Effect of differences in food texture on swallowing-related muscle activity in older people

In this study, the effect of different rice-flour mixtures,used to modify steamed-bread texture, on swallowing-related muscle activity in older people, was explored. The objective was to identify the texture associated with reduced swallowing-related muscular activation accompanied by reduced bread hardness.

Sixty-eight community-dwelling people aged ≥65 years were recruited. Swallowing ability was assessed using the eating assessment tool 10 (EAT-10) swallowing screening tool, and each participant consumed 5 g of steamed bread containing 0 %, 10 %, 20 %, or 30 % rice flour in a randomized order. Suprahyoid muscle activity during swallowing was recorded using surface electromyography (sEMG), and peak swallowing-related EMG amplitude, extracted from the swallowing-related burst, was analyzed.

Bread containing 20 % rice flour had the lowest hardness (199 × 10³ N/m²) and required the least suprahyoid muscle activation (F = 4.26, p = 0.007). Regression analysis confirmed that rice-flour percentage was significantly associated with peak swallowing-related EMG amplitude (β = 0.41, p = 0.01; adjusted R² = 0.717). Among participants with an EAT-10 score ≥3, the Wilcoxon signed-rank test indicated a significant reduction in peak swallowing-related EMG amplitude when consuming 20 % rice-flour bread (p = 0.01).

A 20 % rice-flour substitution provided a favorable steamed-bread texture associated with reduced swallowing-related muscular activation in older people. This simple dietary modification may facilitate safer swallowing by lowering the demand for muscle activation.