Depression. Thankfully this is something I have never had to deal with. But, depression is one of the most common health issues diagnosed today and many of my patients, friends and family members have suffered with this challenging disease. In fact, depression is the most common psychiatric disorder in the general population and the most common mental health condition in patients seen in primary care.
As well, anti-depressants are one of the most commonly prescribed medications by doctors today. The pharmaceutical industry is making a killing off of anti-depressants. And unfortunately, the role that diet and nutrition play in depression is basically overlooked in the modern medical era. But, what if I told you that the food you are eating could be causing or at least contributing to your depression? What if you could get off your medication by changing your diet? Would you be interested? I hope so!
Now, I never suggest stopping any medications before talking to your doctor. In fact, stopping antidepressants on your own can be extremely dangerous, so if you ever decide to go off your medications please do so under the supervision of a physician who can monitor you closely.
You may be asking, how on earth can the food I am eating be related to my mood? Well, there are actually many different ways that food can contribute to depression including:
1. Altering the microbiome
2. Causing leaky gut
3. Causing nutrient deficiencies
4. Leading to inflammation in the body
So let's talk about each of these factors individually.
1. The Microbiome
The microbiome has gained a lot of attention in recent years when it comes to our health. Humans live in a co-evolutionary association with huge quantities of microorganisms/bacteria that live on the exposed and internal surfaces of our bodies. The entirety of microorganisms in a particular habitat or environment is termed the microbiota, or microflora, and the collective genomes of all the microorganisms in a microbiota are termed the microbiome (yes science likes to make things sound really fancy don't they?). In other words, all of the bacteria (and their genes) that live in or on our bodies are known as the microbiome (it sounds kind of creepy doesn't it?)/
These organisms live in many places including on our skin, in our respiratory tract and lungs and in our gut or intestines. The population in our gut has gained the most attention because of its enormous size. In fact, the genome of our microbiome is about 100x larger than that of its human host. It's pretty incredible.
For the remainder of this discussion I am going to focus on the gut microbiome, as that is the one that is most well studied and the one that our diet can directly impact.
Our gut microbiome is thought to have four major functions:
1. It defends against pathogens/disease causing agents by producing anti-bacterial substances.
2. It strengthens the intestinal lining, creating a barrier between the intestine and the rest of the body. This barrier prevents bacteria and other foreign particles that we ingest from entering our bloodstream and reaching other body tissues and organs.
3. It helps us absorb nutrients by helping digest and metabolize compounds that are otherwise indigestible.
4. It helps develop and maintain our immune system.
In other words, it has some pretty important functions. And the proper function of the microbiome depends on the proper balance and maintenance of certain species of bacteria. Upset this balance, and allow certain types of bacteria to take over and problems start to occur. And one of the main ways that this imbalance begins, and the unhealthy bacteria start to thrive and take over is through eating the modern, North American style diet. You see, this diet, with its heavy reliance on grains, processed foods and refined sugars sets up the perfect environment for these bad bugs to thrive and multiply. Slowly starving out the good bacteria that our intestinal tract needs to function properly. And this breakdown of function then starts to interfere with all of those things the microbiome is supposed to do. Our immune system can become compromised, we can develop infections, we start malabsorbing vitamins, minerals and other important nutrients and the tight junctions between the intestinal cells start to break down, allowing the gut to become "leaky." And all of these things can ultimately impact our mood.
Some of the best evidence that alterations in the microbiome can affect our mood come from studies where probiotics were used to treat depression. Probiotics directly change the bacteria in our intestines by adding specific strains of bacteria into the gut and have been shown to have multiple health benefits. In other words, if you add back the right bacteria to your gut, you can help treat your depression. The same can be said if you can alter the gut microbiome by eating the proper foods. The foods that allow the good bacteria to thrive, and keep the bad bacteria at bay.
2. Leaky Gut
Leaky gut is being linked to more health issues everyday. I could spend hours discussing leaky gut alone. But I will keep it short and sweet today because I know this post is already getting long. Leaky gut occurs when the connections between the intestinal cells, called tight junctions, start to separate and breakdown. This allows bacteria, food particles, toxins and other substances that normally stay in our intestines to gain access to the bloodstream, and then potentially gain access to any organ in our body. And in some people, these substances affect the brain and central nervous system, leading to many different diseases, including depression.
