Tomatoes and Liver Health: The Surprising Benefits of Lycopene

Why Lycopene Was Not the Whole Story

Lycopene has long received credit for the health benefits of tomatoes because it acts as an antioxidant and creates the red pigment in ripe fruit. Yet, previous animal experiments showed that whole tomato powder outperformed purified lycopene. This performance gap suggested that other components inside the fruit contribute significantly to liver health.

Both lycopene and phytoene are present in significant quantities in tomatoes and tomato-based foods, though the human body absorbs phytoene more efficiently, as explained by Na Youn Lee, a Ph.D. candidate at the Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University and the study’s lead author.

Plants use phytoene as an early building block to synthesize lycopene and other colorful carotenoids. Unlike those pigmented compounds, phytoene remains entirely colorless.

How Phytoene Helps the Liver Burn Fat

To test the effects of the compound on metabolic dysfunction-associated steatotic liver disease—a condition affecting an estimated 100 million U.S. adults and up to 75 percent of Americans with obesity or diabetes—researchers fed mice a diet high in refined carbohydrates for six months. This diet modeled human eating patterns linked to fatty liver disease, including frequent consumption of sugary foods and beverages.

Half of the test animals received a daily dose of phytoene equivalent to a person consuming three to four medium raw tomatoes or roughly 100 grams of tomato paste. According to findings published in Molecular Nutrition & Food Research, mice given phytoene developed far less severe fatty liver disease than those eating the same unhealthy diet without the supplement.

Changes in gut bacteria did not drive the protective effect. Instead, phytoene activated specific proteins that regulate liver metabolism, shifting the organ toward burning excess fat for energy rather than storing it inside cells.

The Role of Enzymes and Biological Sex

The experiment revealed unexpected variables in how the body processes phytoene. Mice missing two specific enzymes that convert carotenoids into active metabolites accumulated much larger amounts of phytoene in their tissues, yet they failed to receive the same liver protection. That result indicates the body may need to break phytoene down into smaller metabolites before it delivers health benefits.

Biological sex and genetics may also influence outcomes. Female mice accumulated higher concentrations of phytoene in their livers than males, pointing to differences in absorption and metabolism between sexes.

Pending further scientific verification, Xiang-Dong Wang—a senior researcher at Tufts University’s Jean Mayer USDA Human Nutrition Research Center on Aging and the study’s senior author—suggested that promoting increased intake of fruits and vegetables rich in phytoene could eventually become a method for preventing metabolic liver disease or slowing its progression among high-risk individuals.

Frequently Asked Questions

What is metabolic dysfunction-associated steatotic liver disease?
It is a chronic condition characterized by fat accumulation inside liver cells, which can lead to inflammation, tissue damage, and cirrhosis if left unchecked.

How much phytoene did the mice receive in the study?
The mice received a dose comparable to a human eating three to four medium raw tomatoes or about 100 grams of tomato paste daily.

Does phytoene give tomatoes their color?
No. Phytoene is a colorless precursor that plants use to manufacture lycopene and other pigments.

Are tomatoes the only source of phytoene?
No. Phytoene is found in many common fruits and vegetables, including carrots, red peppers, pink grapefruit, watermelon, and apricots.