TRIGLYCERIDES LINKED TO HEART DISEASE
July 4, 2008
High levels of triglycerides are strong indicators of cardiac trouble and this strengthens the case for including measurement of the blood fats in prevention programs, says a study in the Journal of the American College of Cardiology.
"Triglycerides traditionally have been viewed as second-class citizens," says lead author Dr. Michael Miller of the University of Maryland Medical Center.
"LDL cholesterol has always taken center stage," says Dr. Miller. "We know that LDL is intimately involved in bringing cholesterol to scavenger cells, which deposit them to form plaques in the arteries.
This study shows that triglycerides in and of themselves are also lipids to blame," notes Miller.
Anne Hedelt, FNP, MSN, R.N., a family nurse practitioner at the University of Virginia Health System's Heart & Vascular Center, says the study's findings aren't shocking."I am not surprised by the study given that we are increasingly seeing more complex cholesterol or lipid abnormalities with the increase in obesity and diabetes."
UNDER 150 MILLIGRAMS PER DECILITER TRIGLYCERIDES IS BEST
The original study was designed to test the effectiveness of two LDL-lowering statins called Pravachol© and Lipitor© in reducing recurring coronary disease after a heart attack.
The new study went over the data on the 4,162 participants in the trial, looking at the association between triglyceride levels and the incidence of heart problems and death.
"The patients who had heart attacks came back after 30 days," says Dr. Miller. "We measured LDL levels and triglyceride levels and followed them over the next two years, evaluating for the occurrence of new events and death. If a patient had triglyceride levels below 150 [milligrams per deciliter], there was a 27 percent lower risk of having a new event over time. After multiple adjustments for such things as age, diabetes, high blood pressure and obesity, the risk reduction was 20 percent."
That risk is lower, UVA's Hedelt says, because high triglyceride levels is among the risk factors for metabolic syndrome, a group of risk factors that increase your chances of heart disease and diabetes. Other risk factors for metabolic syndrome include abdominal obesity, high blood pressure and insulin resistance or glucose intolerance (meaning your body can't properly use insulin or blood sugar).
Unlike LDL cholesterol, for which there is a recommended blood level of 70 or below, there is no recommended blood triglyceride level but 150 milligrams per deciliter or below is "considered as desirable," says Miller. When the participants were divided into four groups on the basis of both LDL and triglyceride levels, those in the group with under 150 for triglycerides and under 70 for LDL did the best. They had a 28 percent lower risk than those in the group with the highest readings for both LDL and triglycerides, he says.
"At the present time, we don't have a recommendation for triglyceride lowering, so the next logical step is a study to determine whether lowering triglycerides and LDL reduces risk more than lowering LDL alone," he says. Two studies examining that issue are in progress, he notes.
MEDITERANEAN DIET A GOOD APPROACH
Previous research has already pointed toward such a connection: A study that appeared in the medical journal Neurology last December found a link between triglycerides and stroke risk. And research published in the Journal of the American Medical Association (JAMA) last July showed that when high triglyceride levels showed up in nonfasting cholesterol tests, there was an increased risk for a future heart attack.
Dr. Leslie Cho of the Cleveland Clinic notes that the new report "is not a huge surprise."
"The unique thing about this study is that even if you control bad LDL cholesterol to less than 70, you still need to look at triglycerides.
The problem with triglycerides is that they are the most unstable fats in the body, so at least two readings are needed to get an accurate measure of blood levels," she explains.
Several measures can be taken to lower triglyceride levels - many of them are already recommended on general principles for reduction of coronary risk. One is to eat a Mediterranean diet, rich in fish. Omega-3 fatty acids can lower triglyceride levels, as can niacin, and exercise has a beneficial effect, says Dr. Miller. Statins also have some triglyceride-lowering effect, he notes. "If you can effectively get both LDL cholesterol and triglycerides down, you are going to do better," says Miller.
Along with Omega-3 fatty acids, Hedelt says, the American Heart Association has several additional recommendations for lowering your triglyceride levels, including:
- Reduce all sources of calorie intake to lose weight and reach your ideal body weight.
- Reduce your consumption of saturated fat, trans fat and cholesterol content. Substitute monounsaturated and polyunsaturated fats - such as liquid margarine, canola oil or olive oil - for saturated fats.
- Exercise for at least 30 minutes most days or every day.
- Considerably reduce your alcohol intake.