Updated: Oct 28
Fascinating science about hidden things that change our minds!
The gut microbiome may have a number of effects on our mental state
Our immune system (especially inflammation) changes how we think and feel
Research indicates that certain types of fat cells (around our bellies) may change our state of mind
Humans have long been obsessed with understanding mood. This quest takes many to self-help books, others to therapists, and some all the way to the stars in an attempt to gain a bit of insight. But even if you think you know all the causes of your ups and downs, it’s worth reading on. That’s because, in the last several years, scientific research has discovered some rather unexpected contributors to our mental state.
1. Your Microbiome
You’ve likely heard people talk about the microbiome, and for good reason. Research on this subject has captured the interest of scientists and the lay public worldwide. More recently, we’ve learned that this science may play a key role in our mood.
First off, what is the microbiome? The term actually refers to all of the bugs living on and in your body. This includes viruses, bacteria, and a host of other microbes. However, most available science refers to the bacteria in the gut. This is more specifically called the gut microbiome.
The gut microbiome is impressive enough without it actually doing anything. It’s thought that it contains more cells than the entire human body. Luckily for us, many of these bugs are lending us a helping hand. They help us metabolize food, support our gut cells, and even produce vitamins.
Gut bacteria are thought to communicate with the brain through a variety of pathways. This helps explain why the gut microbiome has been implicated in conditions like anxiety and depression. In fact, multiple studies have shown that giving people probiotics (beneficial gut bacteria) may help reduce symptoms of anxiety and depression.
The data connecting mood and the microbiome continue to mount. In the meantime, there’s a lot we can do to put it into action. Eating fiber-rich and fermented foods supports our gut bacteria. On the other hand, we should try to avoid added sugars (natural and artificial), as these may have the opposite effect. Exercise, sleep and stress-lowering interventions are all known to have positive effects on mood, but may additionally buttress the health of the gut microbiome.
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2. Your Immune System
For a long time, discussions about immunity seemed only concerned with infections. We’ve come around to appreciate that immune function is intimately involved with basically every part of our health. Everything from high blood pressure, diabetes, and even dementia have been linked to changes in immune cells. It turns out that mood issues are yet another piece in the puzzle. To understand why this is the case, we have to know a bit more about immunity.
Our immune systems are pretty incredible. They somehow manage to protect us against most of the nasty viruses, bacteria, and other microbes that cause disease. Immunity is great when it’s working well. But when it’s imbalanced, disaster ensues.
Most of the top causes of death and disability are linked to immune dysfunction. These include cancers, heart disease, and stroke, in addition to infectious conditions like pneumonia. One of the key players in this process is inflammation.
Inflammation is usually represented as something to avoid. The truth is, we need it to survive. It’s mainly when it becomes chronic that we develop problems. In fact, it is this smoldering inflammation which is strongly linked to depression.
At the moment, multiple studies are looking at the effects of immune drugs to improve mood. Early data have been promising, but there is still lots to learn. Luckily there’s plenty we can do to improve our immune function and more specifically, to help lower inflammation. Consuming a Mediterranean-style diet, engaging in moderate-intensity physical activity and practicing stress-reduction techniques are great places to start.
3. Excess belly fat
It’s no secret that people worldwide are getting bigger around the belly. Rates of global obesity have almost tripled since 1975. Higher weight is associated with a variety of health issues. But to be clear, it isn’t just any fat that’s messing with our mood. Our belly fat (sometimes called visceral fat) is the problem. That’s because it sends all the wrong signals to our brains.
If different fats were characters in a play, belly fat would be the villain. It’s linked to a higher risk for diabetes, heart disease, and even some cancers. Belly fat is also called “active fat” because it makes hormones and increases inflammation. Remember, chronically elevated inflammation is a major risk factor for depression. This helps explain the connection between more belly fat and more depressive symptoms. Belly fat has also been linked to symptoms of anxiety.
Another reason for these findings may relate back to the gut microbiome. Researchers have discovered that our gut bugs influence the storage of fat in our bodies. This is leading them to investigate the role of probiotics in preventing and treating obesity.
Here, the actionable steps are relatively established. Cutting refined carbohydrates and sugars out of your diet is a great place to start. Limiting alcohol is another practical tool. Bumping your sleep up to 7-8 hours a night could also help. Exercise, while not a great overall weight-loss strategy in isolation, has also been shown to decrease belly fat.
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A version of this article I wrote was also published on Psychologytoday.com