“Dear Dr. Talia,

I have been a vegan for 6 years. I also suffer from mental health conditions and possible hormonal imbalances. After doing some research on diets for anxiety and depression, I found that most of them include meat and animal products. I’m wondering: can my vegan diet be harming my mental health? I am primarily a vegan for ethical reasons and would hate to have to harm animals unless you think it’s absolutely necessary for promoting my mental health and wellness.”

 

Nutrition, especially where it pertains to more emotionally-charged topics like human health, the environment, or animal welfare, is surprisingly controversial.

I know that broaching this subject is a little bit like walking into a lion’s den (lions, for the record, are not vegans), therefore let me preface this conversation with a few disclaimers. 

In writing about veganism and mental health, I’m not looking to get into a debate. I am writing to provide information for those who are wondering if it is possible to heal mental health and hormonal conditions, including women’s health conditions, thyroid conditions and adrenal conditions, while following an entirely plant-based diet.

If you feel that you might be triggered by this information and are not willing to approach this essay with an open mind, then this article is not for you.

Let me point out that I fully understand and sympathize with the ethical arguments for veganism. In my 20’s I was vegetarian for five years. For one of those years I was a vegan. Contrary to what some die-hard vegan fans have suggested, I did follow the diet “right” by eating whole foods, balancing the macronutrients of my meals (as best I could), and striving to eat enough. I eventually had to stop, but it was not because I “missed meat”.

While following a vegetarian diet, I took comfort in the fact that no animal had to die for me to survive. I loved the taste of plant-based foods and the ease of preparing them. I was satisfied in knowing that my diet was having a minimal impact on the environment. 

(I also enjoyed bathing in the feelings of moral superiority that this diet earned me. However, that’s besides the point.)

Around that time, I read The Ethics of What We Eat by Peter Singer, which remains the single most thought-provoking book on human nutrition that I have read to this day (and I have read mountains of books on human nutrition).

In no way do I advocate for factory farming practices. I urge omnivores to consume the most ethically sourced meat, fish, eggs, and dairy that they can afford. Not only is sustainable animal farming better for animal welfare and for the environment, it is better for human health.

I don’t push for any single one-size-fits-all diet. I believe that an individual determines his or her “perfect” diet through experience. I carefully approach conversations about diet with my patients to avoid shaming their eating habits and pressuring them into a diet that they feel uncomfortable with.

That being said, it is my duty as a doctor to provide my patients with all the information they need to make empowered choices by drawing on the 15 years I have spent studying nutrition through formal education, and personal and clinical experience.

While it may certainly be possible to survive and, perhaps even thrive (depending on your genetics, most likely), on a vegan or vegetarian diet, there are major limitations to this diet that we need to face if we’re committed to supporting optimal mental and hormonal health.

The intention of this essay is to outline some of these limitations. 

Protein quality and quantity: 

Protein makes up 16% of the human body (62% is water). It is required for body structure: our bones, muscles, connective tissues, skin and hair.

Amino acids, which make up protein, comprise the hormones and neurotransmitters that regulate our mood and gene signalling.

Tryptophan, an amino acid, is used to make serotonin and melatonin, hormones that enable use to regulate our feelings of well-being and circadian rhythms, respectively. Cysteine is used to make glutathione, the main antioxidant of the body that neutralizes cancer-causing free radicals, prevents damage to our DNA, and protects us from the incessant chemical onslaught of our increasingly toxic lives. Glycine and GABA calm the nervous system, prevent over-activation of our brains’ fear centres, and soothe anxiety. Glutamine stimulates the nervous system and fuels our gut and kidney cells, allowing us to absorb the nutrients from our food and filter waste from our bodies. 

The human body is essentially a protein sac filled with water that hums with the metabolic activity orchestrated by tens of thousands of enzymes, which are also protein. 

When it comes to dietary proteins, not all are created equal. Foods that claim the title “complete proteins” boast all 9 essential amino acids that are not synthesized by the body and must be obtained exclusively from diet. Many vegetarian sources of protein are not complete proteins, and therefore protein-combining must be practiced to avoid deficiency in specific amino acids

Proteins also differ in their absorbability. Some vegan foods rich in protein contain anti-nutrients or fibres that make them difficult to digest. For example, the protein digestibility of whey (from dairy) or egg is 100%, meaning that 100% of the protein from these foods is absorbed. In contrast, only 75% of the protein in black beans is absorbed. Even more dismally, those who hope to get a significant source of their protein from the peanut butter on their morning toast are only absorbing about 52% of it.

