Protein
What is Protein?
Protein is vital for proper growth & development, as well as bone and muscle health. Due to texture preferences, selective eaters may avoid tender protein foods, like meat. Children with ASD may have a hard time digesting protein, which could potentially cause GI discomfort and behavioral issues.
They help regulate appetite, encourage muscle growth and development, aid in building bones, and benefit the immune system. [1-2]
The building blocks of proteins are called amino acids.
Protein and fats help keep us full and satiated! Add them to your child’s meal or snack if they are getting hungry quickly after eating. See our recommended protein sources in the list below!
If your child doesn’t get enough protein from their diet, you can add a protein supplement while you are working on expanding your child’s diet! Not all protein supplements are created equal, so be sure to read through our suggestions on what to look for!
Sources of Protein
For a list of the protein foods we’ve written about and creative ways to eat them, see the “Protein” section on the Foods page. We recommend eating a variety of protein sources, including both animal-based and plant-based. Animal-based proteins will contain more protein per serving and is easily used by our bodies. Plant-protein will have less protein per serving, but does often include fiber, which is great for our guts and bowel movements!
Animal-Based
Plant-Based
Quinoa
Soy products including tofu, tempeh, and edamame
Recommended Intake
Protein recommendations are based on the Recommended Dietary Allowance (RDA), which is the average daily level of intake sufficient to meet the nutrient recommendations of nearly all (97-98%) of healthy individuals. The amount of protein needed varies by age and weight in kilograms. See reference ranges to calculate your child’s needs. [3]
Infants = 1.5 g/kg/day
1-3 years = 1.1 g/kg/day
4-13 years = 0.95 g/kg/day
14-18 years = 0.85 g/kg/day
18+ years = 0.8 g/kg/day
Example: Calculating the protein needs of a 4 year old female who weighs 40 pounds
40 pounds ÷ 2.2 = 18.2 kilograms
18.2 kg x 0.95 = 17.3 grams of protein per day
Under-Consumption of Protein
Intake of too little protein and/or calories can result in protein-energy malnutrition. When protein intake is not enough, dietary protein is used for energy rather than its more important roles in the body. [1]
Low protein diets can induce fatty liver, worsen digestion, and decrease lean body mass and weight. [4]
Children who are picky eaters may be at risk for consuming too little protein. Those who eat low protein diets may replace the protein with carbohydrates and fats, which will increase caloric intake. [4]
Over-Consumption of Protein
Eating too much protein, to the extent that it decreases the intake of other essential nutrients, can lead to an unhealthy and unbalanced diet. [1]
A high-protein diet may increase the risk of heart disease, kidney stones, osteoporosis, and some cancers. [1]
High protein intake during early childhood has been associated with risk of being overweight or obese later in life. [5]
Children who are picky eaters may be at risk for consuming too much protein. Consuming a high protein diet, primarily from high protein meat, fish and poultry, can displace other nutrient- and fiber-rich foods. [1]
Supplements
For protein supplements, see the Protein Supplement note.
DISCLAIMER: Before starting any supplement or medication, always consult with your healthcare provider to ensure it is a good fit for your child. Dosage can vary based on age, weight, gender, and current diet.
Protein & Autism in the Research
Opioid Reactions to Certain Proteins
Gluten & Casein
Two nutritional proteins gluten (wheat) and casein (dairy) are metabolized into two peptides: gluteomorphine and casomorphine. These peptides have been shown to bind to opiate receptors in the nervous system and mimic the effects of opiate drugs. There is speculation that these opioid peptides resulting from digestion lead to higher activity in the endogenous opioid system, which is linked to symptoms of autism. This is known as the opioid excess theory. [6]
Children with autism who have GI disturbances who have tried the gluten-free, casein-free diet have shown better improvement in behavior/temperament, physiological symptoms, and social behaviors compared to children with autism who do not have GI disturbances. [7] For more information, visit the Gluten-Free, Casein-Free Diet note.
Protein Digestion in Autism
Children with autism may have a decreased protein digestive capacity, in which they have less activity of digestive enzymes. This is a main component of GI symptoms associated with autism. Due to lack of enzymes, proteins that are undigested can cross through the intestines and get into the blood, which can cause behavioral symptoms. [7-8]
Protein Intake in Autism
One study found that children with autism consume less protein compared to children who do not have autism. [9]
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[1] Blake JS, Munoz K, Volpe S. Nutrition: From Science to You. 3rd ed. Pearson; 2016.
[2] Górska-warsewicz H, Laskowski W, Kulykovets O, Kudlińska-chylak A, Czeczotko M, Rejman K. Food Products as Sources of Protein and Amino Acids-The Case of Poland. Nutrients. 2018;10(12)
[3] Dietary Reference Intakes for Energy, Carbohydrate. Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2002/2005). This report may be accessed via www.nap.edu.
[4] Pezeshki A, Zapata RC, Singh A, Yee NJ, Chelikani PK. Low protein diets produce divergent effects on energy balance. Sci Rep. 2016;6:25145.
[5] Hörnell A, Lagström H, Lande B, Thorsdottir I. Protein intake from 0 to 18 years of age and its relation to health: a systematic literature review for the 5th Nordic Nutrition Recommendations. Food Nutr Res. 2013;57
[6] Lange KW, Hauser J, Reissmann A. Gluten-free and casein-free diets in the therapy of autism. Curr Opin Clin Nutr Metab Care. 2015;18(6):572-5.
[7] Sanctuary MR, Kain JN, Angkustsiri K, German JB. Dietary Considerations in Autism Spectrum Disorders: The Potential Role of Protein Digestion and Microbial Putrefaction in the Gut-Brain Axis. Front Nutr. 2018;5:40.
[8] Chidambaram SB, Bhat A, Mahalakshmi AM, et al. Protein Nutrition in Autism. Adv Neurobiol. 2020;24:573-586.
[9] Sharp WG, Berry RC, Mccracken C, et al. Feeding problems and nutrient intake in children with autism spectrum disorders: a meta-analysis and comprehensive review of the literature. J Autism Dev Disord. 2013;43(9):2159-73.
