How Metabolic Dysfunction Shows Up in the Liver, and How to Support It

What is Non-Alcoholic Fatty Liver Disease? (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) happens when too much fat builds up in the liver. It is now the most common liver condition worldwide, affecting around 37% of men and 26% of women. ¹ It is strongly linked with metabolic issues like obesity, high blood pressure, abnormal cholesterol and type 2 diabetes, which is why in 2020, the name was changed to Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) to better reflect how the condition develops. ²

Symptoms associated with fatty liver disease

MASLD is often asymptomatic, but some people may experience fatigue, a dull pain in the upper abdomen or yellowing of the skin. ⁴ A diagnosis can be made from blood tests, imaging or biopsy. Having MASLD increases the risk of non-alcoholic steatohepatitis (NASH), ⁵ which can involve cirrhosis, inflammation, liver failure, or even cancer.

MASLD and metabolic dysfunction

Insulin resistance is a major driver of MASLD. When cells stop responding properly to insulin, more glucose and fatty acids circulate in the bloodstream and are pushed into the liver. This leads to fat accumulation and “lipotoxicity”, ⁶ meaning the liver becomes stressed and damaged by excess fats.

As the liver becomes overwhelmed, it produces more inflammatory molecules and more oxidative stress. ⁷ These further affect insulin function, creating a cycle where inflammation and insulin resistance feed into one another. Over time, this increases the risk of obesity, type 2 diabetes, and cardiovascular disease. ⁷

Lifestyle factors can intensify this process. Ongoing stress, ⁸ poor sleep, ⁹ and even not drinking enough water ¹⁰ can worsen insulin resistance and make MASLD more likely.

The bidirectional relationship between the gut and the liver

The liver and gut are connected via the hepatic portal vein, which transports nutrients and toxins from the gastrointestinal tract directly to the liver for processing. Consequently, the liver is exposed to gut-derived metabolites.

A diverse microbiome helps to maintain the gut barrier, metabolise bile acids, ¹³ and ensure the intestinal lining remains intact. Bile and pancreatic secretions help shape the microbial environment, and the ratio of primary to secondary bile acids stay under tight control. ¹⁴ A poor diet, however, can disrupt this two-way relationship quite dramatically. A Western-style diet rich in saturated fat and added sugars (from fast food, processed snacks, fizzy drinks, energy drinks) increases gut permeability. High fructose intake from simple sugars like cakes, sweets and sugary drinks damages tight junction proteins, ¹⁵ literally making the gut barrier leaky. This is affected further by low fibre intake which leads to a reduction in short-chain fatty acid (SCFA) production, that would normally protect the gut lining.

When the gut barrier becomes weaker, bacterial toxins such as LPS (lipopolysaccharides) can pass into the bloodstream and travel to the liver. There, they trigger inflammation and worsen insulin resistance. ¹⁶ This process is a key reason why gut imbalance is so strongly linked with MASLD.

How an imbalance in your gut bacteria can affect the liver

A disrupted gut microbiome may also contribute to changes in the metabolism of intestinal bile acids, affecting the conversion of primary to secondary bile acids. ¹⁷ This further drives inflammation and disrupts signaling pathways involved in regulating glucose and lipid metabolism, increasing the risk of developing MASLD. ¹⁸ On top of this, certain gut bacteria also produce metabolites such as TMA (Trimethylamine) ¹⁹ made from nutrients like choline and carnitine found in foods such as eggs and red meat. The liver converts TMA into TMAO (Trimethylamine N-oxide), a compound associated with cardiovascular risk. ¹⁹ This demonstrates how gut changes can link MASLD with broader metabolic and cardiovascular issues.

As the liver becomes more damaged, its ability to produce and regulate bile acids decreases, which then worsens dysbiosis and gut permeability. This ongoing cycle can cause MASLD to progress from simple fat accumulation to NASH, cirrhosis, and even liver cancer. ²⁰

The genetic link associated with MASLD

There are certain genetic variants that can increase the risk of developing MASLD. One of the most well researched is patatin-like phospholipase domain-containing protein 3 (PNPLA3). ^21,22 PNPLA3 affects how the liver processes fats. ²² When this gene is less effective, the liver struggles to package and export fats efficiently, causing triglycerides to accumulate within liver cells.²² Over time, this can lead to higher liver enzymes and a greater risk of fatty liver disease. ²³

