This column is the first in a series about risk factors for atherosclerosis (hardening of the arteries), the cause of several health problems, including heart attacks — the number one cause of death in societies on a Western diet.

Cholesterol is a component of cell membranes and is important in the formation of bile acids and certain hormones. It is synthesized by cells throughout the body, but particularly liver cells. In addition, some of our cholesterol comes from dietary sources: meat including poultry, dairy, butter, seafood, and eggs (One egg yolk has the whole recommended daily allowance of cholesterol).

 While cholesterol is necessary for human life, high levels can cause gallstones and hardening of the arteries.

A “cholesterol test” (also known as a “lipid test”) includes the level of total cholesterol; HDL (good cholesterol); LDL (bad cholesterol); and triglycerides. Think of your LDL as garbage in your arteries, so if you have too much garbage, you’ll have a problem with your arteries. Think of HDL as garbage trucks, so you’ll also have a problem if you don’t have enough garbage trucks.

There are caveats though with HDL, because some people have a low number of garbage trucks (low HDL), but the ones they have are super-charged, and these people have normal arteries. Other people have lots of garbage trucks (high HDL) but their garbage trucks are dysfunctional and cause rather than prevent atherosclerosis.

There are caveats with LDL, as well: 1) LDL particle number — or ApoB, a surrogate marker for LDL particle number — is more meaningful than the usually-measured level of LDL. 2) There is a particularly harmful type of LDL called Lp(a) (pronounced “LP little a”) that is often elevated in families with early heart disease. 3) Size of LDL particles matters — small, dense, bb-like LDL particles are particularly harmful, compared to large, fluffy, ping-pong-like particles. Blood tests that measure these things are inexpensive but rarely ordered.

National cholesterol guidelines specify that ideal lipid levels are total cholesterol less than 200; HDL greater than 40 in men and postmenopausal women, greater than 50 in premenopausal women; LDL less than 100, and less than 70 in people with a history of heart attack, stroke, or diabetes; triglycerides less than 150. However, half of people who have heart attacks meet these guidelines. Heart attack prevention doctors feel that — given that 20% of heart attacks victims die — LDL should be less than 70 if atherosclerosis can be demonstrated in a patient by studies such as a coronary calcium score (CT scan of the heart) or carotid IMT (ultrasound picture of the carotid arteries in the neck).

Plant-based providers feel that normal lipid levels should be what people who are never develop atherosclerosis have and who are therefore heart attack-proof — such as people in the Blue Zones. These people have total cholesterol levels of less than 150; LDLs in the 30s and 40s; and triglycerides less than 70.

To prevent atherosclerosis, ideally the cholesterol-containing foods mentioned above should be avoided. Furthermore, saturated fat should be avoided because it causes the liver to make more LDL. This harmful fat is found in the following: all animal products; palm and coconut; and vegetable oils. Over 30 years ago, Dr. Dean Ornish proved that heart disease can not only be prevented but can also be reversed with a plant-based, whole food diet with no salt, sugar, or added oil.

Plant foods that are especially good at lowering cholesterol include: high-fiber fruits and vegetables; legumes; unprocessed grains; and ground flaxseed. The following herbs and spices also lower cholesterol: amla (1/2 teaspoonful of powder daily, which also lowers Lp(a); and ground black cumin 1/4 teaspoon daily. Red yeast rice contains a weak, natural statin that lowers cholesterol a little; but being a supplement, it is unregulated, so you don’t know for sure what you’re getting.

For genetic reasons, diet isn’t enough in some people to achieve ideal lipid levels because their liver makes too much LDL no matter what they eat. For these people, and for people unwilling to change their diet, drug options are available: statins prevent the liver from making so much cholesterol; ezetimibe prevents absorption of cholesterol; and for people who don’t tolerate statins there are the newer but more expensive PCSK9 inhibitors, which are given by injection.

Atherosclerosis can start in infancy, and the National Heart, Lung, and Blood Institute recommends that all children have a cholesterol screen between age 9 and 11, and again at 17-21. Obese children, children with a family history of very high cholesterol (called familial hyperlipidemia), and children with a family history of early heart disease are advised to get screened earlier than 9. Adults should have their cholesterol checked every 5 years starting at 20 — more often if their lipids are abnormal. Eating prior to a cholesterol test results in higher triglyceride levels, so fast (water only) for at least 6 hours before getting blood drawn to check lipid levels.

Dr. Greg Feinsinger is a retired family physician who started the non-profit Center For Prevention and Treatment of Disease Through Nutrition. For questions or to schedule a free consultation about nutrition or heart attack prevention contact him at gfeinsinger@comcast.net or 970-379-5718.