There are multiple factors that can lead to leaky gut including poor diet, certain medications, stress, alterations in the microbiome and certain infections. Treating leaky gut is a key to treating almost any chronic disease, including depression and other mood disorders.
3. Nutrient Deficiencies
Now, there are not many scientific studies that have looked at this. Trust me, I looked! Unfortunately, modern medicine likes to study drugs and not diet or supplements because, let's be honest, there is no money to be made in studying diet and supplements. A true but sad fact. But, that being said, there is significant evidence that both zinc deficiency and iron deficiency can contribute to depression, and that treating these mineral deficiencies can lead to decreased depressive symptoms. And the Western diet is the perfect diet to lead to nutrient deficiencies. Not only is the soil that our food is grown in these days extremely nutrient poor, the high amounts of grains, refined sugars and processed foods that people typically eat actually make it very difficult to absorb any of the vitamins and minerals contained in our food. I wrote an entire post about this topic called Why Grains Are Not Healthy, which I highly suggest you read, as there is way too much information for me to summarize it here. So many people are living with nutrient deficiencies today and they don't even know it. Many of these can be easily diagnosed by simple blood tests so if you are dealing with depression I highly suggest asking your doctor to check your vitamin and mineral levels.
Low grade inflammation in the body can cause a multitude of health problems, and has been linked to depression in multiple studies, and across multiple populations. And unfortunately, the modern North American diet is highly inflammatory. Our reliance on grains, sugars and processed food leads to inflammation in the body. As well, eating meat that has not been raised properly (eg. cows eating grains rather than grass) is also extremely inflammatory. Did you know that cows fed grass product meat with an omega 6 to omega 3 ratio of 1:1, while cows raised on grains product meat with an omega 6 to omega 3 ratio of 20:1. The same goes for fish. If fish is fed corn or other grains it actually has a very high omega 6 level and a very low omega 3 level. And since omega 3 is an anti-inflammatory fatty acid, and omega 6 an inflammatory fatty acid, all this extra omega 6 that most people are consuming leads to systemic inflammation.
But the news isn't all bad. There are many things you can do to change your diet to help address all of these issues I just outlined. And I want to show you how. In my next post I will discuss just How To Eat To Treat Depression. Now, I don't know when that post will be ready, so to ensure you don't miss it please sign up for my newsletter below and you will be informed as soon as the post goes live.
In the mean time, if you would like to start reading about what you can do on your own, I highly suggest reading the book The Gut and Psychology Syndrome. This was one of the first books ever written that connect food to depression (as well as many other psychological issues). It is a great read. You can find the book here:
And if you would like to look at some scientific studies that address what I talked about in this post here is a list of 15 references for you to check out. The evidence that depression is linked to diet is overwhelming. I could fill books just listing the scientific papers related to this issue but I hope these select few will do for now.
1. The Inflammatory Potential of the Diet Is Associated with Depressive Symptoms in Different Subgroups of the General Population.
2. Food and Mood: Diet Quality is Inversely Associated with Depressive Symptoms in Female University Students.
3. Obesity-Induced Neuroinflammation: Beyond the Hypothalamus.
4. Probiotic treatment reduces depressive-like behaviour in rats independently of diet.
5. Food matters: how the microbiome and gut-brain interaction might impact the development and course of anorexia nervosa.
6. Breaking down the barriers: the gut microbiome, intestinal permeability and stress-related psychiatric disorders.
7. The role of microbiome in central nervous system disorders.
8. Modulation of Gut Microbiota-Brain Axis by Probiotics, Prebiotics, and Diet.
9. The role of IgG hypersensitivity in the pathogenesis and therapy of depressive disorders
10. Association of Mood Disorders with Serum Zinc Concentrations in Adolescent Female Students.
11. Zinc Deficiency Is associated With Depressive Symptoms-Results From the Berlin Aging Study II.
12. The efficacy of early iron supplementation on postpartum depression, a randomized double-blind placebo-controlled trial.
13. The efficacy of early iron supplementation on postpartum depression, a randomized double-blind placebo-controlled trial.
14. The acute-phase mediator serum amyloid A is associated with symptoms of depression and fatigue.
15. Association between C-reactive protein (CRP) with depression symptom severity and specific depressive symptoms in major depression.
Until next time, happy eating everyone!