My Microbiota Made Me Do It!

This holiday season, you’re going to be able to resist that second piece of apple pie.

Not because you’ve been bolstering your willpower all year (although power to you if you have!), but because you’ll know you’re not the only one craving that sweet, gooey, triangle of deliciousness.

You will know that something else is filling up your craving cup, letting it overflow past one piece of pie. But first, let’s cover some basics.

The Gut-Brain Axis

Do you ever wonder why your stomach may cramp up from swimming in cool water after eating a large amount of food? Your brain slows your digestive system to focus on moving and keeping you warm, cramping up your gut!

The gut-brain axis is a communication system between, you guessed it, your digestive system and your nervous systems.

This communication system is what triggers your cravings of warm apple pie, even on a full stomach: your brain releases appetite stimulants and your gut suddenly opens up room for dessert unlocking that “second stomach”.

However, the gut is not alone. There’s an enormous party of microorganisms that can have influence on this gut-brain axis, and they’re living inside of your gut!

Manipulating Microbiota

The something else driving your cravings is the community of microorganisms living in your gut called your microbiota.

We benefit from them about as much as they benefit from us; microbiota are involved in nutrient metabolism, anti-microbial protection (against disease causing bacteria), immunity, development, and more.

Microbiota Mind Control

The crazy thing is, research suggests that microbiota within the gut seem to have some level of control over appetite, taste perception, and even behavior.

Don’t take this to mean that your gut microbiota are controlling your mind. After all, we have grown up and evolved with them.

Nevertheless, you are still their host, and your microbiota will try and sway you in their favor using hormones, neurochemicals, or any other trick they have up their sleeve.

Your Microbiota likes dessert as well

The microbiota have their own food preferences and will release more reward chemicals than your own body does after you eat something they need. Depending on the microbiota, that could mean cravings for the fatty, sugary, holiday desserts!

The more of one type of microbiota you have in your gut, the stronger that signal is presumed to be. This is partially why obese individuals have a much harder time keeping weight off, and why a varied diet is generally praised as healthy.

Lost In The Masses

Studies have reported a decreased gut microbial diversity for either side of the appetite spectrum, obesity and anorexia nervosa. It may even be associated with depression and anxiety.

With a varied diet of micro and macronutrients, you should be feeding several different kinds of microbiota. The more kinds of microbiota you have in your gut, the more competition each microbial organism encounters.

Imagine you are going out to eat with two of your friends. They are a bit more similar in food taste than you are and inch toward one option, leading you, the odd one out, to follow.

If you were a group of ten friends, your food interest would likely be a bit more varied based on culture, preferences, etc. and the decision would not be so clear. It would be easier to make your own decision over the larger discussion.

In principle, this is how your microbiota would work: even if they have enough resources to try and manipulate you after the competition, no matter what method of manipulation they try on you, any particular signal would likely be lost in the variety of signals, allowing your own signal to dominate.

This holiday season, be conscious of your diet variety to prevent any extra cravings!

To Sum It Up

Microbiota within your gut make use of the gut-brain communication system attempting to manipulate your food intake to support their own preferences.

The more of a particular food you eat, the more microbiota that feed off it will survive, and continue to drive your cravings for those particular foods. This is why a varied diet is recommended; it will feed several different species of microbiota, leading to more competition and each distinct signal trying to sway your cravings will be lost in the masses.

Happy Holidays!

- Lucas Roldos

Disclaimer: The information provided is meant to spread knowledge and induce interest for educational purposes. It is based on limited research. We try to pull the overall message of the literature, but further research may be necessary.  What is done with the information or suggestions is solely the consumers decision. The information provided is not meant to treat or diagnose any medical condition. References are provided for informational purposes only and do not constitute endorsement of any website or other sources.

References provided within the text as hyperlinks.

Traditional Diets and Gut Bacteria: A tale of Two Microbes (Part 2)

To recap where we left off from Part 1 of this article; 

Hunter-gatherer societies have unique gut bacteria—known as the gut microbiota—that are likely protective against obesity and all the negative health consequences that come with being overweight. This is due in part to the large quantity of prebiotics that these traditional societies consume in their diet. What differs between our gut bacteria and theirs, and why might it be such a big deal? 

