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From: iayork@panix.com (Ian A. York)
Newsgroups: alt.folklore.urban
Subject: Re: Death by breathing flatus - debunked!
Date: 15 Mar 1997 20:09:49 -0500

In article <3329E8B1.945@slc.unisys.com>, Helge S. Moulding <hsm@slc.unisys.com> wrote: >
>Can we only assume 1 mole of gas per mole of protein? Which protein
>are we talking about, what is its proportion in beans or cabbage by
>weight, and how much of it is left to be metabolized by intestinal
>fauna? Medline boy?
>
>Finally, the flow rate of the gas is only about 1/4 cubic foot - less
>than 10 liters - per minute. Is this doable without waking the sleeper?

I'm pleased--yes, I suppose "pleased" is the right word--to find that this vital scientific subject has not been neglected by the research community. There are over 500 articles on flatulence available in Medline.

Let's start off with some basics Phacts 'n' Phigures. We find, first of all, that the 14-toots-per-day figure is a reasonable average, but this can be increased by the careful selection of diet: "Over a one-week period on their usual diet, subjects passed gas 10 +/- 1 times/day [upper limit of normal (mean + 2 SD): 20 times/day]. The addition of the nonabsorbable disaccharide lactulose (10 g/day) to the diet significantly (P < 0.01) increased flatus frequency to 19 +/- 2.4 times per day. Gender, age, and the ability of an individual's colonic flora to produce methane had no significant influence on flatus frequency either on the basal or lactulose-supplemented diets." (Furne JK. Levitt MD. Factors influencing frequency of flatus emission by healthy subjects. Digestive Diseases & Sciences. 41(8):1631-5, 1996).

Note that the key factor is carbohydrate, not protein, incidentally.

Moreover, we find (as we already knew, really) that some individuals are unusually talented in this art: "Some subjects consistently passed gas more often than did others. These individual differences appeared to result, in part, from differences in the ability of the flora to produce gas from a given quantity of fermentable material." These individuals are, of course, the ones sitting beside you in the plane.

Moreover, apparently some people are more prone to producing methane, while others are more likely to produce sulphides: "In about 50% of a European and North-American population and in 90% of rural black Africans, methane is generated from H2 and CO2. In methane-negative individuals, sulfate reducing bacteria utilize H2 to reduce sulfate to sulfide. Methanogenesis and sulfate reduction are usually mutually exclusive." (Christl SU. Scheppach W. Kasper H. Hydrogen metabolism in the large intestine--physiology and clinical implications. Zeitschrift fur Gastroenterologie. 33(7):408-13, 1995)

What foods are most flatus-inducing? It partly depends on the person. If, for example, you're lactose-intolerant and you ingest lactose, then it's not digested in your upper intestine and the colonic bacteria are treated to a veritable feast of lactose, which they celebrate in the usual way.

Some of the foods which are mentioned as being particularly devastating are cowpeas (which lead to "indigestion, vomiting, diarrhoea, increased belching, bad breath, offensive stool, flatulence, constipation, mild abdominal discomfort and sleepiness", which raises the question as to why they haven't become more popular than they are), (Ndubuaku VO. Uwaegbute AC. Nnanyelugo DO. Flatulence and other discomforts associated with consumption of cowpea (Vigna unguiculata). Appetite. 13(3):171-81, 1989), beans, cabbage, lentils, brussel sprouts, and legumes (Friedman G. Diet and the irritable bowel syndrome. Gastroenterology Clinics of North America. 20(2):313-24, 1991; Price KR. Lewis J. Wyatt GM. Fenwick GR. Flatulence--causes, relation to diet and remedies. Nahrung. 32(6):609-26, 1988), and perhaps wheat products (Levitt MD. Follow-up of a flatulent patient. Digestive Diseases & Sciences. 24(8):652-4, 1979).

How much volume of gas is produced? In normal volunteers supplemented with baked beans by a daring researcher:

Total daily volume ranged from 476 to 1491 ml (median 705 ml). Women and men (both n = 5) expelled equivalent amounts. The median daily flatus hydrogen volume was 361 ml/24 h (range 42-1060) and the carbon dioxide volume 68 ml/24 h (range 25-116), three volunteers produced methane (3, 26, and 120 ml/24 h), and the remaining unidentified gas (presumably nitrogen) or gases contributed a median 213 ml/24 h (range 61-476). Larger volumes of flatus were produced after meals than at other times. Flatus produced at a faster rate tended to contain more fermentation gases. Flatus was produced during the sleeping period, but the rate was significantly lower than the daytime rate (median 16 and 34 ml/h respectively). (Tomlin J. Lowis C. Read NW. Investigation of normal flatus production in healthy volunteers. Gut. 32(6):665-9, 1991)

I want to draw particular attention to the point that "Women and men expelled equivalent amounts", and sternly observe that a lot of women owe a lot of apologies to a lot of dogs.

Now, let's make the assumption that the victim of flatus in this story was specially talented in this ability--that is, let's assume that he was several standard deviations away from these normal volunteers. The normal volunteers produced up to 1.5 liters of gas. Previous references suggest that even in normal people, flatus can be doubled by the use of the appropriate dietary aids: so that gives us a 3 liter production. All we really know about standard deviations is that in the frequency of "19 +/- 2.4" times per day, the "2.4" is two standard deviations. That's a pretty narrow range, it seems to me, but let's say our victim is capable of the prodigious feat of reaching six liters per day: that should be near the top of the normal distribution, I'd think.

I've forgotten what question was asked, so I'm not going to go any further right now. Maybe this will be enough for Helge to perform some calculations on LD50.

I'll leave you all with this thought: "Analysis of the tracings showed that both artificially induced and spontaneously occurring flatus-related motor phenomena were characterized by colonic propagated contractions associated with a rise in rectal pressure and early relaxation of the anal sphincter, in a sequence resembling that observed following swallowing. Spontaneous flatus events were associated with colonic waves of lesser amplitude than those following insufflation of air into the colon. (Bassotti G. Germani U. Morelli A. x Flatus-related colorectal and anal motor events. Digestive Diseases & Sciences. 41(2):335-8, 1996).

Ian "tooting my own horn" York