Researchers reviewed existing data on dietary patterns, foods, and nutrients to ameliorate nonalcoholic fatty liver disease (NAFLD).
While often overlooked, NAFLD (non-alcoholic fatty liver disease) represents a significant global health concern, currently lacking effective pharmaceutical treatments and specific dietary guidelines to address its serious consequences.
Left unchecked, NAFLD can progress to NASH (non-alcoholic steatohepatitis), increasing the risk of cirrhosis and hepatocellular carcinoma. This translates not only to individual suffering but also to increased healthcare costs and diminished quality of life.
Fortunately, lifestyle interventions offer promising avenues for managing NAFLD. Dietary adjustments, combined with physical activity and overall lifestyle modifications, can significantly improve liver health. It’s important to note that NAFLD is often linked to other health conditions like metabolic syndrome, obesity, cardiovascular disease, hypertension, diabetes, and chronic kidney disease. Addressing these underlying conditions can also contribute to improved liver function.
Insights from Dietary Strategies
This review delves into various dietary approaches for managing Non-Alcoholic Fatty Liver Disease (NAFLD). Researchers combed databases like MEDLINE, Web of Science, Google Scholar, and Scopus (January-July 2023) for relevant studies in English or Spanish.
The Mediterranean Edge
- Plant Power
The Mediterranean Diet (MedDiet) emphasizes plant-based foods rich in monounsaturated fatty acids (MUFAs) while limiting red meat. This stands in stark contrast to the high-fat Western diet, linked to increased NAFLD risk. - Carbohydrate Control
MedDiet distinguishes itself by its low intake of refined carbohydrates and sugar, favoring olive oil as the primary source of added fats. This approach has been shown to reduce NAFLD risk, weight gain, insulin resistance, and NAFLD development.
Why MedDiet Matters
- A Healthier Alternative
MedDiet’s low-carb, plant-based focus offers a viable alternative to Western diets linked to NAFLD development. - Combating Saturated Fats
Saturated fats, prevalent in Western diets, disrupt phospholipid metabolism, leading to mitochondrial dysfunction, increased reactive oxygen species (ROS) production, and cell death. High animal protein intake has also been linked to NAFLD in obese individuals.
Fructose: A Culprit to Watch
- De Novo Lipogenesis
Diet directly impacts de novo lipogenesis, where liver cells convert excess carbohydrates, particularly fructose, into fatty acids. Regular fructose consumption raises fibrosis risk, especially due to industrial fructose use. - Sweet Danger
Diets high in fructose (sucrose, high-fructose corn syrup) are associated with an increased risk of steatosis and non-alcoholic steatohepatitis (NASH), particularly in overweight and obese individuals.
DNA and Telomeres: The Nutritional Connection
- Diet can influence DNA stability and repair through essential nutrients like folate, calcium, and vitamins. Conversely, trans fats may damage DNA.
- Shortened telomeres, linked to aging and disease, are found in NAFLD. Fiber, omega-3s, and vegetables might counteract this, while high-glycemic carbs, processed meats, and saturated fats likely worsen it.
PNPLA3 Gene and Dietary Influence
- This gene plays a key role in liver fat accumulation and NAFLD development. Diets high in carbohydrates and fats can trigger specific protein production from this gene.
- Diet has the potential to modify how the liver uses lipids, manage insulin resistance, impact oxidative stress, and influence mitochondrial function through epigenetic changes.
Nutrient Deficiencies and DNA Methylation
- Deficiencies in betaine, choline, folate, and vitamin B12 may promote DNA methylation, potentially increasing hepatic triglycerides.
- Including nuts, seeds, seafood, and high-fiber diets could significantly reduce NAFLD risk. Nuts, for example, have shown positive effects on lipid profiles, liver health, and inflammation.
Nutrient Deficiencies & Fatty Liver Risk
- Boosting Defense
Deficiencies in betaine, choline, and vitamin B12 can promote DNA methylation, increasing liver fat production. Nuts, seeds, seafood, and high-fiber diets can significantly reduce NAFLD risk. - Omega-3 Power
Fish rich in these fatty acids can help reduce liver fat accumulation and prevent NAFLD progression.
Gut Microbiome & Dietary Influence
- Gut-Liver Connection
High-fiber diets and whole grains can influence gut bacteria, potentially affecting NAFLD development. Legume-rich diets are linked to a decreased NAFLD risk. - Plants for Protection
Though the exact mechanism is unclear, vegetables and fruits likely offer protection due to their lower energy density and antioxidant properties from polyphenols and carotenoids.
Dairy & Probiotics for Liver Health
- Whey Protein Advantage
Dairy products, particularly yogurt with specific probiotic strains, are linked to reduced NAFLD risk due to whey protein’s role in weight management and fat reduction. - Probiotic Powerhouse
Probiotics like Bifidobacterium and Lactobacillus can decrease liver damage and reduce hepatic fat.
Prebiotics & Choline’s Role
- Unsweetened Coffee’s Gut Impact
Prebiotics like coffee can influence gut bacteria linked to NAFLD. - Choline: Friend of the Liver
This essential B vitamin plays a crucial role in liver function.
Micronutrients for Overall Health
- Micronutrient Power
Zinc, copper, vitamins A, C, D, and E, along with carotenoids, offer antioxidant, anti-fibrotic, and immune-modulating benefits, potentially mitigating NAFLD.
Abstract
Background: Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease without pharmacological treatment yet. There is also a lack of specific dietary recommendations and strategies to treat the negative health impacts derived from NAFLD. Objective: This scoping review aimed to compile dietary patterns, foods, and nutrients to ameliorate NAFLD. Methods: A literature search was performed through MEDLINE, Scopus, Web of Science, and Google Scholar. Results: Several guidelines are available through the literature. Hypocaloric Mediterranean diet is the most accepted dietary pattern to tackle NAFLD. Coffee consumption (sugar free) may have a protective effect for NAFLD. Microbiota also plays a role in NAFLD; hence, fibre intake should be guaranteed. Conclusions: A high-quality diet could improve liver steatosis. Weight loss through hypocaloric diet together with physical activity and limited sugar intake are good strategies for managing NAFLD. Specific dietary recommendations and a Mediterranean plate have been proposed to ameliorate NAFLD.