Tomato Compound Phytoene Linked to Less Fatty Liver in Mice

What Happened

A study from Tufts University, published in Molecular Nutrition & Food Science, reported that mice given phytoene developed substantially less fatty liver disease than mice fed the same unhealthy diet without phytoene.

The work focuses on metabolic dysfunction-associated steatotic liver disease, a condition the article describes as affecting up to 38% of U.S. adults and involving excess fat buildup in liver cells that can progress to inflammation, damage, and cirrhosis in advanced cases.

What Phytoene Is and Why Researchers Studied It

Phytoene is a colorless precursor that plants convert into lycopene and other carotenoids, the pigments behind many red, yellow, and orange fruits and vegetables.

The researchers’ rationale was that tomato powder has outperformed purified lycopene in protecting the liver in animal studies, suggesting tomatoes contain additional compounds that may contribute to liver-protective effects.

• Phytoene and lycopene are both found in substantial amounts in tomatoes and tomato products, according to the study’s lead author quoted in the article.
• The same quote notes prior research suggesting phytoene is more readily absorbed by the body than lycopene.

What the Evidence Shows and Who It Applies To

This was an animal study in mice, not a human trial, so the findings directly apply to the tested mouse model and diet conditions rather than to people.

In the study design described, two groups of mice were fed a diet high in refined carbohydrates for six months to mimic dietary patterns associated with fatty liver disease in humans, including high consumption of sugary foods and beverages.

• Half of the mice received phytoene supplementation at a dose the researchers described as equivalent to a person eating about three to four medium-sized raw tomatoes or 100 grams (3.5 ounces) of tomato paste (a little more than a third of a cup) per day.
• The researchers compared liver health, metabolism, and gut bacteria between mice that received phytoene and those that did not.
• They also examined male vs female mice and compared normal mice with mice lacking two enzymes involved in converting carotenoids into biologically active metabolites.

How Phytoene May Be Working in the Liver

The article reports that phytoene did not appear to protect the liver by altering the gut microbiome in this model.

Instead, phytoene appeared to activate several key proteins involved in regulating liver metabolism, with the suggested effect of helping the liver burn excess fat for energy rather than allowing it to accumulate.

• Mice lacking the enzymes needed to metabolize phytoene accumulated much higher levels of phytoene but did not show the same protection against fatty liver disease.
• The authors interpret that pattern as suggesting the protective effects may come from smaller compounds produced when the body breaks down phytoene.

Practical Context and Key Caveats for Metabolic Health

Metabolic dysfunction-associated steatotic liver disease is described in the article as widespread in the United States, with estimates of as many as 100 million adults affected and up to 75% of Americans with obesity or diabetes estimated to have the condition.

The researchers note that genetic differences in the enzymes that metabolize phytoene could matter, and they call for more research to identify phytoene metabolites and determine whether some individuals may benefit more than others; they also observed that female mice accumulated more phytoene in the liver than male mice, suggesting sex may influence absorption or metabolism.

• The findings are from mice fed a high refined-carbohydrate diet and supplemented with phytoene, so they do not establish that phytoene supplements or tomato intake prevent or treat fatty liver disease in humans.
• The study’s mechanism signal depends on phytoene metabolism, which may vary between individuals if similar enzyme differences exist in people.