Hidden Acidity and the Use of Natural Thickeners to Manage Pediatric Dysphagia

When infants and children aspirate liquids there are few options available to optimize their safety while being mindful of nutritional needs. Adjusting the feeding method or equipment, utilizing feeding and swallowing strategies, and offering thickened liquids are the primary tools available to improve oral feeding safety.

The primary thickening agents used in the pediatric population include starch-based thickeners (e.g., corn starch), gum-based thickened (e.g., Xanthan or Carbo gum), infant cereals (e.g., rice or oatmeal), and the use of food purees. Thickening liquids in the pediatric population can be challenging due to several factors. The benefits and limitations of using each type of thickener are listed in Table 1 below.

Hidden Acidity of Naturally Thickened Liquids

Over the last several years, there has been an increase in the practice of using pureed foods to thicken liquids for children who are aspirating thinner viscosities. It could be theorized that pureed foods are more natural than commercial thickening options and may provide additional nutritional value to a child’s diet.

The hidden dilemma is that while shelf-stable baby foods like apple sauce may be a quick and easy way to thicken liquids to a safe consistency, they can have very high acid contents. Ascorbic acid, folic acid, and citric acid may be added to shelf stable foods to preserve them and reduce the risk of bacteria. These products are required to maintain a pH of at least 4.6 according to the Food and Drug Administration regulations, but many have a much higher acid content. Dr. Zur tested various brands and types of apple sauce (pouch, jar, container, organic/non-organic) and the pH was found to hover around 3.6.

For children with existing reflux, this inundation of extra acid into their diets could potentially exacerbate reflux symptoms. For children without a history of clinical reflux, the addition of more highly acidic foods into their diet could possibly increase their chances of having reflux/regurgitation related symptoms.

Lastly, there is a subset of children whose aspiration may be partially due to the impact reflux has had on the tissues lining the pharynx and upper larynx. The acid can irritate these tissues resulting in reduced sensation when swallowing, which in turn can lead to aspiration (Suskind, et al). Increasing the acidity in these children’s diets could potentially increase the risk for aspiration in this population of children.

What Now?

Knowing the acidic content of the pureed foods that are being used to thicken the liquid is an important the first step. Refer to Table 2 for list of the pH values for common baby foods. Encourage caregivers to use purees that are lower in acid when thickening their child’s liquids. When using shelf-stable foods, selecting those purees that have a lower acid content will help further reduce the acid content. (See Table 3.)

Making homemade purees is another way to reduce the acid content. The added acids found in shelf-stable purees are not present in homemade recipes and thus would be less likely to be a contributing factor. Making homemade purees can be time consuming, but they can be prepared in larger batches and frozen for later use. It is important to advise caregivers to select the less acidic food/fruit/vegetables to prepare these purees at home (for example, granny smith apples and berries are much more acidic than sweet red apples and bananas). Additionally, caregivers should be advised to refer to labels and choose pureed foods with fewer preservatives and lower sugar content and those that list the pureed food as the first ingredients. Using yogurts or puddings can also be a thickening option if the child does not have a milk allergy or sensitivity.

Other Considerations When Using Purees to Thicken Liquids

The nutritional content of the added purees could inadvertently displace needed nutritional elements in a child’s diet, and therefore the medical team and nutritionist need to be consulted prior to initiating use of purees as thickening agents.

In addition, whenever thickened liquids are initiated, close monitoring is required to ensure that the child is able to meet nutritional and hydration needs by mouth. Thickened liquids can take longer to drink and the child may start to drink less over time. Monitoring stooling patterns is recommended as the addition of purees could cause constipation or loose stools depending on the amounts and types of purees are being added to the child’s diet. 

Lastly, it is important to assure the liquids are being thickened correctly based on the child’s dysphagia needs. Please refer to Table 4 for thickening instructions.

