*Geek Box: The ‘ALP’

*Geek Box: The ‘Atherogenic Lipoprotein Phenotype’

The ‘atherogenic lipoprotein phenotype’ is the technical term describing a particular pattern of blood cholesterol levels that is considered a significant risk for cardiovascular disease. The pattern includes high levels of triglycerides, high levels of LDL-cholesterol, and low levels of HDL-cholesterol.

This profile is considered highly ‘atherogenic’, meaning it is implicated in the process of lipoproteins carrying cholesterol [i.e., VLDL and LDL] penetrating the arteries, leading to plaque formation, a process known as atherosclerosis. What it describes is a profile that looks like this:

  • Low HDL: because HDL is needed to clear cholesterol from circulation, low HDL is problematic for heart disease risk. When excess TGs are offloaded onto HDL, HDL becomes broken down in the liver and removed from circulation.
  • High LDL: all LDL particles, irrespective of size, are capable of penetrating into the arteries. However, in the ALP, LDL remodels into smaller, denser particles. They carry less cholesterol than larger LDL, but as more of them penetrate the arteries, they lead to as much cholesterol being trapped in the artery wall, generating atherosclerosis.
  • High TGs: high triglycerides is important to the development of the ALP, as it is when HDL and LDL become overburdened with carrying TGs that they are forced to remodel.

Traditionally, cardiovascular disease [CVD] risk has been focused on high LDL alone, however, we now know the ALP phenotype is also a significant risk for CVD, and that indirect processes, i.e. the impact of refined carbohydrate/added sugars on liver fat accumulation, insulin resistance, and the resulting increase in circulating free fatty acids, and new triglyceride formation, are important factors, in addition to the impact of dietary fat on blood cholesterol levels.