Understanding & Supporting Our Liver Health

As a clinical nutritionist, I often emphasise the liver’s critical role in maintaining overall health. The liver is a powerhouse organ responsible for detoxification, metabolism, and nutrient storage. Liver enzyme tests are an essential diagnostic tool that provides insights into liver function and systemic health. At FROM WITHIN, we explore commonly tested liver enzymes, including the significance of the AST/ALT De Ritis ratio, what their levels indicate, the impact of common medications on liver health, and evidence-based dietary, lifestyle, and nutraceutical strategies to support optimal liver function.

Liver Enzymes: What Are They and Why Are They Tested?

Liver function tests (LFTs) measure specific enzymes and proteins in the blood to assess liver health. These tests are routinely ordered to screen for liver damage, monitor chronic conditions, or evaluate the effects of medications. The most commonly tested liver enzymes include:

Alanine Aminotransferase (ALT)
ALT is primarily found in the liver and is a sensitive marker of liver cell damage. Elevated ALT levels often indicate hepatocellular injury, including hepatitis or non-alcoholic fatty liver disease (NAFLD). Normal ranges vary by lab, but elevated levels may suggest inflammation, liver injury or damage (Kwo et al., 2017).

Aspartate Aminotransferase (AST)
AST is present in the liver, heart, and muscles. While less specific to the liver than ALT, an elevated AST-to-ALT ratio can indicate specific conditions, such as alcoholic liver disease when the ratio exceeds 2:1. Elevated AST may also reflect muscle damage or other organ dysfunction (Kwo et al., 2017).

Alkaline Phosphatase (ALP)
ALP is found in the liver, bones, and bile ducts. Elevated levels may indicate bile duct obstruction, cholestasis, or bone disorders. In liver disease, ALP elevation often accompanies other markers such as gamma-glutamyl transferase (GGT) to confirm biliary issues (Newsome et al., 2018).

Gamma-Gutamyl Transferase (GGT)
GGT is highly sensitive to liver and bile duct issues. Elevated GGT levels are associated with alcohol consumption, cholestasis, and drug-induced liver injury. It is also a marker of oxidative stress and metabolic syndrome (Koenig & Seneff, 2015).

Bilirubin
Bilirubin, a byproduct of red blood cell breakdown, is processed by the liver. Elevated levels (hyperbilirubinemia) can indicate liver dysfunction, bile duct obstruction, or haemolysis. Total bilirubin includes both direct (conjugated) and indirect (unconjugated) forms, providing further diagnostic clues (Newsome et al., 2018).

Lactate Dehydrogenase (LD or LDH)
LD is less specific to the liver but can be elevated in liver injury, haemolysis, or malignancy. It’s often used in conjunction with other markers for a comprehensive assessment (Kwo et al., 2017).

The AST/ALT De Ritis Ratio: A Key Marker of Liver Health

The AST/ALT ratio, also known as the De Ritis ratio, is a valuable diagnostic tool that compares the levels of AST to ALT in the blood. A normal ratio is typically around 0.8–1.0, but deviations can provide critical insights into liver health. A ratio greater than 2:1 is strongly associated with alcoholic liver disease, as alcohol-induced damage tends to elevate AST more than ALT due to mitochondrial injury in hepatocytes. Conversely, a ratio less than 1 is often seen in NAFLD or viral hepatitis, where ALT predominates due to hepatocellular inflammation. In advanced liver disease, such as cirrhosis, a high AST/ALT ratio may indicate worsening fibrosis or reduced liver synthetic capacity. The De Ritis ratio is a reliable marker because it helps differentiate between various liver pathologies and assess disease severity, particularly when combined with other clinical findings and imaging (Botros & Sikaris, 2016). Monitoring this ratio over time can also guide treatment decisions and evaluate disease progression or response to interventions.

Pharmaceutical Medications and Their Impact on Liver Enzymes

Certain pharmaceutical medications can cause drug-induced liver injury (DILI), which may elevate AST and ALT levels and alter the AST/ALT De Ritis ratio, providing insights into the type and severity of liver damage. Medications including statins, paracetamol, NSAIDs, antibiotics e.g., amoxicillin-clavulanate or erythromycin, arthritic drugs e.g., azathioprine or methotrexate, antifungal drugs, steroids, allopurinol for gout, antiviral drugs for HIV infection are known to cause hepatotoxicity in susceptible individuals. For example, paracetamol overdose can lead to acute hepatocellular injury, significantly elevating both AST and ALT, often with a De Ritis ratio close to 1 due to widespread liver cell damage. Statins and NSAIDs may cause idiosyncratic reactions, resulting in elevated AST and ALT with variable ratios depending on the extent of mitochondrial versus cytosolic damage. The De Ritis ratio in DILI can help distinguish between hepatocellular (ratio ~1) and cholestatic patterns (lower ratio) or indicate more severe damage when AST predominates due to mitochondrial toxicity. Regular monitoring of liver enzymes and the De Ritis ratio is crucial for patients on these medications to detect early signs of liver injury and guide clinical management (Björnsson, 2017).

