By Dr. Mercola

While it’s long been said that “you are what you eat,” a more accurate description might be “you are what your microbes eat.” There are more bacteria and other microorganisms in your body than there are human cells, and your unique microbial community is constantly changing in response to your environment.

In fact, a new diet can rapidly reshape the microbes in your gut, which has implications not only for your digestive health but far beyond this to your weight, risk of chronic diseases, and more. According to research published in the journal Nature, such changes may occur in as little as one day:1

Gut microbes known as Firmicutes have been detected in higher numbers in obese individuals, who also may have 90 percent less of a bacteria called bacteroidetes than lean people.2

It’s been suggested that altering gut bacteriacould therefore play a role in obesity, although a computer analysis led by Katherine Pollard, a biostatistics professor at the University of California, San Francisco suggests it’s much more complex than that.

While it’s becoming increasingly clear that microbes play an integral role in your health, it’s not only the phylum or species of bacteria that matter.

Research by Pollard and colleagues suggests the same species of bacteria may act differently in different people, but most studies don’t get into that fine level of detail.

Pollard’s research suggests it’s not only the species of bacteria that is important but also what each microbe produces that matters.

For instance, some microbes produce anti-inflammatory molecules or vitamins while others speed the conversion of calories you eat into body fat.3 Further, the same species of bacteria may have vast genetic differences. NPRreported:4

So while there’s clearly a connection between gut bacteria and obesity, researchers are still trying to pin down exactly what that connection is. In the meantime, intriguing studies continue to be published.

Preliminary research from the Netherlands, for instance, has even revealed that transplanting fecal matter from healthy thin people into obese people with metabolic syndrome led to an improvement in insulin sensitivity.5

What is known is that obesity rates have been increasing steadily over the last several decades, and it appears to be a much more complex issue than the simple “calories in, calories out” explanation promoted by the USDA.

Metrocosm’s Max Galka put together a clear example of how obesity rates in the US keep rising, and its pervasiveness suggests a variety of factors, from gut bacteria to environmental chemicals, are likely to blame. Check out the revealing graphic below.6

While the role of your gut bacteria on your weight continues to be explored, so, too, does its role in other chronic diseases, including liver disease – specifically non-alcoholic fatty liver disease (NAFLD).

Differences in gut microbiota between people with NAFLD and lean individuals have been detected. Those with NAFLD are also more likely to have bacterial overgrowth in the small intestine along with increased intestinal permeability.

In one study by researchers from the National University of Ireland, NAFLD patients were found to have over double the frequency of small intestine bacterial overgrowth compared to the healthy patients.7

Bacterial overgrowth refers to the growth of an excessive amount of pathogenic microbes, which release waste products known as endotoxins (which travel through your intestinal walls and eventually must be filtered by your liver). This becomes an even greater issue if you have increased intestinal permeability, or leaky gut, as it allows more of the waste products to enter your bloodstream.

It makes sense, then, that restoring the health of your gut with probiotics to balance out the bacterial overgrowth would be beneficial to NAFLD patients, and this is what the research suggests. According to the World Journal of Hepatology:8

Further, one of the most severe effects ofeating too much sugar is its potential to wreak havoc on your liver, including causing NAFLD. Excess sugar will also upset the balance of bacteria in your gut, making it easier for pathogenic strains to flourish…

Researchers from MIT are undertaking the so-called “Underworlds” project beginning this year. They intend totest Boston-area sewage for the presence of viruses, bacterial pathogens, and pharmaceutical and illegal drugs. As the Boston Globe reported:9

The US National Institute of Health’s Human Microbiome Project (HMP) is also underway to “characterize microbial communities found at multiple human body sites and to look for correlations between changes in the microbiome and human health.”

So far, this data gathering has resulted in nearly 200 scientific papers, along with a repository of resources that scientists can access to explore the relationships between human gut bacteria and disease.

The American Gut Project decided to take it a step further by allowing the American public to participate. (I published an invitation tojoin the project in 2012. Hopefully, some of you decided to join, as I did. If you didn’t, you can still sign up to participate on the Human Food Project’s website.10)

All the gathered information from this project will be made public. It’s an extremely ambitious project seeking to identify the parameters for the ideal gut flora and how diet affects it. According to the American Gut Project:11

All of this information should really drive home the point that optimizing your gut flora – living in harmony with your microbiome instead of assaulting it – is of critical importance for disease prevention and optimal health. Reseeding your gut with beneficial bacteria is essential for maintaining proper balance here. In light of this, here are my recommendations for optimizing your gut bacteria.

Sources and References

1 Nature. 2014 Jan 23;505(7484):559-63.

2 Nature.com December 20, 2006

3, 4 NPR August 20, 2015

5 EASD September 22, 2010 Presentation

6 City Lab August 18, 2015

7 Epoch Times August 19, 2015

8 World J Hepatol. 2015 Mar 27;7(3):559-65.

9 Boston Globe January 9, 2015

10 Human Food Project, American Gut

11 Microbio.me American Gut