Pigment found in tomatoes and watermelon could help cure depression — but there’s a catch

Red alert!

Lycopene — a natural plant extract that gives color to red and pink fruits and vegetables such as tomatoes, watermelons and papayas — may ease depression symptoms by enhancing brain cell communication, a new study found.

“Compared to synthetic drugs, natural plant extracts offer the advantages of being suitable for long-term consumption, having fewer side effects and being safer,” researchers from Chongqing Medical University in China wrote recently in the journal Food Science & Nutrition.

“As research has progressed, plant extracts such as lycopene and curcumin have been proven to have neuroprotective effects, with lycopene standing out due to its powerful antioxidant properties and wide availability,” the report continued.

The scientists were able to induce depressive-like behaviors in 60 mice for the study. The anxious mice were divided into two groups — one cohort received 20 milligrams of lycopene per kilogram of their body weight while the other took a corn oil placebo.

Compared to the placebo group, the participants that consumed the lycopene socialized more with other mice and expressed greater interest in a sugar water mixture that’s meant to spark joy.

The researchers determined that stressing the mice out impaired their synaptic plasticity, a crucial mechanism for learning and memory formation, allowing the brain to store information and adapt to new experiences.

The lycopene treatment helped restore the damaged synaptic plasticity and reverse the depressive behavior via one particular signaling pathway in the nervous system.

There were several limitations to the study, to be sure. Researchers only used male mice and focused solely on the effects on the hippocampus, the part of the brain primarily responsible for learning and memory.

“Additionally, considering that depression is a chronic disease, its pathological mechanisms often take longer to fully manifest,” the researchers wrote. “Therefore, extending the behavioral observation time after lycopene intervention may provide a more comprehensive evaluation of its efficacy.”

A major catch is that the mice were given 20 milligrams of lycopene per kilogram of body weight, with the human dose roughly equivalent to 1.62 milligrams per kilogram.

For a 200-pound person, that’s about a 147-milligram daily dose.

Some research indicates that only up to 75 milligrams a day of lycopene is safe. A study that came out in June reported that there’s no harm with up to 100 milligrams.

Where can you find lycopene

• Sun-dried tomatoes boast the highest concentration of lycopene among tomato products, with 45.9 milligrams of lycopene per 100 grams.
• A 130-gram serving of fresh tomatoes contains 4 to 10 milligrams.
• Ketchup has 3.3 milligrams per tablespoon.
• Tomato paste includes about 16 milligrams of lycopene per 100 grams.
• Watermelon contains 4.5 milligrams of lycopene per 100 grams.
• Papaya features 1.8 milligrams of lycopene per 100 grams.
• Pink grapefruit has 1.1 milligrams of lycopene per 100 grams.