7 facts about caffeine

1. Caffeine is good for both short-term and long-term memory. Early studies have found that caffeine helps short-term memory, and recent studies have found that caffeine is also good for long-term memory. Dr. Jacklin London, a senior nutritionist at Mount Sinai Hospital in New York, said that consuming 300 to 400 mg of caffeine a day can help prevent cognitive decline and Alzheimer's disease.

2. Caffeine can improve athletic performance. Drinking coffee one hour before a competition can improve your performance. The reason is that caffeine can increase alertness and shorten reaction time.

3. Caffeine can instantly refresh you. Caffeine easily crosses the blood-brain barrier and quickly stimulates the central nervous system. You will feel refreshed immediately after taking caffeine, and the euphoria will reach its peak after 30 to 60 minutes.

4. The caffeine content in coffee varies greatly. A study published in the Journal of Analytical Toxicology found that a 16-ounce (about 454 ml) cup of a famous brand of coffee contained 100 mg more caffeine than the same amount of other coffees. The study also showed that even the same brand of coffee can have different caffeine contents in each bottle, which can vary by up to 300 mg. Dr. London said that a 16-ounce cup of standard coffee contains between 90 and 225 mg of caffeine.

5. The caffeine content of espresso is much lower than that of regular coffee. Everyone thinks that espresso must have the most caffeine. However, Dr. London said that the caffeine content of a cup of espresso is only 40 to 70 mg, which is much less than the same amount of regular coffee. Therefore, if you are sensitive to caffeine, it is best to choose espresso such as cappuccino.

6. Caffeine does not cause dehydration. According to the U.S. Food and Drug Administration, since 98% of caffeine is ingested through beverages, you are also replenishing water while consuming caffeine. Therefore, although caffeine is a diuretic, it will not really cause dehydration. However, coffee should be consumed in moderation. Drinking water is the gold standard for hydration.

7. Caffeine does not only come from beverages. Chocolate is also a major source of caffeine. Caffeine is also found in certain foods and even in medications such as painkillers. People with heart disease or high blood pressure should seek professional medical advice before taking caffeinated painkillers.