Coffee is one of the world's most popular drinks, but it didn’t get there through its health virtues. Most people started drinking their cups of Joe to feel more alert and awake, to get them through classes or work. And yet scientific study after scientific study has appeared reporting the hidden health benefits of the liquid lightning. Here, we take you through some of the greatest of this year alone – to vindicate people who drink it religiously, and to guilt those who don't drink it, to start.

Longer Lives

Researchers from the National Institutes of Health and the AARP, led by Neal D. Freedman, conducted a longitudinal study beginning in 1995 and ending in 2008. From the beginning, over 400,000 people participated, ranging in age from 50 to 71 years old. All were relatively healthy at the beginning of the trial, with none reporting a history of heart disease, stroke or cancer. Of that number, 50,000 passed away during the course of the trial. Interestingly, they found that people who drank three or more cups of coffee a day had a 10 percent chance of living longer than their coffee-abstaining peers. Coffee protected against various forms of death with the exception of cancer.

Alzheimer's Disease

In older adults, people who drank three cups of coffee daily had lower instances of dementia and Alzheimer's disease. The participants in the study were all over 65 years old and were already suffering from slight memory impairment. The University of South Florida's Chuanhai Cao and colleagues found that, of the coffee drinkers followed over the course of four years, not one developed Alzheimer's disease. For those studied who did develop dementia, their blood caffeine levels were 51 percent lower than those whose cognitive impairment remained level.

Skin Cancer

Jiali Han, PhD, an associate professor at Harvard conducted a study with her colleagues that found that coffee decreases the risk of developing the most common form of skin cancer, basal cell carcinoma. In fact, the more cups of coffee that you drink, the greater that the benefit seemed to be. They studied 112,897 people, 22,786 of whom developed basal cell carcinoma. But as coffee consumption increased, the less likely they were to develop the cancer. Further studies will test if the link is correlative or causative.

Heart Failure

Researchers had been more equivocal about the link between coffee consumption and heart health. With every article released that touted the link between coffee and positive heart health, another one stated the opposite, giving readers whiplash. Elizabeth Mostofsky, MPH, ScD, from Beth Israel Deaconness Medical Center, and her colleagues found that coffee is good for your heart – until the fourth cup of European-sized coffee, or the second American size. Before that point, however, coffee drinkers had an 11 percent decreased risk of suffering from heart failure.

Risk of Stroke

Investigators at Cleveland Clinic's Wellness Institute and Harvard University found that drinking coffee – even decaffeinated coffee – can decrease the risk of strokes, because coffee is filled with beneficial antioxidants. When compared against soda, which elevated the risk of strokes, coffee was associated with a 10 percent decrease in stroke risk.

Parkinson's Disease

Dr. Ronald Postuma from McGill University and colleagues found, in a study published this month, that coffee can lessen the symptoms of Parkinson's disease. In 61 patients with Parkinson's disease, participants were given 100 milligrams of caffeine pills for two weeks and 200 for the following two weeks, which add up to two to four cups of coffee, respectively. The caffeine helped to boost movement control and muscle stiffness for people with Parkinson's disease, though, interestingly, it did not help with their sleepiness. Though the effect was a moderate one, coffee is so easy to make or buy, and is so cheap, that the researcher considered the benefit worthwhile to Parkinson's sufferers.

Bonus: Decaf Benefit

The Mount Sinai School of Medicine found that decaffeinated coffee helped to ward off, and possibly treat, cognitive decline. The study, conducted by Giulio Maria Pasinetti, PhD, MD, professor of neurology and psychiatry, and his colleagues, administered decaffeinated coffee to mice over the course of five months, and then evaluated the brain's response. Their findings hold particular weight for sufferers of the increasingly common type-2 diabetes, because the brain metabolizes glucose better when drinking decaffeinated coffee on a regular basis.