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Health & Lifestyle Articles

Lifestyle Management

We will be bringing you a series of articles on lifestyle management. The first of these is one that talks of caffeine and its effect on the human body. Keep visiting this space for more articles.

Caffeine and your body

Caffeine (C 8 H 10 N 4 O 2 ) is a chemical that stimulates the central nervous system. It belongs to a class of organic compounds called alkaloids, which also include morphine, codeine, LSD, cocaine and nicotine. Caffeine is found in a variety of food items, including coffee, tea and chocolate. Varying amounts is found in over 60 plants, including the following:

People have been consuming caffeine since the first pot of tea was brewed in China around 2700 B.C. It is widely used for its ability to help people wake up, stay alert, maintain energy levels and respond quickly. Today, almost 50 percent of people in the United States have at least one cup of coffee per day, and about 70 percent of people drink it in the United Kingdom. In India, tea is more popular in the North, East and parts of the West, while South Indian can seldom do without their morning cup of "filter coffee". While there is no unanimous opinion on the addictive powers of caffeine, a lot of research points to it being an addictive substance.

Studies have also suggested that high levels of caffeine consumption canincrease the risk of certain cardiovascular conditions. Drinking more than five cups of brewed (filter) coffee daily (more than 687 milligrams of caffeine per day) could increase risk of cardiac arrest. Other studies have shown that caffeine can:

Research also suggests that drinking coffee is associated with higher cholesterol levels.

Most experts encourage people to use caffeine only moderately - between 250 and 350 milligrams per day - because there are very few studies that have associated moderate caffeine use with health risks. However, extraordinarily high caffeine intake (150 milligrams per kilogram of body weight) can be fatal, and even moderate caffeine intake can create symptoms of caffeine overdose in some people. Symptoms of caffeine overdose include the following:

Amount of caffeine in some common food items:

Food item Amount of caffeine (in mgs)
Milk Chocolate, 1 oz 1-15
Coffee ice cream ( ½ cup) 20-30
Chocolate ice cream (1/2 cup)
Filter Coffee (8 oz)
60 - 160
Instant Coffee (8 oz)
30 - 120
25 -110
Soft drinks
15 - 50

Effects of caffeine on the body

Once consumed, caffeine quickly enters the bloodstream through the stomach and small intestine. It travels through the bloodstream and goes directly to the central nervous system. There, it stimulates certain chemicals in the brain that produce an energizing effect on the body. This effect can be felt approximately 15 to 45 minutes after consumption, and reaches a peak within 30 to 60 minutes.

Scientists originally thought that caffeine stimulated the central nervous system by doing the exact opposite of what tranquilizers were doing. However, further research revealed that caffeine's stimulating effect is due to its relationship with a chemical called adenosine, which appears to be the body's natural sleep-enhancer. Normally, an adenosine molecule fits neatly into the receptor on a cell like a key fitting neatly into the ignition, which turns on the cell's activity and facilitates sleep. However, caffeine fills some of those receptors - like gum in the ignition - so that fewer adenosine molecules can get in to turn on the cells' activity. Consequently, the body's natural sleep-enhancing effect is partially blocked, and the person feels less fatigued and more alert.

Caffeine neither accumulates in the bloodstream nor is stored in the body. The half-life of caffeine is roughly five to seven hours, meaning that it will take about that long for 50 milligrams of caffeine to be metabolized (broken down) after 100 milligrams have been consumed. Until the liver has fully broken down the caffeine (getting the gum out of the ignition), the central nervous system will continue to be stimulated. Once broken down, however, caffeine is then quickly expelled from the body through urine, breast milk, saliva or semen.