For years, coffee has been at the center of a heated debate. Viewed as a benign, guilty pleasure by some, American's favorite beverage has been branded a major health hazard by others.

In the past decade, however, a growing body of scientific evidence supports the notion that moderate coffee consumption offers a number of important perks, especially for the brain.

The results of a study published last year in the medical journal Neurology revealed that coffee consumption protected elderly women from memory loss. Compared to those who did not drink coffee, female coffee drinkers were found to be 30 percent less likely to have memory decline at age 65, and 70 percent less likely to have memory decline at age 80 or older.

In an article published in the April 3, 2008 edition of the Journal of Neuroinflammation, researchers at the University of North Dakota School of Medicine and Health Sciences served up more good news for coffee lovers. Their findings suggest that a daily jolt of java may do more than just boost your brain power — it might even help protect you from Alzheimer's disease.

Alzheimer's disease is an important public health problem in the U.S., one that is expected to worsen in coming years. Currently, this devastating condition affects one in eight Americans over the age of 65 and nearly half of adults aged 85 and older.

Several previous studies established a link between coffee consumption and a lower risk for various types of dementia, including Alzheimer's. Until now, the reasons for this association were poorly understood.

University of North Dakota researchers speculated that the caffeine in coffee could help protect the blood brain barrier from damage caused by a high-cholesterol diet. A semipermeable structure, the blood brain barrier helps shield the central nervous system from potentially harmful substances in the bloodstream.

Long-term consumption of foods rich in saturated fat and cholesterol — typical of the American diet — is known to damage the blood brain barrier and compromise its ability to protect the brain. Individuals with high cholesterol levels are believed to have an elevated risk for Alzheimer's disease.

In the current study, rabbits were given 3 milligrams caffeine each day, the equivalent of a daily cup of coffee for an average-sized adult.

The animals were also fed a cholesterol-enriched diet.

After 12 weeks, a battery of laboratory tests revealed that caffeine consumption appeared to protect the blood brain barrier from damage associated with cholesterol-rich diets. Based on their findings, the researchers concluded that caffeine and drugs similar to caffeine might be useful in the treatment of Alzheimer's disease.

Coffee might also help protect against Alzheimer's disease in other ways. After an 18-year study involving more than 120,000 adults, Harvard researchers concluded that coffee drinkers were significantly less likely to develop type 2 diabetes than those who abstained.

Diabetes is a known risk factor for Alzheimer's disease, since high blood sugar levels can irreversibly damage blood vessels in and around the brain. Following a six-year study of more than 800 adults, researchers at Rush University Medical Center in Chicago concluded that compared to non-diabetic individuals, diabetics faced a 65 percent greater risk of developing Alzheimer's disease.

Most folks don't consider coffee a health elixir, but there's no doubt that it is a plant-based beverage. Like other plant-based beverages, including wine and tomato juice, coffee is rich in disease-fighting antioxidants.

While fruits, vegetables, grains and nuts are undoubtedly better sources of antioxidants, the vast majority of Americans don't even come close to eating the recommended amounts of these wholesome, nutritious foods on a daily basis. Data from the National Health and Nutrition Examination Survey reveals that only about 11 percent of Americans meet the current USDA guidelines for fruit and vegetable consumption.

Nearly 52 percent of Americans adults do, however, drink coffee on a daily basis and another 25 percent drink coffee on occasion, according to surveys conducted by the National Coffee Association. Given this data, it's not surprising that coffee is the largest source of antioxidants in the typical American's diet.

A cup of coffee offers a number of potential health benefits, but there's really no advantage to drinking an entire pot or adding lots of sugar, cream and artificial flavorings. If you drink your coffee unadorned and in moderation, you can relax and enjoy all the perks it has to offer — guilt free.

Rallie McAllister is a board-certified family physician, speaker and the author of several books, including "Healthy Lunchbox: The Working Mom's Guide to Keeping You and Your Kids Trim." Her website is www.rallieonhealth.com. To find out more about Rallie McAllister, M.D., and read features by other Creators Syndicate writers and cartoonists, visit the Creators Syndicate Web page at www.creators.com.

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