Nutrition and Mental Health (Depression/Anxiety)

Mental health. I talk about it a lot on my social channels, and in-person if you're unfortunately drawn into a lengthy conversation with me. I'm a Nutritionist, though. It isn't in my scope of practice to talk about anxiety, depression, or any form of mental health disorder. Well, that's not entirely true. You see, it's kind of a grey area because your mental health has a lot to do with the way your feed your body, and conversely, the way you fuel your body has a lot to do with the outcome of your mental health (if you haven't already, check out my piece about nutrition and disordered eating). It's kind of like the chicken and the egg, we're not really sure which comes first but as far as the current literature is concerned, we do know that there is a two-way relationship between mental health and nutrition.

Depression and mental illness is the second leading cause of disability in the WORLD. Since the 1990's there has been a steady upward trend in the prescription of antidepressant drugs, especially to people aged 20-44 years in UK, Canada, Australia, and the U.S. This holds true despite the controversy surrounding the clinical efficacy of these drugs. A meta-analysis published in the JAMA concluded that the efficacy of anti-depressant medication may be minimal or nonexistent on average, in patients with mild or moderate symptoms, but that the efficacy increases with those displaying more severe symptoms. What is certain is that medications are effective for certain individuals but less effective for others. This article is being written not to bash medicine, but rather to try and outline alternative treatment options available for those with more mild/moderate symptoms.

The Role of "Macros"

First, let's cover the burning question; what is a macro? Simply, a macro or macronutrient is a substance that is required in larger amounts in the diet. There are three distinguishable macronutrients which are Carbohydrates, Fats, and Proteins. We know that independent of one another, neither of these nutrients is definitively "bad" for you. In fact, we need all of these nutrients to carry out certain roles in the body. Carbohydrates are utilized as the main source of energy for cells, proteins along with rebuilding muscle cells can also be used as energy and promote many metabolic reactions in the body (like secreting tears from your tear ducts), and fats are used to help protect organs, to help absorb certain nutrients, improve communication between entities in the body, while also providing energy, just to name a few. While we know that no one nutrient is bad, we know that when consumed in either a deficit or in excess, both situations can be negative for the body. A systematic review looking at the role of healthy dietary patterns and risk of depression concluded that there is an increased risk for depression associated with a "Western Dietary pattern" (unhealthy, high fat, high sodium, calorie surplus). Contrary to popular belief, the Mediterranean diet (high in fruits/veggies, lower in saturated fats, high omega 3, lower-calorie density) touted as one of the "healthiest" popular diets in the world actually showed no statistical significance in improving symptoms or reducing the risk of depression when compared to other healthy diets. However, compared to the western-style diet it still showed significant improvements. Blah blah blah, so what did that all mean? Essentially, eating a diet that is healthier in terms of being NUTRIENT dense rather than calorie-dense showed both improvements to symptoms of depression and also lowered the risk of development of symptoms. So while you might not need to consume a Mediterranean diet (you totally can, if you want) you should definitely consider a diet lower in saturated fats, higher in fruits and vegetables, and at the maintenance of total calories rather than a surplus.

Another perspective to consider when looking at our macros is the glycemic index rating of foods and how that might affect blood sugar and insulin response. If you pay attention to food science or you take a keen interest in pseudoscience or follow pretty much anyone on social media that pushes a low carb diet, you'll be familiar with the idea of insulin/blood glucose response. In short, the blood glucose response in the body identifies when you consume a sugar/carb, how fast it will raise your blood glucose. Conversely, the insulin response is how quickly your body will react to that blood glucose increase and secrete insulin from your pancreas to start lowering blood sugar levels. Why is this important? Well, pseudoscientists might use this to scare you into thinking you're going to get fat from eating sugar. The reality of the situation is that while it's not likely going to make you fat (but that caloric surplus sure will 😉 ), blood sugar spikes have been shown in some studies to negatively impact mood. We know from studying the effects of higher blood glucose on insulin-resistant individuals and type 1 diabetic that lack of mood control is one of the symptoms, so we can extrapolate that high glycemic index foods (or foods that will raise blood sugar quickly) especially in high doses, have the potential to negatively impact mood. Therefore, if you're going to consume high glycemic index foods, either consume them with proteins and fats in a balanced meal, or in smaller doses, or both.

