To B or not to B

Apoprotein B (apo B) is the principle protein that resides in LDL particles along with other proteins, phospholipids, triglycerides, and, of course, cholesterol.

There's a curious thing about apo B. Just like one child per family in China or one television per household in 1950s America, there is only one apo B for every LDL particle.

So measuring apo B, in effect, provides a virtual count of LDL particles. (Actually, VLDL particles, the first lipoprotein to emerge from the liver, also have one apo B per particle but LDL particles far outnumber VLDL particles.) While apo B structure can show limited structural variation from individual to individual, the effect on measured apo B is negligible.

One apo B per LDL particle . . . no more, no less. What about the other components of LDL particles?

The other components of LDL particles are a different story. Cholesterol and triglycerides in LDL particles vary substantially. Diet has profound effects on cholesterol and triglyceride content of LDL particles. A diet rich in carbohydrates, for instance, increases triglycerides in LDL particles while reducing cholesterol. This means that measuring cholesterol in the LDL fraction will be misleading, since cholesterol will be falsely low. LDL cholesterol is therefore a flawed means to assess the behavior and composition of LDL particles. In particular, when LDL particles become enriched in triglycerides, they go through a process that transforms them into small LDL particles, the variety most likely to cause atherosclerosis.

In other words, when the worst situation of all--an abnormal abundance of small LDL particles develops--it is usually not signalled by high LDL cholesterol.

Because apo B is not sensitive to the composition of LDL particles--high cholesterol, low cholesterol, high triglycerides, etc.--it is a superior method to characterize LDL particles. While apo B doesn't tell you whether LDL particles are big, small, or in between, it provides a count of particles that is far more helpful than measuring this deeply flawed thing called "LDL cholesterol."

(Even better: Count LDL particles and measure LDL size, since size gives us insight into sensitivity to oxidation, glycation, adhesiveness, ability to trigger inflammatory pathways via monocyte chemoattractant protein, various interleukins, tunor necrosis factor and others. This is why cholesterol panels should go the way of tie dye shirts and 8-track tapes: They are hopelessly, miserably, and irretrievably inaccurate. Cholesterol panels should be replaced by either apoprotein B or lipoprotein measures.)

Comments (11) -

  • arnoud

    12/5/2010 2:53:08 PM |

    The NMR Lipoprofile test provides LDL particle counts, and the VAP test provides Apo-B measurement.
    Is there a direct conversion factor to determine Apo-B for a given total LDL count, and vice versa?

  • Anonymous

    12/5/2010 2:55:39 PM |

    Hi Dr. Davis,
    Is there an advantage to ordering the VAP along with the NMR Lipoprofile?  Does the information from one or both of these two tests greatly improve on measuring the apo B and apo A ratio?

  • Dr. William Davis

    12/5/2010 2:56:28 PM |

    Hi, Arnoud--

    Apoprotein B and NMR LDL particle number are roughly correlated with a difference in units by a factor of 10. An LDL particle number of 1000 nmol/L is approximately equal to 100 mg/dl apo B.

    By the way, apo B is calculated on VAP, not measured.

  • Martin Levac

    12/5/2010 4:18:26 PM |

    LDL does not cause atherosclerosis. Thus, there is no possible gradient such as "most likely". It might look like a semantics argument but I'm really just exposing the flawed hypothesis behind the semantics.

    What is truly most likely, is that whatever causes atherosclerosis also causes small LDL.

    Carry on.

  • Eugene

    12/5/2010 5:39:07 PM |

    Hi Dr. Davis,
    Is there an advantage to ordering the VAP along with the NMR Lipoprofile? Does the information from one or both of these two tests greatly improve on measuring the apo B and apo A ratio?
    E. John

  • Travis Culp

    12/6/2010 4:20:19 AM |

    I was previously unaware of this information; thanks for the heads up.

  • Anonymous

    12/8/2010 7:54:55 AM |

    Dr. Davis,

    I've been following your dietary advice for a few years (low carb, little to no wheat, lots of nuts and flax) and all my biomarkers are excellent... Except.. my serum phosphorus, which tends to be either above the normal range or at the very high end of the normal range... this isn't an issue with my kidneys since all other markers are optimal... I wonder if you've seen similar results before with this nut/flax rich diet?


  • Anonymous

    12/8/2010 10:04:41 PM |

    I had an ApoB of 43 mg/dl, an LDL particle number on NMR of 593 nmol/L, and an LDL on NMR of 78 mg/DL with particle size of 21.6 nm.  My ApoB seems much lower than my LDL particle number (even after adjusting for the factor of 10). Weird?

  • Might-o'chondri-AL

    12/9/2010 3:24:37 AM |

    Glycosaminoglycan (dermatan sulfate form, a bi-glycan) and ApoB together make the type of plaque that is rupture prone.

    The enzyme hyaluronidase increases glycosaminoglycan synthesis when lack ApoE. In animal models the aorta collagen increases, plasma volume drops, proteinuria rises, endothelium degrades and atherosclerosis begins.

    The poly-anion hyaluronate is available (water soluble) in a pectic polysaccharide as hyaluronic acid in fruit of Abelmoschus esculentus; "okra" is the plant in English.

    This may partiallly explain the autopsy analysis of the differences seen in arteries of Africans (who eat okra) & Westerners. Maybe the okra hyaluronate "uses up" the excess enzyme hyaluronase, which effectively "neutralizes" the Apoliprotein risk factors (ApoE deficiency & hypothetically here the ApoB excess).

  • karl

    12/17/2010 9:48:44 PM |

    My hunch is apo-b is correlated with oxLDL, but I've seen no papers that show that small LDL or apo-b count is more predictive than oxLDL.

    We know that high carb yields high blood sugar and that alone is oxidative of LDL. What if apo-b is correlated with oxLDL because both are driven by high BG?

    Unless this is separated out,  we might be wasting money on expensive apo-b tests instead of cheap oxLDL tests or even cheaper postprandial BG testing.

  • Adriana

    10/5/2011 12:23:43 PM |

    This is interesting as there are reports of okra water reducing some people's fasting blood glucose.