Flatulence (farting) at altitude (e.g. in the mountains, in airplanes, etc.) makes perfect sense, and can be explained by what you might have learned in your general chemistry class (if you took general chem.)
Follow me all the way through on this one: Does anyone remember Le Chatelier’s principle? It states that a chemical reaction will proceed in the direction that minimizes a stress placed on the system. Well, the production of gas in the intestine is an example of a decomposition reaction. And this type of reaction is characterized by the production of MORE MOLES OF GAS. OK now, what happens when altitude increases? Pressure goes DOWN. Well then, the production of more moles of gas REDUCES the pressure placed on the system, and the decomposition reaction is driven forward. You can also think of it this way: lowering pressure sucks the moles of gas out of the reaction system responsible for flatulence.
Now, there is one more thing to make it worse: Boyle’s law. When pressure goes DOWN, then volume goes UP. So on top of more moles of fart gas being PRODUCED in a (set of) chemical reaction(s), the VOLUME of that gas goes up as the pressure goes down. So the result is that you get a heck of a lot more gas at higher altitudes.
So I propose that the production of more moles of gas combined with the increased volume of that gas increases the incidence of flatulence. And yes, for those of you wondering, I have my own anecdotal evidence for my proposal. In my experience, the higher I go, the more I blast! I had my worst incident at Mt. Whitney, the highest peak in the contiguous United States. It just would not quit!
His law gives the relationship between pressure and volume if temperature and amount are held constant.
Sure, if the volume of a container is increased, the pressure decreases and if the volume of a container is decreased, the pressure increases, but (and it’s a big but), it all hangs on the same amount of gas. Therefore your statement “the production of more moles of gas REDUCES the pressure” doesn’t follow.
Not to mention that the production of gas in the gut is performed by bacteria, who do not follow simple equilibrium principles like LeChatelier’s (which, by the way, you’ve applied incorrectly).
And finally, post a link to the article you’re commenting on, like this:
OK. The temperature is fairly constant (usually 37 C) in the intestine. So is the amount of reactants. Therefore Boyle’s Law does apply.
And yes, I recognize that the biochemistry of decomposition of various compounds by bacteria is not just describing one reaction but several convoluted and overlapping reaction pathways, as well as reaction kinetics and compartmentalization. So yes, you are absolutely right–other counteracting forces (or facilitating forces) are likely to be present in the relevant systems. My intent was to describe a substantial change of environmental conditions on a biological or physiological system and the chemical basis for the response of these systems. Without neglecting other effects, we attempt to isolate our discussion of certain relevant driving forces, in this case, a shift in equilibrium of a decomposition reaction due to a change in pressure.
Biochemists, physiologists, pharmacologists and many other scientists have to resort to simplifications to explain what happens in biological systems, but as we are learning evermore, living systems are exceedingly convoluted.
So really, the only really practical experiment on this subject would be a clinical trial. I would propose a randomized, crossover design. So you would take two groups (say A and B) and feed them the same thing. You would have to measure the amount of colonic gas production in all subjects, and compare what happens at, say 9,000 to 10,000 ft vs. sea level. To do this, Boyles Law would probably need to be applied.
After three readings, I think I might have decyphered what you were saying.
First, on the Boyle’s Law part… the important unstated point is that the external pressure has reduced. This means the internal gas pressure is greater than the external pressure, and would like to equal that pressure. Thus, the gas expands the internal volume, in order to reduce the internal pressure. Ergo, more farting. This is in line with the answer in the Column.
Second, regarding LeChatelier’s principle…
Okay, the external body pressure goes down, so the internal gas pressure wants to go down to match. So you’re saying that this drives the decomposition reaction to increase to make more gas? I think part of the confusion is your use of “pressure” to mean two different things. One is gas pressure (measured quantity), and the other is influence on the reaction, or to use LeChatelier’s word, stress. I think perhaps you meant to say, “…the production of more moles of gas REDUCES the stress placed on the system,…” That removes one ambiguity.
The second part, is this true? Is the reaction controlled by the pressure? If there’s feedback from system pressure regulating the rate of decompression, maybe you have a point, but I don’t believe this is the case.
I do follow that if the reaction rate is increasing and making more gas, and at the same time the intestine is expanding to try to equalize the higher internal pressure with the lower external pressure, this would make the situation doubly bad. This is what you were trying to say, right?
Yes, Irishman got what I was trying to write, and his point is well taken; I used the word “pressure” to mean two different things–‘ambient pressure’ and ‘stress on a reaction system’–not good writing on my part. I should have made that distinction. And it seems that Irishman really got what I was saying. And of course, I did oversimplify a bit in my original communication.