The active ingredients of tomatoes and lemons, including lycopene(46), vitamin C(47), citric acid(48) and flavonoids(49), are also known to be effective in improving cognitive function and memory through the regulation of BDNF and alleviating other neurological diseases, such as Alzheimer’s disease, schizophrenia, Parkinson’s disease and depression(50). Here, BDNF is linked to depressive symptom measurement.