When most people think of a healthful diet, fresh fruits and vegetables typically top the list.
Surprising: An eight-ounce cup of caffeinated or decaffeinated coffee contains more disease- fighting antioxidants than a typical serving of fresh blueberries or oranges.
Although coffee does not contain some of the other nutrients found in healthful foods, it is the main source of antioxidants in the American diet (followed by tea and chocolate, respectively). Of course, the stimulating effects of coffee's caffeine are not always desirable—some people experience nervousness, insomnia or even spikes in blood pressure.
But most people who drink moderate amounts of coffee (typically defined as one to three cups daily) seem to have a lower risk for a number of chronic conditions, including heart disease, diabetes and age-related cognitive declines.
WHAT'S IN A CUP?
The amount of caffeine that is found in coffee varies, depending on how the coffee is prepared.
Examples: One ounce of espresso contains about 50 mg...an eight-ounce cup of instant coffee has 95 mg...and eight ounces of plain, brewed coffee has 150 mg.
A serving of espresso, instant or brewed coffee each contains roughly the same amount of antioxidants. In fact, coffee contains hundreds of antioxidants, particubny polyphenols—plant compounds that can inhibit cell damage or inflammation, two of the main causes of many chronic diseases. The addition of milk and/or sugar does not appear to affect the antioxidant levels.
Important: Most of the research linking col fee to reduced disease rates is based on epidemiological studies, in which scientists have analyzed the past dietary habits of large groups of people.
This type of research helps to develop hypotheses that deserve further study, but definitive answers won't be possible until scientists conduct more large-scale clinical studies, in which factors such as coffee consumption are tightly controlled (rather than merely self-reported by test subjects).
What the newest research on coffee consumption tells us...
GOOD FOR THE ARTERIES
New finding: In a study published in the American Journal of Clinical Nutrition, Norwegian researchers found that postmenopausal women who drink one to three cups of coffee daily are 24% less likely to develop cardiovascular disease than non-coffee drinkers.
Theory: The antioxidants in coffee—like those in fruits and vegetables—are thought to inhibit the damaging effects of free radicals on cells lining the arteries.
Result: A decrease in inflammation, now thought to be the underlying cause of heart disease.
Caution: Because of the stimulating effects of caffeine, blood pressure rises temporarily (for about one hour) when regular coffee is consumed. People who drink several cups in a row may keep their blood pressure elevated, thus increasing the risk for heart disease or a heart attack.
Helpful: Space out coffee consumption. For example, have one cup in the morning and another at lunch or in the afternoon. Or switch to decaf, which doesn't cause the blood-pressure spikes of regular coffee—but offers the same health benefits, except for those that improve cognitive function.
BLOOD PRESSURE STABILIZER
New finding: An analysis published in the American Journal of Clinical Nutrition found that older adults (age 65 and over) who have four or more daily servings of caffeine—in the form of coffee, soft drinks, etc.—have less than half the risk of dying of heart disease than those who consume smaller amounts.
Theory: Older adults are prone to occasional hypotension (low blood pressure). They are especially vulnerable to drops in blood pressure after meals, which can increase the risk for heart attack. Caffeine, by quickly raising blood pressure, appears to reduce the risk for such coronary events.
Caution: The oils found in steeped coffee, such as that made in a French press (a glass beaker to which hot water and ground coffee are added...then a plunger is depressed, filtering out all the grounds and sediment), can significantly raise cholesterol and increase the risk for elevated blood pressure.
Better for health: Coffee that is drip brewed (water is poured over ground coffee and seeps through a filter into a pot). The filter traps most of the oils.
New finding: Research published in the Archives of Intemal Medicine found that among 28,812 postmenopausal women studied, those who drank four to five cups of coffee (especially decaffeinated) per day were 16% less likely to develop type 2 diabetes than women who didn't drink any coffee.
Theory: The antioxidants in coffee may protect the pancreas's insulin-producing beta cells from oxidative damage.
BETTER BRAIN HEALTH
New finding: Coffee appears to slow the rate of cognitive decline in elderly adults. In a study published in the European Journal of Clinical Nutrition researchers gave memory tests to 676 healthy men in Finland, Italy and the Netherlands, then repeated the tests 10 years later. Non-coffee drinkers had four times more cognitive decline than men who drank three cups of coffee a day.
Theory: The antioxidants in coffee reduce age-related damage to brain cells (neurons) and/or cause beneficial changes in the hormones/neurotransmitters that are involved in cognitive function.
Scientific studies also suggest that moderate consumption of coffee reduces the risk for Parkinson's disease as well as Alzheimer's disease. Researchers have yet to explain why coffee reduces risk for these two diseases, but the mechanism is thought to be similar to that associated with reduced cognitive decline.
A HEALTHIER LIVER
New finding: According to research published in the Archives of Internal Medicine, coffee may reduce the risk for cirrhosis (irreversible liver scarring that, in severe cases, can be life-threatening without a transplant), especially in alcoholics. This link may be due to the anti-inflammatory effects of the antioxidants in coffee.
In addition, coffee may help protect against gallstones. Specifically, data from the ongoing Harvard Nurses' Health Study found that women who drank four or more cups of coffee daily required fewer operations for gallstones than women who didn't drink coffee.
Theory: Caffeine stimulates gallbladder contractions, which cause the gallbladder to empty more often and may reduce the risk for gallstone formation.
Caution: Caffeine interacts with certain medications, causing some to become more potent or increasing the amount of time caffeine remains in the body. These drugs include certain selective serotonin reuptake inhibitors (SSRIs), such as fluvoxamine (Luvox). . . antiarrhythmics, such as mexiletine...and bronchodilators, such as theophylline. Caffeine also may interact with the herbal dietary supplement ephedra. In addition, consumption of more than five cups of coffee daily has been linked to higher risk for bone fractures in postmenopausal women.