Study finds link between vitamin D deficiency and schizophrenia

Tuesday , August 12, 2014 - 12:00 AM

Standard-Examiner staff

WASHINGTON — People with schizophrenia are more likely to have low levels of vitamin D in their blood, according to an analysis of 19 observational studies. 

According to the study published in the Endocrine Society’s “Journal of Clinical Endocrinology & Metabolism,” individuals who are deficient in the vitamin are twice as likely to be diagnosed with schizophrenia than those with sufficient levels. 

The combined studies examined the mental health of 2,804 adults, using blood tests to determine the levels of the vitamin D in each individual. The analysis found that participants with schizophrenia had “significantly lower levels of vitamin D in the blood compared to the control groups,” according to the press release published July 22. 

“This is the first comprehensive meta-analysis to study the relationship between the two conditions,” stated one of the study’s authors, Ahmad Esmaillzadeh of the Isfahan University of Medical Sciences in Isfahan, Iran, in the release. “When we examined the findings of several observational studies on vitamin D and schizophrenia, we found people with schizophrenia have lower vitamin D levels than healthy people. Vitamin D deficiency is quite common among people with schizophrenia.”

The analysis found that 65 percent of participants who were schizophrenic were also deficient in the vitamin; people with a deficiency were found to be 2.16 times more likely to also be diagnosed with schizophrenia than those with a sufficient amount of the vitamin in their blood. 

Schizophrenia, a chronic and severe mental illness with symptoms that may include hallucinations and delusions, is found in one percent of Americans, according to the National Institute of Mental Health. The illness is also believed to be influenced by genetics; the NIMH has found it occurs in 10 percent of people with a first-degree relative with the illness, such as a parent or sibling. Schizophrenia is found to effect men and women equally.

Researchers have theorized that vitamin D may be connected to the schizophrenia, considering it occurs more frequently in high latitudes and cold climates. Although small amounts are added to a variety of foods, such as milk, cheese and tuna canned in water, the skin naturally produces vitamin D with exposure to sunlight. The vitamin is essential to absorbing calcium and promoting bone growth in the body, and works to regulate the immune system.

“There is a growing trend in the nutrition science field to consider vitamin D and its relationship to conditions such as diabetes, cancer, heart disease and depression,” Esmaillzadeh stated in the release. “Our findings support the theory that vitamin D may have a significant impact on psychiatric health. More research is needed to determine how the growing problem of vitamin D deficiency may be affecting our overall health.”

To read the full results of the analysis, “Serum Vitamin D Levels in Relation to Schizophrenia: A Systematic Review and Meta-analysis of Observational Studies,” visit

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