Is Sunlight Deprivation Triggering Suicides?
As reported by Jeff Nicklas Vitamin D Council (10/14) Inflammation And Suicide Attempts: Where Does Vitamin D Fit In?
In a new study from the journal Psychoneuroendocrinology, researchers found a
high prevalence of vitamin D deficiency in suicidal patients, as well as a
negative correlation between vitamin D levels and pro-inflammatory markers.
Suicide is a complex event that involves a multitude of genetic, environmental
and psychological influences. It is widely known that psychological conditions
such as depression, stress, personality disorders, and other forms of mental
illness play a major role leading up to a suicide attempt. What is less
understood is how the unique biological markers seen in suicidal patients
contribute to suicidal behavior. Previous evidence suggests that inflammation
can contribute to depressive disorders, which in turn increases the odds of a
Taking this a step further, researchers have found that patients who attempt
suicide have elevated levels of pro-inflammatory markers such as interleukin-6
(IL-6) and C-reactive proteins when compared to depressed patients who were
non-suicidal. While these studies support the hypothesis that inflammation is
an underlying factor in those who attempt suicide, the cause of that
inflammation remains unknown.
Researchers of the current study speculated that vitamin D, a known modulator of
inflammation, may be involved in the etiology of suicide attempts and could
subsequently be a cheap and effective therapy in these patients. To test their
hypothesis, Dr. Cécile Grudet and her research team out of Sweden enrolled participants from three
distinct groups. They recruited 59 patients who had been admitted to Lund
University Hospital after a suicide attempt, 17 patients with major depressive
disorder but who were non-suicidal, and 14 healthy participants from the
surrounding area to serve as a control group. All participants underwent a
structured interview by a psychiatrist in order to detect any psychiatric
disorders and determine the severity of these disorders. Blood samples were
then taken within a week after the interview. The researchers used these blood
samples to measure the participants’ inflammatory markers, including IL-6, interleukin 1-beta (IL-1β) and tumor necrosis factor alpha (TNF-α), as well as their vitamin D status. IL-1β is an important inflammatory marker that is associated with pain sensitivity in
the . TNF-α is an inflammatory cytokine produced by adipose tissue and is responsible for
immune regulation. Improperly functioning TNF-α has been implicated in the development of depression.
The researchers wanted to determine the prevalence of vitamin D deficiency,
defined as having levels below 20 ng/ml, and whether this deficiency was
correlated with increased inflammatory markers in suicidal patients when
compared to non-suicidal depressed patients and the control group. Here’s what the researchers found:
• Overall, 92% of the suicidal patients had 25(OH)D levels below 30 ng/ml
compared to 59% in the non-suicidal depressed patients and 71% in the control
group (P < 0.01).
• The average vitamin D level in the suicidal patients was significantly lower
than the other groups with an average of 18.8 ng/ml, compared to 24.8 ng/ml in
the non-suicidal depressed patients, and 26 ng/ml in the healthy control group
(P < 0.05).
• There was no significant difference in vitamin D levels based on psychiatric
diagnosis or severity of the disorder.
• A significant negative relationship was observed between vitamin D and IL-1β in the suicide attempters (P < 0.05).
• There was a significant negative correlation between vitamin D and IL-6 in the
non-suicidal depressed patients (P < 0.05).
• There was no significant effect of psychiatric medications or anti-epileptic
drugs on vitamin D in any of the participants.
The researchers concluded, “As we and others have previously shown that peripheral and central inflammation
is increased in suicidal patients, we here suggest that low levels of vitamin D
could be a contributing cause of this inflammation.” They went on to add, “As inflammation is suggested to directly be part of the neural mechanisms
underlying depressive and suicidal behavior, it should be of high relevance to
detect and cure the vitamin D deficiency in these patients.”
The researchers acknowledge a few key factors missing from their analysis. They
did not collect data on the participants’ ethnicity, sun exposure behavior, or smoking habits, which may impact their
results. As with other observational studies, the design limits the ability to know for
sure whether vitamin D deficiency causes increased inflammation or suicide
While this research hints at the possibility that vitamin D may influence
biological factors relating to suicides, it is important to keep in mind the
complex nature of suicidal behaviors. These events often arise from life
issues, such as social or financial problems, and may not be able to be
controlled through nutritional or medical intervention. Nonetheless, if
biological factors do significantly contribute to risk of suicide attempt then,
as the researchers mention, vitamin D may be a cost-effective and easily
administered therapy to help in those with suicidal behaviors. For this reason,
clinical trials looking at how vitamin D supplementation to treat deficiency
affects suicidal behavior are still needed.
Finally: Missing Link Between Vitamin D, Prostate Cancer
From ScienceDaily (10/14):
A University of Colorado Cancer Center study published in the journal Prostate
offers compelling evidence that inflammation may be the link between Vitamin D
and prostate cancer. Specifically, the study shows that the gene GDF-15, known
to be upregulated by Vitamin D, is notably absent in samples of human prostate
cancer driven by inflammation. "When you take Vitamin D and put it on prostate
cancer cells, it inhibits their growth. But it hasn't been proven as an
anti-cancer agent. We wanted to understand what genes Vitamin D is turning on
or off in prostate cancer to offer new targets," says James R. Lambert, PhD,
investigator at the CU Cancer Center and associate research professor in the CU
School of Medicine Department of Pathology.
Since demonstrating that Vitamin D upregulates the expression of GDF-15, Lambert
and colleagues, including Scott Lucia, MD, wondered if this gene might be a
mechanism through which Vitamin D works in prostate cancer. Initially it seemed
as if the answer was no. "We thought there might be high levels of GDF-15 in
normal tissue and low levels in prostate cancer, but we found that in a large
cohort of human prostate tissue samples, expression of GDF-15 did not track
with either normal or cancerous prostate tissue," Lambert says. But then the
team noticed an interesting pattern: GDF-15 was uniformly low in samples of
prostate tissue that contained inflammation. "Inflammation is thought to drive
many cancers including prostate, gastric and colon. Therefore, GDF-15 may be a
good thing in keeping prostate tissue healthy -- it suppresses inflammation,
which is a bad actor potentially driving prostate cancer," Lambert says.
The study used a sophisticated computer algorithm to analyze immunohistochemical
(IHC) data, a task that in previous studies had been done somewhat subjectively
by pathologists. With this new technique, Lambert, Lucia and colleagues were
able to quantify the expression of the GDF-15 protein and inflammatory cells by
IHC staining on slides taken from these human prostate samples. Additionally
encouraging is that the gene GDF-15 was shown to suppress inflammation by
inhibiting another target, NFkB. This target, NFkB, has been the focus of many
previous studies in which it has been shown to promote inflammation and
contribute to tumor formation and growth; however, researchers have previously
been unable to drug NFkB to decrease its tumor-promoting behavior. "There's
been a lot of work on inhibiting NFkB," says Lambert. "Now from this starting
point of Vitamin D in prostate cancer, we've come a long way toward
understanding how we might use GDF-15 to target NFkB, which may have
implications in cancer types far beyond prostate."
The above story is based on materials provided by University of Colorado Denver.