Introduction to the Gluten-Free, Casein-Free, Soy-Free Diet


The gluten-free, casein-free, soy-free (GFCFSF) diet removes all sources of gluten, casein, and soy from the diet. The word “diet” is really a misnomer because this is a lifestyle change. It is a way of seeing food as nourishment for the body and brain. Once you see what gluten, casein, and soy can do to some people’s bodies, you will begin to understand why this diet is important.

What is Gluten?

Gluten is a protein found in wheat, rye, barley, and some oats. Most bread, pasta, cereals, cookies, cakes, and pretzels contain gluten. They must be removed from the diet.

What is Casein?

Casein is a protein found in dairy. Cow’s and goat’s milk both contain casein as does butter, yogurt, ice cream, cheese, and cream. Ghee is butter that has had the casein removed from it, so it may be used if tolerated and if there is no dairy allergy.

Why Soy?

The protein structure of soy is similar to gluten and casein, therefore, it can cause the same issues. In addition, because most soy is now genetically modified, it should be avoided. Soy should not be introduced as a substitute for casein.

Reported Improvements on the GFCFSF Diet

Here is a list of the most commonly reported improvements:

  • Reduced aggression
  • Improved expressive and/or receptive communication
  • Better bowel movements (less constipation and/or diarrhea)
  • Improved ability to focus
  • Reduced self-stimulatory behavior
  • Reduced illnesses, including ear infections
  • Appropriate response to pain stimuli
  • Eczema clearing

There are reasons why kids improve on this diet. To learn about the science behind these improvements, click here.

What to Eat

If you shop the perimeter of the grocery store, you will find tons of delicious foods that are naturally gluten, casein, and soy free: fruit, vegetables, nuts, beans, legumes, seeds, meat, and fish. Gluten-free grains include corn, rice, quinoa, buckwheat, millet, sorghum, teff, and amaranth.

There are a number of good dairy-free milk substitutes, such as coconut, almond, hemp, flax, and rice milk. But, water is the most important drink.

Keep it simple and uncomplicated with whole foods as the goal, such as:

Helpful Things to Know

  1. Eggs are not dairy and do not contain casein. Eggs are allowed.
  2. Lactose-free milk is not casein-free. Lactose is the sugar component of milk, casein is the protein component. Do not use lactose-free milk.
  3. Organic does not mean gluten and casein free. Organic refers to how the product was grown.
  4. This diet requires that all sources of gluten, casein, and soy be removed no matter how high or low the content is. Unfortunately, this diet does not allow even small amounts of casein and gluten to be consumed. The body will react to the proteins no matter how much is ingested.
  5. The ultimate goal is a healthier, whole foods diet free of these large proteins.
  6. This is a lifestyle change, so take it one day at a time.
  7. Try to keep sugar to a minimum.
  8. Food coloring and food additives should be avoided as well. They are not food - they are chemicals that are known to cause behavioral and health issues.
  9. Keep a journal. It can be a video journal, a written journal, or even an app on your phone. Keep track of:
    • Behavior
    • Eating Habits
    • Skin Condition
    • Bowel Movements

What to Replace

Avoiding Cross-Contact and Hidden Sources of Gluten, Casein, and Soy

Don’t allow cross-contact or hidden sources of gluten, dairy, or soy to undermine your efforts. Cross-contact occurs when a food that is GFCFSF comes into contact with foods or surfaces that contain restricted ingredients; making it unsafe for your child to eat. Cross-contact can occur at home, restaraunts, the grocery store, and even during the manufacturing, packaging, growing, and harvesting processes.

Be sure to read ingredient labels to look for hidden sources of gluten, casein, and soy. Even some items that are advertised as safe are, in fact, not safe.

Hidden sources of gluten, casein, and soy are often found in:

Reading Food Labels

Thankfully, laws have been passed to help consumers read food labels. Below the food ingredients, the package will list any of the top eight allergens: milk (casein), wheat (gluten), soy, peanuts, tree nuts, egg, fish, and shellfish.

The less processed food you buy, the less you will have to read labels. In the beginning, you may need to use some prepackaged foods in order to transition your child, but the goal is to get away from prepackaged foods and buy whole foods. Shop the perimeter of the grocery store, where the fresh foods are kept.

Food Allergy and Sensitivity Testing

Most of our kids are sensitive to foods like casein, gluten, and soy, but not allergic them. The best test is a six month trial of the gluten and casein free diet.

  • This type of allergic response results in rash, hives, runny nose, watery eyes, and even anaphylaxis.
  • This is done via skin prick or blood test and measures the body’s response when it comes into contact with an allergen.
  • This type of test will not be reliable for a child that is sensitive to foods and not allergic.

  • Food sensitivities can affect a child’s behavior for up to 72 hours after they have eaten the food.
  • This type of test is considered controversial, so most allergists will not order it. However, many functional medicine doctors trust this type of test to verify food sensitivities in their patients.

