contributor in the standard American diet) and trans fat (predominantly found in cakes, cookies, fried foods, and margarines) tend to increase blood levels of cholesterol in most people when consumed in high amounts. Additionally, highly refined, processed and packaged foods (particularly those with high fructose corn syrup) can worsen dysplipidemia and insulin resistance. Avoidance, or significantly lowering consumption of the above, can also help to lowering cholesterol.
Next steps: what if I can’t lower my cholesterol with diet?
While many people find they can dramatically lower their LDL cholesterol and particle number with dietary and lifestyle changes alone, pharmacologic intervention is not infrequently needed. Luckily, doctors have an increasing number of well tolerated medications in their tool belt to lower cardiovascular risk in those individuals. Promise to tackle this (including debunking myths on statins, which I know everyone has questions on) in another post.
Want to work with Dr Harkin to lower your cholesterol?
