Your Microbiome Is Directly Linked To Your Body Weight and Appetite (Part 2 of 3)

What is the difference between someone who eats until feeling full and maintains a healthy weight and someone who consumes much more food and has a resulting weight problem? Frequently, we assume one person has a more ‘active’ metabolism than the other. However, new research reveals something else may be going on, and it has to do with your microbiome. Your microbiome includes trillions of different kinds of bacteria and non-bacterial organisms that live inside the gut and perform essential bodily functions.

It seems these bacteria may be undermining our self-control when it comes to eating and appetite and sending us unwanted signals. It’s now understood certain strains of bacteria are associated with an increase in the undesirable results of being obese, such as insulin resistance, type 2 diabetes, hypertension, and elevated blood lipids.

Old Thoughts Regarding Appetite and Satiety

Science’s working model for appetite and satiety assumed obesity was dependent upon an intrinsic gut-brain axis of circulating gut-tissue molecules and hormones and was unrelated to the microbiome. It was thought when people eat and begin to digest, gut tissues send signals of fullness and satisfaction to specific centers in the brain, such as the hypothalamus or amygdala, in which the nutritional and sensory aspects of food trigger an eating control regulatory circuit.

New Thinking About Appetite and Satiety

Recent research has shown our gut microbes are directly participating in that regulatory circuit mentioned above by releasing bioactive molecules that tell us whether we are full or still hungry. And most surprisingly, this circuit is dependent on their assessment of their own needs--the gut microbes, that is. The "old thinking" circuits certainly exist, but gut bacteria can produce some of the same types of chemicals that regulate satiety, such as proteins and peptide hormones, that are part of the regulatory system of our own cells. So our gut bacteria directly participate in the body’s triggering mechanisms determining both hunger and fullness.

E. coli's Involvement In Satiety

There’s a massive amount of microbial life in the stomach and intestines. A new study investigated proteins produced by one type of bacteria in the stomach, known as E. coli. When we eat, these bacteria go through a biphasic pattern of response to the nutrients entering our stomach. At first, they begin to multiply very rapidly, producing one set of proteins. After about 20 minutes of eating, the bacteria stop their rapid growth phase and begin to produce proteins that are distinct and different from the earlier proteins produced. It’s the second type of protein that seem to directly influence our feeling of satiety.

After tests on rats, it was found bacterial proteins from E. coli are involved in the same pathways of hormonal stimulation used by our own cells to issue signals to the brain indicating sensations of hunger and fullness. 

The microbiome and the weight/appetite/satiety connection is fascinating. But weight isn't the only heath aspect the microbiome is involved in (Part 1 of 3). Part 3 focuses on foods and snacks for building a powerful microbiome that works for you, not against you.

In Health and Happiness,

Kelly Harrington, MS, RDN

Registered Dietitian Nutritionist for Healthy Goods