HEALTH TALK: Pros and cons of coffee

Coffee may taste good and get you going in the morning, but how will it affect your health?

A growing body of research shows that coffee drinkers, compared to non-drinkers are:

•    Less likely to have type 2 diabetes, Parkinson’s disease, and dementia.
•    Have fewer cases of certain cancers, heart rhythm problems, and strokes.

Some experts say there is certainly much more good news than bad news, in terms of coffee and health. But, they say, coffee isn’t proven to prevent those conditions.

Researchers don’t ask people to drink or skip coffee for the sake of science. Instead they ask them about their coffee habits. Those studies can’t show cause and effect. It’s possible that coffee drinkers have others advantages, such as better diets, more exercise, or protective genes.

So there isn’t solid proof. But there are signs of potential health perks – and a few cautions.

Here is a condition-by-condition look at the research.

TYPE 2 DIABETES

One expert calls the data on coffee and [type 2] diabetes, “pretty solid,” based on more than 15 published studies. He says that the vast majority of those studies have shown a benefit of coffee on the prevention of diabetes, and that there is also evidence that decaffeinated coffee may have the same benefit as regular coffee.

How might coffee keep diabetes at bay?

“It’s the whole package,” says this one expert. Antioxidants – nutrients that help prevent tissue damage caused by molecules called oxygen-free radicals – have been pointed to. Coffee does have a very strong antioxidant capacity.

Coffee also contains minerals such as magnesium and chromium, which help the body use the hormone insulin, which controls blood sugar. In type 2 diabetes, the body loses its ability to use insulin and regulate blood sugar effectively.

It’s probably not the caffeine, though. Studies allow researchers to safely say that the benefits are not likely to be due to caffeine.

HOLD THE CAFFEINE?

Just because coffee contains good stuff, it does not necessarily follow that it’s good for us. It has not really been shown that coffee drinking leads to an increase in antioxidants in the body. We know that there are antioxidants in large quantities in coffee itself, especially when it’s freshly brewed, but we don’t know whether these antioxidants appear in the bloodstream and in the body when the person drinks it. Those studies have not been done.

Regular coffee, of course, also contains caffeine. Caffeine can raise blood pressure, as well as blood levels of the fight-or-flight chemical epinephrine (also called adrenaline).

HEART DISEASE AND STROKE

Coffee may counter several risk factors for heart attack and stroke.

First, there’s the potential effect on type 2 diabetes risk. Type 2 diabetes makes heart disease and stroke more likely.

Besides that, coffee has been linked to lower risks for heart rhythm disturbances (another heart attack and stroke risk factor) in men and women, and lower risk for strokes in women.

And, for women, coffee may mean a lower risk of stroke.

In 2009, a study of 83,700 nurses enrolled in the long-term Nurses’ Health Study showed a 20% lower risk of stroke in those who reported drinking two or more cups of coffee daily, compared to women who drank less coffee or none at all. That pattern held regardless of whether the women had high blood pressure, high cholesterol levels, and type 2 diabetes.

PARKINSON’S AND ALZHEIMER’S DISEASES

For Parkinson’s disease, the date have always been very consistent: higher consumption of coffee is associated with decreased risk of Parkinson’s. That seems to be due to caffeine, though exactly how that works isn’t clear.

Coffee has also been linked to lower risk of dementia, including Alzheimer’s disease. A 2009 study from Finland and Sweden showed that, out of 1,400 people followed for about 20 years, those who reported drinking 3 – 5 cups of coffee daily were 65% less likely to develop dementia and Alzheimer’s disease, compared with nondrinkers or occasional coffee drinkers.

CANCER

The evidence of a cancer protection effect of coffee is weaker than that for type 2 diabetes. But for liver cancer, the data seem to be very consistent. All of the studies have shown that high coffee consumption is associated with decreased risk of liver cirrhosis and liver cancer. As interesting a finding as it is, it’s not clear how it might work.

Again, this research shows a possible association, but like most studies on coffee and health, does not show cause and effect.

PREGNANCY

In August 2010, the American College of Obstetricians and Gynecologist (ACOG) stated that moderate caffeine drinking – less that 200 mg per day, or about the amount in 12 ounces of coffee – doesn’t appear to have any major effects on causing miscarriage, premature delivery, or fetal growth. But the effects of larger doses are unknown, and other research shows that pregnant women who drink many cups of coffee daily may be at greater risk for miscarriage than non-drinkers or moderate drinkers. Again, it’s not clear whether the coffee was responsible for that.

CALORIES, HEART BURN, AND URINE

You won’t break your calorie budget on coffee – until you start adding the trimmings.

A 6-ounce cup of black coffee contains just 7 calories. Add some half and half and you’ll get 46 calories. If you favor a liquid nondairy creamer, that will set you back 48 calories. A teaspoon of sugar will add about 23 calories.

Drink a lot of coffee and you may head to the bathroom more often. Caffeine is a mild diuretic – that is, it makes you urinate more than you would without it. Decaffeinated coffee has about the same effect on urine production as water.

Both regular and decaffeinated coffee contain acids that make heartburn worse.

See you next week.