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What is GGT?

Gamma-glutamyl transferase (GGT) is an enzyme found mainly in the liver that helps protect your cells from damage. GGT is a microsomal enzyme found in cell membranes of many tissues, primarily the liver, kidney, and pancreas, and is also found in the intestine, spleen, heart, and brain. Although GGT activity in the kidney exceeds that in the liver, serum GGT predominantly originates from biliary canaliculi and serves as a biomarker for hepatobiliary function.

GGT functions in the body as a transport molecule, helping to move other molecules around the body, and plays a significant role in helping the liver metabolize drugs and other toxins. GGT is a key enzyme in the metabolism of glutathione, a major antioxidant that protects cells against oxidants and is essential for mitochondrial metabolism

Why is GGT important?

GGT is one of the most clinically sensitive markers for liver and metabolic health. GGT is typically the first liver enzyme to increase in your blood when any of your liver bile ducts become blocked or constricted, making it the most sensitive liver enzyme test for finding bile duct issues.

Beyond liver health, elevated GGT has been associated with broader systemic risks. Higher serum GGT levels are associated with increased all-cause mortality, as well as elevated risk of death from cardiovascular disease, cancer, respiratory disease, and liver disease, regardless of smoking, alcohol consumption, and history of previous cardiovascular disease or cancer. High levels of GGT are also associated with increased risk of metabolic syndrome and type 2 diabetes in both men and women

How can I better understand my GGT levels?

A GGT blood test is a tool healthcare providers use to help diagnose liver disease and bile duct issues, and it is often ordered alongside other liver function tests to help reach a diagnosis, as GGT levels alone cannot diagnose a specific disease.

Higher than normal GGT levels may indicate several conditions. Test results that are higher than normal could be a sign of liver damage from diseases such as hepatitis, cirrhosis, tumors, or pancreatic cancer. GGT may also be higher with diabetes, heart failure, hyperthyroidism, or pancreatitis, and higher GGT levels may mean liver damage from heavy, chronic alcohol abuse. It is also worth noting that levels of GGT increase with age in women, but not in men.

Lower than normal GGT levels are generally not a cause for concern. Low GGT levels generally indicate good mental and physical health, reflecting adequate glutathione levels, balanced vitamin and mineral intake, and a plant-forward diet. However, in rare contexts, low GGT levels have been linked to conditions like gastric and cervical cancer, preeclampsia, and anemia, often due to oxidative stress.

Normal reference ranges (may vary slightly by laboratory):

  • Men: 0-50 U/L
  • Women: 0-30 U/L

How can I maintain optimal GGT levels?

If you need to lower or maintain healthy GGT levels, consider the following evidence-based strategies:
Limit Alcohol Consumption: Alcohol is one of the primary causes of elevated GGT. Reducing or eliminating alcohol intake can significantly lower GGT levels and improve liver health.
Dietary Changes: Adopt a liver-friendly diet rich in fruits, vegetables, whole grains, and lean proteins. Limit processed foods, saturated fats, and added sugars. Consider incorporating foods high in antioxidants, such as berries, leafy greens, and nuts.
Weight Management: If overweight, losing even 5-10% of body weight can improve liver health and reduce GGT levels. Regular physical activity helps reduce fatty liver disease and inflammation.
Medication Review: Certain medications can elevate GGT levels. Consult with your healthcare provider about any medications or supplements you are taking that may affect liver enzymes.
Manage Underlying Conditions: Properly managing conditions like diabetes, metabolic syndrome, and cardiovascular disease can help maintain healthy GGT levels.

Where can I learn more?

DISCLAIMER: IF YOU ARE CONCERNED WITH ANY OF YOUR RESULTS, PLEASE CONSULT WITH YOUR PHYSICIAN.