Is Diet Really Linked to Depression?

Our guts are amazing. Charged with the task of breaking down the foods we eat and converting them into real, usable energy, it’s worth taking a minute to consider the role the gastrointestinal (GI) tract actually plays in our day-to-day lives. In addition to the major organs that our food encounters along the journey to becoming the fuel we use to conquer each day, our diet has to deal with enzymes and chemicals in order to function – all of which can be influenced by hormones, medicines and various treatments. And with billions (maybe trillions) of bacteria making up the flora (microbiome) inside the intestine, we’re actually less ‘us’ than us.

What we put into our bodies is critical, and scientists, researchers and the growing field of nutritional psychiatry are beginning to connect the dots between diet and depression. Considering the fact that mental disorders, including depression, are the leading cause of death in many well-developed countries, this association is important. For cancer patients, who are already at high risk for depression and Post Traumatic Stress Disorder (PTSD), this link also plays a significant role during treatment and beyond. To explore this important new association and how it can impact our cancer journey, read on.

We Really Are What We Eat.

According to research, a diet low in nutritional value actually leads to depression (and not the other way around). Depression is one of the leading causes of illness and disability. Our collective mental health in this country has seen better days. Stress is at an all-time high, and the uncertainty of our future changes by the minute. Access to low-nutritional diets, junk-food, and processed foods is ubiquitous. So called “food deserts,” or areas where people have limited access to healthy food options, now impact over 23 million Americans. Researchers have studied how a healthy diet impacts mental health and depression (using the Mediterranean Diet as an example) compared to a low-nutrient diet and found profound improvements in mental health with groups who received dietary support. Further studies on the impact of mood and mental health show that beyond simply better physical health, our diets do more for our minds than we ever realized. 

Happy Gut, Happy Mind

We’ve all had “gut feelings” before – butterflies and warm – but what is the connection between our bellies and our brains? And how much can our diet influence this symbiosis toward the positive? When scientists started studying the gut, they got more than they bargained for. For starters, as mentioned, there’s more to our guts than meets the eye. In addition to the flora (or microbiota) living within the walls of our guts – and making up about 3% of our entire body mass, no kidding – they are teeming with very important nerve cells. More than 100 million nerve cells line the walls of the GI tract, in fact. And these cells have a direct line to our central nervous system. Scientists refer to this second brain as the Enteric Nervous System (ENS) and it plays a major role on our mood. So, those gut-checks and gut-feelings? They really are our gut’s way of communicating with our head. 

So, now that we understand that our belly is full of powerful nerve cells, important microbiotica, and 10 times more organisms than our other human cells, what do scientists and nutritional psychiatrists recommend we do to take care of it? According to clinical research from Harvard Health (and just about everyone) diversity is key. A diet rich in plants, unprocessed foods, whole grains, fruits and healthy vegetables is the best way to stave off depression and build a better environment for our gut flora to grow. The more diverse our plant-based and non-processed food intake, the healthier and happier we’ll be.

The Microbiome and Cancer Treatment

A healthy balance of leafy greens, whole grains, and veggies are essential to our mental health, but what happens when our digestive tract is ransacked after rounds of chemotherapy, radiation or other cancer treatments? For those of us impacted by cancer, how well we manage our diets is suddenly more important than ever. Yet, often, the advice we’re fed doesn’t fit our new reality.  According to one breast cancer survivor, and author of the blog “Dam Mad About Breast Cancer” sometimes the overwhelming nutritional advice for breast cancer survivors hurts more than it helps. Yes, the foods we choose to nourish our body before, during and after treatment are more important now than ever. And, yes, our diet has a long-lasting impact on both our emotional health as well as our recovery. But as she also reminds her readers, refusing to eat broccoli won’t bring your cancer back. “Because you’re a grown-up, you’ve earned the right to refuse any food you don’t want to eat.” Coupled with the fear and anxiety of recurrence, many cancer patients carry guilt and shame when trying to adhere to the healthiest post-treatment options available. However, stress management can still be found through the meals we consume. It takes some searching and trial and error (since everyone is different and cancer treatments impact us in unique ways). Take heart, don’t give up and remember to reach out for help.

Treatments, Prevention, and Hope

Since nearly 70% of our immune system lives inside our digestive tract, a healthy diet is extremely important. Yet cancer treatments often leave us with bad bouts of intestinal distress and diarrhea. When these symptoms occur, we may be losing much of the beneficial bacteria that makes up the microbiome of our gut., seriously increasing the risk of depression and emotional distress. One such infection, Clostridium difficile or C. diff, is diagnosed in approximately 10% of cancer patients. Thankfully, doctors have new treatment options to combat this infection. Now, with the aid of prebiotics and probiotics, medical professionals are treating GI distress with fecal transplants in order to maintain the microbiome and reduce further infection for patients. It sounds extreme, but both depression and digestion have shown improvement in lab tests and in patients. 

Most importantly, for those of us undergoing treatment for breast and other cancers, is to monitor our gut with our healthcare providers. Now more than ever, we know that taking extra care to select the right nutrients in our diets helps encourage a healthy, well-balanced environment for our gut flora to flourish as we heal. 

“The belly rules the mind.” - Spanish Proverb