Understanding Transitional Foods in Dysphagia Management: Behavior in the mouth defines use

Transitional foods have become a vital part of dysphagia management, offering innovative solutions for individuals with swallowing difficulties. These foods, which were formally defined by the International Dysphagia Diet Standardisation Initiative (IDDSI), rapidly change texture in response to moisture or temperature, making them ideal for individuals with dysphagia.

What are IDDSI Described Transitional Foods?

Transitional foods are a category of food formalized by the International Dysphagia Diet Standardisation Initiative (IDDSI) to describe foods that rapidly change texture in the presence of moisture or temperature change (Cichero et al., 2017). IDDSI was created in response to a need for global standardization of texture-modified foods and liquids to provide a common, international taxonomy in an effort to improve safety, reliability and quality of all foods for individuals with dysphagia (swallowing disorders – visit www.asha.org to learn more). The final IDDSI framework (www.IDDSI.org) is composed of a food and liquid pyramid. The transitional foods category is represented by a bar spanning the side of the food pyramid demonstrating the dynamic nature of this category.

The Foods levels in the IDDSI Framework:

The IDDSI Framework is split into many levels with some overlap between foods and liquids. These items are ranked on their texture and consistency to provide the best diet for those living with dysphagia. 

Per the IDDSI, food and liquids are broken down into varying levels based on texture, flow and other food properties. A quick breakdown of the scale as it pertains to foods is:

IDDSI transitional foods – Foods that transition from one IDDSI level to another. *Although the transitional side bar is graphically shown spanning from level 7 to level 5, this doesn’t indicate the full variability in transition between products.

Medical Disclaimer: All content and material of this website is for informational purposes only and is not intended to serve as a substitute for the consultation and/or medical treatment of a qualified physician. Always seek the medical advice of your speech-language pathologist and/or the official IDDSI website for your prescriptive plan. 

History of use of transitional foods with children

Historically, transitional foods were used primarily to aid in the development of masticatory skills as toddlers advance from a puree to a solid diet. The ease of consumption poses an  advantage for those with less mature or underdeveloped sensorimotor systems of mastication (Dovey et al., 2013; Gisel, 1991).

Although adults with dysphagia have vastly different etiologies for their condition, the resultant benefits of transitional foods can be the same. However, the use of transitional foods in the adult population has been limited due to lack of ready-made options that are marketed to the adult and the psychosocial detriment for adults with dysphagia to be fed “baby food”.

Further Defining Transitional Foods:

Given the special textural properties of these foods, minimal chewing is required, with tongue pressure often being sufficient to break the solid apart in the right environment.

Transitional foods can be divided into two categories: solid foam or solid gel/liquid. Gel and liquid transitional foods tend to be more dependent on temperature than additional moisture to dissolve. Solid foams are stable at room temperature and tend to remain so with increased temperature, but transition more so in the presence of moisture than temperature.

Method of testing of transitional foods:

The IDDSI guidelines indicate that transitional foods are solids that when tested as a shape no greater than 1.5 cm × 1.5 cm will squash, disintegrate, or melt (i.e., no longer resembles its original shape) after soaking in one mL of water for one minute and given the application of approximately 17 kPa of fork pressure (IDDSI Framework, accessed 5 Feb, 2020) However such testing only accounts for the presence of one mL of water for an entire minute, which does not mimic saliva in enzymatic activity, oral quantities, and temperature nor typical oral preparation and transit times. Thus, it is likely of benefit to also test transitional foods with each individual patient as part of the assessment protocol.

To note, the 1.5 cm x 1.5 cm size restriction is only for the sample testing to allow for standard specification of food particle size relative to the 1mL amount of water that is used in the testing procedure. There is no size restriction for serving a transitional food item. The expectation would be that the particle size of the final state would be one of the characteristics that determine the texture level after transition. So, if the particles end up being between 4 mm and 1.5 cm in largest dimension after transition, then the lowest possible level to describe the food after transition would be Level 6 Soft and Bite-sized (provided that other characteristics of that level are also met). If the particles end up being smaller than 4 mm after transition, then Level 5 Minced and Moist may be the appropriate level to describe the state after transition, provided that the other characteristics of Level 5 are also met. For pediatric population, the specific pediatric particle size guidelines would need to be considered in defining the texture of the end-state after transition.

Examples of transitional foods:

 Gel and liquid transitional foods tend to be more dependent on temperature than additional moisture to dissolve. Solid foams are stable at room temperature and tend to remain so with increased temperature, but transition more so in the presence of moisture than temperature.

Please note that transitional foods are highly variable in what IDDSI texture level they start at and what they transition to in the mouth. The speed of dissolving is variable from 5 seconds to a full minute to transition. There is variability in the oral behavior from forming a cohesive bolus to high particle formation, from low residue to stickiness and gumminess.  Finally, the nutritional value and presence of sugar, dairy and gluten is highly variable. It is important to evaluate a transitional food for a specific patient and their oral impairment status, dysphagia severity, and dietary restrictions.

Table 1. Categories of transitional foods

Figure 1.  Examples of transitional foods. A. Savorease cracker^TM; B Shortbread cookie cracker; C shrimp chip; D Japanese training jelly; E Magic Cup^TM; F ice cream.    

