Evaluating swallowing capacity in older adults with dysphagia: high protein, low carbohydrate smoothie formulas versus commercial formula

Abstract

Background: Dysphagia is a common problem in older adults that can lead to nutritional deficiencies. Oral nutritional supplements (ONS) are products used for oral nutrition support as an alternative nutritional therapy, specifically manufactured for the older individuals at risk of dysphagia. This study aimed to develop four high protein (23-34% energy ratio) and low carbohydrate (25-38% energy ratio) smoothie formulas (white sesame (WS) vs. white sesame and low carbohydrate (WSLC) vs. black sesame and low carbohydrate (BSLC) vs. chicken shitake (CS); 1 kcal/ml) for the older people with dysphagia and to assess their effect on swallowing capacity compared to widely used commercial formula (Ensure^®).

Methods: A cross-sectional study involved 63 participants aged 65 years or over. Subjects were divided into asymptomatic (n = 32, aged 72.9 ± 5.66 year) or symptomatic swallowing difficulty (n = 31, aged 75.0 ± 6.48 year) groups based on swallowing screening questionnaires. Swallowing capacity was assessed using Fiberoptic Endoscopic Evaluation of Swallowing (FEES), performed by experienced physicians, for three drinks (WS, CS vs. Ensure^®) in a blinded, randomly crossover sequence.

Results: Spare retention of a food bolus in each formula had been identified in the asymptomatic (47-66%) and symptomatic (61-71%) groups. WS had fewer premature spills than Ensure^® in the symptomatic group, but not in the asymptomatic group (5 ± 0.03 vs. 4.7 ± 0.12, p < 0.05), while CS had fewer premature spills than Ensure^® in both groups.

Conclusions: The findings suggest that smoothie drinks, particularly WS (51-350 centipoise), may offer a viable alternative to commercial formula (1-50 centipoise) for older adults with dysphagia, potentially reducing premature spillage. The findings provide useful preliminary insights into the potential of these formulas to support safer swallowing. Further research, including longer-term studies, would help to more fully explore their nutritional benefits, safety, and applicability across broader populations.

Trial registration: Clinical Trial ID NCT04901182, https//clinicaltrials.gov/ct2/show/NCT04901182 (25/05/2021).

Keywords: Aging; Dysphagia; Smoothie drink; Swallowing capacity.

Fig. 1

Participants evaluation of key properties of test diets on a 9-point hedonic scale. Panel (A) Pre-test: participants evaluation before tasting, Panel (B) Pre-test: participants evaluation after tasting. ^*Significant difference between test diets using the nonparametric Kruskal-Wallis method (p < 0.05). Different superscript letters (a, b,c, d) indicate significant differences between test diets using Mann-Whitney comparisons (Bonferroni adjusted) (p < 0.05). Abbreviations: BSLC, black sesame soy milk smoothie (low carbohydrate); CS, chicken shitake smoothie; IQR, Interquartile range; WS, white sesame soy milk smoothie; WSLC, white sesame soy milk smoothie (low carbohydrate)

Fig. 2

Severity of swallowing disorders in test diets detected by FEES evaluation. Panel (A) premature spillage when the bolus leaks or falls into the hypopharynx before swallowing, Panel (B) retention of the bolus and/or secretion, Panel (C) entrance of the bolus into the larynx or trachea, Panel (D) sum score of severity problem. ^*Significant difference between test diets using Friedman test and pairwise Wilcoxon signed rank test (p < 0.05). Higher scores mean less severe swallowing disorders. Abbreviations: ASD, asymptomatic swallowing difficulty; BSLC, black sesame soy milk smoothie (low carbohydrate); CS, chicken shitake smoothie; SSD, symptomatic swallowing difficulty; WS, white sesame soy milk smoothie; WSLC, white sesame soy milk smoothie (low carbohydrate)