Food and Behaviour Research

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Suicidal patients are deficient in vitamin D, associated with a pro-inflammatory status in the blood

Grudet C, Malm J, Westrin A, Brundin L (2014) Psychoneuroendocrinology 50 210-9. doi: 10.1016/j.psyneuen.2014.08.016. Epub 2014 Sep 2. 

Web URL: Read this and related articles on PubMed here. Free full text of this article is available online



Low levels of vitamin D may play a role in psychiatric disorders, as cross-sectional studies show an association between vitamin D deficiency and depression, schizophrenia and psychotic symptoms. The underlying mechanisms are not well understood, although vitamin D is known to influence the immune system to promote a T helper (Th)-2 phenotype.

At the same time, increased inflammation might be of importance in the pathophysiology of depression and suicide. We therefore hypothesized that suicidal patients would be deficient in vitamin D, which could be responsible for the inflammatory changes observed in these patients.


We compared vitamin D levels in suicide attempters (n=59), non-suicidal depressed patients (n=17) and healthy controls (n=14). Subjects were diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, 4th edition, and went through a structured interview by a specialist in psychiatry. 25(OH)D2 and 25(OH)D3 were measured in plasma using liquid-chromatography-mass-spectrometry (LC-MS). We further explored vitamin D's association with plasma IL-1β, IL-6 and TNF-α.


Suicide attempters had significantly lower mean levels of vitamin D than depressed non-suicidal patients and healthy controls. 58 percent of the suicide attempters were vitamin D deficient according to clinical standard.

Moreover, there was a significant negative association between vitamin D and pro-inflammatory cytokines in the psychiatric patients. Low vitamin D levels were associated with higher levels of the inflammatory cytokines IL-6 and IL-1β in the blood.


The suicide attempters in our study were deficient in vitamin D. Our data also suggest that vitamin D deficiency could be a contributing factor to the elevated pro-inflammatory cytokines previously reported in suicidal patients.

We propose that routine clinical testing of vitamin D levels could be beneficial in patients with suicidal symptoms, with subsequent supplementation in patients found to be deficient.


Numerous different factors can contribute to the risks for suicide and self harm - but nutritional status is one risk factor that still receives relatively little attention.

This study found significantly lower blood levels of Vitamin D in patients who had attempted suicide, compared with both depressed but non-suicidal patients, and healthy controls.  Six out of ten such patients showed clinical-level Vitamin D deficiency.  

Furthermore, Vitamin D levels were inversly related to biomarkers of inflammation in the psychiatric patients - consistent with both;
  1. the established importance of Vitamin D for immune health, and
  2. the evidence that inflammation may be an important contributory factor to depression and other mood disorders, which is now substantial.
Vitamin D deficiency in humans is associated with a very wide range of physical health problems - and with poor mental health. Furthermore, animal studies have long confirmed that adequate supplies of Vitamin D are essential for normal brain development and function. 

While more controlled clinical trials are still needed to confirm whether Vitamin D deficiency also plays a causal role in depression and related conditions in humans, there is already a clear case for clinicians to ensure that all patients have adequate Vitamin D status.

For more information on the links between Vitamin D and depression, see:

And for more information on the potential links between nutrition, suicide and self-harm, see: