Green leafy vegetables
These kinds of vegetables help lift your mood as they are high in antioxidants, minerals and fibre.
High in essential fatty acids, improves your mood, improves your memory.
Avocado, walnuts and almonds are high in vitamin B. They also help boost your immune system. Just one small handful of nuts is all you need each day. Olives, olive oil are high in essential fatty acids plus help the body absorb nutrients.
All citrus fruit are high in vitamin-c helping to lower cortisol levels (stress hormones) and boosts your immune system. The old saying an apple a day keeps the doctor away holds true as it has cancer fighting properties and according to recent studies, slows down mental aging.
Note there are many other benefits to the few foods I have mentioned above. Go ahead and look them up!