Across two Irish population cohorts, NICOLA (n = 2,791, mean age 64) and TILDA (n = 3,999, mean age 66), fermented dairy intake did not consistently track with muscle strength, frailty or functional limitations once confounders were adjusted. Crude associations in NICOLA vanished after adjustment, with no dose-response pattern. In TILDA, the top intake tertile showed higher odds of low grip strength (OR 2.71; 95% CI 1.12, 6.88), an association driven by yoghurt and attenuated with covariate adjustment.
The headline is a null result, and that is informative. Mechanistic appeal for fermented dairy is real: high-quality protein, leucine content and plausible gut-muscle axis effects. Yet this cross-sectional analysis suggests food-frequency-based intake does not translate into measurable strength advantages in free-living older adults. The TILDA signal pointing toward harm is almost certainly reverse causation or residual confounding. People with declining strength, poorer appetite or health problems often shift toward soft, easy-to-eat foods like yoghurt, and the wide confidence interval signals instability. Treat it as noise, not a warning. Key limitations: cross-sectional design prevents causal inference, FFQs differ between cohorts and misclassify intake, and fermented dairy was not separated by probiotic content or fat level. The practical takeaway is modest: yoghurt and cheese are not a shortcut to preserving strength, so resistance training and adequate total protein remain the evidence-backed levers. This is confirmatory of an unsettled field, and only longitudinal cohorts or randomised trials can resolve whether fermented dairy matters for sarcopenia.
