An increased level of apolipoprotein A-1 is generally considered to be protective. However, under extreme inflammation, oxidation, or exposure to autoantibodies, it may become proinflammatory, especially in the presence of myeloperoxidase.
Apolipoproteins represent the protein portion of lipoprotein carriers in the blood. Apolipoprotein A-1 is the major component of HDL and, like HDL, it is considered to be cardioprotective. Apo A-1 levels can increase with physical exercise, alcohol intake, niacin, and various medications. Levels may decrease with smoking and a diet rich in polyunsaturated fats and carbohydrates. Low levels appear to increase the risk of coronary or peripheral artery disease. (Pagana 2019).
Maintaining an optimal BMI, not smoking, consuming fermented dairy products, and minimizing added sugar, especially from sugar-sweetened beverages, pastry, sweets, chocolate, and jams can help increase ApoA-1 (Frondelius 2017).
Apo A-1 possesses anti-inflammatory and antioxidant properties. Under normal circumstances, it helps prevent lipid peroxidation and LDL oxidation and helps sequester lipopolysaccharides. However, under conditions of excess inflammation, oxidative stress, and glycation, researchers hypothesize that ApoA-1 may become modified in a way that makes it pro-inflammatory, especially in the presence of myeloperoxidase (MPO). Autoantibodies to ApoA-1, as seen in autoimmune conditions such as lupus, can impair the function and integrity of ApoA-1 as well (Vuilleumier 2013).
Ultimately, we see that a higher ApoA-1 is considered protective unless overwhelmed by excess inflammation and oxidative stress, conditions under which it may become pro-inflammatory.
References
Pagana, Kathleen Deska; Pagana, Timothy J.; Pagana, Theresa N. Mosby's Diagnostic and Laboratory Test Reference. Elsevier Health Sciences. 2019.
Frondelius, Kasper et al. “Lifestyle and Dietary Determinants of Serum Apolipoprotein A1 and Apolipoprotein B Concentrations: Cross-Sectional Analyses within a Swedish Cohort of 24,984 Individuals.” Nutrients vol. 9,3 211. 28 Feb. 2017, doi:10.3390/nu9030211
Vuilleumier, Nicolas et al. “Pro- or anti-inflammatory role of apolipoprotein A-1 in high-density lipoproteins?.” Swiss medical weekly vol. 143 w13781. 25 May. 2013, doi:10.4414/smw.2013.13781