99 percent of the genetic material in our bodies is bacterial. Change the bacteria and you change the whole person, scientists are discovering.
Whether by dietary changes, probiotic pills or even fecal transplants, changing our gut bacteria can reverse autism, depression and obesity and cure all kinds of disease, says Rob Knight, founder of the American Gut Project.
From our appearance, to our mood, to our personality, changing the type of bacteria in our guts, transforms the very essence of who we are, Knight explains in the Ted Talk below:
Bacterial cells in our bodies outnumber human cells ten to one, Knight says, and 99 percent of the genetic material (DNA) in our bodies is bacterial.
Our microbes determine how often we get bitten by mosquitoes, which painkillers are toxic to our liver, which drugs will work on our hearts, and maybe even who we are sexually attracted to, says Knight, author of the TED book Follow Your Gut: The Enormous Impact of Tiny Microbes.
Our gut flora are responsible for digesting our food, educating our immune systems, resisting disease, and even regulating our moods and behavior.
But gut flora varies greatly from person to person. You and the person sitting next to you may only share 10 percent of the same bacteria.
Our microbial composition is determined mostly in the first six months of life, Knight says. Vaginally delivered babies have totally different gut flora than c-section babies, and breast-fed babies have totally different gut flora than formula-fed babies.
If you give children antibiotics in the first 6 months of life, they are much more likely to become obese and have asthma later on, he adds.
“When gut bacteria are not balanced, it’s called dysbiosis, and this causes all sorts of disease, says Dr. Warren Peters, an epidemiologist, in another Ted Talk.
In the past few years, microbes have been linked to a whole host of diseases, including irritable bowel syndrome, celiac disease, colitis, heart disease, cancer, cavities, eczema, epilepsy, ulcers, HIV, Parkinson’s, arthritis, schizophrenia, multiple sclerosis, and Crohn’s disease.
But how can we determine whether the correlations are cause or effect?
“One thing we can do is raise mice without any microbes of their own, in a germ-free bubble and then add microbes in,” Knight says.
Scientists have done just that to study the effects of microbes on obesity, depression, anxiety and anti-social behavior that resembles Autism in mice.
In one study, scientists took the microbes from obese mice and and transferred them to normal-sized mice that had all their own bacteria wiped out with antibiotics. The “germ free” mice also became obese.
The “germ-free” mice who received microbes from lean mice, became lean.
Scientists have since repeated the experiment with microbes taken from humans and given to mice, with the same results.
Knight says the microbes of the lean mice help them digest more efficiently, so they take more energy from the same diet and need fewer calories.
In yet a third Ted Talk, microbiolgist Elaine Hsiao talked about experiments she and her colleagues are doing at CalTech in which certain microbes make mice “talk” more to each other.
Changing a mouse’s bacteria can change it from a social mouse to an anti-social mouse, and vice versa she says.
In Peters’ words, “the germ-free mice are kind of Autistic.”
“They don’t hang out with others or eat well,” he says. “But if you transplant normal gut flora into them, they become socially normal.”
“Probiotics are being given to autistic children with fabulous results,” Peters adds.
Additionally, swapping the microbes of a high anxiety and low anxiety mouse completely swaps their behaviors, Hsiao says.
The mouse who was scared to jump from a platform will jump without thinking twice, while the formerly fearless mouse becomes frozen with anxiety, she says.
Both animal and human studies have shown how beneficial microbes can reduce symptoms of depression, suggesting possibilities for a new “psychobiotic” class of antidepressants.
“The gut affects the brain and the brain affects the gut,” Peters says, noting stress can change the composition of gut bacteria.
Peters says we have to take care of our bacteria, so they can take care of us.
High-quality protein, healthy fats and fermented vegetables are essential for a healthy biome, he says, while refined carbs and sugar are altering our bacteria in a bad way.
Our gut bugs also have their own circadian rhythm, Peters says. “To keep them healthy, we must give them plenty of sleep. When you don’t sleep, your bugs don’t sleep.”
Your gut bugs also need you to exercise, he says.
“Take care of your bugs, feed them well, give them plenty of rest and exercise. If you have happy bugs, you’re going to be a healthy person.”