The Pros: When Caffeine Helps
- Sleep Deprivation: Caffeine combats drowsiness by tricking your brain into feeling alert. It temporarily blocks adenosine, a naturally sedating brain chemical, to prevent fatigue. Without a full night’s sleep, you’ll wake with more adenosine in your brain than normal. A hit of caffeine neutralises adenosine and helps you feel less sleepy.
- Workouts: “Caffeine can improve physical performance in an endurance exercise like running, but the effect is less for short bursts of movement,” says Matthew Ganio, a professor of kinesiology at the University of Arkansas. Caffeine prompts the body to burn more fat stores instead of the limited stores of carbohydrate in our muscles. When the muscles run out of carbohydrate, you get tired. The benefit may be smaller in regular caffeine users.
- Parkinson’s: Several large studies have found that people who drink several cups of coffee a day have a lower risk of developing Parkinson’s disease. Parkinson’s patients gradually lose the nerve cells that produce the neurotransmitter dopamine. Caffeine may protect those nerve cells.
- Painkiller: When a headache comes on, the blood vessels in your brain widen; caffeine constricts them. It’s also a mild pain reliever.
The Cons: When Caffeine May Hurt
- Pregnancy: Women who are pregnant or trying to become pregnant should consume no more than 200mg of caffeine a day because the harmful effects of more than that on fertility and foetal health cannot be ruled out, according to perinatal organisations.
- Disrupted Sleep: “People don’t realise how much caffeine affects their sleep,” says Laura Juliano, a professor of psychology at American University in Washington. “For those who are slow metabolisers of caffeine, there’s still enough in their system to disrupt sleep at night even if they stop consuming it much earlier in the day.”
Neutral Ground: When Caffeine Doesn’t Matter
- Heart Rhythm: In a study of more than 130,000 men and women for 30 years, drinking coffee (regular or decaf) didn’t increase the risk of cardiac arrhythmias, even among those with existing heart conditions.
- Weight: Many companies add caffeine to weight-loss pills to speed up the metabolic rate, at least for a short period of time. Yet “there’s little evidence that consuming caffeine leads to significant weight loss or helps people keep weight off,” says Ganio.
- Blood Pressure: While caffeine users experience modest increase in blood pressure, long-term studies don’t show a clear link between coffee consumption and the development of hypertension, notes Rob van Dam of the National University of Singapore.
Source: Center for Science in the Public Interest (December 2012), © 2012 by nutrition.com, nutritionalaction.com