Are Plant-Based Diets Hurting or Helping Your Mental Health? A Scientific Deep Dive

Introduction

Plant-based diets are on the rise, whether for health, environmental, or ethical reasons, and more people are embracing meals built around plants. But as interest in this lifestyle has grown, so has a question that deserves careful attention: can cutting out animal products affect your mental health?

The short answer: yes it can, depending on how the diet is planned. Here, we dive into what the research tells us about the connection between plant-based diets and mental health.

The Brain-Diet Connection

Mental health is pretty complex, influenced by factors like genetics, environment, and lifestyle. Nutrition plays a key role here by influencing factors like serotonin and dopamine, inflammation, and the gut microbiome. A poorly planned diet, whether omnivorous or plant-based, can disrupt these processes. A nutrient-rich diet supports a balanced mood, energy levels, and a clear mind.

Nutrients to Watch on a Plant-Based Diet

Some of the nutrients that are very critical for brain function are predominantly found in animal products. This means that if you’re eating plant-based and not paying attention to these nutrients, it could increase your risk for mood imbalances or brain fog over time.

Vitamin B12

B12 is essential for nerve health and the production of neurotransmitters. It’s only naturally found in animal products, so it may be one of the most important nutrients to supplement with on a plant-based diet. Deficiency can cause fatigue, poor memory, and even symptoms that mimic depression or anxiety.

Studies have linked low B12 levels with an increased risk of depressive symptoms (1).

Iron

Iron plays a role in oxygen transport and dopamine synthesis. While plant-based diets can include iron, the form of iron found in plants (non-heme iron) is less readily absorbed than iron from animal sources (heme iron). Deficiency in iron has been associated with fatigue, brain fog, and low mood (2).

Pairing iron-rich plant foods with vitamin C can help absorption, but some individuals may still require supplements or careful planning.

Omega-3s (EPA & DHA)

Omega-3s are vital to brain function. While plant foods like flaxseeds and chia seeds contain ALA (a precursor to EPA and DHA), the body must convert ALA into EPA and DHA to use it for most of its brain and anti-inflammatory functions. The problem: that conversion is extremely inefficient (only about 5-10% of ALA becomes EPA, and less than 0.5-4% becomes DHA). EPA and DHA are important because they are the forms shown to support mood, cognition, and reduce inflammation.

Plant-based eaters can benefit from algae-based omega-3 supplements, which directly provide EPA and DHA in a vegan-friendly format.

If you’re looking for a vegan supplement that contains omega-3s in the form of DHA to support you on your plant-based diet, you can shop the plant-based essentials here.

Zinc

Zinc helps regulate the activity of glutamate and GABA, two critical neurotransmitters involved in mood balance. Low zinc levels are consistently linked to depression and irritability (3).

While plant foods like pumpkin seeds and legumes provide zinc, phytates in these foods can inhibit absorption, making it harder to meet daily zinc needs without careful planning.

What the Research Says

There’s no simple answer when it comes to how plant-based diets affect mental health. The evidence is mixed, and context matters.

Some studies have found higher rates of depression and anxiety among vegetarians and vegans, particularly those who don’t supplement or who follow restrictive diets (4). However, these findings may reflect nutritional gaps rather than the plant-based diet itself.

Other research suggests that plant-based diets rich in whole foods can actually protect against depression. Diets that emphasize fiber, antioxidants, and anti-inflammatory compounds from plants can improve gut health, reduce systemic inflammation, and support brain function (5).

The key takeaway here is that it’s not the label of the diet, but the quality. A diet built on Oreos, white bread, and fries is still technically vegan. A nutrient-dense plant-based diet, on the other hand, can be supportive of mental well-being if it’s planned properly.

Common Misconceptions

Let’s clear up a few common myths:

“Plant-based diets cause depression.”

There’s no evidence that a well-planned plant-based diet causes depression. But nutrient deficiencies, which can be more likely on a vegan diet, can contribute to symptoms over time.

“You only need to eat whole foods.”

Even if you’re eating 100% whole foods, some nutrients like B12 and Omega-3s still need to be fortified or supplemented with. Whole doesn’t always mean complete.

“If I feel tired or moody, it’s just stress.”

Nutrient deficiencies often show up as fatigue, low mood, or brain fog, and they can be mistaken for burnout or anxiety. Blood tests can help pinpoint if it’s nutritional.

Tips to Support Mental Health on a Plant-Based Diet

Here are some science-backed steps you can take to support your brain on a plant-based diet:

• Supplement with vitamin B12
• Consider an algae-based EPA/DHA supplement
• Each iron-rich foods and pair them with vitamin C for better absorption
• Choose iodized salt or incorporate sea vegetables like nori
• Get regular blood work, especially if you’re dealing with mood changes

Conclusion

A plant-based diet, when approached with intention and education, can support good mental health. Just as a standard diet can be nutrient-poor, a vegan diet that lacks key vitamins and minerals can also fall short.

The good news? With the right knowledge and supplementation, you can reap the benefits of plant-based eating while protecting your brain and mood.

Your diet should be a source of nourishment for both your body and mind. If you’re unsure, speak with a registered dietitian or healthcare provider who can help.

References

1. Seppälä J, Koponen H, Kautiainen H, Eriksson JG, Kampman O, Leiviskä J, Männistö S, Mäntyselkä P, Oksa H, Ovaskainen Y, Viikki M, Vanhala M, Seppälä J. Association between vitamin b12 levels and melancholic depressive symptoms: a Finnish population-based study. BMC Psychiatry. 2013 May 24;13:145. doi: 10.1186/1471-244X-13-145. PMID: 23705786; PMCID: PMC3674945.
2. Arshad H, Arshad A, Hafiz MY, Muhammad G, Khatri S, Arain F. Psychiatric Manifestations of Iron Deficiency Anemia-A Literature Review. Eur Psychiatry. 2023 Jul 19;66(Suppl 1):S243–4. doi: 10.1192/j.eurpsy.2023.560. PMCID: PMC10595923.
3. Swardfager W, Herrmann N, Mazereeuw G, Goldberger K, Harimoto T, Lanctôt KL. Zinc in depression: a meta-analysis. Biol Psychiatry. 2013 Dec 15;74(12):872-8. doi: 10.1016/j.biopsych.2013.05.008. Epub 2013 Jun 24. PMID: 23806573.
4. Michalak J, Zhang XC, Jacobi F. Vegetarian diet and mental disorders: results from a representative community survey. Int J Behav Nutr Phys Act. 2012 Jun 7;9:67. doi: 10.1186/1479-5868-9-67. PMID: 22676203; PMCID: PMC3466124.
5. Lee MF, Eather R, Best T. Plant-based dietary quality and depressive symptoms in Australian vegans and vegetarians: a cross-sectional study. BMJ Nutr Prev Health. 2021 Oct 21;4(2):479-486. doi: 10.1136/bmjnph-2021-000332. PMID: 35028517; PMCID: PMC8718860.