Tag: selenium

Categories : Environmental EffectsTags :

Selenium Reduces Health Impact of Pollutant Mixtures

On By ModernMedia
Photo by Bill Oxford on Unsplash

A study in mice conducted by the University of Cordoba proves that exposure to mixtures of metals and drug residue exacerbates health impacts, and evaluates the positive effects of a diet enriched in selenium to reduce this harm.

People are exposed daily, through the environment and their diets, to external substances that can be harmful to their health. Metals and the residue of pharmaceuticals, for example, in high doses, contaminate water and food, creating mixtures where they can interact, with this increasing their individual toxicity.

Analysing the effects of environmental pollution on organisms is essential to develop regulations establishing maximum doses of these pollutants for people. But mixtures of pollutants pose unknown challenges as they may interact with each other.

To understand the health effects of exposure to these ‘cocktails of contaminants’, a team at the University of Cordoba, evaluated, in mice, the toxicity of a mixture of contaminants that is very common in the environment and that accumulates along the food chain: a combination of metals (arsenic, cadmium, mercury) and drugs (diclofenac, flumequine).

In order to determine how these compounds interacted with each other, “we studied the controlled exposure of mice to this mixture and analysed how it affects the proteins in the liver; that is, how their liver proteostasis changes when ingesting these mixtures of contaminants for two weeks,” explained Professor Nieves Abril, senior author of the paper published in Science of the Total Environment.

Their conclusion is negative: the cocktail effect synergises these compounds, doing increased damage to health when the compounds act together.

“We used a massive protein detection technique (shotgun proteomic), which allowed us to compare how the proteins of the group exposed to the mixture of contaminants were altered compared to the control group,” April explained.

Of the proteins affected, they selected 275 as sentinels to verify what was changing and, after computer analysis, they were able to determine the metabolic pathways that were altered and their consequences for health. These analyses revealed a disproportionate defence response having a contrary and harmful effect on the system.

The researcher stressed that “although these pollutants generated oxidation in the cells separately too, when they acted together we found that the oxidation was so intense that all the antioxidant defence responses were activated continuously, without deactivating them, which ends up doing damage and causing many proteins to stop working.” The analyses showed a sustained expression of the response mediated by NRF2, which is the regulator that sets in motion a good part of the antioxidant defences, which caused a reducing stress.

Selenium as hope

It’s not all bad news in the study, as selenium could be a way to reduce the damage caused by exposure to these pollutants. A third group of mice were given doses of selenium, a mineral often found in vitamin supplements found in pharmacies, and proteomic analyses showed relief from the molecular damage done by the pollutants.

Selenium itself is an oxidant, but in low doses it activates responses in a controlled manner, predisposing the body to better defence.

Source: University of Córdoba

Categories : Diet and Nutrition Diseases, Syndromes and ConditionsTags :

Selenium Could Help Reverse Cognitive Decline

On By ModernMedia
Photo source: Pixabay

The trace metal selenium could help reverse the cognitive impact of stroke and boost learning and memory in ageing brains, according to a study published in Cell Metabolism.

Previous studies on the impact of exercise on the ageing brain found levels of a protein key to transporting selenium in the blood were elevated by physical activity.

Lead researcher Dr Tara Walker said: “We’ve known for the last 20 years that exercise can create new neurons in the brain, but we didn’t really understand how,” Dr Walker said.

The research team sought to find out whether dietary selenium supplements could replicate the effects of exercise.

“Our models showed that selenium supplementation could increase neuron generation and improve cognition in elderly mice,” Dr Walker said. “The levels of new neuron generation decrease rapidly in aged mice, as they do in humans. When selenium supplements were given to the mice, the production of neurons increased, reversing the cognitive deficits observed in ageing.”

Selenium is an essential trace metal which can play an important role in human health. It is absorbed from soil and water and is found in foods such as grains, meat and nuts, with the highest levels found in Brazil nuts. The researchers also investigated whether selenium would have an impact on post-stroke cognitive decline.

“Young mice are really good at the learning and memory tasks, but after a stroke, they could no longer perform these tasks,” Dr Walker said. “We found that learning and memory deficits of stroke affected mice returned to normal when they were given selenium supplements.”

Dr Walker said the results opened a new therapeutic avenue to boost cognitive function in people who were unable to exercise due to poor health or old age.

“However, selenium supplements shouldn’t be seen as a complete substitute for exercise, and too much can be bad for you,” she said. “A person who is getting a balanced diet of fruits, nuts, veggies and meat usually has good selenium levels. But in older people, particularly those with neurological conditions, selenium supplements could be beneficial.”

Source: University of Queensland