by Sue Rose, MS, RD
Blood triglycerides may be an important factor in your risk for heart disease.
The magic number for total cholesterol is 200. That is, your doctor may become concerned if your blood cholesterol level exceeds that number. But another type of fatty substance found in the blood, known as triglycerides , may also need to be monitored in the effort to prevent heart disease. That's because recent research has identified high triglyceride levels as a risk factor for cardiovascular disease within families, even when cholesterol levels were normal.
Researchers from the University of Washington School of Public Health in Seattle studied families with elevated triglyceride levels over a 20-year period. They found that there was an increased risk for cardiovascular disease in families who had elevated triglyceride levels independent of cholesterol levels. However, researcher and professor of epidemiology Melissa Austin, PhD, cautions that "we don't know if the results are applicable to individuals without a family history of high triglycerides."
What Are Triglycerides?
Triglycerides are a form of fat present in food, human body fat, and blood. Blood triglyceride levels are affected by dietary fat and are manufactured in the body from other energy sources, such as carbohydrates. Triglycerides are also stored as body fat.
An elevation of blood triglycerides is referred to as hypertriglyceridemia . The blood test to measure triglyceride levels is easy and can be done in conjunction with a routine blood test that also measures various types of cholesterol. (The most accurate results are obtained when a person fasts for 10-12 hours before this test.) Triglyceride levels can be quite variable, so several measurements may be necessary to provide accurate baseline values.
An elevated triglyceride level can be an independent medical problem or can be due to another existing medical problem. For instance, people with poorly controlled type 1 or type 2 diabetes often have elevated triglyceride levels. Jacqueline King, MS, RD, FADA, CDE, a dietitian and certified diabetes educator in Glenview, Illinois, frequently sees this connection. She notes that as people's blood sugar levels normalize, their triglyceride levels will come down. Elevated triglycerides can also be brought on by thyroid disorders , kidney problems, obesity , excess alcohol, and taking certain medications.
The National Cholesterol Education Program (NCEP) classifies the ranges of fasting triglyceride levels in the following way (all measurements are in milligrams per deciliter, or mg/dL):
"normal" less than 150 mg/dL (1.7 mmol/L)
"borderline high" 150-199 mg/dL (1.7-2.2 mmol/L)
"high" 200-499 mg/dL (2.3-5.6 mmol/L)
"very high" > or equal to 500 mg/dL (5.7 mmol/L)
Robert Rosenson, MD, director of the Preventive Cardiology Center at Rush Medical College in Chicago, feels that the NCEP guidelines are too lenient. Speaking at the 1996 American Heart Association meeting, Rosenson said that at levels above 190 mg/dL (2.2 mmol/L), triglycerides start contributing to the viscosity, or thickness, of blood. The thicker the blood, the harder it is for the heart to pump it to the tissues, thereby contributing to cardiac disease risk. Triglyceride limits were lowered by NCEP in 2001.
Further studies are necessary to determine just how much of an impact blood triglyceride levels have on risk for heart disease. However, current studies show that elevated levels may be a risk factor for cardiovascular disease, particularly in women. So, if you have elevated triglycerides, there are some simple steps you can take to try to lower them.
The Therapeutic Lifestyle Changes Diet
The NCEP therapeutic lifestyle changes diet is a recommended first step for patients with high triglyceride levels. This plan recommends eating the following proportions of dietary fat and other dietary components:
Up to 25%-35% of total calories from various types of fat
Up to 6% of calories from saturated fat (found in butter; cheese; meat; whole milk; and palm, palm kernel, and coconut oils)
Up to 10% of calories from polyunsaturated fat (found in corn, soybean and safflower oils, salad dressings, and seeds)
Up to 20% of calories from monounsaturated fat (found in olive, peanut, and canola oils, avocados and nuts)
Less than 200 milligrams of cholesterol
About 15% of total calories from protein
From 20-30 grams of fiber per day
Some ways to follow the step-one diet include limiting animal protein to no more than six ounces per day, along with only one to two "visible" fat servings per day (a "visible" fat serving is one teaspoon of oil, margarine, butter, or about six nuts). Replacing whole-fat dairy foods with low-fat and fat-free versions and eating at least five servings of fruits and vegetables a day are also important.
Other Ways to Tame Triglycerides
Other factors can play a role in high triglyceride levels. Here are some tips from the experts:
Maintain a Healthy Weight. Studies have shown losing weight and maintaining an ideal weight to be associated with decreased levels of blood triglycerides and cholesterol.
Increase Physical Activity. Aerobic exercise can help with weight loss and can decrease triglyceride levels at the same time. In fact, both short bouts of aerobic exercise as well as long-term repetitive exercise have been shown to decrease triglyceride levels. Most studies find that the best bet is to do 30-45 minutes of moderately intensive exercise five times a week. First, get your doctor's approval if you're not accustomed to exercise.
Cut Down on Carbs. Carbohydrates are basically divided into two categories: simple and complex. Simple carbohydrates tend to be sweet, such as soft drinks, desserts, candies, and syrup. Complex carbohydrates are found in bread, pasta, rice, fruits, and vegetables. It's generally recommended that people with hypertriglyceridemia avoid simple carbohydrates. Some people are so sensitive to sweets that their triglyceride levels increase drastically when they eat too much sugar. In any healthful diet, complex carbohydrates should provide about 50%-60% of overall calorie intake, but even high-fiber, nutrient-dense complex carbohydrates can aggravate triglyceride levels when eaten in amounts exceeding 60% of total calorie intake. Note: These are general guidelines for healthy people. According to the NCEP, people with increased triglyercides should consume 50%-60% of total calories as carbohydrates, perferably as complex carbohydrates.
Limit Alcohol. According to the American Heart Association (AHA), even small amounts of alcohol can increase triglyceride levels. For some people, cutting out alcohol can elicit a marked decrease in their triglyceride levels.
Choose Fats Wisely. The AHA recommends that up to 30% of the calories you get from fat come from foods containing monounsaturated and polyunsaturated fatty acids (see section on the therapeutic lifestyle changes diet above).
Eat More Fish. The AHA also recommends eating more fish because of the omega-3 fatty acids found in fish, which have been associated with decreased triglyceride levels. Omega-3 fatty acids also help make the blood less sticky, so it is less likely to forms clots that contribute to heart attacks. Omega-3 fatty acids are found in all types of fish, but are more abundant in fatty fish like mackerel, salmon, sardines, and herring. Other good sources of omega-3 fatty acids include tofu, soybeans, flaxseed, canola oil, nuts, and green leafy vegetables.
American Heart Association
National Cholesterol Education Program
Austin MA, et al. Cardiovascular disease mortality in familial forms of hypertriglyceridemia: a 20-year prospective study. Circulation . 2000;101:2777-2782.
National Cholesterol Education Program website. Available at: http://www.nhlbi.nih.gov/about/ncep/index.htm .
National Heart, Lung, and Blood Institute website. Available at: http://www.nhlbi.nih.gov
Triglycerides American Heart Association website. Available at: http://www.americanheart.org/
Last reviewed June 2006 by Jill D. Landis, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.