Narrative review of palmitoleic acid links to metabolic health and fatty liver outcomes

Palmitoleic acid (POA; 16:1 n-7) has been proposed as a lipokine linking adipose tissue, liver, and skeletal muscle metabolism, but its relevance to human metabolic health remains uncertain. This narrative review integrates observational, clinical, and mechanistic evidence across circulating lipids and lipoproteins, glucose homeostasis, inflammation and vascular markers, adiposity, and hepatic endpoints. In observational studies, higher POA in esterified lipid fractions often tracks with de novo lipogenesis, hypertriglyceridemia, adiposity, insulin resistance, and fatty liver, whereas findings for free POA are more heterogeneous. In human interventions, POA-rich food matrices such as macadamia-based diets can improve LDL-cholesterol and related ratios when they replace saturated fat, but these studies do not isolate the specific contribution of POA from the broader monounsaturated-fat matrix. By contrast, short-term trials of purified POA supplementation have largely reported neutral effects on standard fasting lipids, glycemic markers, and inflammatory biomarkers. Pre-clinical and in vitro studies support biological plausibility, with reported effects on insulin signaling, hepatic lipid metabolism, adipose remodeling, and inflammatory pathways. Overall, current evidence supports cautious interpretation: POA is biologically interesting, but clinically meaningful benefits of purified POA supplementation remain unproven and require adequately powered trials in well-characterized at-risk populations.