food for (our) thought(s)

The darker winter months and shorter days can bring along some doom and gloom.  I've recently written a paper analyzing two different diets, the Specific Carbohydrate Diet ("SCD") and veganism, in terms of how each diet may prevent or contribute to depression.  I had a lot of fun with this paper and learned a ton.  Warning: it's pretty much a copy and paste of my paper, so it is lengthy!  But I promise it has some awesome information. Buckle in...

Many of us don’t realize that what we eat can greatly affect our mood, and that we can help prevent depression with our diet.  Studies have shown that single sugar carbohydrates, Omega 3 fatty acids, vitamins B-12, B-6 and folate, and vitamin D may help to prevent depression and potentially assist the body’s response to antidepressant medication, while sugar and refined carbohydrates may contribute to depression.

Depression: causes and effects and how our diets might be contributing

According to the Canadian Mental Health Association (“CMHA”), approximately eight percent of adults will experience major depression at some time in their lives, caused by various factors including genetics, biology, personality, and environment.  The CMHA describes depression as “experiencing feelings of severe despair over an extended period of time”.  An individual experiencing depression is likely to suffer both short-term and long-term effects in their emotional and physical lives, as well as in their relationships and work.  Common symptoms are loss of interest and lack of pleasure in activities that were once pleasurable, social withdrawal, ongoing feelings of sadness and hopelessness, changes in appetite and unexplained changes in weight, lack of energy, decreased focus and concentration and complaints of unexplained physical illness.  The brain is the main organ affected by depression; however, some evidence shows a relationship between depression and an increase in heart disease and other cardiac problems.

The mainstream treatments of depression (depending on the severity) can include medication, cognitive behavioural psychotherapy, psychiatry and/or counseling.  However, there are some in the medical field who believe that we can treat depression by treating our gut and bowel.  For example, Dr. BernardJensen has long believed that the health of the mind is directly related to the health of our bowels.  He believes an unhealthy diet and overuse of prescription medications has led to bowel toxicity, which he links directly to numerous health disorders, including depression.  An online article by Dr.Mercola published in 2011 refers to the gut as the “second brain” and suggests that gastrointestinal inflammation due to unhealthy microflora in the intestine plays a role in the development of depression.  Similarly, a more recent article from the American Scientific Mind published online in October 2013 discusses how gut bacteria may exacerbate depression when intestine walls are compromised, allowing toxic substances to flow into the bloodstream. 

Others are of the opinion that there are specific foods we can eat that provide essential nutrients which may assist in preventing depression.  In that light, it makes sense that the changes in the qualities of our diet over time may be contributing to the health of our minds.  A study published in 2006 by the United Kingdom’s Mental Health Foundation called “Feeding Minds” suggests the increase in consumption of sugars, and saturated and trans fats, as well as foods containing pesticides and additives, can prevent the brain from functioning properly.  There are also some who argue that vitamin deficiencies are linked to depression, and that the addition of vitamins B-6, B12 and folate, vitamin D and Omega 3 fatty acids may help prevent depression, as well as assist the body in its response to antidepressant medication.  An online article put out by The Mayo Clinic in 2011 suggests that low levels of vitamins B-12 (as well as B6 and folate) may be linked to depression.  A study in The American Journal of Psychiatry published in 2012 found that patients with depressive disorders responded better to antidepressant medication with the addition of folate.  A possible explanation for this is that folate is essential to the brain for making compounds and neurotransmitters to carry messages.  The American Journal ofPsychiatry published research in 2011 that found that depression improved when individuals were given Omega 3 fatty acids, which specifically help to build the mood regulating neurotransmitter, serotonin.  Finally, a large study by researchers at the Universityof Texas Southwestern Medical Center found that low levels of vitamin D have also been linked to depression. 

Based on these studies, it seems beneficial to consume foods that are good sources of vitamins B-12 and D, folate, and Omega 3 fatty acids, in order to prevent depression.  Such sources of vitamin B-12 include fish, meat, poultry and eggs.  Foods that contain a good source of folate are all types of beans, spinach, avocado, and eggs.  Good sources of Omega 3 fatty acids are found in fish oil and flax seeds.  Salmon is a great source of vitamin D, as well as fortified cereals. 

