Possible Caffeine Benefits
If you asked people what the biggest benefit to caffeine is, most would probably list the lift in energy and mood. But there may be other health benefits to caffeine, as well as to other components in coffee and tea. (All you veteran java junkies should note that some of caffeine's effects may lessen with long-term consumption.)
Here's what research has found out about some of the possible benefits of coffee, tea, and caffeine:
- Some researchers suggest that the caffeine in coffee may increase the body's sensitivity to insulin. (This is a good thing; insulin is a hormone made by the body to control blood sugar.) In fact, a recent review of nine studies on coffee consumption and risk of type 2 diabetes supports the idea that habitual coffee consumption is associated with a lower risk of the disease. Other research has found that some compounds in tea may increase insulin activity in fat cells by as much as 15 times. Still, other research has reported that caffeine impairs the metabolism of glucose (a type of sugar found in carbohydrate foods) in people with type 2 diabetes.
- Chlorogenic acid, a compound in coffee that has antioxidant activity, may improve the body's metabolism of glucose.
- Drinking four or more cups of coffee a day has been linked to a reduced risk of colon cancer (compared with drinking no coffee at all). Studies in animals have indicated that an antioxidant in coffee may protect against colon cancer.
- Studies looking at coffee and heart disease risk are all over the map. One study found that drinking two or fewer cups of coffee a day reduced the chance of a first heart attack or chest pain, while drinking more coffee appeared to have the opposite effect. Other study results differed. Future research should pay attention to the type of coffee used and the different brewing methods because this affects which compounds show up in your cup. For example, filtered coffee removes two compounds that are known to raise both total and LDL "bad" cholesterol levels (the filters trap these compounds).
- Tea contains powerful antioxidants (polyphenols, which are in the flavonoid phytochemical family) that may help protect against cancer, heart disease, and stroke. A Dutch study found that men who ate and drank the most flavonoids (black tea was the major source) had a much lower risk of heart disease.
- Preliminary research suggests that the flavonoids in green tea may help reduce cancer risk.
- More research is needed on this, but it has been suggested that green tea may help boost metabolism and lower body fat.
- According to one study, older women (aged 65-76) who drank tea had higher bone mineral density measurements than women who did not drink tea. The authors propose that the compounds in tea may improve bone mineral density and that drinking tea may protect against osteoporosis. By comparison, another study noted that consuming more than 300 mg of caffeine per day sped up bone loss in the spines of postmenopausal women aged 65-77.
- While fruits and vegetables are thought to be the richest sources of health-promoting antioxidants, a recent study found that coffee is the main source from which most Americans get their antioxidants.