Substance that protects the liver has been found in tomatoes

In the study, mice were kept on a diet high in refined carbohydrates for six months — this diet mimics eating habits that increase the risk of fatty liver disease in humans (for example, an abundance of sweet foods and drinks). Half of the animals were additionally given phytoene in a dose equivalent to what a person could obtain by eating 3–4 medium fresh tomatoes or slightly more than a third of a glass of tomato paste per day. Then, they compared the condition of the liver, metabolism, and gut microbiota in both groups, and also separately examined the differences between males and females and between ordinary mice and those in which two enzymes required for the conversion of carotenoids into active metabolites were disabled.

Phytoene significantly reduced the severity of fatty liver disease. The effect appears to be related not to changes in the microbiome, but to the activation of key proteins that regulate metabolism in the liver; they help burn excess fat to produce energy, rather than storing it.

Experiments on mice lacking the necessary enzymes proved particularly revealing: much more phytoene accumulated in their bodies, but there was no protection against fatty liver disease. This suggests that it is not phytoene itself that provides the benefit, but its derivatives — small compounds formed during its breakdown. This means that due to genetic differences in the functioning of these enzymes, the effect of phytoene may vary from person to person, and this needs to be studied separately.

Female mice accumulated more phytoene in their livers than males, which means that sex can also influence how the body absorbs and processes this substance. In the future, this may become a separate topic for research.

Phytoene is found not only in yellow, orange, and red tomatoes, but also in many other common foods — carrots, red peppers, pink grapefruit, watermelon, and apricots. As the author of the study, Xiang‑Dong Wang, notes, if further research confirms these results, increasing the proportion of phytoene‑rich fruits and vegetables in the diet could become a useful strategy for preventing or slowing the progression of metabolic liver disease in people at risk.