How to support a fatty liver through diet

• A mediterranean diet, focusing on wholefoods including vegetables, wholegrains, nuts, seed, fish, poultry and olive oil can be supportive for a fatty liver. ²⁴ This diet is naturally high in fibre which supports cardiometabolic markers, lowers triglycerides and inflammatory cytokines. ²⁵Soluble fibre in particular, which is found in oats, beans, apples and seeds, feed SCFA producing microbiota, which can help to decrease the activity of certain bacteria that produce secondary bile acids. ²⁶ Fermented foods from kefir, sauerkraut and kimchi as well as prebiotic foods found in onions, leeks, garlic, green bananas can also help to make SCFA’s, supporting the gut barrier function. ²⁷
• Monounsaturated fatty acids from extra virgin olive oil, nuts and seeds as well as omega 3 fatty acids from oily fish are anti-inflammatory, inhibiting NF-κB and NLRP3 activation, ²⁸ helping to support the systemic inflammation found in MASLD.
• Reducing refined carbohydrates and added sugars can support a fatty liver by improving insulin sensitivity. These include sugary drinks, sweets, pastries and ultra-processed snacks. High-glycemic loads and fructose accelerate a fatty liver and triglyceride accumulation²⁹ so prioritising complex carbohydrates (quinoa, legumes, vegetables and beans) is more favourable. We have a whole blog on Natural ways to support healthy blood sugar levels, have a read for more ideas.
• Bitter, choleretic foods (rocket, chicory, watercress, artichoke, radicchio, lemon, turmeric) can aid bile flow, supporting the gut-liver axis.

Supporting a fatty liver with lifestyle

• Time-restricted eating
  with a 12-hour overnight fast can support insulin sensitivity and help to increase hepatic lipid oxidation whilst decreasing de novo lipogenesis (new fat production). ³⁰
• Daily movement, even a 15-minute walk after a meal can support blood glucose regulation. ³¹ Resistance training 2-3 times a week is also excellent for supporting glucose management, helping with fat oxidation and improving GLUT4 translocation. ³² Obesity is a risk factor for MASLD, so maintaining a healthy weight through exercise and a whole food diet can support inflammation and metabolic dysfunction that obesity perpetuates.
• Having a consistent sleep pattern, where you go to bed and wake up at the same time helps to improve insulin sensitivity. Those with persistently good sleep quality are less likely to develop MASLD compared to those with consistently poor sleep. ³³
• Chronic stress can contribute to cortisol dysregulation, driving insulin resistance, activating inflammatory pathways which increase oxidative stress. ³⁴ Relaxation techniques such as meditation, mindfulness and movement can be an effective way of managing stress.

Key nutrients to support a fatty liver

• Glutamine has protective effects on tissue integrity, inflammation, and intestinal permeability in IBS patients. ³⁵
• N-Acetyl Glucosamine (NAG) encourages the growth of beneficial bacteria, mucosal tissue, binds to lectins and inhibits secretion of pro-inflammatory cytokines (interferon-γ, TNF-α, IL-17, and IL-22). ³⁶
• Digestive enzymes support food breakdown and are used in the management of pancreatic insufficiency in chronic pancreatitis, pancreatic cancer, cystic fibrosis or diabetes. ³⁷
• Artichoke, taurine and choline improve bile production and flow, ^38,39 supporting fat digestion, reducing cholesterol and triglycerides, and helping maintain a healthy microflora balance. ³⁹ Low choline diet is linked to liver damage, NAFLD, hepatic steatosis and hepatic cell death. ³⁸
• Curcumin attenuates liver fat deposition and improves the integrity of the intestinal barrier, helping alleviate hepatic steatosis. ⁴⁰
• Magnesium and chromium help to support glucose metabolism, improving insulin sensitivity. ^41,42 Chromium is also a cofactor for glucose tolerance factor (GTF), helping to increase the effectiveness of insulin.
• Vitamin D: Low levels of vitamin D are linked to a higher risk and severity of MASLD; optimising vitamin D levels may help reduce chronic inflammation associated with MASLD whilst also supporting insulin sensitivity.

Supporting MASLD requires dietary and lifestyle interventions that help target not just the liver, but the whole-body metabolic function including insulin sensitivity, weight management as well as the diversity and integrity of the gut microbiome.

References:

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