Think Zinc: Surprisingly Low Levels Found in Depression Sufferers
(4 min read)
Many of us are already quite familiar with the association between Omega-3 Fatty Acids and depression, but recently, researchers at the Institute of Pharmacology, Polish Academy of Sciences, and Jagiellonian University in Poland, have shed some important light on a new and concerning problem – that people suffering from depression display very low blood levels of zinc compared to their non–depressed counterparts.
In their recently published chapter, “Zinc Deficiency and Depression,” as found in Nutritional Deficiency (Rafalo, Sowa‐Kucma, Pochwat, Nowak, & Szewczyk, 2016), the authors provide a comprehensive overview of the literature pointing towards this surprisingly widespread problem – surprising because zinc deficiencies are often associated with malnourishment in developing countries, and yet, may actually be an underlying cause of one of the most debilitating and quickly growing mental illnesses in western nations today.
The role that zinc plays in the body is extremely complex, the authors explain, with the mineral acting on numerous receptors and enzymes. Many of these targets are those that play a crucial role in the development and functioning of various neurotransmitters, which, when disrupted, can result in the development of depression.
To date, zinc may be largely overlooked by many family physicians, but the role that it plays in depression seems to be too significant to be ignored. In their chapter, Rafalo and colleagues (2016), discuss what we know about zinc deficiency and depression to date, and why this might be so important when it comes to preventing and battling this frightening diagnosis.
You can download the book chapter here, but below, I provide a summary of the authors’ main findings:
1| People who eat foods that are low in zinc display symptoms of depression
In 7 out of 8 studies examined, the authors found that individuals (especially women) who had a lower dietary intake of zinc tended to suffer from depression symptoms, whereas those with a higher intake of zinc did not. Results were consistent amongst pregnant women and the elderly, the latter of whom were shown to be zinc deficient in up to 1/3 of cases in a western population sampled.
2| Having low blood levels of zinc is a predictor of depression
Regardless of diet, the authors also found that individuals with low serum zinc suffered from depression in 16 out of 19 studies examined. Those with treatment-resistant depression had zinc levels that were even lower than those with ‘normal’ depression, and results held consistent across depression outpatients, women with postpartum depression, those with end-stage renal disease, and the elderly.
3| Treating depression with zinc supplements shows promising results
5 out of 7 studies examined support the use of zinc supplementation as a successful treatment option for depression sufferers. To date, evidence suggests that zinc supplements can augment the effectiveness of antidepressant medication (including SSRIs), as well as speed up response to treatment times. Furthermore, as a stand-alone treatment, zinc has been used to effectively reduce symptoms of depression and improve brain function in populations of Chinese- and Mexican-American low-income children, middle-income premenopausal women, middle-income US adolescents, middle-income US men, and overweight and obese individuals.
4| Depression symptoms are induced when zinc is withheld
While all of these findings are good and well, the evidence doesn’t necessarily prove that low zinc is a cause of depression, rather than a consequence of other mechanisms underlying an already existing depressive disorder. However, animal studies of induced zinc deficiency help clarify this question. Findings suggest that healthy mice with a normal intake of zinc fall into a state of depression after their diet is restricted to 40% of their daily requirements of the mineral. What this suggests is that people, like mice, should also exhibit symptoms of depression when their dietary intake of zinc is restricted (of course, to test this hypothesis on humans would be unethical). Results are still preliminary, but they suggest that zinc deficiency, or even borderline zinc-deficiency, could play an important role in the onset of depression.
Perhaps it even begs the question: is depression really a “mental illness,” or is it actually a “symptom” of an underlying mineral imbalance? …
Either way, the findings discussed are both frightening and exciting – frightening because the problem of zinc deficiency in western nations might be much larger than previously thought (the authors explain the role that chronic stress plays in stripping zinc from our bodies… and it seems that our stress levels are on the rise), but also exciting because it suggests a potentially simple and effective adjunctive treatment option for those suffering from depression. I stress the word adjunctive here, because, like anything, zinc shouldn’t necessarily be taken as a single, miracle cure (especially since research on the subject is still in its infancy).
When it comes to treatment, depression is best approached from various angles, including psychotherapy (CBT & mindfulness-based therapy), adopting a healthy lifestyle (regular exercise, social interaction, meaningful activities, a balanced, whole foods diet, etc.), and prescription medication when deemed necessary. However, with its low cost and low risk of side effects (when taken within the recommended daily limits – most of the studies discussed by the authors “prescribed” 25-30mg/day), zinc might just help us pave the way towards a happier and healthier future.
This is an avenue that, I believe, is certainly worth further exploration.
Rafalo, A., Sowa‐Kucma, M., Pochwat, B., Nowak, G. & Szewczyk, B. (2016). Zinc Deficiency and Depression. In P. Erkekoǧlu (Ed.), Nutritional Deficiency (2-22). InTech, DOI: 10.5772/63210.