Long-term excessive salt intake is a risk factor for hypertension, but its impact on lipid metabolism and gut microbiota remains poorly understood. This study aims to evaluate the effects of inadequate or excessive salt intake on lipid metabolism and gut microbiota composition, and explore the underlying relationship between these effects. Male Syrian golden hamsters were randomly assigned to six groups and fed diets with sodium chloride levels of 0.4, 0.8, 3.0 (a normal dose), 6.0, 12.0 or 24.0 g/kg for nine weeks. Lipid levels in plasma, liver and feces were measured, and fresh feces were analyzed via 16s rRNA gene sequencing. Results showed that neither inadequate nor excessive salt intake altered plasma lipids. However, excessive salt intake led to a dose-dependent increase in liver lipid accumulation. Additionally, it significantly modified gut microbiota composition at the family and genus levels. Notably, higher salt doses reduced both the relative abundance of Allobaculum and fecal short-chain fatty acids (SCFA) concentrations, with a positive correlation being observed between the two. These findings suggest that excessive salt intake aggravates hepatic lipid accumulation, likely by modulating gut microbiota involved in SCFA production.

One of the major diseases that threatens human health all over the world is cardiovascular disease, which has become the leading cause of death in adults in China. Hypercholesterolemia is one of the risk factors for cardiovascular diseases. Statins, cholestyramine and eztimibe are currently used clinically to treat hypercholesterolemia. However, long-term administration of these drugs may cause various side effects. Cholesterol-lowering functional foods have begun to be used as an alternative to drugs since they exert an efficacy similar to that described for drugs without any side effects. The present review discusses the synthesis, metabolism and excretion of cholesterol and how the body modulates plasma cholesterol balance. Additionally, this review summarizes recent studies on cholesterol metabolism and cholesterol-lowering functional foods as well as their active components and action mechanisms.