Colonizing the Colon

Over the recent Memorial Day weekend Mr. Scienticklish and I were lucky enough to participate in not one, not two, but THREE barbecues! There was a lot of corn, burgers and sweet treats to go around, but probably the most interesting food we consumed was Water Kefir, thanks to a new friend met at BBQ #2. While in conversation, this new friend was referred to as the "King of Fermentation" - a title that I'm sure only a small demographic is excited to have. Our new friendship resulted in him offering up various bacterial and yeast cultures, including a sourdough bread starter and Kefir grains. Similar in theory to the fermented Kombucha beverages, Water Kefir uses various bacteria strains (together called Kefir grains) to break down sugars. When you make Water Kefir yourself you add table sugar or fruit juice to feed the bacteria, which they use to produce CO2 and a small amount of ethanol, making the drink bubbly and about 0.5% alcoholic. In the end you get a fruity, carbonated drink that is very low in calories, high in active bacteria cultures and absent of the vinegar taste you find in Kombucha. The one we sampled the next day was so good in fact that we wondered why the producers chose to market the drink as a pro-biotic, fermented drink as opposed to a healthy alternative to soda? Anyway, if you can find some you should try it for the taste alone, if not for any health benefits you may get from the bacteria.

Don't be fooled by those good-for-nothing amateur biotics

Pro-biotic foods and beverages have been getting a lot of hoopla lately. I think it's pretty exciting stuff too. The more we learn about the functions of all of those bacteria living in our gut, the more we realize how integral they are for our own health. These colonies of bacteria exist mostly in the colon, some make it past the ileocecal valve into the small intestine, but when we think of the gut microflora generally we're thinking of the colon. So how did this bacteria get there? When you were a fetus you were sterile, it wasn't until you were born that mom passed on her bacteria to you as you traveled through her birth canal. As expected, babies that are born via cesarean section have a different composition of gut flora than those born vaginally. After delivery, it seems like almost everything, and then nothing, can change your gut flora. Some studies show that what the infant eats (breast fed versus formula fed for example), and whether the baby was born in a hospital or at home can affect what bacteria colonizes their gut. However when adults are given pro-biotic foods it's still not certain what the results are. For example, the live cultures in the yogurt you eat may be doing something beneficial while they're passing through your gut, but whether they hang around and make your colon their new home isn't really known yet.

The war in your colon?

A potential way to change what bacteria grow in your gut is to change what you feed them. For example, when comparing vegans vs vegetarians vs meat eaters you see different types of bacteria growing in the colon. Additionally, lean people and obese people also have a different world of bacteria taking up residency. To study the latter in more detail, researchers looked at the types of bacteria growing in the colons of obese and lean mice. They also looked at the contents of the fecal matter (taken from the caecum) and found differences in lengths of fatty acids between lean and obese mice (part a in the figure below). Next,they looked at differences in fecal material between lean and obese mice, finding that the obese mice had less energy (kcal) per gram of waste, perhaps showing that the obese mice were better able to absorb that energy into their blood stream as opposed to pooping it out (part b). Finally, in what I think is the coolest part of this experiment, the researchers did a "fecal transplant" into mice that were devoid of bacteria in their gut. This means that someone, a lowly grad student I'm sure, took poop from the lean and obese mice and fed it to the bacteria-free mice so that those bacteria would grow in the colons of the new mice. And now we know why people think scientists are crazy... BUT look at the cool results in part c below! The mice that got poop from lean mice (+/+) had less than half the percent increase in body fat compared to mice that got poop from obese mice (ob/ob). Keep in mind that these mice were on the same diet, and the mice that gained more weight didn't eat any more food than the mice that didn't gain the weight. Perhaps the bacteria from the obese mice helped breakdown the nutrients to make them more readily absorbed, thus permitting those mice to take in the energy and store the fat. So now we need to convince the world that the future of weight loss lies in fecal transplants.

I'm realizing that this is becoming quite a long blog post about poop and colons. I'm also realizing that I may have a strange fascination with these topics. I haven't even really got into what these little creatures may do for our health. Perhaps a future post about Jamie Lee Curtis and her empty promises with her Bifidus Regularis will be necessary. As for now I'm going to leave you all to digest this fecal-filled post, just like those poor mice.

