March 19, 2009

You Ask, I Answer: Caffeine & Calcium

Is it true that coffee causes osteoporosis?

-- Linda (last name withheld)

New York, NY

Before I answer, allow me to get something off my chest.

Statements like "[insert name of food here] causes [insert disease/condition here]" are tremendously inaccurate.

If someone ever tells you that a food causes a particular disease, promise me your "BS" alarms will go off.

Unless you are talking about contamination issues, food as a whole does not cause disease.

Rather, it is particular components in certain foods that, when consumed often over long periods of time, can elevate one's risk of developing a certain condition.

This reminds me of absurd statements like "ice cream makes you fat."

While a 600-calorie sundae every day after dinner will surely result in weight gain, a one-scoop ice cream cone every Saturday night is no cause for concern.

"Ice cream makes you fat" wrongly categorizes 150 calories and 900 calories of the same food as nutritionally equal.

Similarly, saying that "coffee causes osteoporosis" is too broad a statement. At the very least, whoever is making such a statement should identify what specific component in coffee is believed to affect bone mass.

Which brings us to the question at hand.

Since caffeine is a diuretic that results in a higher-than-normal excretion of calcium in the urine and feces, some people jump to the conclusion that, therefore, caffeine intake is related to osteoporosis.

However, studies have demonstrated that the average cup of coffee -- 8 ounces and approximately 150 milligrams of caffeine -- increases calcium excretion by a practically insignificant 5 milligrams (remember, you should be getting 1,000 milligrams a day).

To balance this out, all you need to do is add a single teaspoon of milk to your coffee.

Keep in mind that all the studies looking at caffeine's effect on calcium levels assume people drink black coffee (an 8-ounce latte, meanwhile, contains two thirds of a cup of milk!).

Another concern with caffeine is that it inhibits intestinal absorption of calcium. While true, our bodies are smart and make up for this by increasing calcium absorption at the next meal.

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