DEAR DR. BLONZ: I've been a coffee drinker for most of my adult life, but have now read that coffee absorbs calcium -- that it can even pull calcium out of bones and lead to osteoporosis. Is that true? And if so, does adding milk or half-and-half to coffee provide calcium to counter the effect and keep it from absorbing calcium elsewhere? I have osteopenia. -- S.T., Tulsa, Oklahoma
DEAR S.T.: Osteopenia is a "warning" state where bone mass is less than normal, but not as severe as osteoporosis. Our bones and skeletal system represent a cumulative record of our general and mineral nutrition and lifestyle. This structure can also be affected by genetic predispositions and medications that affect how bones get made and maintained.
Coffee is not a significant risk factor for osteoporosis in those who eat well. Caffeine doesn't actually "absorb" or "pull" the calcium out of the digestive tract or from your bones. Still, excessive intake can have a diuretic (urine-producing) property that can bring about a minor loss of certain nutrients, including calcium and magnesium. Coffee is also an acidic beverage, and it can irritate a sensitive stomach; having food with your coffee tends to buffer this effect.
Higher intake of caffeine coupled with inadequate calcium can be a risky combination. Eating well overall -- including a sufficient intake of dietary calcium -- counters this negative. The goal is a plant-based, whole-foods diet with adequate intakes of essential vitamins and minerals, including calcium. This will have more sway than adding milk or cream to the coffee cup. (One tablespoon of milk or half-and-half will contain only about 15 to 20 milligrams of calcium.)
In an example from the literature, a study in the American Journal of Clinical Nutrition affirmed that women who drink coffee during their postmenopausal years need to pay particular attention to the calcium in their diet. They found a link between an excessive intake of caffeine and an increased rate of bone loss. In this study, "excessive caffeine" was defined as greater than 450 milligrams of caffeine per day. (Note: Caffeine in coffee can vary according to the type of bean and the way it is brewed, but consider an average to be 100 milligrams of caffeine in a 5-ounce cup of drip-brewed coffee.) The study reported that the caffeine/bone-loss effect was not present in women having diets containing at least 800 milligrams of calcium per day.
Aside from caffeine, physical activity also contributes to the health of our bones, which can be said to have a "use it or lose it" aspect. Weight-bearing exercises such as walking, jogging, gymnastics or aerobics can help strengthen the bones -- no matter what age the activities are begun. Other nutrients -- such as magnesium; vitamins A, B6 and D; phosphorous; and fluoride -- are needed for calcium absorption and healthy bones. It's also important to avoid any habitual excess of dietary protein, as this can increase mineral losses.
Send questions to: "On Nutrition," Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to email@example.com. Due to the volume of mail, personal replies cannot be provided.