What Do Blood Cholesterol Levels Mean?

Having a high (>100 mg/dL) bad LDL cholesterol or a low (<40) good HDL cholesterol has long been associated with increased risk for heart attacks. However, new studies show that you can form plaques and be at risk for a heart attack even if your bad LDL cholesterol is as low as 50. I have also reported recently on studies showing that a very high HDL "good" cholesterol may also not protect against heart attacks; see Both Low and High HDL Can Predict Harm HDL Cholesterol: a New Understanding

The new data show that thick arteriosclerotic plaques start to form in arteries at blood LDL cholesterol levels between 50 to 60 mg/dL (Journal of the Am Coll of Cardiol, December 19, 2017;70:2979-2991). Researchers used ultrasound or cardiac CT scans on 1779 middle-aged adults who had no obvious heart-attack-risk factors such as diabetes, high blood pressure, smoking or high bad LDL cholesterol, and 740 of these people had all of their heart attack risk factors in the optimum range. They found that almost half of their subjects had extensive plaques in their arteries. They also found that plaques started to regress when blood levels of LDL went below 50. Note: if you live in Canada, divide the U.S. numbers by 40.

Heart Attack Risk Starts at LDL Cholesterol Levels of 50 Most doctors in North America do not have any patients who have blood levels of LDL below 50, probably because almost all of us eat too much of the wrong foods. Today, your doctor is told to treat you with diet and perhaps drugs if:

• your bad LDL cholesterol is above 100 and you have never had a heart attack, or

• your bad LDL cholesterol is above 70 if you have had a heart attack or several heart attack risk factors. However, the new study shows that plaques form in arteries even in people who have much lower LDL cholesterol levels. This suggests that we should be looking instead at other heart attack risk factors and encouraging all patients to make heart-heathly lifestyle changes, no matter what cholesterol numbers they may have.

Risk Factors for a Heart Attack All of the factors listed below increase your risk for a heart attack. Your doctor can examine you and order these tests:

• Blood pressure >120/80 at bedtime (when blood pressure is lowest)

• HBA1C >5.7 (diabetes)

• CRP >1 (inflammation)

• Abdominal obesity (increased risk for diabetes)

• Resting heart rate >70

• Lp(a)>125 (blood test for a genetic clotting disorder)

• Triglycerides >150 (increased risk for diabetes)

• Homocysteine >10 (genetic or vitamin deficiency)

• Small LDL particle size (an indicator of diabetes)

• Family history of heart attacks

Try Lifestyle Changes First If you have one or more of the risk factors listed above, see if you can correct them with lifestyle changes. I believe that everyone should:

• lose weight if overweight (I recommend intermittent fasting)

• exercise

• avoid smoking

• not take in alcohol regularly or excessively

• eat a healthful diet with plenty of fruits, vegetables, nuts and other seeds

• avoid sugared drinks including fruit juices, sugar-added foods, red meat, processed meats and fried foods

• keep hydroxy vitamin D levels above 20 ng/ml

More on Heart Attack Prevention

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