Thickening Agents (Table 1):

• Starch-based Thickeners (Thick It, Thick and Clear)
  • Benefits
    • Easily accessible and available over the counter at pharmacies
    • Relatively inexpensive, some insurance companies will cover the product
  • Limitations/Restrictions
    • Generally cannot be used for patients under 1-2 years of age
    • Reports that the “grainy” texture is less accepted in this population
• Gum-based Thickeners (Xanthan gum - Simply Thick, Carbo gum - Gel Mix)
  • Benefits
    • Simply Thick
      • Maintains its viscosity over time and temperature unlike other thickeners
    • Gel Mix
      • Marketed to thicken breast milk
  • Limitations/Restrictions
    • Simply Thick
      • Cannot be used for anyone under 1 year of age OR anyone who was born prematurely or had any history of GI issues (ex: dysmotility, poor intestinal perfusion, etc.)
      • More difficult to obtain as it needs to be ordered online
      • More expensive than other thickening options
    • Gel Mix
      • Not approved for use at CHOP
      • Heating required for thickening
• Infant Cereals (Rice, oatmeal, etc.)
  • Benefits
    • CHOP Thickening Committee approved the use of rice cereal to Thicken formula for preterm and term infants and for the use of oatmeal cereal after 4 months of age
  • Limitations/Restrictions
    • Rice: Concern for high levels of arsenic
    • Cereals tend to clog bottle nipples and continue to get thicker over time
    • May contribute to constipation
    • Cannot thicken breast milk as the amylase in breast milk breaks down the cereal
• Food Purees (Fruits, vegetables, yogurts)
  • Benefits
    • Inexpensive and easy to obtain
    • Add nutritional value
  • Limitations/Restrictions
    • Cannot be considered for use until 6 months of age (adjusted age)
    • Concern for nutritional displacement: Consult a dietician, especially if the child will be consuming a large volume of liquids
    • Consideration of the acid content of the pureed foods that are being added to the liquids

Examples of pH Values in Common Baby Foods (Table 2):

Lower Acid Commercial Baby Foods

• Gerber: Squash
  • pH = 5.9
• Beech Nut: Mixed Vegetables
  • pH = 5.4
• Earth’s Best: Organic Garden Vegetables
  • pH = 5.4
• Beech Nut: Corn and Sweet Potatoes
  • pH = 5.3
• Earth’s Best: Organic corn & Butternut Squash
  • pH = 5.3
• Gerber: Sweet Potatoes
  • pH = 5.2

Higher Acid Commercial Baby Foods

• Gerber: Applesauce
  • pH = 3.7
• Earth’s Best: Organic First Apples
  • pH = 3.8
• Beech Nut: Pears & Raspberries
  • pH = 3.9
• Gerber: Pears
  • pH = 4.0
• Gerber: Prunes
  • pH = 4.0
• Gerber: Peaches
  • pH = 4.0
• Beech Nut: Oatmeal & Apples
  • pH = 4.0

Source: Koufman, Wei and Zur

Acid Content of Commonly Homemade Pureed Foods (Table 3):

• Apples (McIntosh) = 3.34
• Apple Sauce = 3.10-3.6
• Apples (Golden Delicious) = 3.6
• Apples (Delicious) = 3.9
• Peaches = 3.30 - 4.05
• Pears = 3.50 - 4.60
• Pumpkin = 4.90 - 5.50
• Bananas = 5-5.29
• Squash = 5.18 - 6.49
• Papaya = 5.20 - 6.00
• Sweet Potatoes = 5.30 - 5.60
• Yams = 5.50 - 6.81
• Mangoes, ripe = 5.80 - 6.00
• Carrots = 5.88 - 6.40
• Peas = 6.22 - 6.88
• Chick Peas = 6.48 - 6.80
• Avocados = 6.27-6.58
• Yogurt = 4.0-4.6

Source: www.pickyourown.org

References

• Cichero, J. Thickening agents used for dysphagia management: effects on bioavailability of water, medication, and feelings of satiety. Nutrition J. 2013;12(54):1-8.
• Duncan, DR, Larson, K, Rosen, RL: Clinical Aspects of Thickeners for Pediatric Gastroesophageal Reflux and Oropharyngeal Dysphagia. Curr Gastroenterology Rep. 2019;21(30):1-9.
• Koufman, J, Wei, JL, Zur, KB. Acid Reflux in Children. New York: Katalitix Media; 2018.
• McCallum, S: Addressing nutritional density in the context of use of thickened liquids in dysphagia treatment. ICAN. 2011;3(6):351-360.
• Suskind DL, Thompson DM, Gulati M, Huddleston P, Liu DC, Baroody FM. Improved infant swallowing after gastroesophageal reflux disease treatment: a function of improved laryngeal sensation? Laryngoscope. 2006;116(8):1397-1403.
• Pick Your Own. pH of Foods and Food Products. Pickyourown.org. http://www.pickyourown.org/ph_of_foods.htm.  Accessed January 14, 2020.

Contributed by: Karen B. Zur, MD, Julia Welc, MA, CCC-SLP