Zimmer, J. et al. A vegan or vegetarian diet substantially alters the human colonic faecal microbiota. European Journal of Clinical Nutrition (2012)

Penders J. et al. Factors Influencing the Composition of the Intestinal Microbiota in Early Infancy. Pediatrics (2006)

Turnbaug, P.J., et al. An obesity-associated gut microbiome with increased capacity for energy harvest. Nature (2006)

Raspberry Ketones and Your Love Handles

In addition to spending my days chained to the lab bench, I also spend my time moonlighting as a teaching assistant for nutrition classes in the Boston area. In one such class the students were given the assignment to present a nutrient or food that is associated with preventative properties of certain diseases. One student group decided to focus on what is seemingly the next diet craze: raspberry ketones (RK). I thought this would would make a great Scienticklish post because it is a timely topic (having recently been aired on Dr. Oz) and the immediate anger I felt after Googling RK and weight loss and finding so much bad information riddled with lies! Thus, a post to get the facts out there. Science!

First, some background. Raspberry ketones are small molecules found naturally in red raspberries which give them their smell and flavor (see above for the molecular structure). RKs have been used by the food industry for years to put the flavor or raspberries into various treats. They are also used in various perfumes, soaps and lotions, so the synthesis and purification of RKs are nothing new. In the past decade some scientists started taking note of the molecular similarities between RK and capsaicin - the molecule that is responsible for chilies' spiciness that have been shown to increase metabolic rate. Intrigued by this resemblance, researchers in Japan began to study the effects of feeding RK to mice that were eating a diet high in fat. They published a study in 2005 that showed feeding RK to these mice increased lipolysis, or breakdown of fat and decreased the absorption of dietary fat. Overall, the mice fed larger doses of RK were lighter than the mice fed the high fat diet alone (See figure below). A high dosage seemed to be key: the mice that were fed a diet containing 2% RK by weight had a significant decrease in body weight, but the group of mice eating a diet that was either 0.5% or 1% RK by weight did not have any difference in body weight relative to mice fed a high fat diet alone. It's probably safe to bet that the amount of RK needed to see this effect is not available by simply eating raspberries, which brings us to the next published paper I'll discuss: a patent!

ND: Normal Diet;  HFD: High Fat Diet;  RK: Raspberry Ketone

Also in 2005, a different research group (associated with DSM, a leading producer of purified nutrients that are used in supplements and food products globally) published a US patent for a neutraceutical blend of the polyphenol found in green tea called EGCG and an RK precursor. This patented product demonstrated the ability to  prevent weight gain and obesity associated conditions (like type II diabetes), again, in rodents. Showing similar results, their now patented supplement prevented weight gain in both mice and rats fed a high fat diet or a high fat, high sugar diet.

So, should you be taking RK to get ready for the beach this summer? Well, so far it hasn't been shown to have any adverse effects (other than decreasing the size of your summer beer fund), but because published research in humans is so limited (i.e. non-existent), no one really knows if it is safe. More and more nutrition research is coming out to show that supplementation of large doses of a single nutrient are actually harmful for humans, so you should take caution before popping pills of any kind. Plus keep in mind that RK supplementation has only been shown to prevent rapid weight gain in mice that were eating a very high fat diet, you can't expect that it's going to behave the same in humans that are trying to lose weight. The nutrition community goes through these magical weight loss nutrients so quickly without much to show for it. Remember when I said the idea of using raspberry ketones for weight loss stemmed from using capsaicin for weight loss? Well, do you know anyone that has lost a lot of weight by taking capsaicin pills? Right. I hate to be the negative Nancy here, but the best way to lose weight is really to make some major lifestyle changes that include eating foods that will keep you fuller longer (high fiber, high protein), and constantly reminding yourself to keep moving. Yes, it's going to be hard and you're probably rolling your eyes at the nutrition community for sounding like a broken record, but it is what it is. In the end, you'll be better off trying to increase your intake of raspberries (along with other fruits and vegetables) than spending that cash on pills.

Yum!

Morimoto, C. et al. Anti-obese action of raspberry ketone. Life Sciences (2005)

Raederstorff, D. et al. Nutraceutical compositions comprising epigallocatechin gallate and raspberry ketone. US Patent Office (2005)