Micronutrients, Phytonutrients, and Mental Health

National statistics indicate that several nutrient shortfalls are common in the United States, including potassium, dietary fiber, calcium, and vitamin D.¹ Risk of choline, zinc, and B12 deficiency may also be found among select populations.¹ According to the World Health Organization, over 2.4 billion individuals worldwide do not have consistent access to sufficient amounts of nutritious and safe food.²

Multiple factors may play a role in nutrient deficiency, including the prevalence of highly processed Western-style diets with low vegetable, fruit, and whole grain intake as well as food insecurity or limited access to healthy foods and variety. Micronutrient malnutrition, or deficiencies in one or more crucial vitamins or minerals, may negatively impact both physical and mental health and potentially increase risk of chronic illness.¹

To compound the issue, chronic psychological and environmental stress may negatively impact micronutrient concentrations in the body, leading to micronutrient depletion.³ The global burden of mental health is significant, with an estimated one in every eight people in the world living with a mental health condition.^4,5 How does a nutrient-dense diet made up of foods full of vitamins, minerals, and phytonutrients promote mental wellness and impact conditions such as anxiety and depression?

From Magnesium to B Vitamins: Impacts on Anxiety and Depression

Magnesium is one micronutrient commonly under-consumed,⁶ yet it is present in a variety of foods, from greens to whole grains. Although there is some conflicting evidence,⁷ low levels of magnesium intake have been associated with depression.^8,9 A 2019 cross-sectional analysis of medical records from 3,604 adults found a positive correlation between lower serum magnesium levels and depressive symptoms.¹⁰ A 2024 cross-sectional study using data from the National Health and Nutrition Examination Survey 2017-2020 (n=9,232 adults) found that lower intake of vitamin B6 and magnesium correlated with elevated depressive symptoms.⁸

Beneficial effects of magnesium supplementation on anxiety and stress-related symptoms have been suggested, though further trials may be required to confirm efficacy in all populations.¹¹ For example, a 2024 systematic review found that five out of the seven studies included in the analysis reported improvements in self-reported anxiety among pediatric and adult patients after magnesium supplementation.¹² A 2018 RCT found that magnesium intake alleviated stress symptoms in men and women with low magnesemia.¹³ Further, in this RCT, for participants who reported severe stress, a combination of magnesium and vitamin B6 demonstrated greater improvements.¹³

Some B vitamin deficiencies have been linked to an increased risk of depression.¹⁴ A 2019 systematic review and meta-analysis of 18 research articles suggested that B vitamin supplementation benefited both at-risk (poor nutrient and mood status) and healthy populations specific to improving their reported stress symptoms and overall mood.¹⁵

Phytonutrients & Antioxidants 

A diet that incorporates a varied and colorful rainbow of fruits, vegetables, whole grains, spices, and herbs provides essential minerals and vitamins, including antioxidants. In addition, the bountiful phytochemicals that contribute to the color, taste, and smell of plants provide both physical and mental health benefits.¹⁷ A 12-week RCT in 2018 specifically studied curcumin and found that an increasing dose as an adjunctive treatment for major depressive disorder had significant antidepressant effects.¹⁷ Another 12-week RCT in 2017 with similar curcumin doses also indicated similar effects, benefiting depressive symptoms as well as reducing anxiety in depressed adults.¹⁸

Research suggests that acute and chronic psychological stress is associated with increased inflammatory activity in the body, contributing to the adverse mental health symptoms and furthering inflammatory processes.¹⁹ The anti-inflammatory properties of dietary phytonutrients and antioxidants may provide direct benefit. A 2018 RCT evaluated the effects of carotenoids on 59 young, healthy participants and found that carotenoid intake reduced psychological stress and improved emotional and physical health compared to placebo.²⁰ Other antioxidants may also impact anxiety and depressive symptoms.^21,22 A recent meta-analysis of RCTs found that antioxidant supplementation (e.g., selenium and CoQ10) significantly improved depression and anxiety symptoms compared to controls.²²

Clinical Considerations

Nutrition is a cornerstone of functional medicine care. Diet quality and nutrient deficiencies are crucial considerations when evaluating a patient’s chronic physical and mental health conditions and investigating root causes of any health disturbances. They are also important factors to understand when implementing personalized therapeutic interventions that address imbalances and optimize a patient’s overall wellness. A collaborative patient-practitioner relationship is key to this understanding and when identifying a patient’s goals, values, and preferences that may impact sustainability of treatment strategies. 

Dietary patterns that include adequate and varied consumption of foods that are rich in essential micronutrients, including antioxidants and phytonutrients, positively impact physical and mental health. For a deeper understanding of micronutrient imbalances and how lifestyle-based approaches can help address nutrient insufficiencies, hear from the functional medicine experts at IFM’s Applying Functional Medicine in Clinical Practice (AFMCP)^TM .