One of the world’s most popular foods may be quietly changing how our brains function.
Red tomatoes contain a bright pigment called lycopene, a potent antioxidant that can cross the blood-brain barrier and may help reduce neuroinflammation.
But does that impact the function of our brains?
A new randomized clinical trial suggests it might.
Researchers in Spain have now investigated how a single ‘tomato intervention’ impacts the cognitive outcomes of healthy adults.
“To our knowledge,” the authors write, “this is the first clinical trial to link changes in the antioxidant lycopene with alterations in functional brain connectivity.”
The findings are published in Antioxidants.
When 42 middle-aged adults ate 35 grams of tomato paste each day for three months, they showed enhanced selective attention and a slight boost in associative memory on cognitive tests.
These improvements were supported by brain scans among a smaller cohort of 14 participants.
These scans revealed tentative changes in connectivity across large-scale brain networks, although the imaging analysis was small and statistically underpowered – and based on a more lenient statistical threshold than the study’s own planned correction method.
It’s also worth noting that the trial was unblinded – both participants and researchers knew who was eating tomato paste and who wasn’t – so the study authors can’t fully rule out that knowing which diet they were on affected people’s motivation or effort on the cognitive tests.
As with any first trial, it’s important not to get carried away by the results, but even though the evidence is preliminary, the findings are juicy.
They suggest that bioactive compounds in tomatoes, such as lycopene, may promote brain health, which is a hypothesis to be tested further in future, larger trials.
“These findings provide evidence that tomato consumption may support cognitive function and modulate brain connectivity in healthy middle-aged adults,” conclude the study authors, led by nutritionist Ricardo López-Solís from the University of Barcelona in Spain.
The research involved a crossover trial, meaning participants are essentially their own controls.
One week before the randomized trial, participants were asked to avoid lycopene-rich foods, such as tomato, watermelon, papaya, grapefruit, or guava.
Then, they completed two dietary interventions for three months: one involved eating daily tomato paste and the other involved a low-lycopene diet.
The two diets were separated by a one-month ‘washout’ period. Participants ate as they normally would for the first three weeks, then returned to a low-lycopene diet for the final week to reset before the next phase.
After each dietary intervention, scientists measured distinct changes in participants’ blood.
Lycopene concentrations increased markedly on the tomato diet, and there was a borderline increase in a brain-growth protein called BDNF.
The brain-scan part of the study was smaller and less certain, but there was reduced resting connectivity in the frontoparietal and auditory networks when a diet was high in lycopene.
Conversely, when a diet was low in tomato, scientists observed reduced resting-state connectivity in dorsal attention networks.
“Together,” the authors write, “these neural changes suggest that tomato intake promotes functional reorganization of large-scale brain networks, enhancing neural efficiency and adaptability through the pruning of redundant cross-network interactions.”
They note that similar adaptations have been observed after interventions to train a person’s working memory.
The parallel associations between lycopene, BDNF, and network connectivity may be signs of “functional brain reorganization following tomato consumption”, the authors conclude.
The findings are broadly consistent with a previous pilot study in older adults, in which a carotenoid-rich tomato-powder food improved processing speed, attention, and working memory over eight weeks compared with a placebo.
A separate five-week crossover trial found that a mixed-berry beverage containing tomato powder improved older adults’ working memory, but not their selective attention – a discrepancy the study authors suggest may reflect practice effects from repeated exposure to the same cognitive test.
Whether or not that is due to lycopene specifically is harder to glean, as tomatoes are packed with antioxidants and vitamins.
In mouse and human studies, however, lycopene levels have been linked to lower rates of prostate and lung cancer, as well as heart disease and liver disease.
Still, no study has yet proved cause and effect.
Larger, longer-term trials are needed to determine whether the neural changes associated with tomato paste are sustained over time, or if they even translate into clinically meaningful brain changes.
In the meantime, just know that tomatoes are packed with powerful antioxidants and vitamins.
Even when you cook them into a sauce, these key ingredients remain.
In fact, cooked tomatoes may provide more lycopene than raw ones.
Related: Researchers Put Spinach Directly Into Bread And Saw The Body’s Insulin Response Change
Rachel Kopec, a nutritionist at Ohio State University, explained to The New York Times a few years ago that the heat involved in cooking tomatoes breaks down their cell walls, making lycopene easier to digest.
A spoonful of tomato paste can add a hearty dose to any meal.
The study is published in Antioxidants.
This article was fact-checked by Fiona MacDonald and edited by Fiona MacDonald. While we pride ourselves on our process, we are only human. If you spot a mistake, please let us know.
