Wednesday, August 31, 2005

The Roasted Bean and the Person-Quantity

An astute reader brought to my attention the following news story:

Coffee is Leading Source of Antioxidants in U.S.

If that doesn't work for you, try:
Joe Gives Free Radicals a Jolt

Curious, (and excited because I love coffee) I dug up a few more words from the study's lead, Mr. Vinson himself:

"It's not that the antioxidant content of coffee is that high, but it's the one thing that so many of us do every day,"

Background: He and his group settled on about 100+ foods that Americans typically eat, calculated the antioxidant values of those foods, and projected those values onto, I believe, a person-quantity variable.

It's that person-quantity variable that muffles the meaning of this headline. A person-quantity is like a man-hour. If it takes 3 men 2 hours each to perform a task, then the task takes 3 times 2 or 6 man-hours. If 20 million Americans drink 16 ounces of coffee each day, then 20 million times 16 ounces is 320,000,000 person-ounces. That's quite a lot more person-ounces than say 1 million Americans who drink 6 ounces of red wine each day, even though red wine has at least as much antioxidant might as coffee.1

So, you might have a fairly moderate antioxidant value, but if you multiply that by a fairly large person-quantity (lots of Americans who drink lots of coffee) you arrive at a downright flashy and misguided headline.

It reminds me of a study that made the rounds in my graduate years which found inner-city youth - whose diets were a wreck - somehow clocked in with potent vitamin C levels. Where were they getting all that vitamin C? Guess.2 I guess a headline from that study could have read "(This) Provides More Vitamin C Than Any Other Food or Beverage in an Urban Youth's Diet." I quake to think what that might lead people to consume more of. (California quakes too.)

Mr. Vinson also said that his group discovered dates have the highest antioxidant value based on serving size, but "Americans just don't eat that many dates."

Or figs.

1 Numbers [somewhat] fabricated. For explanation purposes only.
2 Rhymes with "clench thighs".

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