In terms of foods that may contribute to or exacerbate depression, research has shown that diets high in sugar and refined carbohydrates can negatively affect our mood.  It makes perfect sense: sugar floods our systems with an excess amount of glucose rather than the steady stream that our brains rely on, causing the body to struggle and use valuable nutrients (like vitamin B) to take the glucose up and convert it into energy.  In contrast, complex carbohydrates help our bodies to release serotonin.  Needless to say, the commonality in all of the available research is that what we put in our mouths has the potential to affect our mood. 

Specific Carbohydrate Diet (“SCD”)

According to Elaine Gottschal, author of “Breaking the Vicious Cycle”, the main principle of the SCD is that an overgrowth or imbalance in our microbial intestinal flora may contribute to various diseases, including Irritable Bowel Syndrome and Celiac Disease.  By changing the nutrients we consume, we can bring the intestinal flora back into balance, thereby improving digestion and absorption.  Carbohydrates largely affect the type and number of intestinal flora.  When carbohydrates are not fully digested and absorbed, they remain in our gut and essentially feed the microbes we host through a process called fermentation, which then leads to an overgrowth of bacteria.  Some of the byproducts of fermentation include methane, lactic acid and toxins, all of which inhibit digestion and absorption of micro and macronutrients (which interestingly may lead to a vitamin B-12 and folic acid deficiency and impair development of the microvilli), as well as irritate and damage our gut.  Digestion and absorption are further inhibited by the bacteria in the small intestine destroying the surface enzymes and the fermentation process damaging the mucosal layer, thus provoking the small intestine to produce an abnormally thick barrier of protective mucus.

The SCD relies on selected monosaccharide carbohydrates that require a minimal digestive process and that leave nothing to be digested by microbes, preventing an overgrowth of bacteria in the intestine.  As the microbial population decreases due to their lack of food, so do the harmful byproducts, thus improving digestion and absorption.  Properly fermented and homemade yoghurt is encouraged in order to repopulate and rebalance the gut with healthy intestinal flora.  Complex carbohydrates and the starches in all grains, corn and potatoes are to be strictly avoided.  Dried beans, lentils and split peas are added to the diet after three months; however, they must be soaked for 10-12 hours prior to cooking and the water discarded.  In sum, the diet’s foundation is in the food that early man ate before agriculture began, namely: meat, fish, eggs, vegetables, nuts, and low-sugar fruits.  Some natural cheeses are also allowed.


Theprinciples of veganism, an extension of vegetarianism, are grounded in living a cruelty-free lifestyle.  Vegans avoid animal products including dairy and eggs, and many also avoid further, leather, wool, down, and cosmetics or chemical products that have been tested on animals.  An individual following a vegan diet is likely to consume vegetable-based proteins such as tofu or tempeh, as well as nuts, seeds, legumes, and of course fruits and vegetables. 

Established in 1944, veganism traces back to ancient Indian and Mediterranean societies.  Over the years, veganism has gained significant popularity among societies, both in its ethical support for animals and the environment, and as well for the health effects.  It is now common to see vegan options on restaurant menus, and there are many companies making convenient (and processed) vegan foods.  In January 2005, author and Professor T. Colin Campbell and his son and physician, Thomas M. Campbell, published a book called “The China Study”.  The book examines the relationship between consumption of animal products (including dairy) and chronic illnesses and concludes that those who eat a whole-foods, plant-based, vegan diet and who also reduce their intake of processed foods and refined carbohydrates, will escape or reverse such illnesses including coronary heart disease and cancer. 

Besides the popular argument and criticism that vegans are likely to be deficient in protein given that they do not eat animal products, another argument suggests that vegans may be deficient in the essential nutrient, vitamin B-12.  Interestingly, “The China Study” recommends taking a small vitamin B-12 supplement on occasion, particularly if you have not eaten animal products in over three years.  Similarly, it suggests a vitamin D supplement during the winter months if sun exposure is not possible.  It is worth noting, however, that there are mixed opinions about whether or not supplementation is in fact necessary.

