Magnesium, Zinc, Iron, Vitamin D and Anxiety
Stress and anxiety are common problems. And while people may think that stressful circumstances or thinking patterns are the full cause of their anxiety symptoms, there can be underlying factors that also contribute. A number of nutrients appear to be tied to stress levels and deficiencies of these nutrients could make stress and anxiety worse. From magnesium to vitamin D, it’s worth exploring what we know about some of the nutrients that can be related to anxiety disorders.
Evidence suggests that magnesium is an important mineral for improving stress levels. Studies have shown that stress depletes magnesium and low magnesium makes stress worse, acting as a positive feedback loop (Cuciureanu 2011). Animal studies clearly show increased depression and anxiety symptoms with magnesium-deficient diets (Singewald 2004, Sarton 2012).
While evidence in humans is somewhat thin, mostly due to a paucity of research, a recent analysis still found potential effects. The study concluded that the latest evidence is suggestive of a beneficial effect for individuals prone to subjective anxiety symptoms (Boyle 2017).
In my clinical experience, it’s important to keep in mind that the full benefits from magnesium are slow to manifest. Magnesium is primarily stored inside cells. As such, it takes time to raise levels throughout the body. Generally, I expect most improvements to occur after at least two or three months of supplementation.
Studies on zinc deficiency suggest anxiety-promoting effects. Young rats fed a zinc-deficient diet display heightened anxiety behaviors after two weeks (Takeda 2007). In addition, they had a significant elevation of stress hormones in the brain. Animal studies on zinc supplementation also show reduced anxiety levels (Joshi 2012).
The research in humans is a little mixed, but still suggests benefits. A study looking at blood levels of zinc found that low levels correlated with increased anxiety and depression (Russo 2011). A study in children found that zinc supplementation in general didn’t help mental health symptoms. However, the study did find improved outcomes in children whose levels increased from supplementation and were initially at risk of deficiency (DiGirolamo 2010).
A more recent analysis found that zinc appears to be helpful for both depression and anxiety symptoms (Wang 2023). Yet a separate analysis of anxiety and depression following pregnancy claims that zinc supplementation is not helpful. If the study is evaluated carefully, the statistics show fairly solid trends towards benefits with zinc. Based on the research, it appears likely that zinc could be helpful, but additional studies are needed to fully confirm the findings (Tsai 2023).
When supplementing zinc, it’s important to remember potential risks from higher doses. Taking 40 mg or more of zinc long term can deplete copper levels. A zinc-induced copper deficiency could cause anemia and nerve damage among other symptoms.
Iron may also have a place for anxiety treatment in those that are iron deficient. A recent review found that the evidence from both human and animal studies suggests that low iron levels can worsen anxiety (Totten 2023). Direct clinical trials are quite limited, but a full review of the evidence is available in a previous blog entitled Iron and Mental Health.
When supplementing iron, lab levels need to be monitored. Both low and high iron can cause health problems and supplementation should be tracked carefully.
Commonly referred to as the sunshine vitamin, vitamin D appears to play a role in mental health. Low vitamin D levels have been shown to affect brain cell development, nerve growth factors, immune signaling molecules, neurotransmitter production, calcium signaling, antioxidant status and gene regulation of brain cell function and metabolism (Eyles 2021).
Studies have also found correlations between vitamin D status and anxiety. A small study from the Czech Republic found vitamin D levels were around 43% lower in patients with anxiety as compared to healthy controls (Bičíková 2015). A study out of Russia found similar results, noting an inverse correlation between vitamin D levels and anxiety. Lower vitamin D was associated with higher levels of anxiety symptoms (Karonova 2015).
A trial in patients with depression and vitamin D deficiency found modest improvements in some anxiety symptoms with vitamin D supplementation (Zhu 2020). For patients with diabetes, a recent analysis concluded that vitamin D supplementation appears to benefit both depression and anxiety symptoms (Guzek 2021). A similar analysis also found benefits for patients with inflammatory bowel disease and irritable bowel syndrome. Vitamin D supplementation was helpful for both anxiety and depression symptoms in these patients (Glabska 2021).
A separate review of vitamin D on mental health in children also suggests benefits for mental health symptoms, including anxiety (Glabska 2021).
While there is some argument about the veracity of the results (Guzek 2021), in general, it does appear that vitamin D may be beneficial for anxiety disorders (Borges-Vieira 2023). For supplementation, similar to iron, vitamin D levels should be monitored. Supplementation should be tailored to an individual’s blood levels to ensure vitamin D is maintained in the therapeutic range.
Magnesium, zinc, iron and vitamin D may all play a role in stress and anxiety symptoms. For individuals struggling with heightened levels of stress and anxiety, checking for deficiencies in these nutrients and treating them with appropriate supplementation may help to provide relief.