• Caffeine is most commonly found in coffee."coffee" is Copyrighted by Flickr user: Jennie Faber (Jennie Faber) under the Creative Commons Attribution license.
  
  

Caffeine

• According to the International Food Information Council, caffeine is a stimulant found in the leaves, seeds and fruits of more than 60 plants. Popular sources include coffee and cocoa beans, kola nuts and tea leaves. In addition, caffeine is used as a seasoning in certain foods and beverages.
  
  

Foods and Beverages with Caffeine

• Besides coffee and tea, caffeine is found in soft drinks and chocolate. Coffee is usually the highest source of caffeine. According to the IFIC, an 8-oz. cup of brewed coffee typically contains 85 milligrams of caffeine, while an 8-oz. cup of instant coffee has 75 milligrams. An 8-oz. cup of tea can pack anywhere from 20 to 110 milligrams. Disabled-world.com reports that a 1.45-oz. bar of chocolate contains 27 milligrams, pain relievers have 60 milligrams, and a 12-oz. can of Pepsi has 37.5 milligrams.
  
  

Effects

• Disabled-world.com also says caffeine can increase blood pressure quickly, though it is not permanent, particularly in people who do not ingest caffeine on a regular basis. Caffeine is linked to the obstruction of certain hormones that help widen arteries, and tightened arteries can lead to high blood pressure.
  
  

Coffee and Hypertension

• The American Heart Association has found that caffeine does no harm to the blood pressure of those who consume coffee in moderation every day. The AHA also says that even though caffeine's effects on hypertension have been thoroughly researched, results have not "produced any widely accepted conclusions." The organization concludes that drinking two to four cups of brewed coffee daily does not significantly increase blood pressure in those who do not already suffer from hypertension.
  
  

Energy Drinks

• Energy drinks can contain high amounts of caffeine. For instance, one bottle of Red Bull has 80 milligrams of caffeine. According to an AHA study, young adults who were given two energy drinks daily for a week registered blood pressure readings higher after ingesting them. The organization says that further research is needed and that those with high blood pressure should avoid consuming energy drinks.