The Good Side of Bad Cholesterol

A study reveals that low-density lipoprotein (LDL), commonly referred to as "bad cholesterol,” may not be so bad after all.

Researchers at Texas A&M University (TAMU; College Station, USA), Kent State University (OH, USA) and other institutions examined 52 adults aged 60-69 who were in generally good health but not physically active, and none of whom were participating in a training program. The study showed that after fairly vigorous workouts, participants who had gained the most muscle mass also had the highest levels of LDL. According to the researchers, this finding illustrates that a certain amount of "bad" cholesterol is needed to build muscle during resistance training.

The researchers added that building muscle mass is very important to arrest a condition called sarcopenia, which is muscle loss due to aging. Muscle is usually lost at a rate of 5% per decade after the age of 40, and after the age of 60, moderate to severe sarcopenia sets in 65% of all men and about 30% of all women. LDL also serves as a signal that warns of other underlying factors that are more dangerous, such as smoking, improper diet, and lack of exercise. The study is published in the Journal of Gerontology.

"LDL serves a very useful purpose. It acts as a warning sign that something is wrong and it signals the body to these warning signs; it does its job the way it is supposed to,” said lead author Steve Riechman, PhD, MPH, a researcher in the TAMU department of health and kinesiology. "Everyone needs a certain amount of both LDL and HDL in their bodies. We need to change this idea of LDL always being the evil thing - we all need it, and we need it to do its job.”

LDL is one of the five major groups of lipoproteins, which in order of size, largest to smallest, are chylomicrons, VLDL, IDL, LDL and HDL; the lipoproteins enable transport of lipids like cholesterol and triglycerides within the bloodstream. Because LDL particles can also transport cholesterol into the artery wall, retained there by arterial proteoglycans and attracting macrophages that engulf the LDL particles and start the formation of plaques, increased levels are associated with atherosclerosis. Over time vulnerable plaques rupture, activate blood clotting and produce arterial stenosis, which if severe enough results in heart attack, stroke, and peripheral vascular disease symptoms and major debilitating events.

Related Links:
Texas A&M University
Kent State University