DASH diet as a preventive strategy for sarcopenia: integrated observational and mendelian randomization analyses in US adults

Despite the potential of dietary patterns as modifiable interventions, most studies focus on single nutrients and the epidemiological evidence on combined dietary patterns and sarcopenia remains inconclusive. Based on NHANES data from 2011 to 2018, we systematically assessed the dose-response relationship between five dietary indices (DASHI, MEDI, AHEI, DII, HEI-2020) and sarcopenia, aiming to provide an evidence-based basis for the development of nutritional intervention strategies. Dietary indices were calculated based on 24-hour dietary questionnaire recall and sarcopenia was assessed by ASMBMI. Weighted multivariate logistic regression models adjusted for sociodemographic, lifestyle, and clinical covariates were applied. Restricted cubic splines were used to test for non-linear relationships. The potential causal relationship between dietary components and sarcopenia was further analyzed using MR. Among 6,210 participants (491 with sarcopenia), higher DASHI scores demonstrated a dose-response protective effect. In the fully adjusted model, the DASHI continuous score was negatively associated with the risk of sarcopenia (OR = 0.83, 95% CI: 0.72–0.95, P = 0.008). Quartile trend tests were significant (P for trend = 0.018), with a 50% reduction in risk in the highest quartile (Q4) compared to Q1 (OR = 0.50, 95% CI: 0.30–0.84, P = 0.011). With regard to dietary components, macronutrients (energy, carbohydrates, proteins, fats), B vitamins, vitamin D, calcium and magnesium were found to be protective against sarcopenia (P < 0.05). Causal associations between multiple dietary components and features associated with sarcopenia by MR analysis were consistent with the DASH diet structure. The DASH diet demonstrates a robust inverse association with sarcopenia, likely mediated by its anti-inflammatory properties and nutrient synergy. These findings prioritize DASH-based interventions for high-risk populations. It may help reduce the healthcare burden imposed by sarcopenia. This study is pioneering in its use of nationally representative data to systematically compare the effects of multiple dietary indices on sarcopenia, providing a high-quality, evidence-based foundation for the development of prevention guidelines based on overall dietary composition.