Soy

What is Soy?

  • While soy is a plant-based protein that offers a variety of nutrients, its use may be contraindicated in autism due to high levels of glyphosate, genetic modification, and a similar molecular structure to gluten and casein. Some studies show soy-based infant formula may be associated with deficits in language, communication, hypersensitivity, and even seizures.

  • Soy can be a great source of plant based protein and many vitamins and minerals, as well as all 9 essential amino acids that are necessary for humans. Soy is also often enriched with B12, calcium and vitamin D. 

  • Soy is one of the most genetically modified crops (along with corn and cotton) and is commonly sprayed with glyphosate, which can be neurotoxic [8]. If using soy products, be sure to purchase non-GMO and organic, ideally fermented (like tempeh)!

  • There are many names for ingredients that contain soy in the products we eat that may be unrecognizable, thus making it hard to avoid if you are sensitive.

  • Many people who are sensitive to gluten and dairy may also be sensitive to soy, since it has a similar structure. If you are unsure, consume a soy-free milk alternative, such as Ripple Pea Milk.  

  • Gluten-free and soy-free diets along with other treatments like vitamin/mineral supplement, essential fatty acids, Epsom salt baths, carnitine, and digestive enzymes was seen to improve autistic symptoms and developmental age. [2]

  • One study monitoring the use of soy-based infant formula in children with autism may be associated with deficits in language, communication, social overtures and hypersensitivity to environmental stimuli. [5] Their results also suggested that the use of soy-based infant formula may be associated with febrile seizures in both genders and with a diagnosis of epilepsy in males in autistic children. [3]

  • There is often a very divisive line over the health of soy. One research study warns that consumers should be aware that soy contains endocrine disrupting compounds and make dietary choices accordingly. They say that alarm over soy products is likely unnecessary, but so is the belief that a soy-rich diet will cure disease. [10] For healthy individuals, moderation may be key.

Nutrient Breakdown

Soy is a great source of plant based protein and many vitamins and minerals. Soybeans contain:

Soy contains all 9 amino acids that are necessary for humans. This means that soy is a great protein source, especially those who follow a plant-based diet. Soy also contains phytates, which may impair absorption of iron and zinc. Phytate can be decreased by boiling, sprouting, or fermenting.

Soy is often enriched with B12, calcium and vitamin D. Some individuals are sensitive to some of the added vitamins, since they are often unmethylated. If this is a concern, unenriched Soy products are available (just read the labels).

Foods Containing Soy

  • Tempeh

  • Texturized vegetable protein (TVP)

  • Tofu

  • Veggie burgers

  • Soy milk, cheese, ice cream, yogurt

  • Miso

  • Soy sauce and tamari

  • Edamame

  • Vegetable oil, gum, broth and starch

Other names for soy ingredients in products: [9]

  • Soya

  • Glycine max

  • Hydrolyzed vegetable protein (HVP)

  • Hydrolyzed plant protein

  • Monodiglyceride

  • Monosodium glutamate (MSG)

  • Artificial flavoring

  • Natural flavoring

Soy Alternatives

Food Reactions

Soy Allergy: 

One of the common allergies seen is a soy allergy. The allergy often starts when the child is an infant, and while most will outgrow the allergy for some they do not. 

Allergies are caused by an immune system response that identifies something as bad for your body and triggers the production of immunoglobulin E (IgE) antibodies. When someone has a soy allergy, it is the soy that causes this reaction. This response will continue to happen each time you are in contact with soy. The antibodies made will recognize the soy and trigger your body to produce histamine that causes the symptoms of an allergic reaction. 

Tests can confirm a soy allergy, and avoiding soy products is the best way to avoid the allergic reactions. [9]

The body can respond to foods in many different ways including food allergies, food sensitivities, or food intolerances. If you suspect a food reaction, you can either choose to avoid the food or seek food reaction testing. Click here more information on the difference in types of food reactions and testing options

DISCLAIMER: Always consult with your pediatrician and/or your Registered Dietitian to help you test for a food reaction or to aid you in making individualized dietary changes.

