A study published today in eLife reveals that incorporating selenium into diets shields against obesity and delivers metabolic advantages to mice. This discovery opens the possibility for interventions that mimic the anti-ageing benefits linked to dietary restriction while still allowing individuals to maintain their usual eating habits.
Various diets have been identified to enhance healthspan—the duration of life spent in good health. Limiting dietary methionine, an amino acid, has been confirmed as a method to prolong healthspan in several species, including mammals, not humans. Recent research indicates that the benefits of methionine restriction on healthspan might also apply to humans. While some may find methionine restriction achievable through specific diets, such as veganism, it may not be feasible or appealing to all. In response, researchers from the Orentreich Foundation for the Advancement of Science (OFAS) in Cold Spring, New York, US, set out to develop an alternative that emulates the effects of methionine restriction without necessitating a restricted diet.
A significant hint for this research was that limiting methionine decreases levels of IGF-1, a hormone that regulates energy. If a treatment reduces IGF-1 levels, it also promotes healthspan. Previous studies demonstrated that selenium supplementation lowers IGF-1 levels in rats, making it a promising candidate.
The research team first examined if selenium supplementation could protect against obesity as methionine restriction does. The team provided young male and older female mice with one of three high-fat diets: a standard diet, a methionine-restricted diet, and a standard diet with selenium. The study found that selenium supplementation effectively prevented the weight gain and fat build-up seen in control diet mice, mirroring the effects of methionine restriction.
To investigate the diets’ impact on metabolic changes associated with methionine restriction, the team set up tests that measured four metabolic markers in the mice’s blood. The results were promising, showing significant reductions in IGF-1 and leptin levels, a hormone controlling hunger and energy use, in both male and female mice. These findings suggest that selenium supplementation can replicate most of the benefits of methionine restriction, offering enhancements similar to the healthspan.
To understand the broader implications of selenium supplementation, the team explored its effects on yeast, another organism. They assessed yeast healthspan through two metrics: chronological lifespan, the longevity of dormant yeast, and replicative lifespan, the yeast’s ability to produce offspring. Previous research showed methionine restriction increased yeast’s chronological lifespan, leading the team to investigate if selenium would have a comparable effect. Selenium-enriched yeast demonstrated a 62% increase in chronological lifespan (from 13 to 21 days) and a replicative lifespan extended by nine generations compared to controls. That indicates selenium’s capacity to significantly improve health span, as evidenced by various ageing cell tests.
Jay Johnson, Senior Scientist at OFAS and the study’s senior author, highlights the ageing research community’s aim to find simple, effective interventions to boost human healthspan. The study provides evidence that short-term selenium supplementation, whether from organic or inorganic sources, offers numerous health benefits to mice, particularly in preventing diet-induced obesity. Looking ahead, the research team anticipates these selenium compounds will also thwart age-related diseases and increase mice’s overall lifespan, hoping these advantages will extend to humans.
More information: Jason D Plummer, Spike DL Postnikoff, Jessica K Tyler, Jay E Johnson, Selenium supplementation inhibits IGF-1 signaling and confers methionine restriction-like healthspan benefits to mice, eLife. DOI: 10.7554/eLife.62483
Journal information: eLife
