What Is ApoB?
A growing body of research is finding that apoB may be a better predictor of heart disease risk than long-standing federal guidelines for “good” HDL and “bad” LDL cholesterol. What is apoB? (Its official name is apolipoprotein B.) Find out in this article.
What Is ApoB?
To understand apolipoprotein B, it’s important to first understand how cholesterol moves through the body.
Cholesterol, all by itself, cannot dissolve in the blood. It must be carried through the bloodstream by transporters called lipoproteins.
Lipoproteins = Lipids + Proteins
Lipoproteins got their name because they are made up of fats (lipids), such as cholesterol and triglycerides, and proteins.
ApoBs | Part of Artery-Clogging Lipoproteins
ApoBs are proteins found in lipoprotein particles that are artery-clogging.
The apoB-containing lipoprotein particles that are the most damaging to our arteries include not only LDL cholesterol but also remnants of chylomicrons and VLDL (very low density lipoproteins). All three – LDL, VLDL, and chylomicrons – promote atherosclerosis.
What Is Atherosclerosis?
Atherosclerosis is a disease caused in large part by the build-up of excess cholesterol within the artery wall, which leads to cholesterol-rich deposits called plaque. When a plaque bursts or ruptures, blood clots form. They’re dangerous because they can block blood flow to vital organs like the heart and brain.
Atherosclerosis, therefore, is the underlying disease process that leads to nearly all heart attacks and most strokes.
ApoB and Atherosclerosis
Now, let’s get back to apoB.
Since each apoB-containing lipoprotein particle has one apoB molecule, measuring apoB levels in fasting blood gives us a good approximation of the total number of atherogenic lipoproteins in the blood. The greater the number, the greater the risk of more cholesterol ending up in the artery wall and, in the long term, the greater the risk of a heart attack.
In fact, research 1,2 has shown that apoB may be a better predictor of cardiovascular disease than LDL cholesterol.
Two Types of ApoB
Keep in mind, too, that there are two types of apoB. Both are bad news for our arteries. One type is made in the intestines. It’s called apoB-48, and its lipoprotein partner is chylomicrons. Another type is made in the liver. It’s called apoB-100. Its partners are primarily LDL and VLDL.
How To Lower ApoBs
Consuming less dietary fat and cholesterol and many more fiber-rich, whole plant foods, which is essentially the Pritikin Eating Plan, will greatly reduce the amount of chylomicrons and their atherogenic, apoB-48-containing lipoproteins in the blood.
“This same type of dietary pattern will also reduce the liver’s production of apoB-100- containing lipoproteins, which includes VLDLs, LDLs, and IDLs, or intermediate density lipoproteins.”
Fasting Blood Tests | What Shows Up, What Doesn’t
ApoB-100-containing lipoproteins remain in the blood far longer than chylomicrons and their remnants, which means it’s apoB-100s and their lipids LDL, IDL, and VLDL that show up in fasting blood tests, not chylomicrons.
That doesn’t mean chylomicrons don’t do damage to our arteries. They do. They just beat a hasty retreat, long before fasting blood tests can detect them.
ApoA | The Good Apo (Sort Of)
The only other source of cholesterol in fasting blood is found in HDL particles. HDL’s lipoprotein partner is not apoB. It is apoA and other proteins.
That’s critical to know because as far as your arteries are concerned, it is only apoB-containing lipoproteins that are always ‘bad,'”. ApoA- and HDL-containing lipoproteins can be ‘good’ or ‘bad.’
HDL | Jekyll and Hyde
But wait, we can hear you wondering: “Isn’t HDL always the ‘good’ cholesterol?”
Not always. We once thought HDLs were always ‘good,’ and the more HDL cholesterol in the blood, the better. But we now know that HDLs can go ‘bad’ and lose their ability to reduce inflammation and remove cholesterol from the artery wall.
Recent research3 by cardiologist Stanley Hazen, MD, and colleagues from the Cleveland Clinic have documented this Jekyll and Hyde nature of HDL.
Bottom Line: There is HDL that is functioning well and doing good things for our arteries, but there is also HDL that is dysfunctional.
Researchers at UCLA have reported4 on the effectiveness of a heart-healthy lifestyle in repairing HDL. The scientists, led by James Barnard, PhD, and Christian Roberts, PhD, obtained blood samples of men ages 46 to 77 attending a three-week program of healthy eating and exercise at the Pritikin Longevity Center.
