{
  "id": 2588025,
  "title": "This gut microbe may help keep you strong as you age",
  "url": "https://urgent.news/2026/08/22/this-gut-microbe-may-help-keep-you-strong-as-you-age",
  "topic": "health",
  "section": "Health & Medicine",
  "published": "2026-08-22T02:27:20.000Z",
  "source": {
    "name": "ScienceDaily Health",
    "slug": "sciencedaily-health",
    "url": "https://www.sciencedaily.com/releases/2026/08/260820202904.htm"
  },
  "original_language": "en",
  "account": "A type of gut bacteria named Roseburia inulinivorans appears to contribute to enhanced muscle strength in both humans and mice, according to a recent study published in the Gut journal. This discovery implies that the bacterium might be harnessed to develop a probiotic supplement targeting age-related muscle loss. Muscle mass and strength tend to decline with age, leading to frailty, reduced mobility, and impaired physical function, especially in individuals with chronic health issues. Previous research has linked gut bacteria to various health aspects, such as metabolic health, neurodegenerative diseases, and cardiovascular diseases. Moreover, emerging evidence suggests that gut microbiota could play a role in regulating muscle mass and function. To explore this potential link, the research team analyzed stool samples from 90 young adults (age 18-25) and 33 older adults (age 65+) to identify the gut microbiota present. They measured physical fitness using hand grip strength, leg press and bench press performance, and VO2 max (a gauge of cardiorespiratory fitness). Roseburia emerged as the sole bacterial genus associated with both improved muscle mass and strength. However, individual Roseburia species did not display consistent relationships with fitness measures. Among the older adults, those with detectable levels of R inulinivorans had 29% greater handgrip strength compared to those without the bacterium. Interestingly, this improvement did not correlate with an increase in maximal oxygen consumption, indicating better fitness. In younger individuals, higher levels of R inulinivorans were linked to stronger handgrip and higher VO2 max, as well as improved performance in leg press and bench press exercises. Additionally, higher relative abundance of both R inulinivorans and R intestinalis was associated with better performance in the leg press and bench press exercises. Conversely, R faecis and R hominis levels were not connected to any of the muscle strength measures. The findings suggest that different Roseburia species might impact distinct aspects of muscular performance. Roseburia bacteria were generally more prevalent in younger individuals. In the younger group, the relative abundance of R faecis ranged from 0% to 3.3%, R intestinalis from 0% to 5.5%, and R inulinivorans from 0% to 6.6%. In contrast, levels were lower among the older adults, with the relative abundance of R faecis ranging from 0% to 2.2%, R intestinalis from 0% to 0.7%, and R inulinivorans from 0% to 1.3%. To determine whether Roseburia directly influences muscle strength, the researchers conducted an experiment on mice. Prior to the experiment, the mice were treated with antibiotics for two weeks to eliminate their gut microbiome. They were then administered Roseburia species once a week for eight weeks. The animals were divided into four groups: three groups received different Roseburia strains, while a fourth group served as a control with no Roseburia supplementation. While the Roseburia species did not enhance the mice's endurance capacity, they did show a 30% increase in forelimb grip strength, indicating improved muscle function. This benefit persisted after 4, 6, and 8 weeks of treatment. Moreover, the treated mice exhibited larger muscle fibers and a greater proportion of fast-twitch (type II) fibers in their soleus muscle, a key muscle group responsible for standing and walking. However, this difference was not statistically significant when comparing the R inulinivorans group specifically with the R intestinalis group. The muscle fiber size distribution among the control mice appeared relatively uniform. Animals treated with R inulinivorans, on the other hand, displayed a larger proportion of larger fibers compared to the other groups. These muscle changes were accompanied by alterations in proteins and enzymes involved in the metabolic processes that generate energy for muscle activity. The study acknowledges several limitations, including the fact that the human Roseburia species did not permanently colonize the mice's gut in this experiment. Furthermore, the researchers did not directly examine certain pathways involved in inflammation or neuromuscular signaling, which could have contributed to the observed effects. Long-term research is needed to establish whether changes in R inulinivorans levels directly cause changes in muscle function or if the bacterium's abundance changes as a result of variations in muscle function. Despite these uncertainties, the researchers conclude that their findings provide strong evidence of a gut-muscle axis in which R inulinivorans positively modulates muscle metabolism and strength. They also note that the relative abundance of R inulinivorans is lower in older adults than in young adults, a trend that aligns with the increasing prevalence of sarcopenia (muscle loss) during aging. This suggests a potential role for R inulinivorans as a probiotic candidate for combating age-related muscle loss.",
  "summary": "Scientists have linked a specific gut bacterium, Roseburia inulinivorans, to stronger muscles in both humans and mice. Older adults who carried it had 29% greater handgrip strength, while treated mice gained about 30% more grip strength and developed larger, more fast-twitch muscle fibers. The bacterium was also less common in older people. Researchers say it could eventually become a probiotic…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 2,
    "also_reported_by": [
      {
        "outlet": "ScienceDaily",
        "title": "This gut microbe may help keep you strong as you age",
        "url": "https://urgent.news/2026/08/22/this-gut-microbe-may-help-keep-you-strong-as-you-age-2589901",
        "published": "2026-08-22T02:27:20.000Z"
      }
    ]
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}