Tuna Fish and Fatty Liver: Benefits and Safety

Tuna fish is good for fatty liver disease as part of a balanced diet, thanks to its omega-3 fatty acids, lean protein and low saturated fat content. Fatty liver disease, or hepatic steatosis, affects a significant number of UK adults, most commonly as metabolic dysfunction-associated steatotic liver disease (MASLD). Omega-3s found in oily fish such as fresh tuna may help reduce liver fat and inflammation. However, not all tuna is equal: the FSA classifies fresh and frozen tuna as oily fish, while tinned tuna does not count. This article covers what the evidence says, how much to eat and what else supports liver health.

Is tuna fish actually good for a fatty liver?

Yes, tuna is beneficial for fatty liver disease due to its omega-3 fatty acids and lean protein, though fresh tuna contains significantly more omega-3 than tinned tuna, which the FSA does not classify as oily fish.

Tuna fish is a beneficial food choice for people with fatty liver disease, primarily because it is a rich source of omega-3 fatty acids and high-quality protein while being low in saturated fat. Fatty liver disease, known medically as hepatic steatosis, occurs when excess fat accumulates in liver cells. The most common form in the UK is metabolic dysfunction-associated steatotic liver disease (MASLD), previously called non-alcoholic fatty liver disease (NAFLD), which is closely linked to obesity, type 2 diabetes and poor dietary habits.

Omega-3 polyunsaturated fatty acids, found in oily fish such as fresh tuna, may help reduce liver fat, lower inflammation and improve insulin sensitivity, all of which are relevant to managing fatty liver disease. These effects are supported by systematic reviews and meta-analyses of clinical trials, though effect sizes vary between studies and tuna alone is not a cure. Incorporating it regularly into a balanced diet forms part of a broader dietary strategy that supports liver health.

It is important to understand how tuna is classified in UK guidance. The Food Standards Agency (FSA) classifies fresh and frozen tuna as an oily fish, while tinned tuna is not counted as an oily fish because the canning process significantly reduces its omega-3 content. This distinction matters when planning fish intake. Tinned tuna in spring water is generally preferable to tuna in oil, which adds extra calories and fat. If choosing tinned tuna in brine, be aware that brine can be high in salt, which is particularly relevant for people with high blood pressure or cardiovascular risk; rinsing the tuna or checking the label for sodium content can help. Tinned tuna in spring water remains a practical and affordable option widely available in the UK.

If you have been diagnosed with fatty liver disease and are unsure how to adjust your diet, speaking with your GP or a registered dietitian is the most appropriate first step.

What nutrients in tuna support liver health?

Tuna provides omega-3 fatty acids (EPA and DHA), lean protein, selenium, vitamin D, B vitamins and choline, all of which have mechanistic or observational links to reduced liver fat and inflammation.

Tuna contains several key nutrients that may support liver function and could help reduce the progression of fatty liver disease. The most clinically studied of these are omega-3 fatty acids, specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Systematic reviews and meta-analyses of randomised controlled trials have found that omega-3 supplementation is associated with reductions in hepatic fat content and improvements in liver enzyme levels (ALT and AST) in people with MASLD, though results vary between trials and the optimal dose has not been firmly established.

Beyond omega-3s, tuna provides:

• High-quality lean protein, which supports muscle maintenance and helps regulate appetite, both important factors in achieving the weight loss that underpins fatty liver management.

• Selenium, an antioxidant mineral that helps protect liver cells from oxidative stress, a key driver of liver inflammation and fibrosis.

• Vitamin D, in which many UK adults are deficient. Observational studies have associated lower vitamin D levels with greater severity of liver inflammation in people with MASLD, though evidence from randomised controlled trials is inconsistent and a direct causal benefit from tuna intake has not been established.

• B vitamins, including B12 and niacin, which play important roles in energy metabolism and the processing of fats within the liver.

• Choline, a nutrient that plays a mechanistic role in fat transport out of the liver. While dietary choline deficiency has been linked to hepatic fat accumulation in experimental studies, the clinical benefit of the choline content in tuna specifically for people with MASLD has not been established in intervention trials. Other foods such as eggs are richer sources of choline.

Tuna is also low in carbohydrates and refined sugars, which is particularly relevant because excess dietary sugar, especially fructose, is a major contributor to liver fat accumulation. By replacing higher-calorie, processed foods with tuna, individuals can reduce overall caloric intake while simultaneously delivering nutrients that may support liver health. Nutrient claims in this section reflect current mechanistic and observational understanding; where robust intervention evidence is limited, wording is kept appropriately conditional.