What Do These Tests Reveal?

Abnormal liver enzyme levels, including an altered AST/ALT ratio, can indicate various conditions:

• Hepatocellular damage (elevated ALT/AST, low ratio): Seen in NAFLD, viral hepatitis, or DILI.

• Alcoholic liver disease (elevated AST, high ratio > 2:1): Suggests alcohol-related damage.

• Cholestasis (elevated ALP/GGT): Suggests bile duct obstruction or primary biliary cholangitis.

• Metabolic dysfunction: Elevated GGT is linked to insulin resistance and oxidative stress.

• Systemic issues: Abnormal bilirubin or LD may point to haemolysis or malignancy.

These tests provide a snapshot of liver health but must be interpreted in context with clinical history, imaging, and other biomarkers. For example, NAFLD, affecting up to 25% of the global population, often presents with mildly elevated ALT and GGT, and a low AST/ALT ratio, reflecting fat accumulation and inflammation in the liver (Younossi et al., 2018).

Supporting Liver Health Through Diet, Lifestyle, and Nutraceuticals

At FROM WITHIN, we advocate for evidence-based strategies to support liver health, focusing on diet, lifestyle, and targeted nutraceuticals. This holistic approach can mitigate liver stress, enhance detoxification, and reduce inflammation.

Dietary Strategies

Mediterranean Diet: is well-documented for reducing liver fat and improving enzyme levels in NAFLD. A 2019 meta-analysis found that this diet significantly lowered ALT and GGT levels (Asbaghi et al., 2019).

Cruciferous Vegetables: contain glucosinolates, which support phase II liver detoxification by inducing enzymes such as glutathione S-transferase. A 2016 study showed that cruciferous vegetable intake reduced oxidative stress markers in NAFLD patients (Hodges & Minich, 2016).

Limit Added Sugars and Refined Carbohydrates: High fructose intake, particularly from sugary beverages, promotes liver fat accumulation and elevates GGT. Reducing added sugars can lower liver enzyme levels and improve insulin sensitivity (Younossi et al., 2018).

Coffee and Green Tea: Coffee (2–3 cups/day) has been shown to reduce liver fibrosis and lower ALT levels in NAFLD and hepatitis C patients, likely due to its antioxidant properties (Heath et al., 2017). Green tea contain catechins, which can also support liver health by reducing oxidative stress (Mahmoud et al., 2019).

Lifestyle Interventions

Exercise: regular physical activity, including aerobic and resistance training, reduces liver fat and improves enzyme levels. A 2018 study found that 150 minutes/week of moderate exercise lowered ALT and AST in NAFLD patients (Oh et al., 2018).

Weight Management: if overweight, a 5–10% weight loss significantly improves liver enzyme levels and reduces steatosis in NAFLD. Gradual weight loss through diet and exercise is critical to avoid exacerbating liver stress (Romero-Gómez et al., 2017).

Alcohol Moderation: excessive alcohol consumption elevates GGT and AST, contributing to liver damage. Reducing intake to no more than one drink per day for women and two for men can support liver health (Koenig & Seneff, 2015).

Nutraceuticals for Liver Support

Milk Thistle (Silymarin): derived from milk thistle, has antioxidant and anti-inflammatory properties. A 2017 randomised controlled trial showed that a therapeutic dose of silymarin reduced ALT and AST in NAFLD patients (Navarro et al., 2017).

N-Acetylcysteine (NAC)
NAC replenishes glutathione, protecting against paracetamol-induced liver injury and oxidative stress. A therapeutic dose has been shown to lower GGT and improve liver function (Sadowska et al., 2019).

Omega-3 Fatty Acids
Omega-3 supplements can reduce liver fat and inflammation in NAFLD, with studies showing significant reductions in ALT and GGT (Parker et al., 2019).

Vitamin E
Vitamin E is effective in non-diabetic NAFLD patients, reducing ALT and liver fat by combating oxidative stress.

Liver enzyme tests, including the AST/ALT De Ritis ratio, are vital for assessing liver and overall health, providing insights into conditions such as NAFLD, cholestasis, or drug-induced liver injury. Certain pharmaceutical medications can stress the liver, necessitating regular monitoring. If you’re on pharmaceutical medications or feel you need a detox or simply want to learn more about how you can help support your liver function and health, make an appointment here today. As a clinical nutritionist, I encourage proactive steps to nurture this vital organ, ensuring long-term health and vitality.