The Recommended Daily Allowance (RDA) for protein is 0.8 g per kg of body weight for the average person. However, when it comes to supporting optimal health, the RDAs of important nutrients are set notoriously low. In my opinion, even higher nutrients are required for those with chronic health conditions such as mental health issues, chronic stress, hormonal imbalances, obesity, diabetes, cardiovascular disease, cancer, and autoimmune disease, to name a few.

For my patients I tend to recommend between 1.0 to 1.2 g of protein per kg of body weight per day. For those who are particularly active, who need to lose weight, and who are obtaining their protein from lower-absorbable sources, I may even recommend higher amounts. For women with conditions like PCOS, depression, and anxiety, I often recommend at least 30 g of protein per meal, especially at breakfast, to balance blood sugar, fuel neurotransmitter synthesis, sustain energy throughout the day, and promote optimal adrenal function. I believe the RDA for protein to prevent muscle wasting is set far too low. This is especially true if the protein sources are difficult to digest and of lower quality.

But what about claims that high protein diets can be detrimental to our kidney health? A one-year crossover study showed that active men who consumed very high amounts of protein—over 3 g of protein per kg of body weight—suffered no ill effects.

Getting adequate protein is difficult on a vegan diet but not impossible. Tracking your macronutrients and considering supplementing with a high-quality protein powder, may be required.

Understanding exactly how much protein your diet delivers is essential. For instance, while quinoa is a complete protein, containing all 9 essential amino acids, it only contains 8 g of protein per cup. One cup of black beans contains 39 g of protein but only 29 g are absorbed.

Furthermore, for conditions like PCOS that require managing carbohydrate intake, getting the protein without the additional carbs can be a challenge. Legumes typically contain a 3:1 ratio of carbs to protein—one cup of black beans contains 116 g of carbohydrates. This is often too high for the many women suffering from the mental health and hormonal issues that I treat in my practice, who often feel best when keeping their dietary carbohydrate intake well under 150 g a day.

Autoimmunity: 

Chronic inflammation runs rampant in the bodies of many of my patients. More research is coming out showing that inflammation is at the root of most chronic health complaints, such as mental health conditions like depression and bipolar disorder, and hormonal conditions like PCOS and endometriosis. Cardiovascular disease and diabetes are recently thought to begin as autoimmune diseases, spurred on by chronic inflammation.

To manage conditions of autoimmunity and chronic inflammation, it is often appropriate to follow an “anti-inflammatory” diet that is low in allergenic potential.

For patients with hormonal issues, autoimmunity, gut issues, and mental health conditions (which research shows are inflammatory conditions are their root), reducing the diet down to leafy green vegetables, chicken, beef and fish can aid in lowering inflammation, healing the gut and restoring immune function. After a time, foods are slowly reintroduced, to find out what the body can tolerate.

Grains and legumes contain anti-nutrients like lectins and phytates that protect plants from being ingested and destroyed. Along with other common allergenic foods like dairy and eggs, grains and legumes, with their anti-nutrient content, have a high potential for irritating the digestive tract, causing gastrointestinal inflammation and immune system activation, leading to chronic inflammation that permeates the entire body.

The higher protein content in legumes like peas, black beans, lentils, and soy, and grains like wheat and corn, makes these foods staples in plant-based diets. Therefore, even attempting an anti-inflammatory elimination diet as a vegan is virtually impossible. Vegetarian diets are hardly better, as vegetarians often rely on dairy and eggs to balance their diet, both of which are common food sensitivities that can trigger autoimmunity and inflammation.

Vegan studies:

Doesn’t following a plant-based diet confer amazing health benefits, though?

While many studies of vegan and vegetarian diets show benefit for improving markers of various metabolic conditions, like diabetes and cardiovascular disease, it is important to keep in mind that most of these publications are comparing a diet rich in whole grains, vegetables, fruit, nuts and seeds with the Standard American Diet, with its grain-fed, hormone-pumped animal byproducts deep-fried in rancid corn oil.

