Co-author: Angela Van-Sickle, Ph.D., CCC-SLP
The Current State of Practice
Altering diets in patients with dysphagia is a common practice in speech-language pathology (Garcia, Chambers, & Molander, 2005; Steele et al., 2015). One study examining the use of thickened liquids in skilled nursing facilities found a mean of 8.3% (range 0% to 28%) of residents received some type of thickened liquids: 60% received nectar thick liquids, 33% received honey thick liquids, and 6% received pudding thick liquids (Castellanos, Butler, Gluch, & Burke, 2004). Therapists often report clinical benefits of altered liquids and diets (Castellanos et al., 2004). Reduced coughing, decreased meal times, and decreased choking episodes may be benefits of modified diets. This, in turn, may improve the quality of life for many who experience swallowing problems. A recently published article, Things We Do for No Reason: The Use of Thickened Liquids in Treating Hospitalized Adult Patients with Dysphagia (Lippert, 2019), created a stir. Although the article presents complex concepts in simple terms, examination of current practices is always of benefit. We must realize there are potential negative effects of diet modifications. In our zeal to keep patients “safe” from aspiration and possible pneumonia, it is important for speech-language pathologists to consider all the potential outcomes.
Recent Research
In recent years three systematic reviews concerning texture modifications and thickened liquids have been performed (Andersen, Beck, Kjaersgaard, Hansen, 2013; Beck, Kjaersgaard, Hansen, & Poulsen, 2018; Steele et al., 2015). Andersen et al. (2013) examined the evidence related to diet/liquid modifications and aspiration pneumonia and the impacts on nutrition and hydration. The authors initially planned to include randomized controlled trials (RCT), systematic reviews, and meta-analyses. However, due to a limited number of studies, cohort studies also were included. Ultimately, the review included sixteen studies. The authors concluded although there is evidence that thickened liquids can stop immediate aspiration, there is no high level evidence to indicate the use of thickened fluids prevents aspiration pneumonia in chronic dysphagia. The investigators did not find enough evidence to make recommendations concerning modified food. It is interesting to note that the authors suggested the use of modified solids “is justified,” despite the lack of confirmation.
In preparation for developing common terminology for liquid and food modification, The International Dysphagia Diet Standardization Initiative (IDDSI) team, led by Dr. Catriona Steele, examined available evidence in 2015. Steele et al. (2015) investigated the impact of altering diets on physiology and function. This group performed full text reviews of 488 articles and found 36 that met their inclusion criteria. That is, the articles contained specific information comparing oral processing or swallowing behaviors for at least two liquid consistencies or food textures. The group found two trends concerning the impact of thickening liquids on the physiology and function of the swallow. First, similar to Andersen et al. (2013), thicker liquids may reduce immediate penetration and aspiration. Second, thickened liquids may increase post swallow residue. The authors described the sparse amount of research available concerning modification of solids as “disappointing.”
Finally, the most recent systematic review (Beck et al., 2018) asked the same questions as Andersen et al. (2013) using two RCTs, and offered little more than the other two. As for texture-modified foods, the conclusion was “no literature was identified that addressed the effects of using texture-modified food consistencies as a compensatory strategy to facilitate safe and efficient intake of foods.” As for nectar-thickened and honey-thickened liquids, the risk-benefit ratio was “uncertain.” They identified no literature, meeting their inclusion criteria, to show the effects of “moderately thick or extremely thick” levels of liquid on swallowing.
The Possible Consequences
In addition to the systematic reviews concerning the current evidence for the benefits of modified diets, there is also literature concerning possible side effects or potential negative outcomes. Thickening liquids can lead to a plethora of issues. Among them is a decreased feeling of satiety leading to dehydration. Thickened liquids may cause a feeling of “fullness” and the associated flavor suppression provides little motivation to drink. In addition, research has shown that the dissolution and disintegration of medications can be negatively impacted (Cichero, 2013). Other possible side effects include dehydration (Sura, Madhavan, Carnaby, & Crary, 2012), increased reflux, slow gastric emptying, constipation (Gosa, Schooling, Coleman, 2011), increased confusion (Wittbrodt & Millard-Stafford, 2018), and decreased ability to participate in exercise programs (Maughan, 2003). Dehydration, which is the number one side effect of thickened liquid, leads to a number of issues including urinary tract infections, hypotension, and delirium (Bennett, 2000) as well as poor recovery, increased complications and mortality in stroke patients (Bahouth, Gaddis, Hillis, & Gottesman, 2018; Rowat, Graham, & Dennis, 2012).
Modifying solid foods also comes with caveats. Altered diets contain less nutrients than regular diets (Vigano, 2011). When compared with a regular diet, a pureed diet contains 31.4% less calories, 45.4% less protein, and 41% less lipids. One study (Wright, Cotter, Hickson, & Frost, 2005) evaluated dietary intake over the course of a day in hospitalized patients older than 60 years. They compared intake in patients consuming a regular diet to those consuming a texture-modified diet. Patients on the modified diet had significantly lower nutritional intake in terms of energy and protein. A nutritional supplement was recommended for 54% of patients on a texture-modified diet, compared with 24% of patients on a regular diet. This data suggests altering solid foods may contribute to malnutrition. Malnutrition affects the function and recovery of every organ system and specially decreases the immune system (Saunders & Smith, 2010).
Finally, altering liquids and solids has an impact on quality of life (QoL). A systematic review of the literature concerning the impact of modified diets on the quality of life determined that increased bolus modification was associated with decreased QoL measures among populations with dysphagia (Swan, Speyer, Heijnen, Wagg, & Cordier, 2015). (McCurtin, A., Healy, C., Kelly, L., Murphy, F., Ryan, J., Walsh, J. 2018) also noted an increased burden on patients due to cost, undesirable taste, and time.
Facilitating Change
Although diet modification has been and continues to be a mainstay for speech-language pathologists who treat swallowing, there is little to support its use. It is unlikely that this will change any time soon. However, it is important that clinicians consider other treatment approaches including postural techniques, carbonation, and water protocols ((McCurtin, 2018). In addition, it is imperative for therapists to present a realistic view of the evidence concerning the risks and benefits of modified diets to allow a patient to make a true informed decision (Horner, Modayil, Chapman, & Dinh, 2016).
References
Andersen, U., Beck, A., Kjaersgaard, A., Hansen. (2013). Systematic review and evidence based recommendations on texture modified foods and thickened fluids for adults (>18 years) with oropharyngeal dysphagia. European Society for Clinical Nutrition and Metabolism, 8(4), e127-e134.
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Beck, A. M., Kjaersgaard, A., Hansen, T., & Poulsen, I. (2018). Systematic review and evidence based recommendations on texture modified foods and thickened liquids for adults (above 17 years) with oropharyngeal dysphagia – An updated clinical guideline. Clin Nutr, 37(6 Pt A), 1980-1991. Retrieved from https://www.ncbi.nlm.nih.gov/pubmed/28939270. doi:10.1016/j.clnu.2017.09.002
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