Type 2 Diabetes and Triglycerides
What is a triglyceride, and why do some physicians refer to it as the “ugly fat”?
Most people who read the news or watch television know about cholesterol. There are constant warnings about high cholesterol as a very important risk factor for heart disease, and we are continually bombarded with advertisements for foods and pills and exercise programs that promise to lower our cholesterol levels.
But few people have heard about or understand much about triglycerides. Triglycerides are bundles of fats found in the blood stream especially after we eat. The body manufactures triglycerides from the carbohydrates and fatty foods that we eat. Almost 90 percent of the fat content of most non-lean meats is triglyceride.
What are the function and importance of triglycerides?
Triglycerides account for about 99 percent of the fat stored in our bodies. These triglyceride-laden fats serve as the most important source of long-term energy for the body, since they are stored in a much denser form than starches or muscle proteins. Formation of fat requires the presence of insulin. Triglyceride in fat is converted to energy between meals and overnight, or any time when we are fasting or insulin levels are low. Fat cells have a tremendous storage capacity, which may contribute to obesity. With extended fasting or absolute insulin deficiency, the liver converts fat breakdown products to ketones.
High triglyceride levels in the blood tend to coexist with low levels of HDL (“good”) cholesterol, contributing to a condition called diabetic dyslipidemia. The third component of this “dangerous trio” is a tendency for patients with this condition to have the small, dense, undesirable (more atherogenic) type of LDL cholesterol in their blood (even though their LDL cholesterol level may be normal).
The combination of high triglycerides, low HDL and central obesity are the hallmarks of the metabolic syndrome, which occurs in 80 percent of people with type 2 diabetes. The frightening significance of this combination of risk factors is the marked incidence in these people of premature death from heart disease.
What is a normal triglyceride level, and what should be my goal?
Triglyceride concentrations are currently
rated 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 triglyceride level is around 100 to 150 mg/dl or less, but it will rise to 300 mg/dl or more just after a meal. In patients with type 2 diabetes, triglycerides are frequently elevated both in the fasting state and even more so after eating. It is important to be fasting overnight (preferably for 12 hours) when your blood is drawn for a lipid panel that includes triglyceride testing. You should also abstain from all alcoholic beverages for 24 hours before this test.
Just as with LDL cholesterol, the lower the triglyceride level the better. Most clinicians prefer that patients with type 2 diabetes keep their triglyceride level at or below 150 mg/dl to minimize their cardiovascular risk. It is not unusual for some people with type 2 diabetes to have triglycerides over 400 or even over 2,000. Very high triglycerides (over 1,000) can be associated with memory loss, skin lesions (xanthomas), abdominal pain and even life-threatening pancreatitis.
How do physicians treat patients with high triglyceride levels?
Triglycerides respond to both diet and medications. It is very important to know that since uncontrolled diabetes causes an elevation of triglycerides, any behavior modification or drug (and especially insulin) that improves blood glucose control will lower triglycerides. Dietary modifications to lower triglycerides are listed below. Statins and other drugs that lower cholesterol such as Lipitor, Zocor, Pravachol, Crestor Zetia and Vytorin have only minimal effects on triglycerides. Several drugs do an excellent job of lowering triglycerides (see below). Many people with type 2 diabetes will require two or even three different drugs to bring their LDL and triglycerides to target and raise their HDL cholesterol. However, most specialists believe that lowering the LDL to target is the most important goal. Lowering triglycerides and raising HDL are secondary goals to be addressed after the LDL goal is achieved.
Clinical adviser’s note: For more information on medications to treat lipid disorders, see our chart on page 52 of the January 2005 issue of Diabetes Health. You can also download a printer-friendly version from our Web site at www.diabeteshealth.com/charts.
Medications for Patients With High Triglycerides
Nicotinic acid (niacin)
Dietary Principles for Patients With High 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 Elevated Triglycerides
- 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)