By Jennifer Copley (Last Updated 30 March 2012)
According to the University of Arizona (2003), amino acids are protein building blocks, and proteins are critical to the majority of cellular processes. Humans are able to produce half the amino acids they require (10 out of 20) and the rest are obtained via food. People can store fats and starches, but not amino acids, so those that can’t be made in the body must be consumed in food every day.
Evidence of Amino Acid Abnormalities in Those with Autistic Spectrum Disorders
There is evidence that children with autism, particularly children on casein-free and gluten-free diets, are more likely to be deficient in certain amino acids than non-autistic children. Arnold et al. (2007) found that 58%-60% of 150 autistic children studied were deficient in one or more essential amino acids (rates were slightly higher among those on restricted diets). By contrast, just 1 child in the control group of 24 non-autistic children was found to have an amino acid deficiency. Abnormalities have also been found in the way autistic children break down sugars and proteins (Evans et al., 2008).
However, Dr. Stephen Dealler (n.d.) asserts that although there are a number of studies suggesting that autistic children have amino acid deficiencies, many of these studies have not been replicated by additional researchers and in some cases, testing by independent companies has shown no abnormalities.
Research Autism (2012) notes that if amino acid abnormalities are a problem among those with autistic spectrum disorders, there are a number of possible causes, including damaged metabolism, diet (intervention diets, food sensitivities and aversions, etc.), lifestyle, and other influences. The organization cautions that although many people attribute poor language skills, difficulty in controlling temper, and other problems associated with autism to poor nutrition, this theory has not been widely accepted among scientists.
Jepson and Johnson (2007) elaborate on a popular nutritional theory of autism – that of maldigestion. This theory attributes many of the problems associated with autism, and the underlying deficiencies in amino acids and other nutrients, to poor digestion due to low digestive enzyme activity. The authors were able to find just one published study of digestive enzyme supplementation, which yielded improvements in 87% of cases, as noted by teachers and parents. Areas of improvement included reduced gastrointestinal problems, increased eye contact and sociability, and enhanced mood and attention. However, a full third of the subjects dropped out before the study was completed due to either lack of improvement or unpleasant side effects. Also, there was no placebo control group, so it’s possible that the children who did respond positively were simply experiencing a placebo effect. Given these problems, the authors assert that healthy dietary changes are likely to be more beneficial than supplementation with digestive enzymes.
Natural Amino Acid Sources
Dr. Chun Wong (2010) is enthusiastic about amino acids for autism, and advocates for the use of natural sources. Wong notes that neurotransmitter abnormalities have been implicated in depression, anxiety, and panic disorder, conditions that often accompany autistic spectrum disorders, and that amino acids are critical to neurotransmitter function. Dr. Wong also asserts that irritable bowel syndrome and leaky gut syndrome, problems that occur frequently in autistic people, can lead to low amino acid levels. He suggests that although supplements are available, a natural approach can be beneficial.
Dr. Wong recommends a therapeutic diet comprising 40% of calories from carbohydrates, 30% from protein sources, and 30% fats (choose healthy fats whenever possible and avoid trans fats completely). He suggests milk and turkey as great sources of tryptophan, which promotes the production of serotonin. He also says that snacks should be protein-rich rather than refined and sugary. Wong notes that homemade bone broth is a good source of protein, magnesium, and calcium (only broths such as chicken soup made from scratch – most store-bought broths are highly processed and suffer a loss of nutrients as a result).
In general, the best natural sources of amino acids are meat, poultry, fish, eggs, dairy products, nuts, seeds, beans, legumes, and whole grains. If providing a vegetarian diet, it’s important to combine certain plant sources, for example, beans and grains, to make complete proteins (Carter, 2004).
Best Protein Sources – Biological Value
Not all proteins are equally useful. Biological value is the degree to which the body can use a given protein from a particular source. The following is a comparison of biological values for different protein sources:
- Whey – 104
- Egg (whole) – 100
- Milk – 91
- Fish – 83-85
- Beef – 80
- Chicken – 79
- Soy protein – 74
- Wheat gluten – 64
- Rice – 60
- Wheat – 55
- Peas, beans, and other legumes; nuts and seeds – 49 (approx.)
(Sources: Graci, 2006; Hoffman & Falvo 2004; The Cory Holly Institute, 2005)
Concerns Associated with Amino Acid Supplements
High doses of protein may cause a variety of adverse effects (Garlick, 2001). There may also be risks associated with interactions between amino acid supplements and medications, and there are concerns regarding the purity of some supplements as well (Institute of Medicine, U.S., Committee on Military Nutrition Research, 1999). Overall, there hasn’t been much research undertaken to determine the safety and effectiveness of amino acid supplements for various conditions.
More Information on Autism Supplements
For more on the effectiveness of other supplements for treating autistic spectrum disorders, see the main Autism Supplements page. For a full list of articles on autism and Asperger’s syndrome, visit the main Autistic Spectrum Disorders page.
Always consult a qualified medical practitioner before taking supplements or giving them to your child. Many supplements are toxic at certain doses and may interact with some medications or create problems for people with certain medical conditions.
This article is not intended as a substitute for medical consultation or care. Health concerns should be referred to a doctor.
- Arnold, G.L.; Hyman, S.L.; Mooney, R.A.; & Kirby, R.S. (2003). “Plasma Amino Acids Profiles in Children with Autism: Potential Risk of Nutritional Deficiencies.” Journal of Autism and Developmental Disorders, 33(4), 449-454.
- Carter, J.S., UC – Clermont College Biology. (2 Nov 2004). “Complementary Protein and Diet.” Biology.clc, edu.
- Dealler, S, Dr. (n.d.). “Amino Acid Levels Modified in Autism.” Science-Autism.org.
- Evans, C.; Dunstan, R.H.; Rothkirch, T.; Roberts, T.K.; Reichelt, K.L.; Cosford, R.; Deed, G.; Ellis, L.B.; & Sparkes, D.L. (2008). “Altered Amino Acid Excretion in Children with Autism.” Nutritional Neuroscience, 11(1), 9-17.
- Garlick, P.J. (2001). “Assessment of the Safety of Glutamine and Other Amino Acids.” Journal of Nutrition (Supplement), 131, 2,556S-2,561S.
- Graci, S. (2006). The Food Connection: The Right Food at the Right Time. John Wiley & Sons Canada, Ltd, Mississauga, ON.
- Hoffman, J.R., & Falvo, M.J. (2004). “Protein – Which Is Best?” International Society of Sports Nutrition Symposium, June 18-19, 2005, Las Vegas NV. Journal of Sports Science and Medicine, JSSM.org.
- Institute of Medicine (U.S.). Committee on Military Nutrition Research. (1999). The Role of Protein and Amino Acids in Sustaining and Enhancing Performance. National Academy Press, Washington, DC.
- Jepson, B., & Johnson, J. (2007). Changing the Course of Autism: A Scientific Approach for Parents and Physicians. First Sentient Publications.
- Research Autism. (23 January 2012). “Diet, Nutrition and Autism.” ResearchAutism.net.
- The Cory Holly Institute. (2005). “Whey and Soy Protein.” CoryHolly.com.
- University of Arizona, The Biology Project. (2003). “The Chemistry of Amino Acids.” Biology.Arizona.edu.
- Wong, C., Dr. (27 December 2010). “Amino Acid Therapy and Autism.” NewAutism.com.