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.
