Eating concentrated tomato paste every day for three months was linked to better performance on tests of selective attention and face-name memory in healthy middle-aged adults, according to a clinical trial published in Antioxidants. A small brain-imaging subgroup also showed changes in how certain brain networks communicate, and levels of a protein involved in brain cell growth showed a borderline increase. The findings suggest that a single, common food may help support cognitive performance during midlife.
Dietary patterns rich in plant-based antioxidants, such as the Mediterranean diet, are often linked to healthier brain aging and a lower risk of cognitive decline. A primary component of the Mediterranean diet is the tomato, which serves as the main dietary source of a natural pigment called lycopene. Lycopene belongs to a family of fat-soluble plant compounds known as carotenoids, which give red, orange, and yellow fruits and vegetables their bright colors.
Among all dietary carotenoids, lycopene is especially effective at neutralizing unstable oxygen molecules in the body. It is able to cross the blood-brain barrier, a protective layer of tightly packed cells that prevents harmful substances in the bloodstream from entering the brain. Once inside the brain, lycopene is thought to help reduce brain inflammation and oxidative stress, which is cellular damage caused by a buildup of reactive molecules.
Animal and laboratory experiments have helped clarify how this compound protects neural tissue. For example, a 2018 study in mice found that lycopene supplementation prevented inflammation-induced memory loss and reduced the buildup of harmful amyloid proteins linked to Alzheimer’s disease. Lycopene is also thought to support neuroplasticity, the brain’s ability to adapt and form new connections, by regulating brain-derived neurotrophic factor. Often referred to by the acronym BDNF, this protein acts like a growth factor for the nervous system, helping existing neurons survive and encouraging the growth of new ones.
In human populations, several observational studies have connected higher blood levels of carotenoids to better mental performance. In a 2019 neuroimaging study of older adults, higher blood concentrations of lycopene and other nutrients were linked to better memory and more efficient communication across brain networks. Similarly, a 2019 clinical trial in young adults indicated that taking daily supplements of lutein and zeaxanthin, two carotenoids other than lycopene, for six months boosted circulating BDNF levels and improved cognitive scores.
Despite these encouraging connections, direct clinical trials testing the cognitive impact of tomatoes in humans have been rare. Past trials typically combined tomato extracts or lycopene with several other vitamins, herbs, or berries, and they focused mostly on older adults. Because these studies mixed multiple ingredients together, scientists could not tell whether the cognitive benefits came from the tomatoes or from the other substances.
To isolate the effects of tomatoes alone, Ricardo López-Solís, Marina Corrado, Rosa M. Lamuela-Raventós, and their colleagues at the University of Barcelona designed a randomized clinical trial focusing on healthy middle-aged adults. By studying people between the ages of 40 and 55, the researchers aimed to see whether eating tomato paste could support brain health before age-related cognitive decline typically becomes noticeable. They used a crossover design, meaning that every participant completed both the tomato diet and the control diet at different times, allowing each person to serve as their own comparison.
The researchers recruited 47 healthy, non-smoking adults from the Barcelona area who had no history of chronic diseases or cognitive impairment, and 42 participants completed the full study. The participants had an average age of about 47, and two-thirds of the sample were women. Nearly 93 percent of the participants had completed higher or postgraduate education.
Each participant completed two three-month dietary phases separated by a one-month break, known as a washout period, during which they mostly returned to their normal eating habits before avoiding lycopene-rich foods in the final week. During the tomato phase, participants ate concentrated commercial tomato paste containing only tomatoes and salt every day alongside their regular meals, either raw or cooked. The daily dose was tailored to each person’s body weight at 0.5 grams of paste per kilogram of weight, which worked out to an average of about 35 grams of paste (roughly two tablespoons) containing 38.4 milligrams of lycopene per day.
During the three-month control phase, participants followed a low-lycopene diet that restricted tomatoes, watermelon, papaya, pink grapefruit, guava, and any food products made from those ingredients. To help participants keep the rest of their diet consistent, the researchers provided a recipe booklet offering paired meal options, such as dishes made with tomato paste for the active phase and similar tomato-free dishes for the control phase. Throughout the trial, the researchers monitored participants’ broader diet, sleep, body composition, and physical activity using food questionnaires and wrist-worn activity trackers.
At the beginning and end of each three-month period, participants provided fasting blood samples to measure their blood levels of lycopene and BDNF. They also completed three standardized cognitive tests measuring different mental abilities. One paper-and-pencil test evaluated selective attention and visual processing speed by asking participants to scan rows of letters under time pressure and mark only specific target letters with two dashes.
A second test measured associative memory, the ability to learn and remember the relationship between unrelated items, by showing participants 12 pairs of faces and names and testing their recall 15 minutes later. A third test used a card-sorting game to measure executive function, which includes mental flexibility and the ability to adapt when rules change unexpectedly. In addition, a smaller subgroup of 14 participants underwent resting-state functional magnetic resonance imaging, a type of brain scan that measures how different regions of the brain communicate while a person is lying still and not performing a specific task.
