How Does Caffeine Affect Life Expectancy?

Caffeine is the most commonly consumed psychoactive drug in the world. That cup of coffee may make it easier to get through the day, but how does it affect your longevity? Rest assured, research studies have associated regular coffee consumption, in moderation, with a decreased risk for certain diseases; however, no overall effect on life expectancy was seen in studies to date.

Effects

Caffeine is a member of a class of molecules called methylxanthines that block the activity of the neurotransmitter adenosine. The decrease in brain adenosine levels cause a concurrent rise in the levels of other neurotransmitters, leading to feelings of energy and alertness. Moderate caffeine consumption, not exceeding 200 to 300 milligrams daily, is not known to have any adverse health effects, according to the Mayo Clinic. A 200- to 300-milligram dose of caffeine is equivalent to two to four cups of coffee. However, high consumption of caffeine, 500 to 600 milligrams or more, can cause elevated stress hormones, high blood pressure and heart rate, difficulty focusing or sleeping, gastrointestinal issues and muscle tremors.

Overall Risk

Regular caffeine consumption, normally measured by coffee consumption, does not appear to raise mortality risk or decrease life expectancy. Other caffeine sources, such as energy drinks, have not existed long enough to conduct large studies on morbidity. Tea contains much less caffeine than coffee. A 2008 study in the "Annals of Internal Medicine" and a 2010 study in the "Journal of Nutrition" found no effect of reported caffeine or coffee consumption on overall mortality. There appears to be a decreased risk of mortality from heart disease, especially coronary heart disease, although the statistical significance of the effect is questionable.

Specific Risk

Caffeine and other components of brewed coffee may actually be beneficial for you. A 2004 study in the "Annals of Internal Medicine" found that moderate coffee consumption was associated with a decreased risk of developing type 2 diabetes. Similarly, a 2011 study in the journal "Stroke" found that women who did not drink coffee, or drank it rarely, had an increased risk of stroke. However, caffeine may worsen inflammation, especially in liver disease and certain cancers, according to a 2011 review in the "Handbook of Experimental Pharmacology."

Research Considerations

The health benefits and risks of caffeine are by no means a closed book. Most studies have used coffee consumption as a metric of caffeine intake. It is possible that other chemicals in coffee offset effects of caffeine itself. Most studies relied on participants to report their normal coffee or caffeine consumption, a metric that is subject to error.

Recommendations

If you drink coffee in moderation, less than four cups daily, you needn't change your habits. High caffeine intake may indirectly affect your stress level, a known risk factor for many diseases. Caffeine may worsen some disorders and diseases once they develop, so consult with your physician concerning your caffeine consumption if you are currently under treatment.