I used to love eating meat—especially preserved meat. Ever since I became conscious of my diet, I
made an effort on switching from a meat-based diet to a diet consisting mostly
grains, beans (tofu) and vegetables. It
was hard in the beginning—I would stay on my “healthy” diet for a week or so,
and I would crush by eating a big chuck of corned beef, ham or whatever other
preserved meat that has the potential of stopping my heart instantly. But now, after several years, I noticed that
my food preference slowly changed—I miss less of the taste of meat and now
pretty avoid eating meat—not for the sake of health, purely because I no longer
like the taste of it. This made me
wondering—are we truly an animal of habit or there is something more?
It turned out that there is a lot more. In an article published in the journal BioEssays, researchers from several
universities concluded from a review of the recent scientific literature that
microbes influence human eating behavior and dietary choices to favor
consumption of the particular nutrients they grow best on, rather than simply
passively living off whatever nutrients we choose to send their way.
Bacterial species in our gut vary in the nutrients they need:
some prefer fat, and others sugar, for instance. They not only vie with each
other for food and to retain a niche within their ecosystem -- our digestive
tracts -- they also often have different aims than we do when it comes to our
own actions. While it is unclear exactly
how this occurs, the researchers believe this diverse community of microbes may
influence our decisions by releasing signaling molecules into our gut. Because
the gut is linked to the immune system, the endocrine system and the nervous
system, those signals could influence our physiologic and behavioral responses.
For example, gut bacteria may be affecting our eating decisions in part by
acting through the vagus nerve, which connects 100 million nerve cells from the
digestive tract to the base of the brain.
Microbes may be able to manipulate behavior and mood through altering
the neural signals in the vagus nerve, changing taste receptors, producing
toxins to make us feel bad, and releasing chemical rewards to make us feel good. It has been observed that certain strains of
bacteria increase anxious behavior in mice and one clinical trial found that
drinking a probiotic containing Lactobacillus
casei improved mood in those who were feeling the lowest in humans.
Fortunately, it's a two-way street. Our diets also have a
huge impact on microbial populations in the gut. We can influence our gut microbes by
deliberating altering what we ingest.
The changes in the microbiome could be measurable within 24 hours of
diet change. For example, there are even
specialized bacteria that digest seaweed, found in humans in Japan, where
seaweed is popular in the diet.
One researcher
asked--would transplantation into the gut of the bacteria requiring a nutrient
from seaweed lead the human host to eat more seaweed? One thing that I did notice in my own
experience is that—ever since I added seaweed into my diet, I do have cravings
for seaweed once in a while. One data
point never proves anything—but for now, seaweed is staying in my diet. Judging by the benefit of seaweed from a
single google search, so should seaweed be part of your diet.
Journal
Reference: Joe Alcock, Carlo C. Maley, C. Athena Aktipis. Is eating behavior
manipulated by the gastrointestinal microbiota? Evolutionary pressures and
potential mechanisms. BioEssays, 2014; DOI: 10.1002/bies.201400071
Thanks for reading.
Connie
Comments
Post a Comment