Coffee is more than just a morning pick-me-up for me. It is the nectar of the gods. It takes a lot of trial-and-error to find just the right cup. It has to be the right blend, from acceptable sources, brewed to perfection. Or I can get the caffeinated liquid candy from Starbucks.
Caffeine is the drug of choice in our culture. About 90% of Americans consume caffeine daily and about half consume over 300 mg. The most common sources of caffeine are coffee and tea. Other sources include sodas, energy drinks and chocolate.
What is Caffeine?
Caffeine is a naturally occurring stimulant also known as trimethyxanthine. It is found in plants such as coffee, tea and cacao.
How Does Caffeine Work?
Adenosine: Adenosine is a chemical that is involved in many biological processes. One of these is acting as an inhibitor (slows it down) for the central nervous system. This plays an important role in sleep. Because caffeine looks similar to adenosine to your nervous system, caffeine is able to bind to adenosine receptors and block adenosine. Because caffeine blocks he inhibitory process of adenosine, your brain speeds up. Over time, regular use of caffeine results in your body creating more adenosine receptors. As a result of this, lack of caffeine will make you become overwhelmed by adenosine and needing caffeine to compensate.
Adrenaline: The increased brain activity from caffeine tricks your pituitary gland into thinking there is an emergency. This results in it stimulating your adrenal glands. This results in your pupils dilating, your airways opening up, your heart rate increases, your pupils on the surface constrict to slow down blood flow and increase blood flow to muscles, blood pressure rises, blood flow to the stomach slows down, the liver releases sugar into the bloodstream for energy and muscles tighten up for action.
Dopamine: Dopamine is a neurotransmitter that is involved in the brains reward and pleasure centers. In addition to blocking adenosine, caffeine slows down the reabsorption of dopamine, increasing dopamine levels. Dopamine helps regulate movement and emotional responses. It also helps us to see rewards and act on them (reward meaning pleasure).
The Benefits of Caffeine
- In sources such as tea and coffee, it contains antioxidants, which are important from preventing oxidative damage.
- It increases energy levels.
- It improves mood.
- It improves cognitive function, including alertness and memory.
- It increases fat burning and metabolism.
- It improves physical performance.
- Associated with lower risk of Type 2 diabetes.
- Associated with lower risk of alzheimer’s and dementia.
- Associated with lower risk of Parkinson’s.
- May prevent liver damage.
- Associated with lower risk of cancer.
*Association does not mean causation.
The Risks of Caffeine
- Regular use may cause dependency. It may become more about avoiding withdrawal rather than capitalizing on the benefits.
- Often consumed with added sugar, which should be avoided.
- May mess with digestion and nutrient absorption.
- Increases stress levels.
Caffeine has both risks and benefits. For most adults, caffeine isn’t considered risky until consuming over 300 mg daily (~ 2 cups of coffee). However, this doesn’t factor in dependency, is based on association and is relative to the general population.
The healthiest sources of caffeine are coffee and tea. It is best consumed in moderation, limiting added sugar. It is also preferable to avoid dependency and trying to go without it every once in a while.
FDA 2012 Caffeine Consumption Report
ASAPScience: Your Brain on Coffee
You Are Not So Smart: Coffee
How Stuff Works: Caffeine
Chris Kresser: Is drinking coffee good for you?
WebMD: Caffeine Myths and Facts
Authority Nutrition: Top 13 Evidence-Based Benefits of Caffeine
Health Ambition: Negative Effects of Coffee
Mayo Clinic: Caffeine Content for Various Sources