Figure 1.

The flowchart showing the two-step Mendelian randomization methods used in this study. Step 1: Analysis of the association of ω-3 fatty acids on blood lipid levels using Single-nucleotide polymorphism (SNP) loci associated with ω-3 fatty acids as a proxy tool. Step 2: Analysis of the effect of the gut microbiome variation on blood lipid level using SNP loci associated with gut microbiome variation as a proxy tool for intermediate variables. Both genetic instrumental variables were independent of confounders. Tables S9–S11 show the detailed process results of MR analysis.