Health benefits of seal oil supplements on cardio metabolic Health: A systematic review and meta analysis of randomized controlled trial (RCT)

Shima Hajipour
MSc Student 
Department of Biochemistry

Date: March 3, 2025
Time: 1:00 p.m. to 2:00 p.m. 
Room: CSF 1302

Abstract:

Seal oil, a rich source of omega-3 fatty acids, has been suggested to improve cardiometabolic risk factors; however, the findings from randomized clinical trials (RCTs) remain inconsistent. The novelty of our research is that we incorporate both traditional Indigenous knowledge and western scientific understanding of the health benefits of seal oil, and we share the outcomes of our analysis with the Indigenous communities. This study aimed to provide a meta-analysis and comprehensive systematic review to evaluate the impact of seal oil supplementation on cardiometabolic health. A systematic search of RCTs published from database inception and August 2024 was carried out using inclusion and exclusion criteria. Main outcomes included blood lipid levels (total cholesterol, low-density lipoprotein [LDL] cholesterol, high-density lipoprotein [HDL] cholesterol, triglycerides), fatty acid composition, and body weight. The search yielded 2484 studies, of which 12 were eligible for data extraction. To explore the sources of heterogeneity, subgroup analyses, and meta-regression were conducted based on potential moderator variables (including the type of control, population age, BMI, and study duration). In total, the data of 280 participants in intervention groups were compared with 269 participants in the control groups. Seal oil supplementation did not significantly affect total cholesterol, triglycerides, LDL and body weight, compared to the control groups. No significant difference was observed in docosahexaenoic acid between seal oil and control groups. In contrast, a significant increase was observed in eicosapentaenoic acid, while arachidonic acid and linoleic acid decreased significantly in the seal group, compared to the control. The subgroup analysis revealed that control type played a crucial role in heterogeneity, with significant differences observed in several biomarkers, suggesting dietary fat composition may critically influence fatty acid metabolism. The systematic review and meta-analysis suggest that seal oil supplementation improves HDL levels. The effect of seal oil on major parameters assessed was inconclusive due to high heterogeneity; the subgroup analysis identified control type as a key source of heterogeneity. Despite high heterogeneity, sensitivity analyses confirmed the robustness of most findings, with minimal risk of publication bias. Our findings suggest that well-designed RCTs are needed to clarify the clinical implications of seal oil in cardiometabolic health.