Tomatoes are widely consumed around the world, and new research suggests that regularly eating tomato paste may be associated with modest changes in certain aspects of cognition. A randomized crossover trial from Spain found improvements in some measures of attention and memory after healthy adults consumed tomato paste daily for three months.
The study, published in Antioxidants, focused partly on lycopene, the carotenoid pigment responsible for tomatoes’ red color. Lycopene has antioxidant properties and has been investigated for possible effects on oxidative and inflammatory processes, including those relevant to the nervous system. However, whether dietary lycopene meaningfully alters human brain function remains uncertain.
Inside the tomato paste experiment
The study enrolled 42 middle-aged adults in a randomized crossover trial. Each participant completed two three-month dietary phases: one that included daily tomato paste and another designed to contain very little lycopene. The phases were separated by a one-month washout period.
Participants were instructed to avoid major sources of lycopene, including tomatoes, watermelon, papaya, grapefruit and guava. During the intervention phase, they consumed 35 grams of tomato paste each day in addition to their usual diet. During the low-lycopene phase, they followed the restricted diet without receiving tomato paste.
Because every participant experienced both conditions, each person effectively served as their own control, reducing some of the variability that can complicate parallel-group nutrition trials.
However, the intervention was not blinded. Participants and researchers knew when tomato paste was being consumed, creating the possibility that expectations or behavioral changes could have influenced some outcomes.
What the blood and cognitive tests showed
Blood lycopene concentrations increased substantially during the tomato-paste phase, confirming that the intervention altered participants’ lycopene status. Researchers also observed a borderline change in brain-derived neurotrophic factor, or BDNF, a protein involved in neuronal function and plasticity.
On cognitive testing, the tomato-paste intervention was associated with improvement in selective attention and a modest improvement in associative memory.
These findings are potentially interesting, but they should not be interpreted as evidence that tomato paste broadly improves memory or intelligence. Multiple cognitive outcomes were assessed, and the observed differences were limited to particular measures.
Repeated cognitive testing can also introduce practice effects, although the crossover design helps researchers compare performance under the two dietary conditions.
Brain imaging produced exploratory findings
A subgroup of only 14 participants underwent resting-state functional MRI. Researchers reported differences in functional connectivity across several large-scale brain networks, including frontoparietal, auditory and attention-related networks.
These results were interpreted as possible changes in functional brain organization associated with the dietary intervention. However, functional connectivity does not directly measure how efficiently neurons communicate, and increased or decreased connectivity is not inherently beneficial or harmful.
For this reason, describing the findings as evidence that lycopene “prunes redundant connections” or makes the brain more adaptable would go beyond what the imaging data demonstrate.
The imaging findings are particularly preliminary because the subgroup was very small. The researchers also used a less stringent statistical threshold than originally planned, increasing the possibility of false-positive findings.
Larger studies with adequately powered neuroimaging samples will be needed to determine whether the reported connectivity differences can be reproduced.
Lycopene may not be the only explanation
Although blood lycopene increased during tomato-paste consumption, the experiment cannot establish that lycopene itself caused the cognitive differences.
Tomato paste is a complex food containing multiple carotenoids and other bioactive compounds. The intervention also differed from the comparison condition in more than a single isolated nutrient.
Consequently, the findings apply most directly to the tomato-paste dietary intervention rather than to purified lycopene supplementation.
The unblinded design creates another limitation. Participants who knew they were consuming a food perceived as healthy could potentially change their effort during testing or other aspects of their behavior.
What previous research tells us
Earlier small studies have investigated tomato products or carotenoid-rich interventions in relation to cognition, with some reporting differences in measures such as processing speed, attention or working memory.
However, results have not been uniform across cognitive domains, and relatively small studies require replication before firm conclusions can be drawn.
Observational research has also associated higher circulating lycopene concentrations or greater consumption of lycopene-rich foods with some favorable health outcomes. Such associations cannot establish that lycopene itself prevents cardiovascular disease, cancer, liver disease or cognitive decline, because diet and blood nutrient levels are related to many other lifestyle and health factors.
Cooking and processing tomatoes can increase lycopene bioavailability by disrupting the food matrix and making lycopene more accessible for absorption. Consuming tomato products with dietary fat can also enhance absorption of this fat-soluble carotenoid.
Greater bioavailability, however, does not by itself demonstrate greater health benefits.
What comes next for tomato research?
The Spanish trial provides preliminary evidence that three months of daily tomato-paste consumption may influence particular cognitive measures and possibly patterns of functional brain connectivity in healthy middle-aged adults.
It does not demonstrate that tomatoes prevent cognitive decline, dementia or brain aging. Nor can the results establish whether any observed effects would persist after the intervention ended.
Larger and longer randomized trials could determine whether the cognitive findings are reproducible and clinically meaningful. Future studies could also investigate whether effects differ according to age, baseline diet or cognitive status and whether lycopene itself or the broader composition of tomato products is responsible.
For now, tomatoes can reasonably be included as part of a varied, plant-rich dietary pattern. The new study provides an interesting reason to investigate their effects on cognition further, but not evidence that tomato paste should be treated as a specific intervention for improving memory or protecting the brain.
