This is an easy aide-memoire for staying mentally healthy. Mentally healthy does not mean 'not getting mentally ill'. It means feeling happy, confident, settled, and valued. The famous 5-a-day for fruit and veg is fine for nutrition. Your colon will thank you. But the contents of your head and of your heart require attention to these five-a-day.
If you can do this, you've got it cracked, basically.