The Health Benefits of Coffee
From The New York Times
Experts say some of the strongest protective effects may be with Type 2 diabetes, Parkinson’s disease, and liver conditions such as cirrhosis, liver cancer and chronic liver disease. For example, having about five cups of coffee a day, instead of none, is correlated with a 30 percent decreased risk of Type 2 diabetes, according to a meta-analysis of 30 studies.
The potential benefit from coffee might be from the polyphenols, which are plant compounds that have antioxidant properties, according to Dr. Giuseppe Grosso, an assistant professor in human nutrition at University of Catania in Italy and the lead author of an umbrella review in the Annual Review of Nutrition.
However, coffee isn’t for everyone. There are concerns about overconsumption. This is especially true for expecting mothers because the safety of caffeine during pregnancy is unclear. While the research into coffee’s impact on health is ongoing, most of the work in this field is observational.
“We don’t know for sure if coffee is the cause of the health benefits,” said Jonathan Fallowfield, a professor at the University of Edinburgh, and co-author of the British Medical Journal review. “These findings could be due to other factors or behaviors present in coffee drinkers.”
Does the way coffee is prepared matter?
Yes. Do you prefer a dark or light roast? Coarse grinding or fine? Arabica or robusta?
“All of these different aspects affect the taste, but also affect the compounds within the coffees,” said Neal Freedman, a senior investigator with the National Cancer Institute. “But it’s not clear at all how these different levels of compounds may be related to health.”
Roasting, for example, reduces the amount of chlorogenic acids, but other antioxidant compounds are formed. Espresso has the highest concentration of many compounds because it has less water than drip coffee.
A study in JAMA Internal Medicine examined the coffee habits of nearly 500,000 people in the U.K. and found that it didn’t matter if they drank one cup or chain-drank eight — regular or decaf — or whether they were fast metabolizers of coffee or slow. They were linked to a lower risk of death from all causes, except with instant coffee, the evidence was weaker.
The way you prepare your cup of joe may influence your cholesterol levels, too. “The one coffee we know not suitable to be drinking is the boiled coffee,” said Marilyn C. Cornelis, an assistant professor in preventive medicine at the Northwestern University Feinberg School of Medicine and co-author of the JAMA Internal Medicine study.
Examples of this include the plunge-happy French press, Scandinavian coffee, or Greek and Turkish coffee — the kind commonly consumed in the Middle East. (When poured, the unfiltered grounds settle on the tiny cup’s bottom like sludge. To peek into the future, elders in the region have a tradition of reading the sediment of an overturned cup, like a crystal ball.)
However, the oil in boiled coffee has cafestol and kahweol, compounds called diterpenes. They are shown to raise LDL, the bad cholesterol, and slightly lower HDL, what’s known as the good kind.
“If you filter the coffee, then it’s no issue at all,” said Rob van Dam, a professor at Saw Swee Hock School of Public Health at National University of Singapore. “For people with cholesterol issues, it’s better to switch to other types of coffee.” He’s been studying coffee for two decades. (And, yes, he’s had a lot of coffee in that time.)
However, other researchers say not to throw out the boiled coffee just yet. The clinical significance of such small increases in cholesterol may be questionable, given that it’s not associated with an increase in cardiovascular deaths.
Many consumers have also swapped loose grounds for coffee pods. While there are environmental concerns with single use pods, researchers believe them to hold the same benefits as, say, drip coffee. The latter applies to cold brew, too, but more research is needed.