A tomato contains a hidden ingredient that the eye cannot see, and it may be crucial for liver health. Researchers at Tufts University found phytoene sharply reduced fatty liver disease in mice.
The discovery could explain why whole tomato powder has protected liver more effectively than purified lycopene alone. Moreover, this colorless compound may hold key to preventing silent liver disease.
What Is The Growing Silent Liver Disease Affecting 38% Americans?
The study, published in Molecular Nutrition & Food Research, focused on metabolic dysfunction-associated steatotic liver disease. This chronic condition affects up to 38% of U.S. adults, researchers estimate. Metabolic dysfunction-associated steatotic liver disease begins when fat accumulates inside liver cells. It may cause few noticeable symptoms at first, but persistent buildup can provoke inflammation.
Eventually, inflammation damages liver tissue and leads to cirrhosis. As many as 100 million U.S. adults may have this disease currently.
Prevalence rises to 75% among Americans with obesity or diabetes. These conditions connect closely to metabolic problems that encourage fat to collect in liver.
Diet is only one part of disease, but foods influencing how liver stores or burns fat could help prevention. Therefore, tomatoes have attracted interest because animal studies repeatedly linked them to better liver health.
Why Lycopene Was Not The Whole Story Behind Tomato Benefits
Lycopene has received much attention because it gives ripe tomatoes their red color and acts as antioxidant. Yet tomato powder outperformed purified lycopene in previous animal experiments. This suggests fruit’s benefits may come from several compounds working together synergistically. Phytoene became compelling candidate because plants use it as early building block for lycopene.
Unlike colorful compounds, phytoene itself is completely colorless and invisible. “Both lycopene and phytoene are found in substantial amounts in tomatoes,” said Na Youn Lee, lead author and Ph.D. candidate at Tufts Friedman School.
“But we know from previous research that phytoene is actually more readily absorbed by body,” Lee added. Therefore, researchers decided to test its effects directly on fatty liver disease.
How Researchers Tested Phytoene Against Fatty Liver
Researchers fed mice a diet rich in refined carbohydrates for six months. This diet modeled eating patterns associated with fatty liver disease in people, including sugary foods and beverages. Half of mice also received phytoene at dose comparable to human consumption. The dose equaled three to four medium raw tomatoes or 100 grams of tomato paste daily.
This amount represents slightly more than one third of a cup of tomato paste. Moreover, it represents realistic dietary intake, not mega-dose supplementation. The team examined liver health, metabolism, and gut bacteria in both groups. They also compared males with females and typical mice with animals missing two carotenoid processing enzymes.
Key Finding: Phytoene Helped Liver Burn Fat, Not Just Store It
Mice given phytoene developed far less severe fatty liver disease despite eating same unhealthy diet. Changes in gut bacteria did not appear to explain protection. Instead, phytoene activated several proteins that control liver metabolism significantly. This activity shifted liver toward burning excess fat for energy rather than accumulating it inside cells.
Experiment also produced unexpected clue about how compound works. Mice lacking two carotenoid processing enzymes accumulated much larger amounts of phytoene. Yet they did not receive same liver protection despite higher accumulation. That result suggests phytoene may need breaking into smaller metabolites before becoming beneficial. Therefore, simply having more phytoene in liver does not guarantee protection. Instead, body’s ability to process it determines effectiveness.
Analysis: Genes and Sex Could Shape Who Benefits Most
People can carry genetic differences in enzymes that process phytoene naturally. Identifying protective metabolites could reveal why individuals respond differently to same amount in food.
Biological sex may matter as well for phytoene benefits. Female mice accumulated more phytoene in their livers than males, indicating possible differences in absorption.
Researchers do not yet know whether that variation changes compound’s protective power in females. Furthermore, human studies must confirm whether similar sex differences exist.
“Our findings have broad implications, as phytoene is abundant in yellow, orange, and red tomatoes,” said Xiang-Dong Wang, senior author and senior scientist at Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts.
“Phytoene also exists in many common fruits and vegetables, including carrots, red peppers, pink grapefruit, watermelon, and apricots,” Wang added. Encouraging more phytoene-rich produce could help prevent metabolic liver disease. However, further research must validate findings in humans before making dietary recommendations. Moreover, researchers must identify exact metabolites responsible for liver protection.
Q&A
Q: What hidden ingredient in tomatoes helps fatty liver?
A: Researchers found phytoene, a colorless precursor to lycopene, sharply reduced fatty liver disease in mice by helping liver burn fat.
Q: How much tomato equals the phytoene dose used in study?
A: Dose equaled three to four medium raw tomatoes or 100 grams, about one third cup, of tomato paste daily.
Q: Is phytoene better absorbed than lycopene?
A: Yes, lead author Na Youn Lee notes previous research shows phytoene is more readily absorbed by body than lycopene.
FAQ
1. Where was this tomato phytoene liver study published?
Study was published in Molecular Nutrition & Food Research by Tufts University Friedman School of Nutrition Science and Policy researchers.
2. What is metabolic dysfunction-associated steatotic liver disease?
It begins when fat accumulates inside liver cells, potentially causing inflammation, tissue damage, and cirrhosis, affecting up to 100 million U.S. adults.
3. Why did whole tomato powder work better than lycopene alone before?
Researchers suspect multiple compounds work together; phytoene discovery helps explain why whole tomato outperforms purified lycopene alone.
4. What foods contain phytoene besides tomatoes?
Phytoene exists in carrots, red peppers, pink grapefruit, watermelon, apricots, and yellow, orange, and red tomatoes abundantly.
5. Do genetics affect how phytoene protects liver?
Yes, mice lacking two carotenoid processing enzymes accumulated more phytoene but got less protection, suggesting metabolism into metabolites matters.
Disclaimer: This article is for informational purposes only and does not constitute medical or nutritional advice. We summarize animal research published in Molecular Nutrition & Food Research from Tufts University for educational purposes.