THE GUT BACTERIA SPECIES: PREVOTELLA & BACTERIOIDES

For the past year, I’ve been researching the gut microbiota variations between Western peoples and seven different hunter-gatherer and traditional societies: the Yonomami people of Venezuela[1], the Sausi and Asoro of Papua New Guinea [2], the Matses and Tunapuco from Peru [3], the Mossi of Burkina Faso4, and the Hadza of Tanzania[5]. All of them differ quite significantly from each other (and from us) in terms of their gut microbiota ecosystem. But one unifying thread that connect these geographically separate, traditional societies from Western ones is that not only do they have much higher diversity in bacterial species, but they have much higher levels of a species called Prevotella, whereas we have more of the species Bacterioides.

HOW TO INCREASE YOUR LEVELS OF PREVOTELLA?

It is thought that Prevotella thrives best when its host consumes high levels of fibrous, prebiotic-containing plant-based foods, whereas Bacteroides can resist and thrive when there’s more animal fats and processed foods being ingested (as is the case in modern diets). When fiber and prebiotics enter the colon, both Prevotella and Bacteroides can ferment these into products called short-chain fatty acids (SCFAs). Where the two microbes differ, however, is that Prevotella makes two to three times more of the SCFA propionate than Bacteroides does. 

HIGHER LEVELS OF PROPIONATE COULD PREVENT WEIGHT GAIN

A recent clinical trial in humans have demonstrated that propionate has potent anti-obesity effects, mainly by tricking the brain into thinking it’s less hungry than it would be ordinarily; results from the study showed that participants who had received propionate supplementation consumed 14% fewer calories overall in their diet compared to participants who received a placebo. Taken over a lifetime, such a 14% reduction could prevent the weight-gain that comes with ageing.

THINGS ARE GETTING WORSE, BUT UNDERSTANDING THE MICROBIOTA CAN HELP

So as this global pandemic of obesity, diabetes, and high blood-pressure continues to worsen, novel therapies targeting the gut microbiota will become crucial. Expanded research and development into human-to-human microbiota transplantation and over-the-counter synbiotics (supplements which contain both prebiotics and live bacteria) have the potential to alleviate this pandemic. This will require the need for super donors who have optimal gut microbiota profiles—traditional, hunter-gatherer societies harboring Prevotella could become invaluable for providing such super donors. For this reason, the scientific community really needs to expedite gut microbiota research before traditional cultures and their dietary habits are completely wiped out by the advance of the modernized world.

- Tyler Feeney- 
M.Sci (c) in Dietetics

References

Clemente, J. C., Pehrsson, E. C., Blaser, M. J., Sandhu, K., Gao, Z., Wang, B., . . . Dominguez-Bello, M. G. (2015). The microbiome of uncontacted Amerindians. Science Advances, 1(3), 1-12.
Martínez, I., Stegen, J. C., Maldonado-Gómez, M. X., Eren, A. M., Siba, P. M., Greenhill, A. R., & Walter, J. (2015). The gut microbiota of rural Papua New Guineans: composition, diversity patterns, and ecological processes. Cell Reports, 11(4), 527-538.
Obregon-Tito, A. J., Tito, R. Y., Metcalf, J., Sankaranarayanan, K., Clemente, J. C., Ursell, L. K., Zech, X. Z., ... Lewis, C. M. (2015). Subsistence strategies in traditional societies distinguish gut microbiomes. Nature Communications, 1-6.
De Filippo, C., Cavalieri, D., Di Paola, M., Ramazzotti, M., Poullet, J. B., Massart, S., . . . Lionetti, P. (2010). Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa. Proceedings of the National Academy of Sciences, 107(33), 14691-14696.
Schnorr, S. L., Candela, M., Rampelli, S., Centanni, M., Consolandi, C., Basaglia, G., . . . Severgnini, M. (2014). Gut microbiome of the Hadza hunter-gatherers. Nature Communications, 1-5.