In April this year, scholars studied the correlation between the intake of lycopene from tomatoes in the diet of American adults and the risk of depression.

Data from 2007 to 2016 NHANES surveys were analyzed for 18,664 participants aged 20 years and above, of which 90,80 were male and 95,84 were female. 8.98% of the participants were diagnosed with depression, defined as a PHQ-9 score ≥ 10. Compared to participants without depression, depression patients had a significantly lower dietary intake of lycopene. Notably, more than half (55.07% ) of the depression patients had a dietary intake of lycopene that was lower than the median for all participants, while the dietary intake of lycopene was more evenly distributed among the non-depressed group. Dietary lycopene intake was estimated based on the average of two 24-hour dietary recalls.

The study also used binary logistic regression and restricted cubic splines (RCS) models to assess the relationship between the two. After adjusting for potential confounders, the analysis showed that within the intake range of0～10,072μg/day, a higher dietary intake of lycopene was associated with a gradually decreasing risk of depression, which was consistent with the results of the binary logistic regression. However, further increases in dietary intake of lycopene beyond this threshold actually reversed the beneficial effects of reducing the risk of depression.

Although the study has some limitations, it also suggests that a higher dietary intake of lycopene from tomatoes may be protective against depression in adults.

Learn about lycopene

Lycopene is the sixth most common carotenoid in food.

Carotenoids are mainly divided into two large categories: hydrocarbon carotenoids and xanthophylls. Hydrocarbon carotenoids, such asα-, β-, and γ-carotene as well as lycopene, are composed of hydrogen and carbon; while xanthophylls, such as lutein, β-zeaxanthin and lutein, contain oxygen in addition to carbon and hydrogen. Lycopene (C40H56) is an aliphatic straight-chain hydrocarbon with 13 carbon-carbon double bonds, including two non-conjugated double bonds and 11 conjugated double bonds, which are key to the unique red color of plants such as tomatoes, watermelons, and guavas.

Lycopene is the major carotenoid in human plasma, with a half-life of about2 to 3 days. Its concentration range in plasma and tissues is 0.2～21.4 nmol/g and 0.15～21.36 nmol/g. Previous studies have shown that in rats, lycopene is mainly concentrated in the liver, adipose tissue, adrenal tissue, and spleen. The bioavailability of lycopene often decreases with increasing age in healthy individuals, which may be due to the decrease in absorption rate caused by age-related structural changes in the gastrointestinal tract.

Tomato red pigment is approved as a food additive in China by the National Food Safety Standard for the Use of Food Additives (GB 2760-2014), and its function is classified as a colorant. Meanwhile, as a nutritional supplement, tomato red pigment has excellent antioxidant effects, which are noteworthy. The results of the above depression study also reveal that the observed correlation shows a reverse phenomenon after exceeding a specific threshold. This reverse may also be attributed to the oversaturation of antioxidant activity. The main function of tomato red pigment is to alleviate oxidative stress by neutralizing free radicals. However, as the dietary intake of tomato red pigment increases, the antioxidant system will reach saturation, allowing any additional tomato red pigment to further enhance its antioxidant effects, thereby reducing its overall benefits. This finding also emphasizes the importance of controlling dietary tomato red pigment intake within a reasonable range to maximize its health-promoting effects.

The role of lycopene

1876 year, Mirra discovered lycopene in tomatoes,1910 Swiss chemist isolated lycopene from tomatoes and determined its structure. Lycopene has a history of more than a hundred years, and its research results are worth noting for many reasons other than its use as a colorant and antioxidant.

 1）Neuroprotection

2025Yearly published articles investigated the neuroprotective effects of lycopene on cognition-related disorders in maleC57BL/6 mice obesity. Mice were fed a high-fat diet (HFD) for four months to induce obesity, followed by supplementation with lycopene (50 mg/kg). Cognitive function was evaluated in mice throughY maze, Morris water maze, and novel object recognition tests. The experiment also measured systemic and hippocampal inflammatory markers, as well as lipidomics and proteomics signatures. The results showed that supplementation with lycopene significantly improved cognitive function in mice, restored neuronal density, and increased the levels of key neuroprotective proteins including brain-derived neurotrophic factor (BDNF) and neurospecific enolase (NeuN). Lipidomics analysis showed a decrease in pro-inflammatory lipids (e.g., lysophosphatidylcholine, triglycerides) and an increase in neuroprotective lipids (e.g., phosphatidylserine). Additionally, proteomics data showed a decrease in lipid-induced neurotoxic proteins and upregulation of pathways related to taurine and glutathione metabolism, thereby promoting neuronal stability and plasticity. These results suggest that lycopene exerts its neuroprotective effects by restoring lipid homeostasis and regulating amino acid signaling pathways, thereby mitigating cognitive decline in obese mice.

2) Hepatoprotective effects

Recent studies have shown that the intake of carotenoids (such as lycopene) can significantly reduce the risk of liver diseases such as NAFLD. The study used β-carotene-15,15-dioxygenase and β-carotene-9,10-dioxygenase double knockout mice, orally administration of 2.3 mg/g lycopene for continuous 24 weeks, can significantly reduce hepatic steatosis and triglyceride levels, and significantly improve Sirtuin 1 activity and fatty acid oxidation levels, compared to the control group fed a high-fat diet. In addition, lycopene can also reduce inflammation. In a model of tramadol-induced hepatotoxicity, continuous supplementation of lycopene at 15 mg/kg body weight for 15 days can reduce hepatotoxicity by enhancing antioxidant activity, reducing fatty acid decomposition and necrosis, lipid peroxidation, and inhibiting DNA fragmentation and apoptosis. In a NAFLD rat model, continuous administration of lycopene at 5, 10, and 20 mg/kg body weight for 6 weeks showed hepatoprotective effects, as indicated by reduced activities of aspartate aminotransferase and alanine aminotransferase, and corresponding reductions in malondialdehyde, free fatty acids, and low-density lipoprotein cholesterol levels. These study results are associated with increased liver superoxide dismutase and glutathione levels, but not with cytochromeP450 2E1and tumor necrosis factor-α expression was reduced and liver fat was reduced. The above experimental studies clearly showed that the administration of lycopene not only inhibitedROS, but also increased the activity of antioxidant enzymes, thereby producing a beneficial effect onNAFLD.

 3）Skin protection

Lycopene is known for its ability to protect the skin from harmful ultraviolet rays, and is therefore widely used in cosmetics.

Some studies have shown that oralhelps protect the skin from sun damage. Several studies have shown that lycopene can improve the redness or reduce skin redness caused by sunburn. However, it should be noted that lycopene does not act alone. Other compounds are also involved, such as plantene, plant fluorene,β-carotene, three carotenoids, and tocopherol. Therefore, it seems that it is the complex of these bioactive plant nutrients in tomatoes that plays a role in protecting cells and preventing degenerative diseases.

 Also, lycopene extracted from tomatoes is believed to inhibitDNAsynthesis in prostate epithelial cells, preventing prostate diseases. In addition, lycopene can also promote the proliferation (reducing apoptosis) and differentiation of osteoblasts. Moreover, supplementing with lycopene is effective for postmenopausal osteoporosis. Lycopene also helps maintain cardiovascular health, which is associated with reducing the risk of heart-related diseases and the risk of diabetes.