Diet and Nutrition for Liver Health

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The liver is one of the hardest-working organs in the body, performing more than 500 functions vital for life and health, including carrying away waste and breaking down fats in the small intestine (thanks to bile), producing proteins and cholesterol, converting excess glucose into glycogen for storage, regulating blood levels of amino acids, storing iron, clearing the blood of drugs and bacteria, and regulating blood clotting. If any of these functions go awry, the illness that sometimes can lead to death occurs.

"Anyone with obesity, prediabetes, type 2 diabetes, or metabolic syndrome is at increased risk of NAFLD"

Diet and lifestyle factors

Weight

The majority of people with NAFLD are either overweight or obese. Individuals with morbid obesity typically have greatly enlarged livers as a result of fat accumulation. Gradual weight loss can reverse the condition.

Several studies have found that a reduction in daily calorie intake by 500 kcal results in a significant decrease of fat in the liver. Weight loss is advisable for overweight (ie, BMI 25 to 30) and obese individuals (BMI >30) but shouldn't exceed 1 kg (2.2 lbs) per week. Very low-calorie diets should be avoided, as they can worsen the condition and increase inflammation in the liver.

Fat Intake

While there are no human studies linking diets high in saturated fat with NAFLD, animal studies have suggested that diets high in saturated fat worsen NAFLD, as well as insulin resistance and CVD. On the other hand, polyunsaturated fats, specifically omega-3 fatty acids and monounsaturated fatty acids, may play a protective role in NAFLD.

Sugar Intake

Simple carbohydrates in the diet, in particular, fructose, have been linked to NAFLD. People with NAFLD consume a larger quantity of soft drinks than those without the disease. Soft drinks are high in fructose (high-fructose corn syrup), and fructose stimulates fatty acid and triglyceride synthesis in the liver.

One study found that individual metabolic reactions to fructose vary, and those reactions can determine whether fatty liver will develop. Some researchers have suggested that short-term carbohydrate restriction may be more effective at reducing triglycerides in the liver than calorie restriction. However, not all studies have found fructose to be associated with increased risk.

Protein Intake

Limited evidence exists on the effect of proteins on NAFLD. In animals, researchers have observed a reduction in liver fat content when protein intake was increased. Findings from The Rotterdam Study in the Netherlands showed that a diet high in animal protein, but not total protein, was associated with a higher risk of NAFLD.

Physical Activity

Physical activity has been shown to reduce the risk of diabetes by 35% and CVD by 49% in people with NAFLD. One study found that reducing weight by 5% and exercising regularly was associated with a significant improvement in NAFLD.

Recommendations 

Lifestyle changes, including dietary changes, plays a critical role in the prevention and treatment of NAFLD. While no dietary recommendations exist that are tailored specifically to NAFLD, the research to date suggests that following dietary and lifestyle guidelines for maintaining a healthy weight and reducing the risk of type 2 diabetes, metabolic syndrome, and CVD apply to reduce the risk of and treating NAFLD and its complications.