How much tuna should you eat each week if you have fatty liver?

Most adults with fatty liver disease can safely eat two to three fish portions per week, combining fresh tuna with other oily fish; pregnant women must follow FSA limits on tuna due to mercury content.

The NHS Eatwell Guide recommends that adults eat at least two portions of fish per week, one of which should be oily, as part of a healthy balanced diet. A portion is approximately 140 grams (cooked weight). For people with fatty liver disease, meeting this recommendation is especially worthwhile given the liver-protective properties of omega-3 fatty acids found in oily fish.

However, there are important FSA safety considerations around tuna consumption that must be observed.

Fresh and frozen tuna (classified as oily fish by the FSA):

Fresh and frozen tuna count towards your oily fish intake. The FSA advises limits on oily fish consumption primarily because oily fish can contain low levels of dioxins and polychlorinated biphenyls (PCBs), which may accumulate in the body over time. Separate limits apply to tuna specifically because of its mercury content. Current FSA guidance on oily fish portions per week is:

• Men, boys, and women past childbearing age: up to four portions of oily fish per week.

• Girls and women who are pregnant, trying to conceive, breastfeeding, or who may become pregnant in the future: up to two portions of oily fish per week.

For tuna steaks specifically, the FSA advises pregnant women and those trying to conceive to limit consumption; check the current FSA website for the most up-to-date tuna steak limits, as these are reviewed periodically.

The FSA also advises that everyone, including children and pregnant women, should avoid shark, swordfish and marlin entirely, as these fish contain particularly high levels of mercury.

Tinned tuna:

Tinned tuna is not classified as an oily fish by the FSA, so it does not count towards your oily fish portions. General adult consumption of tinned tuna is not formally restricted by the FSA. The FSA advises pregnant women to limit tinned tuna to no more than four medium-sized tins per week (approximately 140 grams drained weight each), due to mercury content.^[1] Check the FSA website for the most current advice, as guidance is updated periodically.

For most adults with fatty liver disease, aiming for two to three portions of fish per week, combining fresh tuna alongside other oily fish such as salmon, mackerel or sardines, and supplementing with tinned tuna in spring water, is a practical and safe approach. If you have kidney disease or other conditions that affect how your body processes protein or certain minerals, consult your GP before significantly increasing fish intake. If choosing tinned tuna in brine, consider rinsing it or opting for a low-salt variety, particularly if you have high blood pressure.

Which other foods help or harm a fatty liver?

A Mediterranean-style diet rich in vegetables, wholegrains, olive oil and oily fish supports liver health, while alcohol, sugary drinks, refined carbohydrates and ultra-processed foods accelerate liver damage.

Alongside tuna, a range of other foods can either support liver recovery or accelerate liver damage in people with fatty liver disease, and understanding this distinction is central to effective dietary management.

Foods that may support liver health include:

• Vegetables and legumes: particularly leafy greens, broccoli, Brussels sprouts and lentils, which are high in fibre and antioxidants. Observational studies and some intervention trials suggest these are associated with reduced liver inflammation, though most evidence is from dietary pattern research rather than individual foods.

• Wholegrains: such as oats, brown rice and wholemeal bread, which help regulate blood sugar and reduce insulin resistance.

• Olive oil: a source of monounsaturated fats and polyphenols. Clinical studies and systematic reviews, including those supporting the Mediterranean dietary pattern, have associated olive oil consumption with reduced liver fat, though most evidence is observational.

• Coffee: observational evidence, including meta-analyses, suggests that regular, moderate coffee consumption (without added sugar or cream) is associated with lower rates of liver fibrosis.^[3] The mechanism is not fully established and this is not a basis for starting coffee consumption if you do not already drink it.

• Nuts and seeds: particularly walnuts, which contain omega-3 fatty acids and antioxidants. Evidence is largely observational.

Foods that harm a fatty liver include:

• Alcohol: even moderate alcohol consumption can worsen liver inflammation and accelerate fibrosis in people with existing liver disease. NHS guidance recommends that people with MASLD avoid alcohol entirely or keep intake well within low-risk guidelines (no more than 14 units per week, spread across three or more days, with several alcohol-free days).^[4] Your clinician may advise complete abstinence depending on the severity of your liver disease.

• Sugary foods and drinks: including fizzy drinks, fruit juices, sweets and pastries, which drive fructose-related fat accumulation in the liver.

• Refined carbohydrates: white bread, white rice and processed cereals raise blood glucose rapidly and contribute to insulin resistance.

