Campesterol

Campesterol is a phytosterol whose chemical structure is similar to that of cholesterol, and is one of the ingredients for E number E499.

Many vegetables, fruits, nuts, and seeds contain campesterol, but in low concentrations. Banana, pomegranate, pepper, coffee, grapefruit, cucumber, onion, oat, potato, and lemon grass (citronella) are few examples of common sources containing campesterol at roughly 1–7 mg/100 g of the edible portion. In contrast, canola and corn oils contain as much as 16–100 mg/100 g. Levels are variable and are influenced by geography and growing environment. In addition, different strains have different levels of plant sterols. A number of new genetic strains are currently being engineered with the goal of producing varieties high in campesterol and other plant sterols. It is also found in dandelion coffee.

It is so named because it was first isolated from the rapeseed (Brassica campestris).

Campesterol can serve as a precursor to a wide range of steroid hormones. This is because it has structural similarity to cholesterol. Anabolic steroids like testosterone and boldenone are among the compounds that can be biosynthesized from either cholesterol or phytosterols like campesterol through a process called steroidogenesis.

Boldenone undecylenate is commonly used in veterinary medicine to induce growth in cattle, but it is also one of the most commonly abused anabolic steroids in sports. This led to suspicions that some of the athletes that have tested positive on boldenone undecylenate did not actually abuse the hormone itself, but had increased levels because they consumed food rich in campesterol or similar phytosteroids.

Plant sterols were first shown in the 1950s to lower LDLs and cholesterol. Since then, numerous studies have reported the lipid-lowering effects of dietary phytosterols, including campesterol.

In basic research, campesterol competes with cholesterol, thus reducing the absorption of cholesterol in the human intestine. Plant sterols may also act directly on intestinal cells and affect transporter proteins. In addition, an effect on the synthesis of cholesterol-transporting proteins may occur in the liver cells through processes including cholesterol esterification and lipoprotein assembly, cholesterol synthesis, and apolipoprotein (apo) B100-containing lipoprotein removal.

Serum levels of campesterol and the ratio of campesterol to cholesterol have been proposed as measures of cardiac risk. Some studies have suggested that higher levels predict lower cardiac risk. However, extremely high levels are thought to be indicative of higher risk, as indicated by genetic disorders, such as sitosterolemia.