Lipid‐lowering mechanism of egg yolk in normal rats

The ingestion of egg has been reported to lower blood cholesterol, but the mechanism is unclear. Here, the biochemical metabolic mechanism by which the oral administration of egg yolk affects blood lipid reduction was investigated using normal rats. Blood triglycerides and total cholesterol were lower and high‐density lipoprotein cholesterol was higher in an egg yolk‐given group compared to other groups, while low‐density lipoprotein cholesterol was increased in the pork belly oil‐given group. HMG‐CoA reductase activity was higher in the pork belly oil‐given group, compared to an egg yolk‐given group, a weekly alternating administration of pork belly oil and egg yolk‐given group, and the saline‐given normal control group. However, faecal excretions of total sterol, neutral sterol and acid sterol in an egg yolk‐given group were higher compared to the pork belly oil‐given group, a weekly alternating administration of pork belly oil and egg yolk‐given group, and a normal control group. The results suggested that ingestion of egg decreased blood lipids.