Zinc is a dietary mineral that humans need to consume in order to function normally. For a number of reasons, a range of population groups across the U.S. have unusually high chances of developing a deficiency of this mineral. In recent years, a number of research teams have attempted to assess the potential role of zinc deficiency in increasing the risks for the onset of depression, as well as the potential role of zinc supplementation in depression treatment. The authors of two recent, large-scale study reviews analyzed the results of these research efforts and came to several important conclusions regarding the connections between zinc and depression.
Zinc is a trace mineral; this means that the human body only needs small amounts to continue working properly. The mineral’s specific essential functions include sparking the chemical reactions that keep the body’s cells going, helping provide the structure that keeps the body’s cells intact, helping the body make new copies of its DNA and supporting the activity of the nervous system and the endocrine (hormone) system. Common food sources of zinc include red meat, oysters and other forms of shellfish, dark-meat chicken and turkey, garbanzo beans and certain other types of beans, peanuts, cashews and dairy products such as yogurt, cheese and milk. A variety of zinc supplements are also available throughout the U.S.
Oregon State University’s Linus Pauling Institute lists a variety of groups known to have increased risks for a zinc deficiency. Examples of these groups include teenagers and younger children, pregnant and breastfeeding women, pregnant and breastfeeding teenagers, people affected by anorexia nervosa, people suffering from malnutrition, people affected by alcohol use disorder (alcoholism), elderly adults, vegetarians who strictly avoid meat consumption and people affected by sickle cell anemia, inflammatory bowel disease, severe diarrhea or chronic kidney disease. Use of certain medications—such as diuretics or anti-seizure drugs—can also potentially trigger a zinc deficiency.
Depression is a single term used to describe the effects of several different mental health conditions, including major depression, premenstrual dysphoric disorder, persistent depressive disorder, substance/medication-induced depressive disorder and disruptive mood dysregulation disorder. All of these conditions exert a damaging impact on a person’s sense of well-being by doing such things as promoting a persistently “down” or negative mood; triggering unusually intense feelings of sadness, worthlessness, guilt or helplessness; promoting excessive sleepiness or sleeplessness; decreasing the ability to concentrate, remember things or think logically; disrupting normal food intake patterns; disrupting normal digestion; and decreasing the desire for pleasurable experiences. People severely affected by depression may also develop psychosis-related symptoms (such as delusions or hallucinations), become preoccupied with suicidal thinking or make suicide attempts.
Depression and Zinc Deficiency
In a study review published in June 2013 in the journal Biological Psychiatry, a Canadian research team used the results from 17 previous studies to help determine whether people affected by depression have unusually low levels of zinc in their bodies. Altogether, the 17 studies included 1,643 people with depression symptoms and 804 comparison subjects unaffected by depression. After analyzing their findings, the Canadian researchers concluded that people with depression do have lower zinc levels than people free from depression. They also concluded that zinc deficiencies are more common in individuals with severe depression symptoms than in individuals with relatively mild or moderate depression symptoms. In fact, people with the worst depression symptoms typically have the lowest zinc levels.
In another study review, published in 2012 in the Journal of Affective Disorders, a team of Australian researchers used the results from four previous studies to examine the potential role of zinc supplementation in depression treatment. After analyzing their findings, these researchers concluded that there is substantial evidence for zinc’s usefulness as an addition to standard treatment with antidepressant medications. However, they did not conclusively determine that zinc supplements have any use for addressing generally depressed states of mind in people not officially diagnosed with some form of depression.
The authors of the review published in the Journal of Affective Disorders note that all of the studies pointing toward the usefulness of zinc supplements as a depression treatment have significant limitations that reduce their overall persuasiveness as definitive scientific evidence. As a result, the authors urge the development of future research projects that meet the highest scientific standards. No one should take a zinc supplement (or any other type of supplement) for diagnosed or undiagnosed depression symptoms without a doctor’s specific approval and authorization.