References

Asbaghi, O., Choghakhori, R., & Ashtary-Larky, D. (2019). Effects of the Mediterranean diet on liver enzymes in patients with non-alcoholic fatty liver disease: A systematic review and meta-analysis. Journal of Clinical Medicine, 8(10), 1624. https://doi.org/10.3390/jcm8101624

Björnsson, E. S. (2017). Hepatotoxicity by drugs: The most common implicated agents. International Journal of Molecular Sciences, 18(2), 356. https://doi.org/10.3390/ijms18020356

Botros, M., & Sikaris, K. A. (2016). The De Ritis ratio: The test of time. Clinical Biochemist Reviews, 34(3), 117–130. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3866949/

Heath, R. D., Brahmbhatt, M., Tahan, A. C., & Coffey, C. J. (2017). Coffee: The magical bean for liver diseases. World Journal of Hepatology, 9(15), 689–696. https://doi.org/10.4254/wjh.v9.i15.689

Hodges, R. E., & Minich, D. M. (2016). Modulation of metabolic detoxification pathways using foods and food-derived components: A scientific review with clinical application. Journal of Nutrition and Metabolism, 2016, 8318376. https://doi.org/10.1155/2016/8318376

Koenig, G., & Seneff, S. (2015). Gamma-glutamyltransferase: A predictive biomarker of cellular antioxidant inadequacy and disease risk. Disease Markers, 2015, 818570. https://doi.org/10.1155/2015/818570

Kwo, P. Y., Cohen, S. M., & Lim, J. K. (2017). ACG clinical guideline: Evaluation of abnormal liver chemistries. American Journal of Gastroenterology, 112(1), 18–35. https://doi.org/10.1038/ajg.2016.517

Mahmoud, A. M., Hernández Bautista, R. J., Sandhu, M. A., & Hussein, O. E. (2019). Beneficial effects of green tea on liver health: A review. Molecules, 24(5), 943. https://doi.org/10.3390/molecules24050943

Navarro, V. J., Belle, S. H., D’Amato, M., Adfhal, N., Brunt, E. M., & Fried, M. W. (2017). Silymarin in non-cirrhotics with non-alcoholic steatohepatitis: A randomized, double-blind, placebo-controlled trial. PLOS ONE, 12(9), e0184307. https://doi.org/10.1371/journal.pone.0184307

Newsome, P. N., Cramb, R., Davison, S. M., Dillon, J. F., Foulerton, M., Godfrey, E. M., ... & Yeoman, A. (2018). Guidelines on the management of abnormal liver blood tests. Gut, 67(1), 6–19. https://doi.org/10.1136/gutjnl-2017-314924

Oh, S., Shida, T., Yamagishi, K., Tanaka, K., So, R., Tsujimoto, T., & Shoda, J. (2018). Moderate to vigorous physical activity volume is an important factor for managing nonalcoholic fatty liver disease: A retrospective study. Hepatology, 68(4), 1208–1218. https://doi.org/10.1002/hep.29844

Parker, H. M., Johnson, N. A., Burdon, C. A., Cohn, J. S., O’Connor, H. T., & George, J. (2019). Omega-3 supplementation and non-alcoholic fatty liver disease: A systematic review and meta-analysis. Journal of Hepatology, 70(4), 835–844. https://doi.org/10.1016/j.jhep.2018.12.006

Romero-Gómez, M., Zelber-Sagi, S., & Trenell, M. (2017). Treatment of NAFLD with diet, physical activity and exercise. Journal of Hepatology, 67(4), 829–846. https://doi.org/10.1016/j.jhep.2017.05.016

Sadowska, A. M., Manuel-y-Keenoy, B., & De Backer, W. A. (2019). Antioxidant and anti-inflammatory efficacy of NAC in the treatment of NAFLD. European Journal of Clinical Investigation, 49(5), e13092. https://doi.org/10.1111/eci.13092

Sanyal, A. J., Chalasani, N., Kowdley, K. V., McCullough, A., Diehl, A. M., Bass, N. M., ... & Tonascia, J. (2019). Pioglitazone, vitamin E, or placebo for nonalcoholic steatohepatitis. New England Journal of Medicine, 362(18), 1675–1685. https://doi.org/10.1056/NEJMoa0907929

Sookoian, S., & Pirola, C. J. (2019). Genetic predisposition in nonalcoholic fatty liver disease. Clinical and Molecular Hepatology, 25(1), 1–12. https://doi.org/10.3350/cmh.2018.0109

Yoon, E., Babar, A., Choudhary, M., Kutyna, M., & Chopra, S. (2016). Acetaminophen-induced hepatotoxicity: A comprehensive update. Journal of Clinical and Translational Hepatology, 4(2), 131–142. https://doi.org/10.14218/JCTH.2015.00052

Younossi, Z. M., Koenig, A. B., Abdelatif, D., Fazel, Y., Henry, L., & Wymer, M. (2018). Global epidemiology of nonalcoholic fatty liver disease—Meta-analytic assessment of prevalence, incidence, and outcomes. Hepatology, 67(1), 54–63. https://doi.org/10.1002/hep.29431