Association of dietary live microbe intake with frailty in US adults: evidence from NHANES

Diets rich in live microbes can bring various health benefits. However, the association between dietary live microbe intake and frailty has not been studied. The study utilized data from the National Health and Nutrition Examination Survey (NHANES) 2007–2018. A total of 11,529 participants were included. Sanders et al. classified the level of live microbes in foods into low (<104 CFU/g), medium (104–107 CFU/g), or high (>107 CFU/g). With the methodology of Sanders et al. and dietary questionnaire data, participants were divided into three groups: (1) low dietary live microbe intake group (only low-level foods), (2) medium dietary live microbe intake group (medium but not high-level foods), and (3) high dietary live microbe intake group (any high-level foods). Additionally, foods with medium and high live microbe content were aggravated as MedHi. Frailty index ≥0.25 is defined as frailty. The weighted logistic regression analysis was conducted to examine the relationship between the intake of dietary live microbe and frailty. The restricted cubic splines (RCS) were employed to detect the nonlinear relationships. In the fully adjusted model, participants with high dietary intake of live microbe had a significantly lower risk of frailty than those with low dietary intake of live microbe (OR = 0.67, 95% CI: 0.56, 0.79). For every 100 grams of MedHi food consumed, the risk of frailty decreased by 11% (OR = 0.89, 95% CI: 0.85, 0.92) after adjusting all covariates. The RCS indicated the existence of non-linear relationships. For those who consumed less than 100 grams of MedHi, increasing MedHi intake may significantly reduce the risk of frailty, but after exceeding 100 grams, the curve gradually levels off. Our results suggested that increasing dietary live microbe intake was associated with a lower risk of frailty. However, more research is needed to verify this.