Cholesterol is the most demonized, misunderstood and controversial substance in our bodies and our diets. To help clear up the confusion, the CDC has designated September as National Cholesterol Education Month. It’s also a great time to get your lipid levels checked — and if they’re too high, to work with your medical provider to reduce them.

Here’s a look at nine common cholesterol myths and some recent discoveries that may surprise you.

Myth: Cholesterol is inherently evil.

Fact: You couldn’t survive without cholesterol. This waxy substance produced by the liver plays many essential roles in our body, from waterproofing cell membranes to helping produce vitamin D, bile acids that help you digest fat, and sex hormones, including testosterone, estrogen, and progesterone.Cholesterol is ferried through your body by molecular “submarines” called lipoproteins, such as low-density lipoprotein (LDL) and high-density lipoprotein (HDL).

Myth: High LDL (bad) cholesterol means you could be headed for a heart attack.

Fact: Most heart attacks happen to people with “normal” levels of LDL. Life insurance companies know a surprising secret about cholesterol that most doctors never tell patients: When it comes to rating your risk for a fatal heart attack, the least important cholesterol number is your level of LDL. In fact, life insurance actuaries don’t even look at LDL levels, because large studies show it’s worst predictor of heart attack risk. In a national study of about 36,000 people who had been hospitalized for a heart attack, nearly 75% had LDL levels that fell within recommended targets and close to half had “optimal” levels.

Instead, life insurance companies use a simple formula, based on two numbers that should be in everyone’s medical record, to rate heart attack risk. They divide your total cholesterol by the level of HDL (good) cholesterol. The result, called the total cholesterol-to-HDL ratio (TC/HDL ratio) was found to be the best predictor of heart attack risk in the Women’s Health Study. Based on evidence from multiple large studies, the BaleDoneen Method considers a TC/HDL ratio of 3.5 to a desirable target and a ratio below 3 to be optimal.

People with a ratio below 3 and no inflammation in their arteries enjoy vastly superior protection against heart attacks and strokes, compared to people with higher ratios, and are also less likely to develop arterial disease at all.

Myth: Conventional lipid testing checks for all cholesterol abnormalities that raise risk for cardiovascular disease (CVD).

Fact: The conventional test doesn’t measure a dangerous type of cholesterol that has been shown to actually cause CVD: lipoprotein (a), or Lp(a). In three large studies, high levels of Lp(a) tripled heart attack risk. Elevated levels (a genetically influenced condition found in about 20 percent of the population) also raise risk for developing CVD at a relatively young age. In 2010, the European Atherosclerosis Society (EAS) issued a scientific statement calling for routine screening and treatment of elevated Lp(a) levels as “an important priority to reduce cardiovascular risk.”

Yet in the U.S., it’s still not the standard of care to treat — or even measure — this dangerous form of cholesterol that is found at elevated levels in up to one-third of heart attack survivors. The BaleDoneen Method recommends that everyone get the Lp(a) blood test, which can be performed at the same time as conventional cholesterol testing, at a cost of about $20.

Unlike LDL (bad) cholesterol, Lp(a) isn’t affected by lifestyle nor can it be effectively treated with cholesterol-lowering statin drugs if it’s elevated, according to a new study published in Circulation. The study also found that aspirin has little, if any, effect on Lp(a) levels. Instead, the best treatment is niacin (vitamin B3), which should only be taken under medical supervision. The EAS reports that niacin therapy can lower Lp(a) by up to 40% — a potentially life-saving benefit. Decreasing Lp(a) was shown to reduce risk for cardiovascular events by about 75% in a recent study published in Circulation, highlighting the value of getting tested and treated if your levels are elevated.

Myth: Triglycerides cause heart disease.

Fact: Triglycerides (TG), a type of blood fat, don’t invade the artery wall and form plaque. However, high triglycerides mark another huge problem: insulin resistance, a pre-diabetic condition that is the root cause of 70 percent of heart attacks. High TG levels are also one of the warning signs of metabolic syndrome, a cluster of abnormalities that multiple your risk for heart disease, stroke, and type 2 diabetes.

To be diagnosed with metabolic syndrome, you must have three or more of the following disorders: high blood pressure, high blood sugar, a large waistline, high triglycerides, and low HDL. This dangerous cluster of risk factors affects 26% of adultsnearly 50 million Americansyet often goes undiagnosed. The good news is that it’s highly treatable, typically with lifestyle changes that include weight loss and increasing physical activity. Always consult your medical provider before starting a new workout to make sure it’s appropriate for you.

Myth: The higher your level of HDL, the safer you are from heart disease.

Fact: While HDL is regarded as the “good” cholesterol because it usually helps reduce the risk of plaque buildup in the arteries, a new study of nearly 6,000 older adults found that people with very low or very high levels of HDL had a higher risk for death from cardiovascular causes. These findings were presented at the European Society of Cardiology conference in August and are considered preliminary until they are published in a peer-reviewed journal.

One theory is that very high levels of HDL may represent “dysfunctional HDL” that promotes rather than protects against arterial disease, one of the study authors explained in a statement, adding that, “One thing is certain: The mantra of HDL cholesterol as the ‘good’ cholesterol may no longer be the case for everyone.” Earlier this year, a very large study published in European Heart Journal also linked very high levels of HDL to increase risk for heart disease and all-cause mortality, a finding that the researchers themselves called “paradoxical.”

Myth: All LDL particles are equally dangerous.

Fact: The size of the particles matters. Think of beach balls and bullets. Some LDL particles are small and dense, making it easier for them to penetrate the arterial lining and form plaque, while others are big and fluffy, so they tend to bounce off the artery walls. People who mostly have small, dense LDL cholesterol are up to three times more likely to have heart attacks than those with big, fluffy particles.

Myth: Americans have the world’s highest cholesterol levels.

Fact: Contrary to the stereotype that most of us are just a few Big Macs away from a heart attack, US men rank 83rd in the world in average total cholesterol and US women 81st, according to the World Health Organization. For both sexes, the average is 197 mg/dL, slightly below the borderline high range (200 to 239 mg/dL).

In Colombia, men average a whopping 244 mg/dL — a level that doubles heart-disease risk — while Israeli, Libyan, Norwegian, and Uruguayan women are in a four-way tie for the highest average with 232.

Myth: Eggs clogs up arteries.

Fact: It’s true that eggs are high in dietary cholesterol, with upwards of 200 mg., mainly in the yolk. Research shows, however, that eating three or more eggs a day boosts blood concentrations of both good and bad cholesterol. The LDL particles tend to be the light, fluffy ones that are least likely to enter the arterial wall, while the increased HDL helps keep the arteries clean, suggesting that most people’s bodies handle cholesterol from eggs in a way that’s unlikely to harm the heart. The researchers say that their findings add to growing evidence that eggs are not “a dietary evil.”

Myth: There are no visible symptoms of high cholesterol.

Fact: Some people with high cholesterol develop yellowish-red bumps called xanthomas that can occur on eyelids, joints, hands or other parts of the body. People with diabetes or an inherited condition called familial hypercholesterolemia are more likely to have xanthomas. The best way to tell if your cholesterol is too high is to have it checked every three years, starting at age 20, or more often, if advised by your healthcare provider.