Caffeine is a substance most of us feel we are all-too familiar with. The media often depicts caffeine as somewhat sinister, but is this deserved?
These days you can find caffeine in coffee, energy drinks, chocolate and even hair and beauty products. Studies have shown that it is linked to numerous health implications. Much research has been carried out to understand the link between drinking coffee and developing heart disease and the truth is, we still don’t know. The results have been conflicting and this might be for a whole host of different reasons, so we’re a long way off from finding the answer yet. However, it’s pretty widely accepted that, for a healthy adult, a moderate consumption limited to 400 mg of caffeine per day isn’t likely to do much harm. That’s equivalent to roughly four cups of instant coffee, ten cans of cola or two energy drinks (although note that caffeine amounts vary from brand to brand).
However, it’s not just your heart that’s affected by caffeine. Caffeine effects the body in multiple ways: it stimulates the nervous system, releases free fatty acids from fatty tissue (also known as adipose tissue) and it affects the kidneys, causing more frequent urination. You might have wondered how caffeine actually makes you feel awake – and this is because of the effect it has on a neurotransmitter (a brain chemical) called adenosine.
Adenosine partially helps your body’s natural rhythm; it builds up in your brain throughout the day, and when it reaches a certain amount, your body knows it’s bed time. Then, while you sleep, your brain removes all the adenosine and you wake up to start the whole process again. This means as adenosine levels increase, the more tired you feel. However, caffeine blocks adenosine from building up and stimulates the release of other brain chemicals such as glutamate (which excites other cells in your brain), dopamine (which influences mood and memory) and serotonin (a major player in positive mood). Together, these chemicals stop you from feeling tired and perk you up nicely. The effects are powerful enough to have a real, measurable impact on depression and increase learning by up to 10%.
Furthermore, caffeine restricts the blood flow in the brain as adenosine dilates blood vessels – this can stop that ‘thumping’ headache in its tracks. This reaction may possibly be behind the effect caffeine has on strokes. Swedish data showed that women who drank more than one cup of coffee per day had a 22 to 25% lower risk of stroke compared to those who drank less; and those who drank low levels, or no coffee at all, appeared to be at an increased risk of stroke! And as if that wasn’t enough, caffeine studies have also shown evidence for a reduced risk of Alzheimer’s and Parkinson’s disease in habitual caffeine consumers.
These are only a selection of the benefits of caffeine, so yes, sometimes caffeine is a good idea. As long as you’re not regularly exceeding 400 mg per day, caffeine can be a powerful drug for your health. So, next time you make that morning coffee, maybe you don’t need to feel quite so guilty after all.
Annie Hill (Trainee Medical Writer, HealthCare21)