7 Things We Learned About Gut Health In 2019 Alone

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In recent years, researchers have been paying a lot of attention to the gut microbiome: the collection of bacteria and other microscopic living things that live in our intestines and digestive system. The gut microbiome is a pretty complex system that plays a role in helping us digest food, obtain energy, and fight disease — and scientists are increasingly finding that it can influence a lot more than our digestion. In 2019 alone, a heap of revelations have been published that reveal just how influential the mix of micro-organisms in our guts really are.

There are a lot of areas in which the gut microbiome is proving to be an important player. Take the gut-brain axis. If you haven't heard of this yet, it's the link between what happens in your digestive system and what happens in your brain. We know that it goes both ways; the nervous system of the gut communicates with the brain and vice versa. And the microbiome itself has a key role in those communication pathways, affecting everything from our immune systems to our moods. As the science from just the first few weeks of 2019 confirms, having a healthy gut is crucial for overall health — and 'healthy' can look very different in different people. Here are just a few facts science figured out about gut health in the last few weeks.

1Scientists Discovered 105 New Bacteria In Our Guts

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The gut microbiome is still uncharted territory in many ways. Research published in Nature Biotechnology in 2019 revealed that scientists have just discovered over 100 new types of bacteria in the human gut that have never been seen before. The discovery was made because researchers from the Wellcome Institute were attempting to make a public database of intestinal bacteria, and sequenced the guts of 20 people from the UK and Canada. With such a small study size, one can only imagine the variety of gut bacteria that remain unknown in guts around the world. It's pretty mind-boggling.

2People With Depression May Have Lower Levels Of Two Gut Microbes

A study published in Nature in January 2019 made a big splash with its revelations about the gut microbiota of people with depression. It turns out that if you have depression, there may be two specific traces of it in your gut. The study, wrote the editors of Nature in an editorial on the research, "found that two groups of bacteria, Coprococcus and Dialister, were reduced in people with depression. And they saw a positive correlation between quality of life and the potential ability of the gut microbiome to synthesize a breakdown product of the neurotransmitter dopamine."

In other words, if you have depression, chances are that you have a low level of two essential groups of bacteria in your gut that can affect how you respond to dopamine — which in turn can impact depression. Dopamine is a neurotransmitter in the brain that has a strong role in mood, and is thought to malfunction in people who experience depression — and it turns out that malfunctioning happens in the gut as well.

3Dementia Might Begin In The Gut Microbiome

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A study published in Nature Scientific Reports in early 2019 found that people with dementia, including Alzheimer's disease, showed pretty clear differences in their microbiome from people of similar ages without dementia symptoms. After studying the gut microbes of 181 people, the researchers found that people with dementia had lower levels of a type of bacteria called Bacteroides (enterotype I), and a higher level of bacteria called enterotype III, then other people with healthier brains.

We've known for a while that the gut microbiome seems to play a role in dementia, particularly in how the brain develops the 'plaque' that characterizes disorders like Alzheimer's. This is the first study to pinpoint what happens in the guts of people who develop dementia symptoms. This is a big deal because it might eventually explain how to prevent dementia from emerging.

4Researchers Found New, Large Lifeforms Living In Intestines

A team of scientists found giant "megaphages" living in the guts of some modern hunter-gatherer societies, though not in the guts of people who have a typical Western diet. They're huge, much bigger than normal bacteria, and they eat bacteria for breakfast. Literally; that's their food.

Interestingly, these phages, which are the largest ever found in humans, also showed up in the guts of baboons and Danish pigs. It's possible that we may get phages from animals and vice versa, though it's not clear what that might mean for our health.

"Megaphages, with fascinating and underexplored biology, may be common but largely overlooked components of human and animal gut microbiomes," wrote the scientists in the study published in Nature Microbiology. These megaphages are also not technically classified as 'life', so they challenge our definition of what 'living' might actually be in biology.

5The Gut Microbiome Could Impact Food Allergies

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Quite a lot of kids are allergic to cows' milk; the National Health Service estimates that between 2 and 7.5 percent of kids under one are allergic to it, though the vast majority will stop being allergic once they hit the age of five. Food intolerances and allergies are strongly related to the gut microbiome, and a new experiment shows just how much they're intertwined.

A study from the National Institute of Allergy and Infectious Diseases took fecal samples from eight babies — who weren't allergic to cow's milk — and injected them into mice who did have the allergy. The result? All the mice who received the samples, which were full of gut microbes, stopped being allergic. This, the scientists behind the experiment believe, reaffirms the idea that some of us are born with gut bacteria that protect us against allergies. Though this study was small, with more research this link could be a lifeline for children who have life-threatening food allergies.

6The Gut Can Help Protect Us From Poisons

The gut is stronger than you might think. A study published in Nature Communications revealed that when it comes to arsenic poisoning, our guts play a pretty serious role in protecting us from the worst effects. The experiment used mice, and found that mice with disrupted gut microbiomes from antibiotic use tended to experience worse arsenic poisoning because the gut couldn't process the arsenic properly.

You might not think this is relevant to you, but the researchers explain that 200 million people worldwide are affected by arsenic toxicity in drinking water, and a 2017 study found that 2.1 million people in the United States were using wells with high arsenic quantities in the water.

7Gut Bacteria Could Play A Role In Schizophrenia

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A study published in Science Advances found two interesting things about the relationship between schizophrenia and the gut microbiome. The first was that people with schizophrenia may have very specific gut bacteria levels that differed from healthy controls, like higher levels of Veillonellaceae. The second was that, when gut bacteria from people with schizophrenia was transplanted into healthy mice, the mice began displaying "schizophrenia-like symptoms," such as hyperactivity. This suggests that the gut microbes of people with schizophrenia may have an impact on their symptoms. It's only a small study and needs to be replicated, but it shows that the link between the gut and the brain may be stronger than we ever thought.

To increase the health of your gut microbiome, Healthline recommends eating diverse kinds of foods, particularly vegetables, whole grains and fermented ingredients. As we discover more of the complicated world of gut microbiota, we're finding that it's more crucial for our health and stability than we ever thought.