Cholesterol in Dogs and Cholesterol in Humans

In humans and in dogs, there are two major lipids or fats in the blood: cholesterol and triglycerides. Humans are usually affected by high cholesterol, but dogs are usually affected by high triglycerides. There are some breeds, such as Briards, with a genetic tendency to develop high cholesterol, but most other dogs with high blood lipids have elevated triglycerides.

In humans and in dogs, there are four molecules called lipoproteins that transport fat between the blood and the tissues:
· chylomicrons,
· VLDL,
· LDL, and
· HDL.
The first three, chylomicrons, VLDL, and LDL, move fats from the intestines and blood into muscles and other tissues. Only HDL moves fats the other direction—from the tissues back to the liver.

Why dogs don’t have high cholesterol
Dogs don’t normally have high cholesterol because:
· 95% of the healthy dog diet is triglycerides and only 5% is cholesterol or other forms of fat.
· Dogs carry most of their cholesterol on the HDL molecule, which moves fats from the tissues back to the liver. (Humans carry most of their cholesterol on the LDL molecule which moves fats away from the liver and into the blood and tissues.)
· In humans, white blood cells called macrophages or “big eaters” pick up cholesterol from lipoproteins in the blood and deposit it in the blood vessels causing atherosclerosis. This occurs infrequently in dogs.