Story highlights

New studies add to growing evidence for the health benefits of coffee

Personal factors like age and genetics can reduce those benefits

The method you use to brew your coffee can make a health difference

CNN  — 

Myth or fact? Coffee is good for you.

If you chose fact, you’re right. New studies this week add to dozens more reporting the health benefits of coffee, including protection from type 2 diabetes, Parkinson’s disease, liver disease, prostate cancer, Alzheimer’s, computer back pain and more.

But if you chose myth, you’d also be right. There are times when coffee is bad for you, and it depends on your genetics, your age and even how you make your coffee.

Good to the last drop

Coffee lovers rejoice! There are more studies than ever encouraging you to sip for your good health.

A huge study of more than 25,000 coffee drinkers in South Korea shows that moderate daily consumption – that’s three to five cups a day – is associated with a decreased risk for coronary artery calcium. CAC is a great predictor of future heart disease and hasn’t been studied much in the past.

Four cups of coffee a day was also recently found to moderately reduce one’s risk for melanoma, a highly dangerous skin cancer. It has to be leaded, though; in the study decaffeinated coffee didn’t provide any protection. The study supports a previous finding of a link between coffee and a reduced risk for basal cell carcinoma, the most common type of skin cancer.

Another recent study looked at coffee consumption and multiple sclerosis. It found high coffee intake – that’s four to six cups a day – reduced the risk of getting MS. So did drinking a lot of coffee over five to 10 years. Researchers now want to study coffee’s impact on relapses and long-term disability in MS.

Add this to the existing research on Parkinson’s and Alzheimer’s, and investigators now believe coffee could be neuroprotective, meaning that it is possible the drink is suppressing the production of inflammatory markers in the brain. And it may be more than the caffeine in coffee that’s responsible. Researchers are starting to look at other compounds in coffee that may help as well.

Coffee may reduce women’s cancer risk

Before you run off to your favorite coffee spot for a double mocha latte, note one thing about these studies.

Most research defines a “cup” of coffee at 5 to 8 ounces, about a 100mg of caffeine, and black or maybe with a bit of cream or sugar. It is not one of those 24-ounce monsters topped with caramel and whipped cream.

Chock full o’ studies

Coffee has been studied a lot, and not just recently.

The Harvard Health Professionals Follow-Up Study, which began in 1986, and the Nurses’ Health Study, which started in 1976, have been following coffee consumption habits of healthy men and women for decades.

“We did not find any relationship between coffee consumption and increased risk of death from any cause, death from cancer, or death from cardiovascular disease. Even people who drank up to six cups of coffee per day were at no higher risk of death,” writes Dr. Rob van Dam of Harvard’s School of Health.

Coffee drinking linked to longer life

So why was coffee given a bad rap for so long?

Earlier studies didn’t always factor out serious health behaviors that used to go along with coffee, such as smoking and a lack of physical activity. Today’s coffee drinker doesn’t necessarily fit that mold and researchers are more likely to screen for those behaviors in their results.

Make mine a tea

While the health benefits of coffee keep rolling in, the complete story isn’t so rosy. In some studies, very high consumption – six or more cups a day – reduced the benefits.

Some populations can find coffee consumption potentially harmful. People with sleep issues or uncontrolled diabetes may need to ask their doctors before adding caffeine to their diets. There’s also a concern about caffeine use among youths.

And there’s a genetic mutation many of us have that can affect how fast our bodies metabolize caffeine. The gene is called CYP1A2 – if you have the slow version, it would explain why you crawl the walls after only a cup or two or why it might contribute to your high blood pressure.

Women should take particular note. Coffee may increase menopausal hot flashes. And pregnant women might be more likely to miscarry – the jury is still out – but caffeine does reach the fetus and might restrict growth. Doctors recommend only a cup a day during pregnancy.

And interestingly enough, the way you make your coffee could also make a health difference – there’s a compound called cafestol in the oily part of coffee that can increase your bad cholesterol or LDL. It’s caught in the paper filters, so as long as you use those to make your morning joe, you should be fine. But if you’re a lover of French press, Turkish coffee or the boiled coffee popular in Scandinavian countries, you could be putting your health at risk.

For many of us, coffee is a blessing. And as long as you avoid its pitfalls, current science seems to be saying you can continue to enjoy it, guilt free.

Coffee good for you, but it’s OK to hold back