Soy & Autism in the Research

Soy-Free Diets

Soy-Based Formulas in Infants and Mothers

  • Higher rates of seizures were found in children diagnosed with epilepsy and autism that were fed a soy-based formula.  [3]

  • The current data does not show soy formula or consumption of such products by expecting mothers jeopardizes offspring brain development and risk for neurobehavioral disorders like autism. [4]

  • One study monitoring the use of soy-based infant formula in children with autism may be associated with deficits in language, communication, social overtures and hypersensitivity to environmental stimuli. [5] 

Conflicting Research for Soy, but Moderation May be Key for Healthy Individuals

  • There is not enough research about soy, and some sources will over-state the pros or the cons of soy. [10]

  • This research study warns that consumers should be aware that soy contains endocrine disrupting compounds and make dietary choices accordingly. Alarm over soy products is likely unnecessary, but so is the belief that a soy-rich diet will cure disease. [10]

  • Moderation is likely key and the incorporation of real foods, as opposed to supplements or processed foods to which soy protein is added, is probably essential for maximizing health benefits. [10]

  • Women who are pregnant, nursing, or attempting to become pregnant should use soy foods with caution and be aware that soy formula may not be the best option for their babies. [10]

  • Older individuals, especially those with high cholesterol, may experience modest benefits including improved bone and cardiovascular health, and perhaps a decreased risk of carcinogenesis. [10]

Phytoestrogens

  • High amounts of phytoestrogens (found in soy) in female mice has been linked to a decrease in several metabolites like (GABA), cysteine, homoserine, ornithine and glycine. Deficiencies in these metabolites are linked with mouse models of autism and other human neurobehavioral disorders [6]

Roundup®, Glyphosate and Autism

  • Research is being done on the presence of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) in soy-based infant formulas and its connection to various diseases such as autism, Parkinson's and Alzheimer's diseases, as well as cancer. Data shows in certain countries, these compounds have been found within some products. [7]

  • Glyphosate is known as an environmental implicant for increased incidence of autism. Most soybeans farms use Roundup® which contains glyphosate. [8]

  • Read more about Glyphosate here.


  • Descriptio[1] 2020. [online] Available at: <https://fdc.nal.usda.gov/fdc-app.html#/food-details/781089/nutrients> [Accessed 10 August 2020].

    [2] Adams JB, Audhya T, Geis E, et al. Comprehensive Nutritional and Dietary Intervention for Autism Spectrum Disorder-A Randomized, Controlled 12-Month Trial. Nutrients. 2018;10(3)

    [3] Westmark CJ. Soy infant formula and seizures in children with autism: a retrospective study. PLoS ONE. 2014;9(3):e80488.

    [4] Rosenfeld CS. Effects of Phytoestrogens on the Developing Brain, Gut Microbiota, and Risk for Neurobehavioral Disorders. Front Nutr. 2019;6:142.

    [5] Westmark CJ. Soy Infant Formula may be Associated with Autistic Behaviors. Autism Open Access. 2013;3

    [6] Marshall BL, Liu Y, Farrington MJ, et al. Early genistein exposure of California mice and effects on the gut microbiota-brain axis. J Endocrinol. 2019;242(2):139-157.

    [7] Rodrigues NR, De souza APF. Occurrence of glyphosate and AMPA residues in soy-based infant formula sold in Brazil. Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2018;35(4):723-730.

    [8] Westmark CJ. A hypothesis regarding the molecular mechanism underlying dietary soy-induced effects on seizure propensity. Front Neurol. 2014;5:169.

    [9] Soy allergy - Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/soy-allergy/symptoms-causes/syc-20377802. Published 2020. Accessed August 12, 2020.

    [10] Patisaul HB, Jefferson W. The pros and cons of phytoestrogens. Front Neuroendocrinol. 2010;31(4):400-419. doi:10.1016/j.yfrne.2010.03.003

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Authors

April Allen, RDN

Brittyn Coleman, MS, RDN/LD, CLT

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