Cholesterol – the good, the bad and the risk for heart disease
Is truly the ratio of total cholesterol and HDL the most effective way to determine our risk for heart disease? Shouldn’t there be another factor we need to consider?
Cholesterol circulates through our body with the help of carriers.
There carriers are called lipoproteins*.
(*consisting of lipo = fat & proteins, hence the name).
Two different lipoproteins carry cholesterol from cell to cell:
- LDL (low-density lipoprotein)
- HDL (high-density lipoprotein)
And, as you know, LDL and HDL can be tested via blood test. I’m sure you might even know your LDL and HDL levels.
But what do they mean and can we really just look at HDL and assume we are protected (in case of high HDL levels) from cardiovascular disease risk?
HDL (High-Density Lipoprotein): the good one
Many of us believe, as long as our HDL (high density lipid) are high (above 60) we are protected from cardiovascular disease.
What makes HDL healthy?
HDL removes LDL from the body. Actually, it caches some LDL out of the blood stream and brings it back to the liver to be broken down and removed, via bowl movements, from the body (Lewis & Rader, 2005).
But HDL can’t remove all LDL; only 1/4 – 1/3 of LDL can be carried by HDL.
HDL is a key factor in determining cardiovascular disease risk.
High HDL levels are thought to protect against heart disease and stroke. But HDL alone don’t say much. We have to look at HDL together with LDL & triglycerides.
LDL (Low-Density Lipoprotein): the bad one
Many of us refer to LDL as the bad cholesterol; the one that leads to plaque or fatty buildup in arteries (also known as atherosclerosis).
What makes LDL bad?
This fatty buildup (= plaque) inside our arteries makes our arteries more narrow. Thus, oxygen rich blood can’t move as easily through the body as necessary.
The worst part perhaps, there aren’t really any symptoms early on. It begins typically to accumulate in early childhood and slowly progresses throughout the years. Symptoms typically show in men in their 40s and in women in their 50s and 60s.
„elevated plasma cholesterol level is …. sufficient to drive the development of atherosclerosis“ (Falk, 2006)
Plaque buildup, which happens within all arteries throughout our body, raises the risk for heart attack, stroke and peripheral artery disease.
And what about Triglycerides?
Triglycerides are a type of fat stored in our body due to a high fat diet. Many of us only monitor our LDL levels or blood pressure but forget about the effects of triglycerides on heart health.
Triglycerides in combination with high LDL increase plague buildup inside our arteries thus increasing our risk for heart disease and stroke.
HDL, LDL, Triglycerides & Heart Disease
As mentioned, HDL or LDL alone don’t say much.
In order to determine our risk for cardiovascular disease (CVD) & stroke, we need to look at HDL, LDL and blood triglyceride levels (Bartlett et al. 2016).
Having high HDL suggests:
• 30% lower risk of CVD* when triglycerides and LDL are at optimal levels.
• 30% lower risk of CVD* when either triglyceride or LDL levels are high
• 10% lower risk of CVD* when triglyceride & LDL levels are high
Having low HDL suggests:
• 30% higher risk of CVD* when triglycerides and LDL are at optimal levels
• 30% higher risk of CVD* when triglycerides or LDL levels are high
• 60% higher risk of CVD* when triglycerides & LDL levels are high
(*compared to a reference group with optimal levels)
Hence, we see, LDL or triglycerides alone don’t give us much information. We need to look at all three parameters to determine our risk for heart disease.
By the way, in case you are wondering
- Low: less than 40 mg/dL are a risk factor
- Borderline low: 41 – 59 mg/dL
- Optimal: 60 mg/dL or more are a protective factor
- Optimal: less than (<) 100 mg/dL
- Near optimal/above optimal: 100-129 mg/dL
- Borderline high: 130-159 mg/dL
- High: 160-189 mg/dL
- Very high: 190 mg/dL or above
Triglycerides (Mayo Clinic):
- Normal: less than (<) 150 mg/dL or < 1.7 mmol/L
- Borderline high: 150 to 199 mg/dL or 1.8 to 2.2 mmol/L
- High: 200 to 499 mg/dL or 2.3 to 5.6 mmol/L
- Very high: 500 mg/dL or above or 5.7 mmol/L or above
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