Why It Matters
Also known as the de Ritis ratio, the AST-to-ALT ratio was originally used as a marker for liver health. Today, its utility as an indicator of health has expanded to many other areas, including cardiovascular health and critical illness (source, source).
Low AST/ALT Ratio: Reduced Liver Reserve and Enzyme Imbalance
A low AST/ALT ratio can be influenced by physiological factors involving liver function, as AST and ALT are enzymes primarily found in the liver. Nutritional factors, such as deficiencies in certain vitamins and minerals that support liver health, can also contribute to imbalanced enzyme levels (source, source, source, source).
Potential Performance Impact
- Imbalanced liver enzyme activity, compromising amino acid metabolism and energy production
- Reduced detoxification capacity, affecting recovery timelines between training sessions
Optimization
Avoid coffee. Coffee consumption has been associated with lower AST levels (source). AST levels are reduced with coffee consumption due to its polyphenol content, which exerts antioxidant properties that mediate liver enzymes (source).
Protocol: Monitor and limit coffee intake.
Limit sugar intake. Sugar intake has been shown to increase ALT concentrations (source). Consuming excess sugar, particularly fructose, has been associated with increased liver fat accumulation, decreasing liver efficiency and negatively affecting function (source). Decreasing sugar intake can help relieve liver stress and decrease ALT concentrations.
Protocol: Monitor and limit excess added sugar intake.
Maintain an athletic body composition. As body fat increases, so do ALT levels (source, source). Body fat is associated with increased cholesterol levels, which is also associated with increased ALT levels (source, source). Cholesterol is metabolized in the liver (source). Reducing body fat can positively affect cholesterol levels and decrease stress on the liver, leading to improved ALT concentrations (source).
Protocol: Maintain a high-performance diet and exercise program that supports a body composition of no more than 15% body fat for men and 20% for women.
High AST/ALT Ratio: Liver Stress and Metabolic Burden
A high AST/ALT ratio can be influenced by physiological factors affecting liver health and function. Nutritionally, excessive alcohol consumption and diets high in processed foods and saturated fats can contribute to liver damage and elevate these enzyme levels (source, source, source, source).
Potential Performance Impact
- Elevated liver enzyme release indicating tissue damage and impaired metabolic processing
- Increased systemic inflammation from alcohol and dietary stress prolonging recovery
Optimization
Drink black coffee. Coffee consumption has been associated with lower AST levels (source). Black coffee is high in polyphenols which exert antioxidant properties that mediate liver enzymes, including AST (source).
Protocol: Drink coffee as desired.
Active recovery. Intense exercise has been shown to negatively affect AST levels (source). An intense exercise bout can induce microscopic tears in the muscle fibers, releasing AST into the bloodstream (source). Recovery days allow these levels to return to a normal state.
Protocol: Prioritize techniques to enhance recovery capacity, such as low-intensity movement and mobility, at least twice a week.
Supplement with milk thistle. Supplementation with milk thistle has been shown to benefit AST concentrations (source). Milk thistle's flavonoid content, particularly Silymarin, exhibits antioxidant and anti-inflammatory properties that help lower liver enzymes, including AST (source).
Protocol: Supplement with at least 420 mg of milk thistle daily.
