“Now, a new study by Eric Martens, David Bolam, and colleagues has looked into how a pair of the most common species of gut bacteria metabolize polysaccharides, showing that each bacterium is highly specialized. Using a high-throughput system for feeding the bacteria dozens of kinds of carbohydrates, one at a time, and tracking the bacteria’s gene expression, they were able to see how these microbes have tailored themselves to fill specific niches in the gut.”
This is a really good study. For me, a better understanding of the gut metabolic ecology will allow for the development of better probiotics. One interesting finding in this study is that some bug don’t grow well on simple sugar because their sensors are built for complex sugars. Made me think of folks in developed world and what effect eating more simple sugars (high-fructose corn syrup) has on gut flora and any consequential obesity.
Read this article…
 When I lived in the US in the 90s, it was hard to find live-culture yogurt in supermarkets (you could find them in natural food stores, of course). The only one I could find was Stonyfield yogurt.
When I lived in Finland, not only were there a bunch of live-culture milk products, but there was one in particular “Valio A+” that was specifically recommended for women to balance their flora.
Now back in the US, it’s hard not to find live-culture yogurt, and some are specifically marketed, yes, for women to balance their flora. Furthermore, the use of live bacterial cultures for health purposes, called probiotics, has become mainstream enough that you can find probiotic supplements for children in the supermarket.
What does this mean?
It means that folks are becoming aware of functional foods, of the importance of microorganism in their diet, and that the feeding desire to find a short cut (a pill rather than eating wholesome yogurt) is always a good business.
I’ve been seeking out all these probiotic products to get an idea of what’s out there, what the message is, and, for me, always on the look out for practical use of microbes, I’ve been trying to understand what microorganisms are in fashion.
OK, so the science behind probiotics is still in progress, so I will not go into that right now.
But, going on the premise that yogurt is the gold standard for beneficial live (with microorganisms) food, then my standard for all probiotic products used for digestive health is Stonyfield’s yogurt. Stonyfield’s has 6 bacteria (S thermophilus, L bulgaricus, L acidophilus, Bifidus, L casei, and L rhamnosus). I’d say that most of the products I have seen have one or more of these bugs. There are some proprietary sub-species and I’ve been pleased to see a few products with S salivarius or some other bacteria.
For me, the type, variety, and number of bacteria in a probiotic food or supplement is key. And I think it’s just snake oil if the product only has one bug.
Nonetheless, I think as probiotics go mainstream, buyers will be more astute as to what they are looking for. Also, I hope that new applications show up, beyond gut and vaginal flora health (I can think of a few).
What I do know, is that doctors are starting to suggest probiotics to patients on antibiotics or with digestive issues such as colitis or C diff.*
And that’s great.
Do you eat probiotic foods or take supplements? Send me pics of the ones you see or take! I could/should create a database of products and attach reviews or commentary. Hm…. not another project….
*Ego boost: A gastroenterologist aked me recently what probiotics I recommended. Ha! My first probiotic consulting gig?
 As you know, I’m always looking for practical uses of microbes. One that I stumbled upon a long while back was “transfaunation”, or, seeding one person’s gut with microbes from another’s. Yes, transfering poop microbes from one to another.
Be an adult. Don’t get grossed out. I’ve read some great papers on the process how our guts get colonized after birth. Also, there are some really interesting papers on how our gut microbes (or lack thereof) are involved in various intestinal disorders. And there are some promising papers on how diet affect the bacterial ecology in the gut. [Sorry, I'll link to the papers in a larger gut related set of posts at some point in the future - you can also just search for gut and microbes in my posts.]
Here’s the basic idea. People suffering from the hardy C. diff bacteria are generally prescribed a powerful antibiotic. Problem is, the drugs don’t just kill the invaders; they also wipe out much of the beneficial bacteria in the gut. With these “good” microorganisms out of the way, any C. diff stragglers have a much easier time regrouping for a second bout of illness. If there were some way to respawn the beneficial bacteria in the intestines, such re-infections could be warded off. Some people, like Ruth, turn to expensive probiotic supplements. (At one point she was spending $350 on them every week.) But in certain cases, a patient who has lost nearly all of her good bacteria will find it nearly impossible to get them back. A fecal transplant seems to work as a sort of mega-probiotic, allowing doctors to repopulate a patient’s intestines with the appropriate microorganisms by placing a robust sample directly into her gut.
Slate had a nice article on the subject (quoted above). It’s a serious subject and for many, the only hope to get a better and healthier bacterial gut fauna (hence the term, transfaunation).
My wife’s a vet and she’s not only heard of this procedure, but performed it on animals. It’s not uncommon to jumpstart an animal’s ability to digest grass by grabbing bugs from one animal and putting it in the right place. And, did you know, some animals eat poop on purpose for this very reason – rabbits, capibaras, hamsters, elephants, termites, pandas, koalas, and hippos – to colonize their gut?
