The biggest threats to Americans' health cause no pain or discomfort, but they lead to deadly heart attacks, strokes and liver disease. Two simple blood tests that analyze cholesterol levels and liver health can uncover these silent threats that plague more than half of all Americans. High levels of cholesterol clog arteries and cause heart disease, but they also overload the liver, leading to fatty liver and liver damage including cirrhosis and even liver cancer.
The Link Between Cholesterol and Liver Health
Doctors know too much alcohol and hepatitis B and C damage the liver, but now they're discovering fat- and sugar-rich diets and sedentary lifestyles lead not only to diabetes and heart disease, but also to liver damage, even in children. And it all begins with high cholesterol. Today, between up to 10 percent of children and one-third of adults have fatty liver disease due to unhealthy diets and little exercise. Diabetes and fatty liver is not only common in the 65 percent of Americans who are overweight, but even in lean people who appear healthy.
How Is Cholesterol Tested?
Cholesterol, produced by the liver, is a waxy, fat-like substance used to make hormones and vitamin D and helps digest food. Cholesterol travels through the bloodstream encased in two types of lipoproteins: low-density lipoproteins (LDL) and high-density lipoproteins (HDL). HDL is the good cholesterol that carries excess cholesterol back to the liver, which usually removes it -- unless there is too much of it. According to the National Institutes of Health, half of all American women have unhealthy levels of cholesterol and 22 percent of young adults in their 20s have already developed high cholesterol. Because of this epidemic, the American Heart Association recommends all adults age 20 and older have their cholesterol checked every four to six years. The test is called a lipoprotein test. Patients fast for at least eight hours and then have a blood test that measures cholesterol levels in milligrams per deciliter of blood (mg/dL). Usually total cholesterol and HDL (good) cholesterol are evaluated, as well as triglycerides. According to NIH: A healthy total cholesterol level is less than 200 mg/dL. A borderline high rate is 200 to 239 mg/dL. And, a high rate is 240 mg/dL or higher.
How Is Liver Health Tested?
When the liver is damaged from infection or has too much fat and cholesterol to metabolize, it becomes inflamed, and the constant inflammation causes scarring (called cirrhosis), which can lead to liver cancer. When liver cells are damaged, they release enzymes into the blood. Liver tests (called a liver panel or liver function test) look for these enzyme levels to see if the liver is damaged. There are two types of liver enzymes that are commonly measured. Normal ALT (alanine aminotransferase or SGPT) liver enzymes levels are generally 10 to 40 international units per liter (IU/L), with lower levels for women. Normal AST (aspartate aminotransferase or SGOT) levels are between 10 to 34 IU/L. These levels may vary between labs, which is why doctors recommend patients use the same lab for every test for consistency. Liver damage is considered serious if enzyme levels are two- to three-times above the normal range, or higher.
What Happens If Cholesterol and Liver Tests Are High?
If cholesterol or liver tests are above normal, doctors will perform additional tests to find out more information about the liver and the impact of elevated cholesterol on the heart and arteries. Patients will also be examined for diabetes, which also contributes to liver damage. If liver enzyme levels are elevated, a patient may be referred to a hepatologist, a medical specialist whose expertise is the liver. The good news is, both fatty liver and high cholesterol are reversible when patients eat healthy diets and start exercising more.
- Pediatric non alcoholic fatty liver disease: old and new concepts on development, progression, metabolic insight and potential treatment targets
- Nonalcoholic Fatty Liver Disease
- American Heart Association: What Your Cholesterol Levels Mean
- NIH: What Is Cholesterol
- U.S. National Library of Medicine: ALT Tests
- U.S. National Library of Medicine: AST Tests