To better paint the picture, coffee is the number one source of dietary antioxidants in the United States, revealing that virtually no one in North America is eating fresh fruits and vegetables. 

Therefore, it makes sense that adding a few servings of micronutrient-containing fruits and vegetables to your daily nutritional intake will radically alter your health status. When I first began my foray into the world of plant-based living I felt amazing too. After a few months, though, the health benefits slowly faltered and I started to suffer negative health consequences: weight gain, fatigue, depression, hypothyroidism, IBS, and various nutrient deficiencies. 

My health improved when I added some animal products to my vegetarian diet and removed dairy, grains and legumes. However, my experience is a mere anecdote.

To my knowledge there hasn’t been a study comparing a whole foods-based diet that includes ethically-sourced animal products with a whole foods vegan diet. I would be very interested in seeing such a study if it is ever conducted. 

Individual variability:

Rich Roll, a vegan super-athlete, is often dredged up as an example of how the human body can thrive on a plant-based diet. However, more than his diet, Rich’s individual genetics may have more to do with his success as an athlete (and his training, clearly).

Even after 8 years of returning to omnivorous living with occasional iron and desiccated liver supplementation, my ferritin level (a measure of iron status) still only hovers around 44 (80 is considered optimal). 

My constitution is that of Parasympathetic Dominance. This means I look at a piece of toast and gain 10 lbs. I tend to suffer from congestive lymphatic conditions and a sluggish metabolism. I tend to have low energy unless I constantly stoke my metabolic furnace. When stressed, I tend to gain weight and slip into lethargic depression. If not taking care of myself, I get headaches and suffer from hormonal imbalances.

Like other parasympathetic doms, I tend to have a higher requirement for dietary iron and crave red meat and leafy green vegetables. I seem to do better with a diet higher in protein and healthy fats.

Many of the  people I work with fit this profile as well. My patients are highly creative and intuitive, but also suffer from mental health and hormonal conditions and are very susceptible to stress. I find that most do better through moderating their carbohydrate intake, ensuring high micronutrient and healthy fat consumption, and eating more protein, particularly from some red meat.

New research into MTHFR genes reveals that certain diets may have more health benefits for certain individuals. About 40-60% of North Americans are unable to convert folic acid (a synthetic nutrient added to multivitamins and fortified grains) into methylfolate, which is used for a chemical process called “methylation”. 

Methylation pathways are involved in the fight-or-flight response; the production and recycling of glutathione (the body’s master antioxidant); the detoxification of hormones, chemicals and heavy metals through the liver; genetic expression and DNA repair; neurotransmitter synthesis; cellular energy production; the repair of cells damaged by free radicals; balancing inflammation through the immune response, controlling T-cell production, and fighting infections, to name a few.

Individuals with impaired MTHFR function often suffer from autoimmune conditions and mental health conditions, such as depression. They tend to feel better when avoiding grains that contain folic acid and eating green leafy vegetables that contain methylfolate. They require higher amounts of protein in their diet. They require higher levels of vitamin B12, which is also important for methylation, and choline, found in eggs and liver, which helps bypass methylfolate pathways, working as an alternative methyl donor. Choline is also necessary for estrogen metabolism. 

Nutrients Deficiencies:

You thought I would lead with this, didn’t you? I’ll bet you were wondering when this would come up: 

B12: 

Of course it’s no secret that the vegan diet is essentially devoid of vitamin B12, an important nutrient for detoxification, methylation, neurotransmitter synthesis and energy metabolism. Animal sources are the only sources of B12. Our gut bacteria can make B12, but how much is absorbed in the colon for the body’s use is not clear.

B12 deficiency is serious. A friend of a friend of mine (no, but really) suffered permanent neurological damage, leading to seizures and almost death, from B12 deficiency. The neurological damage caused by B12 deficiency is irreversible (I’ve had patients who experience some improvement with restoring B12 levels, but it can take some time and the progress is not always linear).

B12 deficiency can have serious neuropsychiatric symptoms that mimic severe bipolar disorder or schizophrenia and that resolve once B12 injections are given. Horrific case reports tell stories of B12-deficient patients treated with rounds of electric shocks for their “treatment-resistant” psychosis, before the true cause of their symptoms was uncovered. 

