Updated: Mar 1
How could food possibly affect mental health? That doesn't make sense. How could something we put in our mouths possibly have anything to do with our moods? Just so happens that our minds and our guts are more connected than we previously thought.
Our brain relies on 3 specific chemicals, called neurotransmitters, to convey chemical messages that we then translate into moods and emotions. You've probably heard of serotonin, dopamine and norepinephrine (also called noradrenaline). They play an important role in mood regulation and are the target of most of our medications we use to treat mental illness. But we also have other important mechanisms that influence our mental well-being.
Although worlds apart, the gut and the brain are completely intertwined. More than 95% of serotonin receptors are actually in the gut, not the brain. It’s no surprise that medication used to treat depression and to increase serotonin can have side effects related to gastro-intestinal upset. Our brain and gut both originate from the same cells in the embryo, and although they separate themselves from each other physically, they remain attached through the vagus nerve and through chemical signaling from bacteria residing in our colon. Wait, what? Bacteria in our colon have an impact on our moods? Yes, you read that correctly.
Increasing fiber intake for mental health?
We know through recent studies that high fiber diets increase the amounts of beneficial bacteria residing in our colon. So what does that have to do with depression? Our beneficial bugs living in our colons feed on fiber and in return, they produce short chain fatty acids (SCFA). These chemicals, also called post-biotics, make their way in our bloodstream, and even cross the heavily guarded blood-brain barrier, where they can exert their protective effects on mental health. Humans have evolved to protect their brains against foreign substances trying to cross the blood-brain barrier, and the fact that we open up the flood gates for SCFA shows that this is something take seriously, and to research further. Anyone who has experienced butterflies in their stomach can appreciate how our mental health and guts are linked. This is explained by neural pathways travelling through the vagus nerve that connects them both. We are now realizing that this connection is a two-way street, and that the connection is not only through nerves, but through the bloodstream too, where the chemicals produced by our gut bugs travel. We call the latter the microbiota-gut-brain axis. Although these studies are relatively new, they’re all very promising and to be followed carefully! Studies are finding that the gut microbiome is often implicated in many of the diseases we see in patients today, and that by modifying the gut bugs, through diet and probiotics, we are able to modify the disease’s course. I don't know about you, but if preliminary studies show that fruits and veggies could potentially improve cognitive function, concentration, and mental health in general, with zero side effects, I don't need other studies to start making dietary changes.
An anti-inflammatory diet for mental health?
Studies have also suggested that inflammation could have negative effects on mood, beyond just being sad about having medical issues. Inflammatory conditions are associated with higher rates of depression, and physically healthy people suffering from mental health issues do show elevated CRP levels (C-reactive protein, a marker for inflammation). Pro-inflammatory drugs have been shown to increase rates of depression and we know that unhealthy diets rich in processed food and animal products are associated with elevated inflammatory markers. Switching these people on plant-based diets can reduce their inflammation by up to 30% in 2 weeks. Could a plant-based diet assist in treating mental illness? We know that eating a diet rich in fruits, veggies, legumes, nuts and seeds can reduce inflammatory markers in our blood. We also know that people suffering from mental health issues tend to have elevated markers of inflammation. Although this doesn't prove causation, it does make a great case for considering a diet rich in anti-inflammatory foods.
Eating anti-inflammatory foods is only half of the story. Avoiding pro-inflammatory foods is the other. Saturated fats are one of the most studied inflammatory nutrients, and experts agree that less is more. Basically, you want your saturated fat intake to be as close to zero as possible. These fats are found in animal meats, dairy, eggs and tropical oils like coconut and palm oil. Yes, some plants have saturated fats too. They increase bad cholesterol, heart disease and inflammation and have no place in an anti-depressant diet. Processed foods are also highly inflammatory, due to their added sugar, fat, salt and preservatives. Keep them to a minimum if possible.
Spices aren’t just for taste. They just so happen to be the most concentrated form of anti-oxidants that exists. We now have randomized controlled trials showing benefits in treating depression, and good evidence to recommend them to people living with anxiety. Adding spices like turmeric, ginger, saffron, or cumin to your meals or smoothies bumps up dramatically its anti-inflammatory potential without increasing calories. Rosemary, parsley and thyme have been shown to improve brain fog and have zero downsides except making your food tastier. They should be used regularly on most days and as a long term lifestyle change.
Omega fatty acids
Not all fat is bad. Fat is one of the essential micronutrients and we need it for optimal health. Just so happens that it isn’t only the amount of fat in our diets that’s important, but the types of fat we eat. Saturated fat, as stated earlier, has pro-inflammatory effects, while unsaturated fats like omega-3, have anti-inflammatory effects. You can find these fats in many plant sources, like ground flax seeds, chia seeds, hemp seeds and walnuts, just to name a few! Their beneficial effects on cognitive function and mental health cost pennies a day, and adding seeds or nuts to meals or smoothies is pretty simple.
Foods that could contribute to mental illness
We know through brain MRI studies, that comfort foods, containing processed sugar, like twinkies or doughnuts, cause the same dopamine release in your brains than street drugs, like cocaine. This chemical high is perceived as a feeling of well-being and calm followed by a period of depressed mood, often inciting us to repeat the behaviour having caused the initial dopamine release. By eating processed foods regularly, we get caught in this vicious cycle, and the process repeats itself continuously. Constant dopamine surges and drops create havoc with our brain chemistry and can lead to food addiction and mood disturbances. Eating processed food will also cause an imbalance of the gut bacteria that make up our microbiome. Processed food is engineered to be shelf stable and hyper-palatable, but this engineering removes fiber and concentrates calories. Our fat storages get fed, but not the beneficial bacteria in our gut. We lose the SCFA that the bacteria produce and their mood improving capabilities.
Supplements like vitamin D, magnesium and omega-3 have been shown to improve cognitive function and help mental well-being in those not hitting their recommended daily intakes through diet alone. You should consider increasing your dietary intake, or supplementing.
The future is bright, and the research will keep growing and enlightening us on which foods are best for mental well-being.
In summary, avoiding pro-inflammatory foods like saturated fats in animal products, dairy and coconut and palm oils is a good place to start. You can achieve this by switching to more plant-based proteins. Adding anti-inflammatory foods is the next step. Start by eating more fruits, veggies, legumes, nuts and seeds. These last two will provide much needed omega fatty acids and fiber. The fiber will feed our gut bugs and in return, they‘ll reward with post-biotics (SCFA) that will cross the blood-brain barrier and directly impact brain function. We still have much to learn, but what we already know, is that eating a plant-predominant diet will give us a head start towards good mental health, while protecting against cognitive decline and neurodegenerative conditions like Alzheimer’s disease.
Now that you know that your diet can affect your mood, what’s your next step?
If you’d like more information about transitioning towards a plant-predominant diet, check out my website plantbaseddrjules.com and look for the “How To” section in the menu. There, you’ll find tips and tricks that helped me on my journey towards a plant-predominant diet. Everything there is completely free, no catches!
Look for me on the socials, @plantbased_dr_jules on Instagram and go like my Facebook Page, Plant-based Dr. Jules. If you’re looking for some fitness motivation and are curious to see what a plant-based athlete can accomplish, follow me, @maritimeninja, on my fitness account on Instagram or check out my fitness group on Facebook, called Maritime Ninja Warrior.
Thanks so much for reading!
Plant-Based Dr. Jules 💚🌱
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