NOVEMBER 9, 2022
https://studyfinds.org/what-motivates-you-oxidative-stress-glutathione/
LAUSANNE, Switzerland — Motivation
can often be the difference between success or failure, reaching goals or
wandering aimlessly, and positive well-being or unhappiness. “What motivates
you” is often asked by life coaches to clients — and as it turns out, it could
unwittingly be your health. A new study finds motivation may depend on the
amount of oxidative stress your cells are experiencing.
Researchers in Switzerland say this unhealthy imbalance in the
cells can lower motivation and cause people to perform worse in certain tasks.
However, good nutrition can reverse this, and one particular antioxidant may be
the key. A team at the Swiss Federal Institute of Technology in Lausanne found
that a protein called glutathione (GSH)
displays a vital connection to motivation and better performance in
effort-related tasks.
“We assessed
relationships between metabolites in the nucleus accumbens – a key brain region
– and motivated performance,” says Professor Carmen Sandi at EPFL’s
School of Life Sciences in a media release “We then turned to animals to
understand the mechanism and probe causality between the found metabolite and
performance, proving as well that nutritional interventions modify behavior
through this pathway.”
What
is oxidative stress?
Study authors explain that as cells “eat” various molecules for
fuel, they produce various toxic waste products in the form of highly reactive
molecules, called oxidative species. Luckily, cells have ways of clearing this
waste out and restoring the balance within cells. When cells can’t remove all
of the waste, it causes a harmful imbalance — which scientists call oxidative
stress.
Brain cells often experience oxidative stress from its
neurometabolic processes. Antioxidants are the “cleaning crew” which balance
out healthy cells. With that in mind, researchers note that glutathione is the
brain’s most important antioxidant.
To find the connection to motivation, the team used a method
called proton magnetic resonance spectroscopy to quantify the biochemistry in
this specific region of the brain. The non-invasive technique measured GSH
levels in the nucleus accumbens of both humans and rats. They then compared
those measurements to each subject’s performance in a standardized,
effort-related task which measures motivation.
Results show higher levels of GSH in the nucleus accumbens
displayed a connection to better and more consistent performances during these
tasks.
To prove that more GSH has a direct connection to more
motivation, the team then injected a GSH blocker into rats, lowering the
production of this antioxidant. These rats displayed less motivation and had
poorer performances during reward-incentivized tests.
Could a daily
supplement give you more motivation?
Conversely, giving the rats a nutritional supplement of GSH
precursor N-acetylcysteine — which increases GSH levels in the nucleus
accumbens — allowed the animals to perform better during tests gauging
motivation. This opens the door to creating a new supplement for patients
lacking motivation due to poor nutrition.
“Our study provides novel insights on how brain metabolism
relates to behavior and puts forward nutritional interventions targeting key
oxidative process as ideal interventions to facilitate effortful endurance,”
the study authors conclude, saying that their findings “suggest that
improvement of accumbal antioxidant function may be a feasible approach to
boost motivation.”
“N-acetylcysteine, the nutritional supplement that we gave
in our study can also be synthesized in the body from its precursor cysteine,”
Sandi adds. “Cysteine is contained in ‘high-protein foods’, such as meat,
chicken, fish or seafood. Other sources with lower content are eggs,
whole-grain foods such as breads and cereals, and some vegetables such as
broccoli, onions, and legumes.”
“Of course, there are other ways beyond N-acetylcysteine to
increase GSH levels in the body, but how they relate to levels in the brain –
and particularly in the nucleus accumbens – is largely unknown. Our study
represents a proof of principle that dietary N-acetylcysteine can increase
brain GSH levels and facilitate effortful behavior.”
The findings are published in the journal eLife.