Viscosity study of maternal and formula milks according to the assessment proposed by the International Dysphagia Diet Standardisation Initiative Model: a comparison with Rheological Assessment.
Ana Maria Hernandez, Maria Isabel Berto, Esther Mandelbaum Gonçalves Bianchini
PMID 40008695WHAT IT FOUND
Adding barium or thickener to infant milk changes its viscosity unpredictably, often making it thicker than intended.
Clinicians must measure the final mixture's flow with the IDDSI syringe test rather than relying on label categories or standard recipes.
Key findings
01Adding 33% liquid barium sulfate to breast milk increased viscosity by approximately 13.5 times compared to pure milk, shifting it from thin to slightly or mildly thick.
02There was a significant discrepancy between IDDSI flow test classifications and rheological data, with 75% of samples receiving different consistency labels depending on the method used.
03Thickening breast milk or formula with barium sulfate reclassified the liquid to a higher viscosity level (mildly thick) than when thickened with the barium-free product.
STILL TO COME
How it was doneWhat they foundWhat it means for SLPs
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What it does not show
The study did not evaluate swallowing performance in infants, so the clinical impact of these viscosity changes on safety or efficacy is unknown. Only specific brands of formulas and thickeners available in Brazil were tested, so results may not generalize to other products. The comparison between IDDSI and rheology relied on data from a previous study for the rheological values, rather than simultaneous measurement in this experiment. Sample size for breast milk was small (13 donors), and factors like time of day or maternal diet were not controlled.
Declared interests
Financial support from CAPES (Brazil). No other conflicts declared.
The easy way to misread this
Do not assume that a standard recipe for thickening or adding barium will produce the intended IDDSI level. The study showed that 75% of samples were classified differently depending on the measurement method, and barium addition alone can significantly thicken liquids beyond the expected category.