People often feel lucky to have a “smart” friend to turn to when medical questions arise. Oldways has a few very smart friends, one of them being Dr. Frank Sacks. Frank is a Professor of Cardiovascular Disease Prevention at the Harvard School of Public Health, a Professor of Medicine at Harvard Medical School and a senior attending physician at Brigham and Women’s Hospital. He’s also published in 175 original research articles. We know we can turn to Frank as a trusted resource to help to clarify the latest research, helping us to understand what the results really mean, and how this relates to people in their day-to-day lives. When we heard about a new study on HDL, we knew what to do. Call Dr. Sacks!
OLDWAYS: A new study recently published in The Lancet found that raising HDL — the good cholesterol — may not make any diﬀerence to the risk of heart disease. Can you explain the results of this study, but start with a basic explanation about the diﬀerence between
HDL and LDL, for those who may not know.
FRANK: LDL and HDL are key pieces in the transport system that moves cholesterol around the body. LDL delivers cholesterol from the liver to other organs and tissues where as HDL removes cholesterol from tissues and delivers it back to the liver for removal from the body.
When the blood level of LDL is too high, its cholesterol deposits in the artery wall causing atherosclerosis (hardening of artery walls) and heart attacks. When HDL is too low, it can’t remove enough of the cholesterol deposited by LDL.
The Lancet Study found that variants of genes that aﬀect HDL levels are not related to heart disease. But we do not know how these genes work in the HDL system and do not yet know how to apply these results to the use of HDL in diagnosis and treatment. Most of our research in terms of HDL has been information gathered from animals or cells cultured in isolation in the laboratory. We need to better understand how exactly HDL does its job in the body to fully understand the impact of this study.
OLDWAYS: Does this mean people should stop focusing on raising their HDL?
FRANK: The short answer is no. The factors that play into raising HDL tend to be ones associated with a healthy lifestyle, so it is safe to say it is better for HDL to be high rather than low. A Mediterranean Diet that is high in unsaturated fat raises HDL, as compared to a low-fat diet. Exercise raises HDL a little bit, except in very strenuous and lengthy exercise like mountain climbing. Alcoholic drinks raise HDL. Weight loss in overweight people raises HDL. All of these are good things to do.
OLDWAYS: Why do some people have low HDL?
FRANK: Genetics plays a role with HDL, but often the number is compounded by an unhealthy lifestyle, such as being overweight, lack of physical activity and other similar factors.
OLDWAYS: What about LDL? Are there any new conclusions about LDL?
FRANK: No, there were no new conclusions in terms of LDL. What we do know is that LDL is still the main target for lipid treatment.
OLDWAYS: Many people take statin drugs. Are there risks with taking statins, or are there more beneﬁts to taking statins, particularly with a healthy diet?
FRANK: As is true with all statins, which are cholesterol-lowering drugs, they can have some adverse eﬀects. However, for those who have high risk of heart disease, the beneﬁts of taking statins outweigh the risks. In addition, some research has shown that statins add to the beneﬁcial eﬀects of a healthy diet.
OLDWAYS: What’s the most important thing someone at risk for heart disease can do to decrease their risk?
FRANK: A healthy diet and physical activity are the best defenses against heart disease.