“Frail individuals exhibited increased pro-inflammatory microbes and decreased anti-inflammatory microbes,” the researchers from Sichuan University in China wrote. “In our study, not only high live microbe diets but also medium live microbe diets, are associated with a reduced risk of frailty.”
The study used data from the National Health and Nutrition Examination Survey (NHANES), a recurring national survey of the U.S. population.
Gut flora and frailty
The population of older adults continues to expand, and with it, the attention to frailty, which can lead to a loss of personal autonomy, increased healthcare expenditures and a higher risk of premature mortality. The researchers on the present study referenced a 2021 review published in the journal Age and Ageing citing that approximately 24% of individuals over the age of 50 years were affected by frailty.
While much of the research has focused on dietary interventions including Mediterranean, anti-inflammatory and Dietary Approaches to Stop Hypertension (DASH) diets, frailty can be mitigated by the intake of foods that benefit the gut microbiome, the researchers suggested. They added that assessing the overall intake levels of dietary live microbes is crucial as dietary live microbes extend beyond fermented foods to encompass peeled fruits and vegetables.
“Gut flora, a critical component of the human life cycle, has gained extensive recognition for its multifaceted roles in health,” they wrote. “Beyond its fundamental functions in digestion and nutrient absorption, it is also instrumental in drug metabolism, antimicrobial protection, immunomodulation and maintaining intestinal tract integrity. Contemporary research underscores the intricate relationship between changes in gut flora’s stability, diversity and composition and the onset of various diseases.”
Only a few studies focus on the probiotic effect on human frailty, including research that shows that administering Akkermansia orally improves the health of aged mice impacted by the condition.
Study details
The researchers analyzed data from a total of 11,529 participants 60 years and older and divided them into low dietary live microbe intake, medium dietary live microbe intake high dietary live microbe intake groups.
They estimated dietary live microbe intake using 24-hour dietary recall data from NHANES and approximated live microbe levels, expressed in colony-forming units per gram for 9,388 NHANES food codes across 48 subgroups. Foods pasteurized or processed at high temperatures are considered low levels. Unpeeled fresh vegetables and fruits fell into the medium levels, and unpasteurized fermented foods and probiotic supplements are classified as high levels.
To calculate frailty, the researchers used diagnostic items criteria such as cognition function, dependency, depression, comorbidities, medical status, hospital usage, general health, anthropometrics and laboratory tests. The frailty index is calculated by dividing the total score by the number of items answered. To ensure the quality of frailty diagnoses, the analysis included participants who responded to at least 80% of the items.
“Our study demonstrated that more intake of dietary live microbes was associated with a reduced risk of frailty among U.S. adults,” the researchers concluded. “Consequently, increasing the intake of dietary live microbes may be considered a novel dietary strategy to alleviate frailty.”
For further study, they noted that large-scale prospective studies are needed to further validate and substantiate their findings, establish causality and explore the mechanistic underpinnings of these associations.
Source: Journal of Nutrition, Health and Aging
doi: 10.1016/j.jnha.2024.100171
“Association of dietary live microbe intake with frailty in US adults: evidence from NHANES”
Authors: Xingwei Huo et al.