Natural mineral may help reverse memory loss

by University of Queensland

Credit: Pixabay/CC0 Public Domain

Selenium—a mineral found in many foods—could reverse the cognitive impact of stroke and boost learning and memory in aging brains, according to University of Queensland research.

20 feb 2022--Queensland Brain Institute (QBI) lead researcher Dr. Tara Walker said studies on the impact of exercise on the aging brain found levels of a protein key to transporting selenium in the blood were elevated by physical activity.

"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 investigated 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 aging."

Selenium is an essential trace mineral 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 scientists also tested whether selenium would have an impact on the cognitive decline sometimes experienced following stroke, which can affect people's memory and ability to learn.

"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."

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More information: Odette Leiter et al, Selenium mediates exercise-induced adult neurogenesis and reverses learning deficits induced by hippocampal injury and aging, Cell Metabolism (2022). DOI: 10.1016/j.cmet.2022.01.005

Provided by University of Queensland 

Outcomes: Selenium Supplements May Raise Diabetes Risk

By NICHOLAS BAKALAR
Findings from animal studies have suggested that the antioxidant selenium improves glucose metabolism, so researchers decided to see whether it would reduce the incidence of Type 2 diabetes. They found that on the contrary, selenium might actually increase the risk.
The researchers used data from 1,250 people with an average age of 63, originally recruited to test selenium as a cancer preventive. The study was randomized, double-blind and placebo-controlled, which is generally considered the most reliable design. Half the people took a 200-microgram dose of selenium daily, and the other half an identical-looking dummy pill. They were followed for an average of 7.7 years. Fifty-eight selenium recipients and 39 of those who took the placebo developed Type 2 diabetes.
The study, published online yesterday, will appear in the Aug. 21 print issue of The Annals of Internal Medicine. (The findings on cancer, which were published in 1996 and 2002, were at best mixed.)
Over all, people who took selenium supplements had more than one and a half times as much risk for Type 2 diabetes as those who did not, and the higher the blood level of selenium, the greater the risk of developing the illness. The findings held even after controlling for age, sex, body mass index and smoking status.
“There is no need for Americans to take selenium supplements,” said Dr. Saverio Stranges, the lead author and an associate professor of cardiovascular epidemiology at Warwick Medical School in England. “There is already enough selenium in the average American diet.” Still, he said, “this is a single study, and no single study gives the final answer.”