Analysis & Recommendation

Given that we rely largely on our diets to provide us with the necessary micro and macronutrients, the argument that our diet plays an important role in the connection between nutrition and mental health is quite persuasive.  Not to mention, a healthy diet will help to optimize the chemical processes in the body of individuals taking medication to treat the depression, as well as potentially help with side effects. 
Based on the information outlined above, and given that I think the argument that the health of our gut contributes to depression is compelling, I would recommend the SCD as a stronger choice for someone who is suffering from depression.  There are strong arguments that support the idea that consumption of refined sugars and carbohydrates affect our mood and therefore contribute to depression.  The benefits of the SCD diet are that it encourages consumption of carbohydrates that help to balance the flora in the intestines, as well as discourages the growth of unfriendly bacteria.  As the gut becomes more balanced, digestion and absorption improves, greatening the body’s ability to benefit from vitamins such as B-12, folate, vitamin D and Omega 3 fatty acids.  Because the diet prohibits refined carbohydrates, there is also no chance for our brains to experience the negative effects that these foods have on our moods.  The only drawback I see to this diet is that it is heavily restrictive and may be difficult to maintain long term. 

While there is little evidence that suggests that vitamin B-12 and folate will reduce the symptoms of depression, there is evidence that not getting enough of these vitamins in your diet can lead to depression.  If I were to support this argument (I’m not saying that I do), and agree that vegans may suffer deficiencies in these vitamins, it seems like a weaker choice for someone who is predisposed to depression, or has suffered with depression in the past.  More than vitamin deficiencies, I think the bigger issue is that unless you are specifically following a whole foods vegan diet, you are not restricted from eating sugar or refined carbohydrates, making you susceptible to the mood peaks and valleys that glucose creates.


Over time, we've evolved from eating what is available off the land, to agricultural diets and convenient and processed foods.  Whether we are consuming animal products or not, it seems that a contributing culprit to mood disorders is the sugar found in refined carbohydrates.  A good choice would be to return to the way we ate before the time of convenience, focusing on whole foods and avoiding the processed ones, until we bring our bodies back into balance and begin to digest and absorb nutrients in a more beneficial way.  At that point, we might ease up on the restrictions, yet continue to make better choices of foods to put in to our “second brain”.

If you're interested in the SCD, I've included a three-day meal plan at the end, inspired by an amazing blog called Gluten Free, SCD and Veggie (thanks for the tip, Di!)  You can find the recipes for the menus in the meal plan on the blog.

stay happy,

Warm water and organic lemon, weak tea or coffee
Homemade fermented yoghurt “parfait” (raspberries, unsweetened coconut, pumpkin seeds)
apple cardamom muffins (almond flour, eggs, honey)
onion soup (onions, carrots, celery, garlic, olive oil), garnished with parsley, grain free rosemary garlic roll (almond flour, rosemary, garlic, olive oil, honey, salt and pepper)
winter vegetable casserole (butternut squash, carrots, leek, celery, black beans, onion) garnished with fresh spinach and flaked organic almonds, piece of fresh halibut
Warm water and organic lemon, weak tea or coffee
Toasted fruit and nut bread with almond butter (almond flour, dried berries, walnuts, sunflower and pumpkin seeds, eggs), small cup of fermented yoghurt
apple cardamom muffins
Mixed bean salad (black beans, kidney beans, navy beans, red chili, red pepper) garnished with cilantro and lemon and olive oil dressing
Zucchini “pasta” (green and yellow zucchini, shallots, sundried tomatoes, garlic, basil) piece of fresh wild salmon
Ginger and lemon tart (gluten free ginger snaps, coconut oil, cashews, honey, almond milk, lemons)
Warm water and organic lemon, weak tea or coffee
poached egg, avocado mash, on grain free rosemary garlic roll
Toasted fruit and nut bread with almond butter
walnut lentil burger lettuce wraps, (walnuts, onion, lentils, cumin, cilantro, garlic) with fermented yoghurt raita (grated carrot, sliced cucumber, red onion, tomato, fresh mint, paprika)
fresh, organic, free-range, hormone-free chicken breast, zucchini and pea salad (green zucchini, fresh peas, olive oil, chili pepper, salt and pepper)