Nutrition news: A healthy cup of coffee?

News of coffee's potential impact on health has for years gone back and forth. Initially, concerns centered on caffeine, a naturally occurring stimulant. The positives about coffee centered on antioxidants, compounds generally associated with potential health benefits. Robert Sheeler, M.D., and medical editor of the Mayo Clinic Health Letter, says it appears coffee may be just fine for most, and possibly even of some benefit.

Here is a look at coffee's pros and cons as related to health, based on the research.

Coffee may protect against:

1. Type 2 diabetes. Researchers found that compounds in coffee -- chlorogenic acid and caffeine -- may thwart protein formation that contributes to the death of pancreas cells. Normally, pancreas cells produce insulin. An earlier study of younger and middle-aged women found that drinking two or more cups of coffee a day was associated with a substantially lower risk of Type 2 diabetes.

2. Parkinson's disease. Numerous studies indicate regular coffee consumption may reduce the risk of Parkinson's disease.

3. Various cancers. A recent study found that women who drank coffee reduced their risk of endometrial cancer by 20 percent. A recent analysis of multiple studies suggests there may be a correlation between drinking coffee and a reduced risk of pancreatic cancer. One study found that drinking an additional two cups of coffee a day was associated with a 43 percent reduced risk of liver cancer.

4. Alzheimer's disease. A recent review of multiple studies reported there's a trend toward a protective effect from coffee, but more study is needed to determine if the trend is significant.

Coffee may possibly be harmful to:

1. Bone health. Caffeine is known to increase the amount of calcium that's passed in urine. It may also interfere with how well calcium is absorbed in the digestive tract. One study found that women who drank 20 ounces of coffee -- about 2 1/2 cups -- or more on a daily basis had a modest increase in fractures related to osteoporosis. However, other studies have found that if coffee drinkers get adequate calcium, the effect is minimized.

2. Blood pressure. For people who consume coffee only occasionally, there may be a temporary rise in blood pressure. However, regular coffee drinkers appear to develop a tolerance so that there isn't much effect on blood pressure.

3. Lung health. A recent overview of 13 different studies concluded that high or increased coffee consumption might increase the risk of lung cancer. However, the authors of the overview also cautioned that other factors -- specifically the effects of smoking -- might have affected their findings. More study is needed to determine a connection -- if indeed there is a connection.

The bottom line is, for most healthy adults, moderate doses of caffeine -- 200 to 300 mg a day, which is two or three cups of regular brewed coffee -- are fine. Coffee is among the top-10 food sources of antioxidants, and it's also a major source of chlorogenic acid, which is one of its star players for antioxidant activity. Antioxidant activity associated with coffee has been linked to protective effects on multiple diseases, including cancer and cardiovascular diseases.

Information courtesy of Mayo Clinic Health Letter.

Q and A

Q: Is it true that you need to eat red grapes to get resveratrol, the compound found in red wine?

A: No, but it's a common misunderstanding because of the many news stories about resveratrol and red wine. Resveratrol is a phytochemical found in grape skins of all colors and is produced by plants to fight off fungus. The amount of resveratrol in grapes depends much more on growing conditions than on the color or type of grape. Much of the resveratrol is in the grape's skin. Red wine contains much more resveratrol than white because red wine is made by fermenting grapes with skins; for white wine, the grape skins are removed before fermenting.

Alcohol -- including red wine -- increases risk for several common cancers, so it's best to avoid or limit alcohol to no more than one standard drink (5 ounces of wine) per day for women, two for men. In laboratory studies resveratrol can inhibit cancer development. However, most of this evidence comes from cell studies using concentrations of resveratrol much higher than a person is likely to reach. We don't have nearly enough good research to make resveratrol content a sound basis for choosing specific types of fruit. Grapes also contain a variety of other phytochemicals and we need more human studies to understand their potential cancer-protective effects. Red grapes' color comes from anthocyanins, compounds being studied for potential antioxidant and cancer-protective effects, too. But the potential for health protection from grapes and other plant foods, including beans and whole grains, comes from more than any one function or compound.

Information courtesy of the American Institute for Cancer Research.

Recipe

These Banana Bran Muffins combine the best of both worlds -- fiber (from the bran) and moistness (from the bananas). The recipe is from "Fit Food: Eating Well for Life" by Ellen Haas, former USDA undersecretary of Agriculture for Food, Nutrition and Consumer Services.

BANANA BRAN MUFFINS

Cooking spray

2 1/2 cups flour

3/4 cups sugar

1 1/2 teaspoons baking soda

1/4 teaspoon salt

2 large eggs, room temperature

1 1/2 cups buttermilk

1 1/2 cups bran

1 cup mashed, ripe bananas

Preheat oven to 350 degrees. Coat two 12-cup muffin pans with cooking spray. Sift the flour, sugar, baking soda and salt together. Whisk together the eggs buttermilk and bran. Let stand for 10 minutes. Make a well in the center of the dry ingredients and add the egg mixture all at once. Stir with a wooden spoon until the dry ingredients are just moistened. Fold in the mashed bananas. (Note: keep mixing to a minimum). Fill the muffin pans 2/3 full. Bake for 25 minutes. Makes 24 muffins.

Per muffin: 100 calories, 3 g protein, 21 g carbohydrate, 1 g fat, 18 mg cholesterol, 2 g fiber, 125 mg sodium.