The blood reference range for B12 is roughly 130-500 pmol/L but I find that people don’t feel their best until their levels are over 600, and many experience severe B12 deficiency symptoms under 300. This means that if your doctor tells you that “your blood levels are normal,” your body could still be operating at a sub-optimal level of B12. 

For vegans, supplementing with a good, absorbable form of B12 is non-negotiable. B12 from vegetarian sources, such as dairy products, is damaged in the pasteurization process and therefore supplementation may still be required.

Other nutrients:

B12 aside, other nutrients that are commonly deficient in vegan diets are iron, zinc, iodine, EPA and DHA, choline, vitamin A and vitamin D, to name a few.

Zinc is essential for immune function, skin health, neurogenesis (making new brain cells), memory and cognition, gut integrity, neurotransmitter synthesis, and hormonal health, among other essential functions. 

Iodine is required for thyroid and ovarian function. It is also important for estrogen detoxification.

Iron is important for supplying tissues with oxygen, optimal thyroid function, and fertility. Menstruating women are commonly operating at a sub-optimal level of iron, resulting in fatigue, dry skin, chronic infections, and heavy periods.

Vitamin D regulates over 1000 different genes in the body. Supplementing with D3 is required for the 70-90% of North Americans who are deficient. Sadly, vitamin D3 supplements are all animal sourced, obtained from the lanolin in sheep’s wool. D2 from mushrooms is a vegan form of vitamin D that is likely not as effective as animal-derived D3.

Vegans are 75% more deficient than omnivores in vitamin D, which is alarming, considering how deficient most North Americans are—that’s 1000 vegan genes that aren’t being properly regulated! 

EPA and DHA, omega 3 fatty acids found in fish and algae, are essential for cell membranes and brain function. While DHA can be made from ALA, found in flax and walnuts, many of us are not effective at converting it. Even the best converters among us only synthesize about 18% of our ALA into DHA. Further, the conversion of ALA to DHA requires zinc and iron, two nutrients that are typically deficient in vegan diets. 

Vegans and vegetarians have lower levels of EPA and DHA than meat eaters.

Even for omnivorous patients with mental health conditions, supplementation of EPA is often required for therapeutic benefit. Vegan supplements of algae-derived EPA and DHA exist, however, many of the studies that show benefit for fish oil supplementation in depression, bipolar and OCD require that the EPA to DHA ratio be 3 to 1 or higher. This high EPA to DHA ratio is not available in algae-sourced supplements that I have seen, making it almost impossible to derive enough EPA from vegan sources. 

That being said, it is possible to supplement with iron bisglcyinate, iodine, zinc picolinate and vitamin A, inject methylcobalamin weekly, chug algae oil by the jugful, and drip vitamin D2 drops on your tongue and hope for the best.

You can pray to the methylation gods that your MTHFR enzymes are all operating at top speed so that your body doesn’t need to depend on protein and choline-dependent pathways for its liver function and DNA repair.

You can dump Vega protein powder into your smoothies and hope that you don’t have a sensitivity to grains and legumes (vegan protein powders usually contain some combo of rice, soy, and pea). You can obsessively track your macronutrients on My Fitness Pal. 

You might still be ok.

There are a few people, the Rich Rolls of the world, who will claim that they feel great on an entirely plant-based diet. They do all of the above-mentioned things and feel amazing and I’m happy to hear it! However, I wonder how these genetically gifted individuals would fare if following a nutritionally complete whole foods omnivorous diet that contains grass-fed chicken, fish, meat, gelatin, eggs and, perhaps, dairy, in addition to a variety of plant foods.

If just one important nutrient pathway that depends on iodine, zinc, vitamin D, iron, B12, EPA or DHA is working sub-optimally, if you’re suffering from a hormonal condition, a mental illness, an autoimmune disease, or a digestive issue, then it’s possible that, if you follow a vegan or vegetarian diet, you’ll never feel as well as you’re meant to. 

In the words of a vegan-turned-omnivore friend of mine, when disclosing why she decided to start eating meat again:

“I still love the environment and animals, of course, but I just love myself more.”

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