Scanning electron micrograph of the cut surface of a ripe Avocado, Persea americana. The picture shows one central cell and parts of five others. Ripe avocado flesh is comprised of about 70% water. This specimen is freeze-dried, and in a vacuum inside the microscope; it is dry. Retained are the structure of the cell walls (brown), a matrix of lamellae within the cells, and spherical particles of lipid (green). The avocado is widely regarded and promoted as a healthy food. This is due in part to the nature of the lipids (fat) that it contains.The laminar matrix is comprised mainly of mono-unsaturated fatty acids; the lipid particles contain small amounts of phytosterols, principally beta-sitosterol. Phytosterols reduce the absorption of dietary cholesterol into the intestines.Trials have shown that eating avocado can reduce the levels of LDL ("bad cholesterol") in the blood.