• Saturated and trans fats: found in processed meats, fast food and many packaged snacks, these promote hepatic inflammation.

• Ultra-processed foods: population-level observational studies have associated high consumption of ultra-processed foods with increased risk of MASLD progression.

A Mediterranean-style dietary pattern, which naturally incorporates many of the beneficial foods listed above, is supported by clinical evidence and aligns with NHS and EASL dietary recommendations for liver health.^[12][7]

What does the NHS recommend for managing fatty liver through diet?

NHS and NICE NG49 guidance recommends sustained lifestyle change, including a balanced diet, weight loss of 7 to 10 per cent, alcohol avoidance and at least 150 minutes of moderate aerobic activity per week.

The NHS recommends that the primary treatment for metabolic dysfunction-associated steatotic liver disease (MASLD) is sustained lifestyle modification, with diet and physical activity forming the cornerstone of management. At the time of writing, no medication is specifically licensed by the MHRA for the treatment of MASLD, making dietary and lifestyle change the most evidence-based intervention available to most patients; however, this is an active area of research and you should ask your GP or specialist about any developments.^[5][6]

NICE guidance (NG49) and NHS recommendations emphasise the following principles for people with fatty liver disease:

• Achieve and maintain a healthy weight: NICE NG49 and supporting clinical evidence indicate that losing 7 to 10 per cent of body weight can significantly reduce liver fat and inflammation. Even modest weight loss of 3 to 5 per cent can produce measurable improvements in liver health markers.

• Follow a balanced, calorie-appropriate diet: based on the NHS Eatwell Guide, prioritising vegetables, wholegrains, lean proteins (including fish such as tuna), and healthy fats while limiting processed and high-sugar foods.

• Reduce or eliminate alcohol: the NHS advises people with fatty liver disease to avoid alcohol, as it can worsen liver damage regardless of whether the original cause was alcohol-related.

• Limit added sugars and refined carbohydrates: particularly fructose-containing foods and drinks, which have a direct relationship with hepatic fat accumulation.

• Increase physical activity: the UK Chief Medical Officers' Physical Activity Guidelines recommend at least 150 minutes of moderate-intensity aerobic activity per week, plus muscle-strengthening activities on two or more days per week.^[8][9] Physical activity independently reduces liver fat even without significant weight loss.^[10][11]

NICE NG49 recommends that people with MASLD are offered structured lifestyle advice and, where appropriate, referral to a dietitian or specialist liver service. Non-invasive fibrosis assessment, including the FIB-4 score (a calculation based on age, liver enzyme levels and platelet count), is used in primary care to identify people who may need specialist referral. Your GP can arrange relevant blood tests, imaging and referrals based on your individual risk.

When to seek medical advice:

Contact your GP if you experience persistent fatigue, right-sided abdominal discomfort or unexplained weight loss, as these may indicate disease progression. Seek urgent medical attention (call 999 or go to your nearest emergency department) if you develop any of the following, as these may indicate serious liver disease requiring immediate assessment:

• Yellowing of the skin or whites of the eyes (jaundice)

• Dark urine or pale, grey or clay-coloured stools

• Vomiting blood or passing black, tarry stools

• Marked swelling of the abdomen

• Confusion, extreme drowsiness or difficulty staying awake

If you have been diagnosed with fatty liver disease, your GP is the most appropriate first point of contact for ongoing monitoring and referral.

Scientific References

1. Fish and shellfish.
2. The Eatwell Guide.
3. Effect of Coffee Consumption on Non-Alcoholic Fatty Liver Disease.
4. Non-alcoholic fatty liver disease (NAFLD).
5. Resmetirom (Rezdiffra) authorised to treat metabolic dysfunction-associated steatohepatitis (MASH) in adults.
6. GID-TA11477 Draft scope post-referral: no medicines approved for MASLD or MASH in the UK.
7. Metabolic dysfunction-associated steatotic liver disease (NG49).
8. UK Chief Medical Officers' physical activity guidelines.
9. Physical activity guidelines for adults aged 19 to 64.
10. Structured Exercise Interventions and Hepatic-Metabolic Outcomes in Adults with MASLD: A Narrative Review of Randomized Controlled Trials.
11. Moderate-Intensity Aerobic vs Resistance Exercise and Dietary Modification in Patients With Nonalcoholic Fatty Liver Disease: A Randomized Clinical Trial.
12. The impact of dietary interventions on liver health biomarkers in individuals with MASLD: a systematic literature review and meta-analysis of randomized controlled trials.

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