On entry, the men tended to have dysfunctional, pro-inflammatory HDL. But blood tests after three weeks at Pritikin showed that HDL had converted from pro-inflammatory to anti-inflammatory, from bad to good.
Totaling Up All the Bad ApoBs
So where do we go from here?
Standard lipid blood testing is not sophisticated enough, at least not yet, to tease apart HDL particles and isolate the good HDL from the bad.
But with standard testing, doctors are able to do something that’s very helpful. They can fairly accurately determine our total amount of apoB-containing lipoproteins (yes, the always bad ones).
They do so by looking at the non-HDL cholesterol number that is now on many standard blood panels. Non-HDL is all the cholesterol in the bloodstream except HDL, which means it’s all the bad apoBs, not just the LDL apoBs.
By paying close attention to our non-HDL cholesterol, and therefore our apoBs, physicians hope to better predict the risk of atherosclerotic plaque growth and heart attacks.
Learn More About Pritikin
What Is an Optimal Number For Non-HDL?
Here is the formula for determining your non-HDL:
Non-HDL cholesterol = Total cholesterol minus HDL cholesterol.
So if your total cholesterol is 190 mg/dL and your HDL cholesterol is 40 mg/dL, your non-HDL cholesterol is 150.
At the Pritikin Longevity Center, the physicians and dietitians recommend that non-HDL be no more than 100 for prevention and no more than 80 for the halting or reversal of plaque build-up in those with established atherosclerosis or those at very high risk, such as people with diabetes.
What Is an Optimal Number For ApoB?
Usually, an apoB of less than 100 mg/dL is considered desirable in low-risk individuals.
Less than 80 mg/dL is desirable in high-risk individuals, such as those with cardiovascular disease or diabetes.
But rarely are apoB numbers included in standard lipid blood tests. That’s okay because non-HDL cholesterol numbers often are, and your non-HDL cholesterol is a good reflection of your apoBs.
More Details For Lowering ApoB-Containing Lipoproteins
Generally, the same lifestyle measures that lower LDL cholesterol will lower apoB.
Key Dietary Actions For Lowering LDL and Apo-B are:
- Eat far fewer saturated fats (such as butter, palm oil, coconut oil, meat fats, and milk fats); trans fats (such as margarine, vegetable shortening, and partially hydrogenated oils); and dietary cholesterol.
- Eat far more fiber-rich foods (especially soluble fiber from beans, yams, oats, barley, and berries, or BYOBB).
- Eat vegetable proteins (such as tofu and beans) in place of meat and poultry.
- Eat fewer refined sugars (especially fructose) and refined grains (such as white flour).
Other Lifestyle Actions For Lowering LDL and Apo-B Are:
- Exercise regularly: 1) Aerobic exercise daily, a minimum of 30 minutes and optimally 60 to 90 minutes, alternating moderate-intensity days with vigorous-intensity days; 2) Full-body resistance routine two to three times weekly; and 3) Stretching exercises daily to greatly enhance your overall flexibility and ability to exercise more freely.
- Lose excess weight, especially weight around the middle. Excess body weight is defined as a BMI (Body Mass Index) greater than 25. More important is lowering your abdominal girth. Of particular concern are males who measure more than 40″ around the waist and females who measure more than 35″. Excess central obesity is a major contributing factor for diabetes, hypertension, elevated cholesterol, and cardiovascular disease.
- Quit smoking. Tobacco smoke can damage arteries, making it easier for more cholesterol to end up in artery walls.
- If necessary, take medications.
All the above dietary, exercise, and other lifestyle actions are part of the Pritikin Program, proven in several studies to significantly lower both LDL and non-HDL, and therefore apoB-containing lipoproteins.
And while the Pritikin Program may reduce HDL cholesterol in some people, it appears to be primarily the dysfunctional or ‘bad’ HDL cholesterol particles that are being reduced.
With healthy Pritikin living, in effect, you’re landing a one-two punch. You’re wiping out the bad apoB-containing lipoproteins and the bad HDL.
- 1 Circulation, 1996; 94 (3): 273.
- 2 Clinical Chemistry and Laboratory Medicine, 2004; 42: 1355.
- 3 Nature Medicine, 2014; 20: 193. >
- 4 Journal of Applied Physiology, 2006; 101: 1727.
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