Obesity and your microbes II

Posted by Tara C. Smith on May 30, 2006
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Busy today, so sequels are on tap. There’s an interesting story from Nature news that’s a nice follow-up to this recent post on how microbes can influence weight. More after the jump.

Scientists have identified a key microbe in our guts that helps us glean more calories from food. The discovery backs the idea that the type of microbes in our gut help to determine how much weight we gain, and that seeding the intestine with particular bugs could help fight obesity.

Samuel Buck of Washington University in St Louis, Missouri, and his colleagues focused on one microbe called Methanobrevibacter smithii, which is effectively a waste-removal bug. “It’s a minor component of the gut flora with a major impact,” Buck says tactfully.

M. smithii may have a dirty job, but Buck and his colleagues have now shown that it is a vital one. They found that by clearing waste products it helps other gut bacteria digest some of the fibrous components of food that we cannot, and turn them into material that our bodies can use. Without these bugs, waste accumulates and blocks the activity of other gut bacteria.

The researchers found that mice with a hefty dose of M. smithii in their guts are fatter than those that don’t have the bacteria.

More details on the findings can be found at the link. The manuscript is forthcoming in PNAS, so I can’t comment much on the methodology, but it’s certainly another intriguing bit of evidence that suggests diet plus exercise isn’t all there is to it, as far as establishment and maintenance of our weight.

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  1. #1 HP
    May 30, 2006

    Random thoughts:

    - None of these findings surprise me.

    - IANA doctor/researcher/scientist, but in my own frustrating history with obesity, I’ve been saying, “Someone should be looking at gut flora” for years now, so I’m glad people finally are.

    - While I’m feeling cocky, let me add that some smart researcher should look into the possibility of a runaway immune response causing increased appetite and lethargy.

    - Won’t it be nice someday when an obese person can go into a doctor’s office, and that doctor can run some diagnostic tests to determine what kind of obesity it is?

    - Why isn’t “bariatric obesiology” or whatever a recognized medical specialty?

    - No matter how much research is done on the etiology of obesity, there will always be some sh*theels who insist that it’s a moral failing.

  2. #2 Abel PharmBoy
    May 30, 2006

    Tara, my apologies on lack of follow-up to discussing the viral etiology of obesity. This general field is fascinating and I know of some studies on the influence of gut microbes on expression of hepatic genes that can influence beta-oxidation and glycogenolysis/gluconeogenesis balance. Gut microbes clearly influence alcoholic liver injury so no surprise about this report. However, I do share your anticipation of seeing the methods when published in PNAS in relation to your caveats in your earlier post on how to truly study this area since not all gut bugs can be cultured.

    After the grant deadline and move to SB, I hope to get back to this in a more substantive fashion. Thanks, as usual, for picking up the slack.

    Hope you had a great holiday!

  3. #3 Mike the Mad Biologist
    May 30, 2006

    Call me bonkers, but do you think we’ll ever use phage therapy or some very narrow spectrum antibiotics as a ‘cure’ for obesity?

  4. #4 Tara C. Smith
    May 31, 2006

    Abel, no worries.

    Mike, I hope so. Obviously it would be only one factor among others (diet, exercise, genetics, etc.) that affect weight as I’ve mentioned many times, but even moderate weight loss can affect chronic conditions such as diabetes and other diseases related to obesity. And as I mentioned in the other thread, it has potential to go the other way as well: for example, dosing people in famine-stricken areas with Methanobrevibacter or some other bacterium that increases calorie retention.

  5. #5 Stephen Uitti
    June 1, 2006

    I know someone who was looking for a diet to maintain her weight. She gained weight on a 700 calorie diet. She settled on a 500 calorie diet. After a year of not gaining weight, she had some excess removed. She was quite active. It does not surprise me that there are efficiency factors.

    While i don’t survive on 500 calories, the whole calories in/calories expended math doesn’t add up. When i was in school, running cross country, i was running 30 miles a day (twin 15 mile workouts – this is common, as odd as it sounds). So, my calories burned must have been over 4,000 per day. My intake (probably around 2500) didn’t change. During this period, i gained weight.

    Would i be willing to drink some bugs for weight loss? I mean, the yuck factor is pretty high. But then again, i eat yogurt.

  6. #6 impatientpatient
    June 2, 2006

    Yoghurt has Lactobacillus acidophilus in it. It is recommended by some as an adjunct to a good weight loss diet. Does it really help, and it this because of LB??