ALT is an enzyme found predominantly within liver cells. Its presence in the bloodstream indicates that liver cells have been injured, causing the ALT to leak out. A reading of 70 units per liter (U/L) is considered mildly elevated and is a common result leading to a physician consultation. While not a cause for immediate alarm, this finding warrants prompt investigation to identify the underlying cause.
Understanding ALT and the 70 Reading
ALT helps convert food into energy by aiding in protein metabolism within the liver. Only small amounts of this enzyme are normally found circulating in the blood. The typical upper limit for a healthy adult is often cited around 55 U/L for men and 45 U/L for women.
The 70 U/L result is only slightly above the conventional upper limit, placing it in the “mildly elevated” category. This is distinct from moderate elevations (two to five times the upper limit) or severe elevations (many times higher). Since ALT is highly concentrated in the liver, even this small increase suggests a recent or ongoing disturbance in liver health that requires follow-up.
Common Causes of Mild ALT Elevation
The most frequent reason for a mildly elevated ALT reading like 70 U/L is Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD), formerly known as NAFLD. This condition involves the accumulation of excess fat within liver cells and is strongly linked to obesity, type 2 diabetes, and high cholesterol. MASLD often presents with an ALT level higher than the Aspartate Aminotransferase (AST) level, which helps distinguish it from other liver conditions.
Recent strenuous physical activity, such as intense workouts, can also cause a temporary, mild rise in ALT. Because ALT is present in skeletal muscle tissue, muscle damage releases the enzyme into the bloodstream, mimicking a liver injury. Certain medications and supplements are another common culprit for mild elevation. Over-the-counter pain relievers containing acetaminophen, especially when taken at high doses, can stress the liver.
Prescription drugs, including cholesterol-lowering statins, can similarly cause an asymptomatic, mild rise in ALT as a known side effect. Various herbal or dietary supplements, such as high-dose green tea extract or kava, have also been documented to potentially lead to liver injury. These non-liver-specific causes emphasize why a detailed review of recent activities and medications is crucial in the initial workup.
What Follow-Up and Testing Are Needed
The mild nature of a 70 U/L reading means the standard first step is a short-term retest rather than immediate aggressive intervention. Physicians often recommend repeating the blood work within two to four weeks to see if the level normalizes on its own. More than 30% of initially elevated results return to the normal range upon retesting, especially if the cause was temporary, like recent exercise or medication use.
The retest usually includes a full liver panel, measuring enzymes like AST, Alkaline Phosphatase (ALP), and Bilirubin. The relationship between these values, particularly the AST:ALT ratio, provides important diagnostic clues. For instance, in MASLD, the ALT is usually higher than the AST (ratio less than one), while a ratio greater than two often suggests alcohol-related liver injury.
If the ALT level remains persistently elevated after the retest, or if other liver markers are abnormal, the doctor will likely order a more extensive workup. This may include specific tests for viral hepatitis B and C, iron overload (hemochromatosis), and autoimmune conditions. Imaging, such as an abdominal ultrasound, is often used to look for structural changes in the liver and confirm fatty liver disease.
Lifestyle Steps to Support Liver Health
For most people with a mild elevation like 70 U/L, the initial management centers on proactive lifestyle modifications. Since MASLD is the most common cause, reducing body weight through diet and exercise is the most impactful action. Losing even a modest amount of weight can significantly reduce liver fat content and may normalize ALT levels.
Limiting or eliminating alcohol consumption is another immediate and beneficial step, as alcohol can directly injure liver cells and complicate the diagnosis. It is also important to carefully review all medications and supplements with a physician. Patients should be cautious about acetaminophen intake, ensuring they do not exceed the recommended daily maximum dose.
Adopting a diet rich in fruits, vegetables, and whole grains, while reducing saturated fats and simple carbohydrates, supports liver function. These changes help reduce the metabolic stress that leads to fat accumulation and inflammation in the liver. Such patient-controlled actions can often lead to a spontaneous resolution of the mild ALT elevation over several weeks or months.