Psychosocial benefits of transitional foods

Both adults and children may benefit from the dissolvable nature of transitional foods. Solid foams in particular start as a regular solid (level 7) and dissolve to either a soft and bite sized (level 6), minced and moist (level 5), or puree (level 4) consistency. It is the final consistency that a transitional food dissolves to that determines the acceptability for those on a texture modified diet. For instance, if a person has restricted diet and can only eat foods that are a minced and moist consistency (level 5), then they likely could also include transitional foods into their diet that begin as a regular food and dissolve in the mouth to a level 4.

The benefits of transitional foods really lie in liberalization of the diet and increasing choices for the person with dysphagia. All transitional solid foods are finger foods which allows for self-feeding in many circumstances. The ability for an adult or child to grasp their own food and advance it to their mouths is part of the oral preparatory phase of swallowing, an important variable in obtaining an effective swallow. In addition, studies in food science show that physically touching food rather than using cutlery, makes the brain think it is tastier and more satisfying, even before it reaches the mouth (Madzharov, 2019), and can increase nutritional intake and quality of life for adults with cognitive impairment (Heelan et al., 2020). Finger foods have been studied in long term care in residents with dementia and have shown to improve food consumption and eating independence (Jean, 1997; Kimura et al., 2019; Pouyet et al., 2014; Soltesz and Dayton, 1995).

The potential psychosocial benefits of solid foam transitional foods can be inferred from research conducted on finger foods in the adult population and are listed in Table 2.

Table 2. Potential psychosocial benefits of solid foam transitional foods derived from literature on finger foods and snacking in adult populations

Studies Evaluating Safety Level of Different Transitional Foods

Two studies to date have been published evaluating transitional foods in the oral environment. Awadalla et al. (2018) examined 9 commercially available first finger foods, including Fruit and Veggie Melts^TM, Yogurt Melts ^TM, Apple Pick-Ups ^TM, Carrot Pick-Ups^TM, Wagon Wheels^TM, Lil’Crunchies^TM, Arrowroot Cookies^TM, Cheerios^TM, Puffs^TM. These foods are marketed to parents of toddlers as rapidly melting in the mouth and can be considered transitional foods. The American Academy of Pediatrics recommends starting with finger foods that are easy to swallow, cut into small pieces, and soft. The study tested the dissolve rate of these foods in the adult mouth. The results of this study showed that there was significant variability in dissolution in the mouth with only a small proportion meeting all the safety criteria specified by the American Academy of Pediatrics. Of even greater concern was that leaving the foods exposed to air led to some test samples becoming as hard as candy.

The second study tested the behavior of transitional foods influenced by different “in-mouth” conditions (time, pressure, saliva) in older adults with and without dysphagia (Barewal et al., 2020). The transitional foods tested were Savorease Crispy Melts, Savorease Crispy Melts and dip, Baby MumMums, shrimp chips and the EAT bar. Thirty individuals ages 50 to 88 participated in this study (10 with diagnosed dry mouth, 8 with dysphagia). Each test food was placed in the mouth for 5 or 12 seconds with or without tongue pressure and then expectorated. A second benchtop preparation following the International Dysphagia Diet Standardisation Initiative (IDDSI) protocol was also completed on all sample types (Figure 1). An IDDSI fork pressure test was then performed on all samples. The results showed that the Savorease Crispy Melts with or without dip were the only test foods to pass the fork pressure test in all participants in 5 seconds with tongue pressure. Baby MumMum samples dissolved least frequently than all others. Moderate tongue pressure positively influenced the dissolution of the transitional foods. Interestingly, Baby MumMum, shrimp chips and the EAT bar performed better in the benchtop preparation than they did in the oral testing. Participants with dry mouth showed slower dissolution at 5 seconds compared to individuals without dry mouth, but there was no significant difference in dissolution by 12 seconds. Overall, there was a wide variability in degree and speed of dissolution across different transitional foods and testing methods. These findings support the need for individual testing of degree of dissolution with transitional foods, especially in slower to dissolve transitional foods, and in people with dry mouth.

Two additional studies evaluating Crispy Melts transitional solid in comparison to puree using instrumental assessments (MBSS, FEES), demonstrate similar oral and pharyngeal pattern to puree (Shune, et al., in press).

Nutritional value

The typical puree diet contains almost 50% less protein than a regular diet (Miles, 2019; Vigano, 2011; Vucea, 2017). Recovery from illness, dysphagia, or poor motor skills can lead to eating fatigue. Plate waste is a serious concern in facility-based care and especially for those on a modified texture diet as it increases risks of malnutrition. This population specifically can benefit from increasing small meals or snacks throughout the day. Transitional foods can be appropriate for snacking and can solve the needs for IDDSI snacks. Transitional foods historically have been known to offer improved texture for children, but are often high in sugar or lack nutritive value. Savorease Crispy Melts^TM has a unique nutritional profile as it is plant-based, and protein enhanced with no added sugars which seeks to optimize quality of caloric intake for older adults (Bayne et al., 2022)

Conclusion

Transitional foods represent a key advancement in dysphagia management, offering safer and more satisfying options for patients. By carefully testing these foods according to IDDSI standards and integrating them into both nutritional plans and therapy sessions, healthcare providers can improve the quality of life for those with dysphagia.