Tomatoes and MASLD (Metabolic dysfunction-associated steatotic liver disease): A surprising Connection
Metabolic dysfunction-associated steatotic liver disease (MASLD), previously called non-alcoholic fatty liver disease (NAFLD), is a growing problem across the globe. In particular, 1 in 3 adults have been found to have MASLD and it is the leading cause of chronic liver disease in the United States. There is currently no medical treatment for MASLD, treatment revolves around diet and lifestyle changes to facilitate weight loss and an overall reduction in ultra-processed foods. MASLD leads to an increased risk of cardiovascular disease, stroke, kidney disease, and cirrhosis of the liver due to the extra stress on the body and changes in body processing. Specifically the increased insulin resistance that occurs disrupts lipid metabolism (the way fats are burned and utilized in the body) which leads to dyslipidemia and inflammation that adds extra stress to the heart and blood vessels.
One of the leading diet modifications for treatment of MASLD and cardiovascular disease is the Mediterranean diet which focuses on healthy fats, lean proteins, and antioxidants which helps regulate blood sugars and reduce inflammation in the body.
A recent study conducted in Italy wanted to break down the Mediterranean diet further and explore the impact of a specific food on MASLD. They looked into a staple in the Mediterranean diet, tomatoes!
The study consisted of 79 participants that were diagnosed with MASLD with a BMI of 30 or less (overweight category). They were split into two groups for 6 weeks. One group followed a tomato-free diet and one group consumed 200 grams of raw tomatoes (about 1 large tomato) and 50 gram (3-4 tablespoons) of tomato sauce daily. After 6 weeks they found the tomato group had a significantly greater reduction in liver fat. This improvement was not associated with any changes in weight, BMI, waist circumference or body fat compositions. Meaning that the diet changes positively impacted liver fat without first having to see changes in weight or body composition.
This brings to question what about tomatoes can have such an impact on liver fat specifically?
Tomatoes are rich sources of lycopene, β-carotene, polyphenols, and other antioxidant and anti-inflammatory compounds. The two main components this study focused on were lycopene and β-carotene.
Lycopene: a carotenoid that provides tomatoes with their bright red color and is known for anti-inflammatory and anti-oxidant properties. This is a fat-soluble compound so is best combined with a source of dietary fat (like olive oil). Heating tomatoes helps increase the bioavailability of Lycopene as well.
β-carotene: a carotenoid that helps provide the pigment in red, orange, and yellow foods. It is often known for the role in converting to Vitamin A which is important in vision, immune function, and cell growth. It has also been studied as a key player in the reduction of accumulated lipids in the liver.
Micronutrients and Phytochemicals: these are often heat sensitive so when heating tomatoes these compounds are broken down and less effective. The study included raw tomatoes daily to help increase the intake of micronutrients and phytochemicals.
These compounds found in tomatoes are hypothesized to help with MASLD through four main processes: reduction in de novo fatty acid synthesis, increase in fatty acid oxidation, reduction in fatty acid uptake by the liver, and improvement in the inflammatory state.
Overall, this study helped to break down one of the main components in the Mediterranean diet to examine which components and compounds may be helping in liver health. The study shows the importance of tomatoes as sources of β-carotene, lycopene, phytochemicals, and micronutrients, however it is important to remember that no one component in the diet can prevent or reverse chronic disease. Sustaining a healthy and balanced diet is the key to prevention and positive outcomes.
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