Caffeine primarily affects the body by interfering with the action of a neurotransmitter called adenosine. Adenosine is responsible for promoting relaxation and sleepiness by binding to its receptors in the brain, which slows down nerve cell activity.
Caffeine resembles adenosine structurally and can bind to adenosine receptors. However, caffeine doesn't slow down nerve cell activity like adenosine does. Instead, it blocks adenosine from binding to its receptors, preventing its calming effects. This leads to increased neuron firing, which prompts the pituitary gland to release hormones that signal the adrenal glands to produce adrenaline, resulting in the "fight or flight" response.
Additionally, caffeine can increase the release of dopamine, a neurotransmitter associated with pleasure and reward. This contributes to the feelings of alertness and improved mood that many people experience after consuming caffeine.
Caffeine also affects other neurotransmitters and hormones in the body, such as serotonin and acetylcholine, which can further influence mood, energy levels, and cognitive function.
Overall, caffeine's effects on the body can include increased alertness, improved concentration, enhanced mood, increased heart rate, elevated blood pressure, and increased metabolism. However, individual responses to caffeine can vary based on factors such as genetics, tolerance, and overall health.
The recommended daily allowance of coffee for an adult is 400mg of caffeine.
The biggest sources of caffeine in the human diet typically include:
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Coffee: Coffee is one of the most popular sources of caffeine worldwide. The caffeine content can vary widely depending on factors such as the type of coffee bean, the brewing method, and the serving size. 1 Cup of Coffee - 238g contains on average 95mg of caffeine
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Tea: Tea, particularly black tea and green tea, contains caffeine. The caffeine content of tea is generally lower than that of coffee but can still provide a significant energy boost. 1 Cup of Tea - 238g contains on average 26mg of caffeine
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Energy drinks: Energy drinks are formulated with caffeine and other ingredients like sugar and B-vitamins to provide a quick energy boost. These drinks can contain high levels of caffeine, sometimes exceeding the amount found in coffee or tea. One 250ml can of red bull contains 80mg of caffeine.
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Soft drinks: Many soft drinks, particularly colas, contain caffeine. While the caffeine content in soft drinks is generally lower compared to coffee or energy drinks, it can still contribute to your daily intake. One 330ml can of Cola contains 33mg of caffeine.
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Chocolate: Cocoa beans naturally contain caffeine, so chocolate products, especially dark chocolate, contain small amounts of caffeine. The caffeine content varies depending on the type and quality of chocolate. One 100g portion of dark chocolate contains 43mg of caffeine.
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Medications: Some over-the-counter and prescription medications, such as pain relievers, cold medicines, and weight loss supplements, may contain caffeine as an active ingredient to enhance their effects.
It's essential to be mindful of your caffeine intake and consider factors such as your sensitivity to caffeine, overall health, and any potential interactions with medications or medical conditions.