And really, folks eat yogurt to populate their gut with good bacteria. Why not poo bacteria as probiotics? I actually think, as we learn more about our gut fauna, this will be come a more accepted course of action for folks with nasty bowel infections, colitis, or inflammatory bowel diseases.
What do you think?
Image of Kristen Paulson’s Anatomy and Guts Embroidery Hoop Art on Etsy (get your own!)
“We normally think of the gut microbiota as the ‘friendly’ bacteria that carry out many beneficial functions, including protecting us from infection. But two studies now identify a different side to the gut microbiota, showing that it can actually facilitate viral infection and promote transmission.”
Another interesting review that is in a CLOSED ACCESS paper. The barrier to casual reading is too high.
Read this article…
“There is a multimillion-dollar industry based on the concept that introducing beneficial bacteria into the human intestines will improve our health. The trillions of symbionts in the large intestine profoundly affect our metabolism and immunity. Accordingly, abnormal bacterial communities have been identified in several human diseases such as inflammatory bowel diseases (1–3), colon cancer (4, 5), irritable bowel syndrome (6), and nonalcoholic fatty liver disease (7). The composition of microbial communities is generally stable within each individual. Past studies of the gut microbiota emphasized the huge impact of nutrition (8), which is likely to outweigh that of the host genotype (9).”
Nice review, with some references too. But it really rounds up and summarizes the latest. Also points to an article in the same issue that reports on some really interesting findings. Alas, not Open Access.
Read this article…
“There is growing evidence that the intestinal microbiota interacts with the host central nervous system (CNS) to modify stress responses and anxiety behaviour; this is the so-called gut–brain axis. Bravo et al.Lactobacillus rhamnosus JB-1 can alter the transcript level for receptors of the neurotransmitter GABA (γ-aminobutyric acid) in the CNS in a region-dependent manner.”
Yet one more data point on the bugs-gut story.
[This is not an open access article. Boo. Hiss.]
Read this article…
“Prebiotics are selectively fermented ingredients that allow specific changes in the gastrointestinal microbiota that confer health benefits to the host. However, the effects of prebiotics on the human gut microbiota are incomplete as most studies have relied on methods that fail to cover the breadth of the bacterial community. The goal of this research was to use high throughput multiplex community sequencing of 16S rDNA tags to gain a community wide perspective of the impact of prebiotic galactooligosaccharide (GOS) on the fecal microbiota of healthy human subjects.”
I’ve seen a ton of papers on “probiotics”, but I think this is the first I’ve heard of “prebiotics”. There is mounting data about the effect of gut bugs on our own systems, and there is a growing set of data on how our diet affects our gut bugs. A wee Google search shows that there’s been a lot of papers data on specific foods that selectively promote the growth of specific gut bugs.
Hm, this is really interesting. It all seems to be coming together. My suggestion: if you’re a grad student or a post-doc in biology, human gut microbiology and ecology is gonna be a big topic in the near future. It’s gonna change the face of medicine.
Read this article…
“A large European-Asian consortium brought some order to the chaos when it reported in a Nature paper in April that humanity can be roughly divided into three “enterotypes” depending on which genus of bacteria dominates in people’s gut: Bacteroides, Ruminococcus, or Prevotella. People’s enterotype appeared to be stable over time, but it remains unclear why your gut population might be so radically different from your neighbor’s.”
Yet another report on diet and gut microbiome. If I could start all over again in grad-school, I’d study this. Human microbiological ecology is going to be big in so many areas, helping us understand the effects that our microbiome has on our health. And of course, this will go hand-in-hand with practical use of naturally occurring microbes.
Read this article…
“A model community of 10 sequenced human gut bacteria was introduced into gnotobiotic mice, and changes in species abundance and microbial gene expression were measured in response to randomized perturbations of four defined ingredients in the host diet. From the responses, we developed a statistical model that predicted over 60% of the variation in species abundance evoked by diet perturbations, and we were able to identify which factors in the diet best explained changes seen for each community member. The approach is generally applicable, as shown by a follow-up study involving diets containing various mixtures of pureed human baby foods.”
Another great report I can’t read at the moment (no subscription). This sounds like a nice analysis of something everyone has been seeing. Looking to see effect of other diets, beyond the baby food tested.
Read this article…
“Nori is, by far, the most likely source of bacteria with porphyran-digesting genes. It’s the only food that humans eat that contains any porphyrans and until recently, Japanese chefs didn’t cook nori before eating it. Any bacteria that lingered on the green fronds weren’t killed before they could mingle with gut bacteria like B.plebius. Ruth Ley, who works on microbiomes, says, “People have been saying that gut microbes can pick up genes from environmental microbes but it’s never been demonstrated as beautifully as in this paper.””
Japanese gut bacteria picking up genes from marine bacteria that live on seaweed. This blew my mind, but I am not surprised. We do know that there can be rapid gene changes in humans (ADH, lactase), why shouldn’t there be rapid changes in our fellow microbiomes? Very interesting implications with respect to therapy and diets.
Read this article…
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