AST (Aspartate Aminotransferase)
| Clinical | Optimal | |
|---|---|---|
| Male | 0 - 50 U/L | Below 40 U/L (optimal below 25 U/L) |
| Female | 0 - 35 U/L | Below 32 U/L (optimal below 20 U/L) |
What is AST (Aspartate Aminotransferase)?
Aspartate aminotransferase (AST) is an enzyme involved in amino acid metabolism that is found in several tissues throughout your body, with the highest concentrations in the liver, heart, and skeletal muscles. When cells in any of these tissues are damaged, AST is released into the bloodstream.
Because AST is present in multiple organs, it is less liver-specific than ALT. However, when interpreted alongside ALT, it provides valuable diagnostic information. The ratio of AST to ALT (known as the De Ritis ratio) helps clinicians distinguish between different types of liver disease. For example, an AST/ALT ratio above 2 may suggest alcohol-related liver damage, while a ratio below 1 is more typical of non-alcoholic fatty liver disease.
AST is a standard component of liver function tests in the UK and forms part of a comprehensive assessment of both liver health and general tissue integrity. Omniwo includes AST alongside ALT and other liver markers to give you the fullest possible picture.
Why AST (Aspartate Aminotransferase) Matters for Your Health
While ALT is the primary screening marker for liver damage, AST adds important context that helps understand the nature and severity of any liver problems. The combination of AST and ALT levels, and their ratio, can point towards specific conditions and help guide further investigation.
AST is particularly useful for detecting alcohol-related liver damage, where it tends to rise proportionally higher than ALT. It is also valuable for identifying damage to heart muscle or skeletal muscle, which can occasionally mimic liver disease in blood test results.
For longevity, monitoring AST alongside your other liver markers ensures that different types of liver damage are not overlooked. The liver's health is fundamentally linked to metabolic function, detoxification, and hormonal balance, all of which are central to healthy ageing and disease prevention.
AST (Aspartate Aminotransferase)& Your Wearable Data
Aspartate aminotransferase (AST) is found in the liver, heart, and skeletal muscle. Because of its presence in muscle tissue, AST is more exercise-sensitive than ALT. Wearable data showing intense training sessions, particularly heavy resistance training or endurance events in the 48-72 hours before blood collection, may explain elevated AST readings that are not liver-related.
Your wearable's exercise intensity data helps distinguish between muscle-derived and liver-derived AST elevations. If AST rises after a period of heavy training while ALT remains normal, muscle damage is the likely source. Tracking your training load and comparing it with AST trends over multiple blood tests helps identify the pattern.
For genuine liver health, the same wearable-tracked factors that apply to ALT are relevant: regular moderate exercise, adequate sleep duration and quality, and stress management all support healthy AST levels. Consistent daily movement tracked by your step counter, combined with good sleep scores, correlates with optimal liver enzyme concentrations.
What High AST (Aspartate Aminotransferase) May Suggest
Elevated AST can indicate damage to the liver, heart, or skeletal muscles. In the context of liver disease, high AST is commonly caused by alcohol-related liver damage, non-alcoholic fatty liver disease, viral hepatitis, medication-induced liver injury, and autoimmune hepatitis.
When AST is elevated disproportionately to ALT (AST/ALT ratio greater than 1), this may suggest more advanced liver disease, alcohol-related liver damage, or cirrhosis. Conversely, when both are elevated but ALT is higher, this more often points to early fatty liver disease.
Non-hepatic causes of elevated AST include intense exercise (particularly eccentric exercise such as running downhill or heavy weightlifting), heart muscle damage (myocardial infarction), muscle injury or breakdown (rhabdomyolysis), and thyroid disorders. This is why interpreting AST always requires consideration of the clinical context and other test results.
What Low AST (Aspartate Aminotransferase) May Suggest
Low AST is generally a normal finding and indicates healthy liver and muscle cells. There are no widely recognised clinical concerns associated with low AST in healthy individuals.
As with ALT, very low AST in elderly individuals has been loosely associated with frailty and reduced muscle mass in some studies, but this is not a standard clinical concern for most people.
A low AST result, particularly when combined with normal ALT, is a reassuring indicator of good liver and tissue health.
How to Optimise Your AST (Aspartate Aminotransferase)
Food
Follow the same liver-supportive dietary approach as for ALT: reduce sugar, increase vegetables, and prioritise antioxidant-rich foods, If alcohol-related damage is suspected, eliminate alcohol entirely, as this is the single most impactful dietary change for AST reduction, Include beetroot and beetroot juice, which contain betalains that support liver detoxification and may help reduce inflammation, Eat foods rich in vitamin E such as almonds, sunflower seeds, and avocado, which help protect liver cells from oxidative damage
Lifestyle
Reduce or eliminate alcohol intake, as alcohol-related damage is one of the most common causes of disproportionately elevated AST, Moderate exercise intensity if recent vigorous training may be contributing to elevated levels, allowing at least 48-72 hours of recovery before retesting, Address underlying metabolic issues through weight management and regular physical activity, Ensure adequate hydration, which supports liver function and the clearance of metabolic waste products
Supplements
Milk thistle (silymarin, 200-400mg daily) supports liver cell protection and regeneration, N-acetyl cysteine (NAC, 600-1200mg daily) boosts liver glutathione levels and aids in detoxification, Vitamin E (as mixed tocopherols, 400 IU daily) has evidence for reducing AST in non-alcoholic fatty liver disease, though it should be used under guidance
When to Speak to Your GP
See your GP if your AST results suggest levels more than twice the upper limit of normal, particularly if ALT is also elevated. Seek urgent medical advice if AST exceeds five times the upper limit, as this may indicate significant tissue damage. Pay particular attention if your AST/ALT ratio is above 2, as this may suggest alcohol-related or advanced liver disease. Also consult your GP if elevated AST is accompanied by chest pain, muscle pain, dark urine, or jaundice.
References
- NHS. Liver disease — Overview. Updated 2024. nhs.uk
- NICE. Non-alcoholic fatty liver disease (NAFLD): assessment and management. NG49. nice.org.uk
- BMJ. Kwo PY, et al. ACG Clinical Guideline: evaluation of abnormal liver chemistries. Am J Gastroenterol. 2017;112(1):18-35. pubmed.ncbi.nlm.nih.gov
- Lancet. Newsome PN, et al. Guidelines on the management of abnormal liver blood tests. Gut. 2018;67(1):6-19. pubmed.ncbi.nlm.nih.gov
Medical Disclaimer— This content is for general educational and informational purposes only. It does not constitute medical advice, diagnosis, or treatment. Omniwo Ltd is a wellness information service and is not a medical device, clinical laboratory, or regulated healthcare provider under MHRA guidelines. The “optimal ranges” presented on this page are based on published clinical guidelines (WHO, NICE, NHS) and peer-reviewed research; they represent functional wellness targets and may differ from standard laboratory reference ranges. Individual results should always be interpreted by a qualified healthcare professional (such as your GP) who understands your full medical history. Do not start, stop, or change any medication or supplement based solely on this information. If you are experiencing symptoms, seek medical attention promptly.