What fatty substance in blood is thought to contribute to hardening of the arteries?

Cholesterol is a fatty substance found in the blood and is known to play a significant role in the development of atherosclerosis, which is the hardening and narrowing of the arteries. High levels of cholesterol, particularly low-density lipoprotein (LDL) cholesterol, can lead to the buildup of plaques on artery walls. This process restricts blood flow and can increase the risk of heart attacks and strokes.

Cholesterol is a necessary component of cell membranes and serves vital functions in the body, including hormone production and vitamin D synthesis. However, when present in excessive amounts, especially when combined with other risk factors like high blood pressure and smoking, it can contribute to cardiovascular disease.

The other substances listed do not have the same impact on arterial health as cholesterol. For instance, amino acids are the building blocks of proteins, phenol is an organic compound not typically associated with cholesterol metabolism, and pectin is a soluble fiber found in fruits that can aid in digestion and has been shown to lower cholesterol levels rather than contributing to cardiovascular issues.