High-salt diets may contribute to depression risk, a new study in mice suggests. Design by MNT; Photography by UniversalImagesGroup/Getty Images.
- The link between diet and
depression is a critical area of research. It could lead to finding
effective strategies to treat depression.
- A study found that mice who
consumed a high-salt diet developed depression. The findings also
suggested that this was because the high salt diets affected the
production of the cytokine IL-17A.
- The results highlight
another potential reason to limit salt consumption.
The World Health
Organization (WHO) estimates that 5%Trusted Source of adults
globally experience of depression.
Experts want to find
effective treatment strategies, and one area of focus is diet, with evidence suggesting
that following a healthy diet and avoiding components like junk food may help
decrease depression risk.
A study recently
published in The Journal of
Immunology looked at
the relationship between consuming a high-salt diet and depression-like symptoms
in mice.
They found that mice who received a high salt diet
developed depression-like symptoms and that this was likely related to the
induced production of the cytokine IL-17A.
The results open the
door for future research into depression and possible treatment.
How
are high-salt diets and depression linked?
Researchers sought to
explore how high salt consumption affected depression in mice. First, they
tested if mice who received high salt diets developed depression.
Mice had either a normal
or a high-salt diet for 5 to 8 weeks. Researchers used a few methods to look at
mice’s behavior. They also had a positive control group of mice that were
exposed to chronic restraint, which is “a common depression-like model.”
The mice on the high-salt diet displayed behaviors
similar to those of the positive control mice. This indicates that the high
salt-diet caused the mice to exhibit depression-like behavior.
They also found that
these mice experienced an increase in the production of IL-17ATrusted Source, a cytokine linked
to depression symptoms.
Their analyses revealed
that certain cells produced more IL-17A, and they also found increased levels
of IL-17A in mice’s spleens and areas of the brain. This suggests that the high
salt diets promoted the production of this critical cytokine.
To further investigate
this, researchers used mice with a RORγt deficiency. They note that this
transcriptional factor is something that is needed for IL-17A to be produced.
They fed these mice the
high-salt diet and then saw if they developed depressive symptoms. These mice
demonstrated much more normal behavior than those with the transcriptional
factor. These mice also did not experience increased levels of IL-17A.
The authors note
that their findings “suggest that [a high-salt diet] drives depression-like
behavior in mice through inducing IL-17A production.”
The researchers note
that several lymphocyte populations can produce IL-17A, so they next tried to
determine the distribution of cells that make IL-17A in the mice’s brains,
peripheral blood, and spleens.
They found that γδT
cells were likely a major cell source of the increased levels of IL-17A in the
mice that received the high-salt diets.
The results also
indicated that mice on the high salt diets experienced an increase in γδT17
cells. Researchers note further that the γδT17 cells were a critical source of
IL-17A in the mice who received the high-salt diet.
Finally, researchers
wanted to see if the production of IL-17A by the γδT cells contributed to the
depression behavior of the mice who received the high-salt diet. To do this,
they used an anti-γδTCR antibody to diminish the γδT cells. They found that
after this, the depression-like behavior in high-salt diet mice diminished.
The authors note that
“[c]ollectively, our findings show that [a high-salt diet] drives
depression-like behavior in mice at least partially through the induction of
γδT17 cells.”
The results uncover
critical information about how salt intake could impact depression.
Richard C.
Calderone, DO, MPH, FAAP, FACP, an osteopathic physician
specializing in internal medicine, who was not involved in this study, noted
to Medical News Today that:
“Although
these findings were in mice, it is reasonable to investigate the effect of
limiting salt intake on depression in humans. It should be noted that
depression is a complex, multi-factorial condition, and that even with
promising studies like this —it remains too early to know the quantity of salt
intake necessary to demonstrate any clinical difference in humans. In addition
to dietary salt restriction, this study identified that new treatments
targeting IL-17A or gamma-delta T cells may also be targets for pharmacologic
management of depression. The study provides a biological explanation for the
association between high salt intake and depression, identifying new targets
for potential treatments.”
Do
these research findings apply to people?
This research used mice,
often a critical data collection component that provides useful information.
However, more research will likely be needed to confirm what this study found.
Robert
Hostoffer, DO, an American Osteopathic Association board member, not
involved in the study, told MNT that, “in general, it is difficult to interpret
data from mouse studies due to their difference in nomenclature of their immune
systems, both soluble and nonsoluble components.”
“Caution should be employed with the data in
reference to human subjects. Also, the determination of depression in mice is
difficult to translate to depression in humans,” Hostoffer advised.
More research would be
required to see if people would experience similar results and what the
long-term effects might be. Additionally, more research to confirm the findings
on the γδT cells may also be helpful.
The study authors noted
that examination of the molecular mechanisms involved in “HSD-induced IL-17A
production in γδT cells” will also be helpful in future research.
The researchers did
acknowledge that high-salt diets might affect depression somewhat differently
because of the behavior they observed in mice when the high-salt diet and
chronic restraint stress components were combined.
It was different than
when the mice only experienced the depressive behavior brought on by chronic
restraint stress. They noted that “this suggests that there might be alternate
effects of HSD or the combined treatment on depression-like behavior.”
How
to minimize salt consumption
This study emphasizes
another potential reason why minimizing salt intake is a good thing, as it
could offer benefits for mental health in addition to the noted physical health
benefits.
As noted by the American Heart AssociationTrusted Source (AHA),
consuming too much salt or sodium can increase the risk of problems like high
blood pressure, stomach cancer, osteoporosis, and stroke.
Registered dietitian
nutritionist Karen Z. Berg, MS, RD, CSO, CDN, not involved in the recent
study, explained to MNT that: “High sodium intake is especially bad for
your heart and kidneys. People who have heart disease, kidney disease,
diabetes, or fatty liver need to really watch their sodium intake so that they
don’t make their conditions worse.”
Berg further noted the
importance of seeing sodium consumption in a realistic way because amounts can
often get confusing:
“The
Dietary Guidelines for Americans recommends that healthy adults limit their
sodium to 2,300 mg [milligrams] per day. That may sound like a lot, but it’s
the equivalent of about 1 teaspoon of salt! It is important to look at all
labels to see how much sodium you’re consuming. In order for an item to be
classified as ‘low-sodium,’ it has to have 140 mg of sodium or less per
serving. Don’t be fooled by labels that say ‘less sodium’. That does not mean
low sodium, it just means that it has less than the original.”
No comments:
Post a Comment