  • Celiac is an autoimmune disease in which people can’t eat gluten because it damages their small intestine. Celiac disease can develop at any age.
  • Most people with autism that are sensitive to gluten have Non-Celiac Gluten Sensitivity (NCGS). This new research is very pertinent to our kids who may not have celiac disease but still react to gluten.
  • If you wish to test for celiac disease, it must be done prior to going on a gluten-free diet. You must be eating gluten to test for celiac.
  • There are several blood tests doctors use when determining whether or not someone has celiac disease; however, an intestinal biopsy is still considered the “gold standard” for diagnosis.
    • Anti-tissue transglutaminase (tTG), IgA
    • Anti-Endomysium (EMA), IgA
    • Anti-deamidated Peptide (DGP), IgA & IgG
    • Total Serum IgA (test for IgA deficiency)
    • If IgA < 10 mg/dL (deficient), the IgG versions of tTG & EMA will need to be run.

Whatever you decide to do, remember that the best test is a trial of a GFCFSF diet.

Common Questions

What Can I Expect?

The first few weeks can be hard on both the child and the parents. The children typically have meltdowns and poor behavior when the foods they are used to are removed and replaced with new things they are not used to.

What About Calcium?

Healthy bone formation depends on calcium, vitamin D, and vitamin K2. Other minerals, such as magnesium and silica, are important as well. The Recommended Daily Allowance (RDA) for calcium for children is 800-1200 mg per day. The best way to get your calcium is through food, which is still possible when not eating dairy.

Foods such as broccoli, almonds, leafy greens, seeds (especially poppy and sesame seeds), calcium and sulfate-rich mineral water, and canned bone-in fish are all great sources of calcium. Find more non-dairy sources of calcium here.

If your child is not eating a wide variety of calcium rich foods, then consider calcium supplementation. Fortunately, calcium supplements are inexpensive and available in pills, liquid, chewable, and powder forms.

Considerations when taking a calcium supplement:

  • Always take calcium with food.
  • Never take more than 500mg at a time because the body cannot absorb more than that at one time.
  • Make sure you have adequate Vitamin D3 and K2. You can test Vitamin D levels with a blood test. Without adequate vitamin D, your body can only absorb 10-15% of the calcium you consume.
  • Calcium can worsen symptoms in kids who have PANS or PANDAS (autoimmune medical conditions common in autism). When inflammatory cytokines cause the breakdown of the blood brain barrier, calcium enters the cells rapidly, causing inflammation.

Can We Just Use Digestive Enzymes Instead?

No. Enzymes should be used in conjunction with a special diet, not instead of a special diet.

Can We Cheat? Even Just a Little?

No. Cheating will only send mixed messages to the child. If you think of this as an allergy to food, then you will understand that you don’t give a child food that they are allergic to.

While this may not be an IgE allergic reaction, it can be an IgG (food sensitivity) which affects behavior for up to 72 hours after the food is consumed.

Can You Absorb Gluten and Casein Through Your Skin?

Some kids are so sensitive that even handling products with wheat or casein will alter behavior. Technically, gluten is too large of a molecule to pass through the skin’s barrier. However, we all know that kids put their hands in their mouth. In addition, with the help of steam, or even some oils (for example, when hydrolyzation occurs), it may allow the ingredients to enter the body via hair follicles. The palms of the hands and the bottom of the feet are especially porous. A good example of this is Play-Doh. It has wheat as an ingredient.
Also be careful of cosmetic products. Examples include skin lotion, shampoo, sunscreen and soap. Check anything you are applying to the child’s skin or that you are allowing them to play with.
Note: Since these are not food products, the labels are not as easy find or understand. When in doubt, call the manufacturer.

Isn’t This Going to Be Hard?

That’s for you to decide. Sure, a lifestyle change is always challenging at first, but dealing with a child who has behavior issues because they are struggling and in pain is hard too. Kids will not get better without interventions. And, don’t forget, kids grow. They get bigger and more difficult to handle. So, really, it comes down to which type of “hard” you prefer… A child who is hard to handle? A child that may be in pain? Or, a lifestyle that requires you to pay attention to what you eat?

We don’t want kids to struggle daily. We want them to thrive. When kids feel better, they behave better. Then suddenly, life becomes easier… despite a diet that is different from their peers. We all have to make hard choices, and change can be hard. Health, and therefore behavior, does not get better by chance. It gets better by change. Be sure to choose your “hard” carefully.

Is This Just Some Lie to Get Me to Put My Kid on a Trendy Diet?

Consider how some people’s behavior changes when they ingest alcohol. A bar at 7:00 pm (opening time) is not the same as that bar at 1:00 am (closing time). Alcohol has altered the way the patrons act. The same can happen with food.

Furthermore, published research and decades of clinical experience and parent reports show that the GFCFSF diet is beneficial for the majority of kids with autism. To learn more, read our article titled, "Top Reasons to Implement a Gluten-Free, Casein-Free Diet."

Further Reading

*All content of this article is for informational purposes only. It is not a substitute for professional advice, diagnosis, or treatment. Always seek the advice of your physician, therapist, or other qualified health provider with any questions or concerns you may have.