Blood tests indicated that lycopene levels responded to the diets as intended on average, while participants’ overall calorie intake, sleep, and exercise habits remained unchanged. Based on a blood-lycopene cutoff, however, the researchers judged that 14 of the 42 participants had not fully followed the diet in at least one phase. During the control period, average blood lycopene levels stayed flat at 0.40 micromoles per liter, whereas during the tomato paste intervention, average blood lycopene levels more than doubled, rising from a baseline of 0.32 micromoles per liter by an average of 0.40 micromoles per liter.
Cognitive testing showed that eating tomato paste improved selective attention and one aspect of associative memory compared to the low-lycopene control diet. On the attention test, concentration performance started at an average baseline score of 171.0 points and increased by 7.8 points after the tomato phase, yielding an adjusted difference of 7.2 points over the control phase. Visual processing speed improved by a similar margin, rising from a baseline average of 188.3 points by 8.5 points after the tomato diet, for an adjusted gain of 8.3 points compared to the control period. These attention gains amounted to roughly 4 percent of baseline scores; in standardized terms, the authors describe the effects as moderate.
When the researchers excluded participants whose blood tests suggested they had not strictly followed the diet rules, these attention gains grew roughly twice as large, reaching a 13.7-point advantage in concentration and a 14.7-point advantage in processing speed. On the associative memory test, participants improved their ability to match faces with the correct names from a baseline average of 9.4 out of 12 points by 0.8 points over the control diet. The overall associative memory score, which combined all three parts of the face-name test, did not differ significantly between the two phases, however. In addition, the card-sorting test showed no meaningful changes in executive function during either phase of the study.
Although the trial’s sample size was originally calculated to detect changes in BDNF, blood levels of the protein showed only a borderline increase after the tomato intervention, with an adjusted average difference of 15.2 nanograms per milliliter compared to the control period (relative to baseline levels of 26.5 to 32.2 nanograms per milliliter).
The researchers noted that participants who completed the tomato diet first still had elevated BDNF levels when they started the control period a month later. An analysis restricted to the first phase, which avoids this carryover problem, found a consistent difference of 11.0 nanograms per milliliter. The authors suggest that this lingering carryover effect may reflect sustained biological changes triggered by tomato consumption that last longer than the four-week break between phases.
In the subgroup of 14 participants who underwent brain scans, the tomato diet was linked to reduced communication within two brain systems: the right frontoparietal network, which helps direct attention toward goals, and the auditory network, which processes sound. Larger drops in connectivity in these networks correlated with larger gains on the face-name matching task.
The authors suggest that this reduction in cross-network chatter may reflect greater neural efficiency, helping the brain filter out distracting background noise and sensory interference during visually demanding tasks. These brain findings came from 14 people and did not pass the study’s strictest statistical correction for multiple comparisons, so they are best treated as preliminary.
During the low-lycopene control diet, brain scans showed weakened connectivity within the dorsal attention network, a brain system responsible for sustaining focus. Across the study, bigger increases in blood lycopene levels were moderately correlated with stronger connectivity in the dorsal attention network and modestly correlated with faster cognitive processing speeds. The findings are consistent with research covered by PsyPost in 2024, which linked higher blood levels of carotenoids and other nutrients to slower brain aging and better cognitive performance in older adults, rather than directly testing a tomato intervention in middle-aged adults.
As with all research, there are some caveats to consider when interpreting these results. Because participants were eating actual tomato paste rather than swallowing an identical-looking pill, they knew which dietary phase they were in, and so did the staff who administered the cognitive tests. Expecting benefits could have boosted participants’ motivation during testing. The authors argue that the parallel changes in blood lycopene and brain scans make a purely expectation-driven explanation less likely.
The design of the control phase also introduces a question about what drove the differences between the two periods. Because participants had to actively avoid tomatoes and several red fruits during the control phase, the authors note that the restriction itself, rather than only the added tomato paste, may have contributed to differences between the phases, such as the weaker dorsal attention network connectivity seen during the control period. In addition, while lycopene was the primary compound tracked in the blood, tomatoes contain other beneficial nutrients like vitamin C, beta-carotene, and plant polyphenols that may have worked together to produce the observed effects.
The study sample was also relatively small, especially the 14-person brain imaging subgroup, and more than 90 percent of the participants had a university or postgraduate degree. Future studies will need to test larger and more diverse groups of people to see if the results hold true across the broader population. Longer trials with extended washout breaks and brain scans conducted while participants actively perform mental tasks could help clarify whether daily tomato intake provides lasting protection against age-related cognitive decline.
The study, “Tomato Intake Improves Cognitive Performance and Modulates Functional Brain Networks in Healthy Adults: A Randomized Crossover Clinical Trial,” was authored by Ricardo López-Solís, Carolina Donat-Vargas, Patricia Ramírez-Carrasco, Rocío M. Gutiérrez-Romero, Maria Pérez, Magda Castellví, Beatriz Bosch, Camila Arancibia-Riveros, Alejandro Hinojosa-Moscoso, Carlos Laredo, Emma Muñoz-Moreno, Ana Maria Ruiz-Leon, Rosa Casas, Ramon Estruch, Anna Vallverdú-Queralt, Marina Corrado, and Rosa M. Lamuela-Raventós.
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