What is a triglyceride, and why do somephysicians refer to it as the “ugly fat”?
Most people who read the news or watchtelevision know about cholesterol. There areconstant warnings about high cholesterolas a very important risk factor for heartdisease, and we are continually bombardedwith advertisements for foods and pills andexercise programs that promise to lower ourcholesterol levels.
But few people have heard about orunderstand much about triglycerides.Triglycerides are bundles of fats found in theblood stream especially after we eat. Thebody manufactures triglycerides from thecarbohydrates and fatty foods that we eat.Almost 90 percent of the fat content of mostnon-lean meats is triglyceride.
What are the function and importance oftriglycerides?
Triglycerides account for about 99 percentof the fat stored in our bodies. Thesetriglyceride-laden fats serve as the mostimportant source of long-term energy for thebody, since they are stored in a much denserform than starches or muscle proteins.Formation of fat requires the presence ofinsulin. Triglyceride in fat is converted toenergy between meals and overnight, or anytime when we are fasting or insulin levelsare low. Fat cells have a tremendous storagecapacity, which may contribute to obesity.With extended fasting or absolute insulindeficiency, the liver converts fat breakdownproducts to ketones.
High triglyceride levels in the blood tendto coexist with low levels of HDL (“good”)cholesterol, contributing to a condition calleddiabetic dyslipidemia. The third componentof this “dangerous trio” is a tendency forpatients with this condition to have thesmall, dense, undesirable (more atherogenic)type of LDL cholesterol in their blood (eventhough their LDL cholesterol level may benormal).
The combination of high triglycerides, lowHDL and central obesity are the hallmarks ofthe metabolic syndrome, which occurs in 80percent of people with type 2 diabetes. Thefrightening significance of this combinationof risk factors is the marked incidence inthese people of premature death from heartdisease.
What is a normal triglyceride level, andwhat should be my goal?
Triglyceride concentrations are currentlyrated as follows:
Desirable/normal: Less than 150 mg/dl
Borderline high: 150-199 mg/dl
High: 200-499 mg/dl
Very high: 500 mg/dl or greater
In the normal fasting state, the triglyceridelevel is around 100 to 150 mg/dl or less, butit will rise to 300 mg/dl or more just aftera meal. In patients with type 2 diabetes,triglycerides are frequently elevated bothin the fasting state and even more so aftereating. It is important to be fasting overnight(preferably for 12 hours) when your bloodis drawn for a lipid panel that includestriglyceride testing. You should also abstainfrom all alcoholic beverages for 24 hoursbefore this test.
Just as with LDL cholesterol, the lower thetriglyceride level the better. Most cliniciansprefer that patients with type 2 diabetes keeptheir triglyceride level at or below 150 mg/dlto minimize their cardiovascular risk. It is notunusual for some people with type 2 diabetesto have triglycerides over 400 or even over2,000. Very high triglycerides (over 1,000) canbe associated with memory loss, skin lesions(xanthomas), abdominal pain and even life-threateningpancreatitis.
How do physicians treat patients with hightriglyceride levels?
Triglycerides respond to both diet andmedications. It is very important to knowthat since uncontrolled diabetes causesan elevation of triglycerides, any behaviormodification or drug (and especially insulin)that improves blood glucose control willlower triglycerides. Dietary modifications tolower triglycerides are listed below.Statins and other drugs that lower cholesterolsuch as Lipitor, Zocor, Pravachol, Crestor Zetiaand Vytorin have only minimal effects ontriglycerides. Several drugs do an excellentjob of lowering triglycerides (see below).Many people with type 2 diabetes will requiretwo or even three different drugs to bringtheir LDL and triglycerides to target andraise their HDL cholesterol. However, mostspecialists believe that lowering the LDL totarget is the most important goal. Loweringtriglycerides and raising HDL are secondarygoals to be addressed after the LDL goal isachieved.
Clinical adviser’s note: For more informationon medications to treat lipid disorders, see ourchart on page 52 of the January 2005 issue ofDiabetes Health. You can also download aprinter-friendly version from our Web site atwww.diabeteshealth.com/charts.
Medications for Patients WithHigh Triglycerides
Nicotinic acid (niacin)
Dietary Principles for Patients WithHigh Triglycerides
- Total fat restriction may help, but in some cases where fat restriction results in increased carbohydrate intake, it actually causes higher triglyceride levels.
- Substitution of healthy fats (monounsaturated fats, such as olive oil) is recommended.
- Avoid a high intake of sugar and white flour products.
- Alcoholic beverages should be eliminated or restricted to no more than one drink per day, if your healthcare provider says that one drink a day is safe for you.
- Oily fish such as salmon, tuna, sardines, anchovies, mackerel and herring contain omega-3 fatty acids, which lower triglycerides.
Common Causes of ElevatedTriglycerides
- Genetic disorders
- Type 2 diabetes
- Excessive intake of refined sugars and fat
- Excess alcohol intake
- Liver disease
- Nephrotic syndrome (common in diabetic renal disease)
- Kidney failure
- Drugs (such as birth control pills, steroids, Tamoxifen, certain blood pressure medications)