Micronutrients, Phytonutrients, and Mental Health

National statistics indicate that several nutrient shortfalls are common in the United States, including potassium, dietary fiber, choline, magnesium, calcium, and vitamins A, D, E, and C.¹ Risk of selenium, zinc, folate, and B12 deficiency may also be found among select populations. 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, topsoil erosion and a decline of nutrient levels in the soil, and 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 lead to chronic illness. To compound the issue, chronic psychological and environmental stress may negatively impact micronutrient concentrations in the body, leading to micronutrient depletion.² In a time when stress-related statistics indicate significantly higher symptoms of anxiety and depression in the US due to the pandemic,³ a nutrient-dense diet made up of foods full of vitamins, minerals, and phytonutrients can be a powerful tool in promoting mental wellness and combating chronic disease.

From magnesium to B vitamins: impacts on anxiety and depression

Magnesium is one micronutrient commonly under-consumed in the US, yet it is present in a variety of foods, from greens to whole grains. Although there is some conflicting evidence,⁴ low levels of magnesium intake have been associated with depression.^5,6 Most recently, a 2019 cross-sectional analysis of medical records from 3,604 adults found a positive correlation between lower serum magnesium levels and depressive symptoms.⁷

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.⁸ For example, a 2017 randomized controlled trial (RCT) found that magnesium and zinc supplementation (320 mg magnesium sulfate and 27 mg zinc sulfate/day) did not reduce depression and anxiety symptoms in postpartum women after an eight-week intervention.⁹ However, a 2018 RCT found that magnesium intake (300 mg/day) alleviated stress symptoms in men and women with low magnesemia.¹⁰ Further, for participants who reported severe stress, a combination of magnesium (300 mg/day) and vitamin B6 (30 mg/day) demonstrated greater improvements.¹⁰

Some B vitamin deficiencies have been linked to an increased risk of depression, and consistent and sufficient intake of those nutrients, specifically folate and vitamin B12, may potentially decrease the risk of depression relapse and the onset of symptoms in an at-risk population.¹¹ 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.¹²