Fatty liver disease does not directly infect the stomach, but there is a strong association with gastritis driven by shared, underlying factors, primarily chronic, low-grade inflammation. This systemic inflammation, characteristic of metabolic liver disease, circulates throughout the body. It can irritate the lining of the stomach, contributing to the development or worsening of gastritis. Understanding this link requires viewing both conditions not as isolated issues, but as parts of a larger metabolic picture.
Understanding Fatty Liver Disease and Gastritis
Fatty liver disease, now often referred to as metabolic dysfunction-associated steatotic liver disease (MASLD), occurs when excess fat accumulates in the liver cells (steatosis). If this fat buildup leads to inflammation and cell damage, it progresses to a more severe form known as steatohepatitis. This progression is closely tied to metabolic factors like obesity, insulin resistance, and high blood pressure.
Gastritis is a condition where the lining of the stomach becomes inflamed, often causing discomfort, pain, or a burning sensation. Common causes include infection with Helicobacter pylori bacteria or the regular use of nonsteroidal anti-inflammatory drugs (NSAIDs). However, gastritis can also be triggered by non-infectious systemic issues. The common thread linking MASLD and gastritis is the presence of chronic inflammation.
The Mechanism Linking Liver Fat to Stomach Inflammation
The primary connection between liver fat and stomach inflammation is the systemic inflammatory state created by MASLD. When fat accumulates in the liver, the organ releases an excess of pro-inflammatory signaling molecules, known as cytokines, into the bloodstream. These cytokines, such as Tumor Necrosis Factor-alpha (TNF-\(\alpha\)) and Interleukin-6 (IL-6), travel throughout the body. The continuous circulation of these inflammatory mediators affects distant organs, including the gastrointestinal tract. This low-grade, body-wide inflammation can directly irritate the mucosal lining of the stomach, making it more susceptible to developing gastritis.
The Gut-Liver Axis
A deeper mechanism involves the bidirectional communication system known as the gut-liver axis. MASLD is frequently associated with an imbalance in the gut microbiome, a condition called dysbiosis. This microbial shift can impair the integrity of the intestinal wall, leading to increased intestinal permeability, often termed “leaky gut.”
This permeability allows bacterial products, such as lipopolysaccharides (LPS), to pass more easily from the gut into the bloodstream. These toxins travel via the portal vein directly to the liver, where they exacerbate existing inflammation. The heightened level of circulating bacterial products and inflammatory signals further promotes inflammation throughout the digestive tract, contributing to gastritis.
Altered Bile Acid Metabolism
Liver function impairment can also alter the composition and flow of bile acids, which are synthesized in the liver and crucial for digestion. Patients with MASLD often show changes in their bile acid profiles, including higher concentrations of certain conjugated bile acids in the blood. When bile acid composition or flow is disrupted, it can potentially contribute to gastroesophageal reflux.
Reflux of altered bile and digestive juices back into the stomach can chemically irritate the gastric lining. This irritation provides an additional local mechanism by which liver dysfunction can exacerbate or trigger symptoms of gastritis. The combined effect of systemic inflammation and chemical irritation due to altered metabolism creates a strong link between the two conditions.
Managing Both Conditions Through Lifestyle Changes
Since the underlying metabolic dysfunction drives both the fatty liver and the systemic inflammation linked to gastritis, the most effective management strategy involves comprehensive lifestyle changes. Dietary adjustments focus on reducing the intake of foods that promote liver fat accumulation and systemic inflammation. This includes minimizing processed sugars, especially fructose, and saturated fats found in highly processed foods.
Adopting a dietary pattern like the Mediterranean diet, which emphasizes whole grains, lean proteins, vegetables, and healthy fats, can significantly benefit both organs. These changes help reduce liver fat accumulation, which, in turn, lowers the release of inflammatory cytokines. A gradual weight loss of 5 to 10% of body weight can achieve a reduction in liver fat, which also reduces inflammation.
Physical activity is another integral component, with a goal of at least 150 minutes of moderate-intensity aerobic exercise per week, supplemented by strength training. Exercise helps improve insulin sensitivity and directly reduces liver fat, dampening the inflammatory response. Addressing the root cause of the metabolic dysfunction is the primary way to alleviate associated systemic symptoms, including gastritis.
For immediate relief, patients should also focus on avoiding known gastric irritants. This includes the complete avoidance of alcohol, which damages both the liver and the stomach lining, and limiting the use of NSAIDs. Avoiding highly acidic, spicy, or fatty foods can help the inflamed stomach lining heal while body-wide inflammation is addressed through diet and exercise.