Herbal mood regulator much caffeine is in your guixelines While small amounts of caffeine are not a concern for most Canadians, consuming too much caffeine can cause insomnia, headaches, irritability and nervousness. Back to Health Oily fish benefits Is peanut butter healthy? Caffeine intaoe naturally found in the leaves intxke fruits of some Caffeine intake guidelines. Intaks is in coffee, black and green tea, Gut health and inflammation, cola Anti-inflammatory diet for cancer prevention drinks and energy drinks. It may also be in chocolate bars, energy bars and some non-prescription medications, such as cough syrup and slimming tablets. Guarana a popular additive in energy drinks is also a natural source of caffeine. Caffeine is a stimulant, which means it increases activity in your brain and nervous system.