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Caffeine Ingestion Decreases Insulin Sensitivity

It feels as though there are never enough hours in a day to complete everything we need to accomplish. Everyone is always playing catch-up trying to finish tasks that are a day or two behind schedule, the corporate world work long hours and those with children are always racing to pick them up from school and take them to soccer practice and other after school activities.

In order to endure the early mornings and late nights required to meet the demands of today’s busy schedules many turn to caffeine. A cup of coffee or two in the morning, maybe some tea at lunch and the occasional caffeine sports drink to get through the afternoon but how much caffeine are we taking in everyday ?

Caffeine consumption has greatly increased over the past 20 years and some authors suggest a mean daily caffeine intake for US consumers of 4 mg/kg meaning the average 75kg adult ingests about 300 mg of caffeine a day. Research shows a connection between caffeine ingestion and the reduction of insulin sensitivity in healthy subjects. When there is a reduction in insulin sensitivity the pancreas of increase the amount of insulin it normally releases in order to decrease the levels of glucose in the blood. A long-term decrease insulin sensitivity is referred to as insulin resistance and is a problem that can progress into type II diabetes. The decrease in insulin sensitivity caused by caffeine can affect healthy people without a history of diabetes although only for a brief period of time.

Contrary to its acute effects, caffeine is also reported have a positive long term benefit of reversing the aging-induced insulin resistance in rats. However, there is also a protective effect of decaffeinated coffee against diabetes, indicating that components of coffee other than caffeine are responsible for the presumptive beneficial effect.

Future research involving long term caffeine ingestion in healthy patients may hold the key to another step in the prevention of insulin resistance and type II diabetes mellitus. Until that research is released caffeine addicts have two choices, decrease the amount they consume or continue to ingest large amounts hoping the benefits in humans are the same as in the rats.



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Juan Antonio Aguilar Garcia, M.D.

Having the knowledge to help people live healthier and longer lives is a privilege. Sharing that knowledge with the world is an obligation.