The Role of "Micros"

When I mention micros admit it, you thought of microscopes. What I am referring to is not microscopes but rather micronutrients. A Micronutrient is defined in the oxford dictionary as a chemical element or substance required in trace amounts for normal growth and development of living organisms. It doesn't mean that because you need less of the substance that it's less important, it's equally as important as macronutrients (carbs, fats, proteins) you just require less of it to positively impact your health. Disclaimer: if you believe you or someone you know is experiencing symptoms due to a deficiency in micronutrients, make sure you have a clinician conduct a thorough assessment before treating. That being said, here are what i believe to be the key micronutrients which might be associated with depression/mental health disorders affecting someone you know. A wholesome diet implemented in patients with mental health disorders such as depression would include alterations as mentioned above in combination with potential increased intake with specific micronutrients, whether through dietary intake or oral supplementation.

B- Vitamins

Vitamins B6 and B12 are involved in a series of methylation reactions in the body that can potentially impact our mental health. Specifically, Vitamin B6 in its active form in the body Pyridoxal 5'-Phosphate (PLP) plays a role in controlling plasma homocysteine concentrations, which when out of control, can often be a risk factor for vascular disease and a steep decline in cognitive aging (the aging of your brain). B12 deficiencies, which are common, but not limited to those consuming a plant-based diet, are associated with memory loss, depression, and cognitive dysfunction and is common in elderly patients, patients with hypothyroidism, gastritis patients or those who take proton-pump inhibitors (which can be used to relieve symptoms of acid reflux/ GERD) or biguinides (which are a class of medication taken by patients with Pre-Diabetes, Type 2 Diabetes). Higher levels of B12 Vitamins in the blood have shown improvements in anti-depressive treatments.


Iron deficiencies are fairly commonplace, especially in women and young children. Low stores of iron in the body may alter the ability to synthesize neurotransmitters and reduce their function, which manifests as symptoms of poor concentration, lack of focus, apathy (or motivation), and in some cases, chronic fatigue. For various reasons, iron deficiencies can lead to serious complications in the body. Just to name a few, iron deficiency in children can increase lead absorption, putting them at an increased risk for depression and developing learning disabilities.


Zinc deficiencies have been predicted to affect about 1/4 of the world's population. Zinc deficiencies have been associated with symptoms including behavioural and sleep disturbances, increased sensitivity to things like allergies, and in some cases, a loss ofsex drive. More recently, there have been suggested relationships between low zinc concentrations and increased risk of mental health problems. Take this randomized control trial, which reported improvements in depression scores following zinc supplementation trials. If you or someone you know has shown low serum zinc concentrations (low zinc in the blood), definitely consider treating with supplementation to help avoid/prevent potential mental/physical health complications.

Closing Remarks

Mental health treatment is complicated. Treatments are dynamic and should be individualized for each patient as these are not the only things that could impact your mental health. Thankfully, speaking out about mental health is much more commonplace now, and should continue as mental health problems have the ability to manifest into physical complications for the way we live our lives. Whether its the above listed concerns, or things like a vitamin D deficiency, chromium, magnesium, folate deficiency or some other cause, there are so many variables that could impact our mental health. A truly inclusive approach to mental health includes a thoroguh assessment of lifestyle and dietary habits, level of exercise/physical activity, environmental impact and exposures, patients medications, any other comorbid conditions/ chronic illnesses, many other external life stressors, level of social support and impact of support system as well as a family history of mental illness. Thats a lot, but that is what it takes to properly treat mental illness. Unfortunately, the traditional western diet doesn't contain an adequate amount of many key nutrients which are critical for the proper functioning of the body and mental health. This is why, nutritional impacts can be great and should be considered as a step forward in responding to mild symptoms related to your mental health. Always speak to your doctor for the best treatment options and do not self-medicate.

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