From the Guidelines
Low AST levels are generally not considered a medical concern and do not typically require further investigation unless accompanied by other concerning symptoms or abnormal test results. AST is an enzyme found primarily in the liver, heart, and muscles, and blood tests typically focus on elevated levels as indicators of tissue damage 1. Low AST levels may simply reflect normal biological variation in some individuals. Occasionally, low AST can be associated with vitamin B6 deficiency, pregnancy, or certain medications like metformin. However, doctors rarely investigate isolated low AST levels unless other concerning symptoms or abnormal test results are present.
Some key points to consider when evaluating low AST levels include:
- The AST:ALT ratio is generally used to differentiate between alcohol-induced and non-alcoholic fatty liver disease, with a ratio >2 suggesting alcohol-induced liver disease and a ratio <1 suggesting metabolic disease-related fatty liver 1.
- Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in first world countries, with a prevalence of 20% to 30% in the general population, and is often associated with insulin resistance and metabolic syndrome 1.
- Low AST levels are not typically a cause for concern in the absence of other symptoms or abnormal test results, and physicians typically focus on high rather than low enzyme levels during routine bloodwork interpretation.
If you're concerned about a low AST result, it's best to discuss it with your healthcare provider who can interpret it within the context of your overall health picture. They can help determine if further testing or evaluation is needed to rule out any underlying conditions that may be contributing to the low AST level.
From the Research
Low AST Levels Meaning
- Low AST levels can be an indicator of good liver health, as AST is an enzyme found in the liver and other parts of the body 2.
- However, it's essential to consider the reference values and analytical pitfalls of AST levels, as well as the differential diagnostic work-up of elevated serum transaminase levels 2.
- Some studies have shown that certain treatments, such as ursodeoxycholic acid, can lower AST levels in patients with chronic liver disease 3, 4, 5, 6.
- In one study, the combination of ursodeoxycholic acid and vitamin E significantly improved liver function tests, including AST levels, in patients with nonalcoholic steatohepatitis 5.
- Another study found that ursodeoxycholic acid treatment normalized liver enzymes, including AST, within the first 3 months of treatment, and improved lipid profile and hepatic steatosis independent of weight loss 6.
- It's crucial to note that low AST levels can also be seen in healthy individuals, and the interpretation of AST levels should be done in conjunction with other liver function tests and clinical evaluations.