Tomatoes and Brain Function: New Research Insights

One of our favorite foods, tomatoes, might be influencing how our brains work. Red tomatoes are rich in lycopene, a vibrant pigment known for its antioxidant properties. This compound can cross the blood-brain barrier, potentially easing neuroinflammation. But does that mean it actually affects brain function?

A recent randomized clinical trial seems to suggest that it does. Researchers in Spain have looked into the effects of a ‘tomato intervention’ on the cognitive performance of healthy adults.

As noted by the authors, “to our knowledge, this is the first clinical trial to link changes in the antioxidant lycopene with alterations in functional brain connectivity.” The results were published in Antioxidants.

In the study, 42 middle-aged adults consumed 35 grams of tomato paste daily for three months, leading to improvements in selective attention and a small enhancement in associative memory as shown by cognitive tests. Brain scans from a smaller group of 14 participants supported these findings, revealing some changes in connectivity within major brain networks. However, it’s important to mention that the imaging analysis was relatively small and not very robust, and it used a statistical threshold that’s less stringent than what was originally planned.

Another factor to consider is that the trial was unblinded—both participants and researchers knew who was consuming the tomato paste and who wasn’t. This means the researchers can’t completely discount the possibility that participants’ knowledge about their diets might have influenced their motivation during cognitive assessments.

It’s wise to take these initial findings with a grain of salt. Although the results might be promising, they are still early-stage. The suggestion that compounds found in tomatoes, like lycopene, could benefit brain health needs further exploration in larger studies.

The study authors, led by nutritionist Ricardo López-Solís from the University of Barcelona, concluded, “These findings provide evidence that tomato consumption may support cognitive function and modulate brain connectivity in healthy middle-aged adults.”

The research adopted a crossover trial design, essentially allowing participants to serve as their own controls. Prior to starting the trial, they were asked to cut out foods high in lycopene—think tomatoes, watermelon, papaya, and others. This was followed by two three-month dietary interventions: one included daily tomato paste and the other involved a low-lycopene diet, separated by a one-month ‘washout’ phase during which participants returned to their usual eating habits.

After each intervention, significant changes in blood samples were observed. Lycopene levels shot up during the tomato diet, and there was also a noticeable increase in a protein associated with brain growth called BDNF. While the brain imaging aspect of the study was less certain, researchers noted decreased resting connectivity in the frontoparietal and auditory networks during the high-lycopene diet. Interestingly, a low-lycopene diet showed reduced connectivity in dorsal attention networks.

According to the authors, “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 draw parallels between these adaptations and those observed when training working memory.

In broader terms, these associations linking lycopene, BDNF, and brain connectivity could hint at “functional brain reorganization following tomato consumption,” as stated by the study’s authors.

This research aligns with earlier studies on older adults, which found that a diet rich in carotenoids, especially from tomatoes, led to improvements in processing speed, attention, and working memory. There was also a five-week study where a mixed-berry drink enriched with tomato powder showed gains in working memory, though it didn’t seem to affect selective attention—an inconsistency the authors attributed to familiarity with the cognitive tasks.

Determining whether these changes are specifically due to lycopene is trickier, given that tomatoes offer a variety of antioxidants and vitamins. Past studies on mice and humans indicated that lycopene might be linked to reduced risks of certain cancers and heart diseases, but direct cause and effect have yet to be established.

There’s a clear need for larger, long-term trials to find out if the neural changes linked to consuming tomato paste last, or if they translate into significant or lasting cognitive improvements.

In the meantime, it’s good to remember that tomatoes are a great source of antioxidants and vitamins, even when transformed into sauces. In fact, cooking tomatoes may even increase the availability of lycopene—something worth considering for your next meal.