parts of our GI tract tends to have a lot of bacteria

You may have seen some news coverage recently about West Virginia lawmakers drinking raw milk and then getting sick (Links to an external site.), so I thought the article below might be interesting. It can help us integrate a lot of different topics we’ve been covering this quarter.

Lactose is a disaccharide sugar that we cannot absorb unless it is chemically digested by the enzyme lactase into its component sugars (glucose and galactose). The bacteria in our GI tract can metabolize sugars like lactose. When these bacteria are exposed to lactose, they break it down chemically using enzymes and they give off hydrogen gas and methane.

Study Shows Once and for All that Raw Milk Doesn’t Help Lactose Intolerance
 (Links to an external site.)Time Magazine, March 10, 2014

For your initial post, you should be using your textbook and the articles linked above as your primary sources to answer the questions below. The purpose of this first post is to apply the information that you’re practicing from your learning objectives. Later, in the comments, I will expect you to do a bit of research online and support your comments with evidence, but in your initial post please stick to your textbook and the article(s).

In your initial post, please address each of the following points:

1.Which part of our GI tract tends to have a lot of bacteria in it?

2.Briefly describe the pathway of ingested lactose in someone who does not produce the enzyme lactase. Start your pathway in the stomach. Include an explanation of why such a person could end up with flatulence (largely composed of methane) if they drink too much milk. How is the pathway different from someone who does produce lactase? What happens to lactose in these people?

3.In the article, the scientists did a hydrogen breath test to assess lactose intolerance. How did the hydrogen get from the site where it is formed to the tube the scientists used to collect the breath sample?

4.Was the experiment described in the article a double-blind placebo controlled study (Links to an external site.)? 5.Explain briefly. What kinds of errors does a double-blind placebo controlled study help to avoid?

What questions do you have about the article, or what did you find most interesting?