When a speech-language therapist (SLT) recommends thickened liquids for a child with dysphagia, parents often have immediate practical questions: Which thickener should I use? Is it safe? How do I prepare it correctly? Will it affect my child’s nutrition? These are the right questions to ask — because in paediatrics, particularly in infancy, thickener selection and use require more careful consideration than in adult practice.
This article provides an evidence-based overview of thickener safety in infants and children, drawing on current clinical guidance to help families understand the rationale behind recommendations and participate confidently in their child’s care.
Thin liquids (IDDSI Level 0) move quickly through the oral cavity and pharynx. For children whose swallow reflex is delayed, whose tongue coordination is poor, or whose airway protection is reduced, this speed creates a risk of aspiration — liquid entering the airway rather than the oesophagus.
Thickening liquids slows their flow, giving the child more time to coordinate the swallow and protect the airway. It is a compensatory strategy — it manages risk rather than treating the underlying cause — and its goal is to enable safe oral hydration and feeding while rehabilitation or development proceeds.
Two main categories of thickener are used clinically:
These include products made from modified maize starch, tapioca starch, or rice starch. They are the traditional type and are widely available. Limitations include:
These use xanthan gum or carrageenan as the thickening agent. They are more stable across temperatures and resistant to salivary amylase — the texture prepared is closer to what the child actually swallows.
Xanthan gum-based thickeners are now the preferred option for most paediatric settings. However:
For older infants and children, food-based alternatives offer a natural and often more acceptable approach:
Food-based thickening is generally preferred where nutritionally appropriate, particularly for infants approaching 6 months corrected age who are transitioning to complementary foods.
This is the highest-risk group. The evidence strongly suggests avoiding starch-based thickeners. Xanthan gum-based products have also not been adequately studied in this group. Clinical decision-making should involve the neonatal team, paediatric SLT, and dietitian on a case-by-case basis, following the unit protocol.
For term infants with clinically confirmed aspiration of thin liquids, thickening may be recommended. Xanthan gum-based thickeners are generally preferred over starch-based options. The risks (including the theoretical risk of aspiration of thickened fluid, which may carry its own consequences) must be weighed against the risk of untreated aspiration.
Breast milk presents an additional challenge: enzymes in breast milk degrade starch-based thickeners rapidly, making it difficult to achieve consistent viscosity. Some families switch to expressed breast milk in a bottle with a gum-based thickener, or to a thickened formula, on SLT advice.
From around 6 months, complementary food introduction provides natural opportunities to adjust texture. Thickening of formula or breast milk may continue alongside food introduction. Nutritional review is important — adding thickener reduces the nutritional density of formula per unit volume if feeds are prepared incorrectly.
Commercial thickeners (gum-based) are generally considered safer in this age group than in infants, with fewer specific contraindications. Preparation consistency remains important — caregivers need clear instruction and ideally a demonstration of how to prepare each IDDSI level correctly.
One of the most common sources of thickener-related risk is inconsistent preparation. Factors that affect final viscosity include:
Parents should receive written instructions and, where possible, a hands-on demonstration from the SLT or dietitian. IDDSI standardised testing (flow test for liquids, fork drip for semi-solids) can be taught to families to verify consistency at home.
Thickened liquids may reduce fluid intake in some children — thicker consistencies are harder to drink, and young children may take less if they find it effortful. Monitor:
Dietetic review alongside SLT is recommended for any child on long-term thickened liquids.
Thickened liquids are a compensatory strategy, not a permanent treatment for most children. Indications for trial of reduced thickening or return to thin liquids include:
Decisions to modify thickening should always be made in conjunction with the SLT following formal reassessment, not based on caregiver observation alone.
Thickener use in infants and children is effective when used correctly and with appropriate clinical oversight, but it carries risks — particularly in premature infants — that require careful consideration. Families who understand the rationale, the correct preparation method, and the signs of concern are better equipped to use thickeners safely. Always follow the specific advice of your child’s SLT and dietitian, and do not hesitate to ask questions if anything is unclear.