#2 Natural Cacao Powder

It doesn’t contain as much as coffee, but enough to produce a response without causing the jittery effects associated with taking in too much caffeine. Caffeine affects the brain by blocking an inhibitory neurotransmitter called adenosine. This way, it increases the firing of neurons and the concentration of neurotransmitters like dopamine and norepinephrine (4Trusted Source, 5). Research has consistently shown that caffeine can improve various aspects of brain function, including mood, vigilance, reaction time, and memory (6).