Sweet Indigestion:
A Directed Case Study on Carbohydrates

by
Peggy Brickman
Department of Plant Biology
University of Georgia

Cow

Part I—Of Cows and Carbs

“What’s so funny?” Gwen asked as she slid next to her friends Sara and Emily at the library.

“Read this,” Sara said. “I’m thinking about getting my dad vaccinated.”

S Y D N E Y, Australia, June 7 — Australian farmers are signing up their sheep and cattle in droves to take part in a vaccine program aimed at reducing harmful methane gas emissions from their animals and help take the heat off global warming.

Methane is a greenhouse gas more potent than carbon dioxide and farm animals produce a lot of it.

Australian scientists said today early results show they may be able to reduce methane emissions per animal by about 20 percent a year, or the equivalent of 300,000 tons of carbon dioxide a year if they can vaccinate three million animals. The methane vaccine discourages Methanogenic archae, organisms which inhabit the animal’s digestive system and which produce methane by breaking down feed.

Reuters 2001

Gwen laughed, “Your dad? What about your dog? He’s got the real problem. But seriously, is farting a major cause of global warming?”

“Well, not all of it, but greenhouse gases could be reduced if people stopped eating meat. Cows actually produce the vast majority of methane released in the U.S.” Emily replied.

“300,000 tons of CO2 in Australia alone,” Gwen said. “I wonder how much people produce?”

“When I visited Space Camp we learned about how the astronauts deal with noxious fumes,” Sara said. “The average astronaut expels about a half liter of gas a day from bacterial break down of undigested carbohydrates in the large intestine. Maybe we all should be vaccinated. You both have been dieting, I bet you think you’re eating a lot less carbohydrates than before. You could be our first test subjects.”

“But what are carbohydrates exactly?” Emily asked looking at Gwen. “And which are undigested?”

Questions

Here’s a list of what the girls had eaten so far:

For breakfast—Cheerios with oat bran, a tall Latte with skim milk, and a PowerBar®.
For lunch—Coke and a salad with lettuce, cabbage, tomato, shredded carrot, green peas, kidney beans, and tuna fish.

  1. Underline all foods containing carbohydrates.
  2. Come up with a rule to help you identify foods containing carbohydrates.
  3. How are carbohydrates made normally (i.e., what organism makes them)?
  4. Which ingredient would cause gas? Why are some foods digestible and others aren’t?

Go to Part II—“Label Analysis”

Date Posted: 10/13/04 nas

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