By: Pallavi Vathiar. Practicing Clinical Nutritionist, Mumbai.
“It feels so refreshing to sit near near the window-pane, enjoying the rain outside sipping your cup of hot coffee… Just you and your cup of coffee in hand!”
As much as it feels good to consume tea and coffee to boost your mood, it is only good when consumption is from low to moderate level where exceeding beyond the limit comes unpleasant and dangerous side effects which would harm your health on a long-term basis.
Caffeine works by blocking the effects of adenosine, a brain chemical that makes you feel tired. At the same time, it triggers the release of adrenaline, the “fight-or-flight” hormone associated with increased energy (1).
Extremely high daily intakes of 1,000 mg or more per day have been reported to cause nervousness, jitteriness and similar symptoms in most people, whereas even a moderate intake may lead to similar effects in caffeine-sensitive individuals (2,3).
One study in 25 healthy men found that those who ingested approximately 300 mg of caffeine experienced more than double the stress of those who took a placebo. Interestingly, stress levels were similar between regular and less frequent caffeine consumers, suggesting the compound may have the same effect on stress levels regardless of whether you drink it habitually (4).
Most of us feel that a morning cup of coffee helps get their bowels in motion.
Coffee’s laxative effect has been attributed to the release of gastrine, a hormone the stomach produces that speeds up activity in the colon (5).
In a small study, when five healthy adults drank caffeinated water, they experienced a relaxation of the muscle that keeps stomach contents from moving up into the throat — the hallmark of GERD (Gastro- Esophageal Reflux disease) (6).
It may lead to psychological or physical dependency, especially at high dosages.
In one study, 16 people who typically consumed high, moderate or no caffeine took part in a word test after going without caffeine overnight. Only high caffeine users showed a bias for caffeine-related words and had strong caffeine cravings (7).
In another study, 213 caffeine users completed questionnaires after going 16 hours without consuming it. Daily users had greater increases in headaches, fatigue and other withdrawal symptoms than non-daily users (8).
Rapid Heart Rate
The high caffeine intake may cause your heart to beat faster.
It may also lead to altered heartbeat rhythm, called atrial fibrillation, which has been reported in young people who consumed energy drinks containing extremely high doses of caffeine (9).
In one case study, a woman who took a massive dose of caffeine powder and tablets in an attempted suicide developed a very rapid heart rate, kidney failure and other serious health issues (10).
Caffeinated beverages are known to boost energy levels but they can also have the opposite effect by leading to rebound fatigue after the caffeine leaves your system.
One review of 41 studies found that although caffeinated energy drinks increased alertness and improved mood for several hours, participants were often more tired than usual the following day (11).
Light-to-moderate caffeine intake seems to provide impressive health benefits in many people. On the other hand, very high dosages may lead to side effects that interfere with day-to-day living and might even cause serious health issues (12).