We are often asked whether coffee is good or bad for the health. The answer is both good and bad.
Many studies have been done that show no overall adverse outcome on health associated with caffeine from coffee. However, there are certain aspects of coffee drinking that may be deleterious to health.
-The Nurses' Health Study and Health Professions Follow-up study done on 130,000 people tracked caffeine consumption for approximately 20 years and found that coffee does not increase mortality.
There was no relationship found between coffee consumption and increased risk of death from any cause including cancer or heart disease.
-Studies around the world consistently show high consumption of caffeinated or decaffeinated coffee is associated with low risk of type 2 diabetes, so scientists hypothesize there may be a long-term benefit from caffeine on diabetes.
-Other preliminary research has shown that coffee may protect against Parkinson's disease, liver cancer and liver cirrhosis, as well as a reduced risk of cardiovascular disease.
-A study led by Harvard School of Public Health researchers published in the Sept. 26, 2011, issue of the Archives of Internal Medicine, found that, among women, drinking coffee may reduce the risk of depression. The study found the risk of depression to be 20 percent lower among women who drank four or more cups of caffeinated coffee than those who drank little or none. Those who drank decaf, tea, soft drinks, chocolate and other beverages containing less caffeine did not appear to be protected against depression.
-Caffeine has been shown to increase alertness and test performance.
-Coffee contains cafestol, which increases LDL cholesterol levels. Usually, this is resolved by using a paper filter. However, if you drink your coffee boiled and unfiltered, via French press, or Turkish style, you will ingest large levels of cafestol. Unfiltered coffee has been shown in some studies to increase LDL by 8 percent.
-There may be a short-term negative effect on diabetes with coffee. In studies that give people caffeine or caffeinated coffee, followed by something rich in glucose, it was found that the subjects' sensitivity to insulin dropped and their blood-glucose levels were higher than expected.
-Coffee prepared black, or with a small amount of milk and sugar may be healthy. However, most coffee drinks contain large amounts of processed sugar, syrups, cream and whipped cream - which can increase blood sugars and cholesterol levels. Further, many coffee drinks have upward of 500 calories - 25 percent of the total calories that are needed for a 2,000-calorie-per-day diet. Thus, the calories alone in these drinks can lead to weight gain.
-Coffee drinking as a lifestyle behavior appears to be linked to other negative lifestyle behaviors, such as exercising less, a less-healthy diet and increased smoking. Thus, whereas coffee may be neutral on the health, other associated behaviors may cause adverse health outcomes.
Explore further: Is there a link between coffee drinking and mortality?