Aggression is a difficult and sometimes devastating symptom that occurs in children for varied reasons—some known and some unknown.
The correlation between food and behavior intrigued me 20 years ago, and sparked my career as a nutrition researcher and clinician.
And aggression is one of the areas parents are most concerned with, when their child has it. I feel for all of them – the children when they can express it later on often feel terrible about it and trapped by this uncontrollable response. And parents worry so much about what this might mean for their child’s future.
It’s a difficult area to study for many reasons, especially for children and adults with autism that cannot speak. Causes and triggers of aggression are difficult for any child to understand and describe (autism or not).
So when can aggression be caused by food and/or improved by dietary choices?
Pain (often gastrointestinal) can cause people to injure themselves or others. We know this because parents and doctors report that when serious GI disorders are addressed, aggression has been known to disappear. Supporting the gut with a special diet can be very beneficial.
Additionally, an imbalance of neurotransmitters or hormones can cause aggression, this can be caused by many things including puberty or microbial pathogens but can also be caused by food reactions, or nutrient deficiencies.
Potential causes of aggression we’ll cover in depth include:
- Gluten, dairy, soy and food allergies
- Phenols and salicylates
- Amines and glutamate
- Nutrient deficiencies
Certainly, aggression can happen from the frustration or anger associated with a child being denied food. For the purpose of this article though, we will focus on foods that can trigger/cause aggression from consumption.
Gluten, Dairy and Food Allergens
There is much support for the notion that gluten and dairy can lead to aggression – including published articles and case studies, and a myriad of online anecdotes.
Gluten and dairy can cause aggression in several ways. While not all of the mechanisms have been identified as yet, I do have some theories. If you are eating these foods and your body is creating opiates, opiates themselves can cause mood changes. Additionally, opiates peak and drop, these “withdrawals” from these opiate-compounds can cause irritability and aggression. Also, pain from these foods could cause aggression. Regardless of the underlying mechanism in each case, aggression can improve with a gluten-free, dairy-free, soy-free diet.
Other food allergens can also cause aggression. Doris Rapp, M.D., explains in her book, Is this Your Child, how aggression can be a symptom of food allergy and describes a variety of child case studies where a food allergen (specific to that individual) caused aggressive behavior (1). It could be wheat, dairy, corn, soy, oranges, or other foods. In these cases, they are associated with allergy or intolerance in the individual.
A gluten-free, casein-free (dairy-free), soy-free, and allergen-free diet (specific to the individual’s BioIndividual Nutrition needs) is often a great place to start with dietary changes.
Have you been to a toddler’s birthday party and watch (almost in unison) as the kids come down from the “sugar high” and the crying ensues? When they consume excess sugar, one result is poor behavior, mood changes, and yes, even aggression!
Maybe you have experienced this yourself, indulging in a sugary treat only to become short tempered or irritable after. Our children (especially those who are nonverbal and cannot explain what they are feeling) can react even more drastically.
Sugar itself can cause aggression. Research shows that high sugar intake and high fructose corn syrup increases the risk of aggression, as well as ADHD (2).
Also, the after effects of sugar can cause low blood sugar levels which have also been shown to cause aggression. (3)
So sugar can cause aggression by two mechanisms, the sugar itself and the aftermath of the low blood sugar levels it can cause.
Reducing refined sugars can be a simple way to support stable blood sugar and mood. I have many resources on my site related to lower-sugar treat options and even recipes with lower sugar or using alternative sweeteners like dates, stevia, or honey.
Phenols and Salicylates
In my one-on-one nutrition practice, I’ve found that phenols, salicylates, and amines are the foods that are (by far) the greatest instigators of aggressive behavior.
Artificial food additives such as artificial colors, flavors, and preservatives are phenol compounds that can trigger irritability, sleeping problems, ADHD, hyperactivity and aggression. Food additives are a well-known cause of aggression—Dr. Ben Feingold and others have been studying this and publishing papers for decades. Dr. Feingold stated in his paper, “Dietary Management of Juvenile Delinquency” that he had 60-70% success with an additive-free diet “for control of behavior.”
In addition to “artificial phenols” there are “natural phenols” in the form called salicylates. Salicylates have a phenolic structure, or aromatic chemical ring, that occur naturally in fruits, vegetables, nuts, herbs and spices, and other plant foods. These foods are rich in wonderful nutrients, but if your body has trouble “detoxifying” the salicylates, they can be a big problem for a child causing significant aggression, hyperactivity, and many other symptoms.
High Salicylate Foods
- Tomato sauce and ketchup
- Herbs and Spices: Cinnamon, cumin, turmeric, rosemary and more
One of my client’s children, a boy 10 years old, had daily aggression toward his family and therapists. It would happen dozens of times per day, seemingly out of the blue. People were getting hurt and it was a scary situation for everyone involved. I suspected salicylates as the culprit, and after a dietary trial removing them, his aggression virtually disappeared—it went from 50 times per day to one time a month (and likely that was an accidental exposure)!
Amines and Glutamates
Amines are a different natural food chemical that is processed by the same detoxification pathway, and therefore, often create similar reactions, and people with salicylate sensitivity are more likely to have amine or glutamate intolerance. Amines and glutamates are found in fermented foods including sauerkraut and yogurt, salami, smoked meats and fish, bacon, canned fish, and broths. Sometimes I find it is amines, not salicylates, that is the main culprit.
Glutamate, also comes in the additive-form of MSG (monosodium glutamate). One client I worked with was a teenager—he was very aggressive and only wanted to eat certain things. When I looked to see what they all had in common, it was MSG as an ingredient. For him, removing both MSG and a food sensitivity made a huge improvement and his aggression diminished dramatically.
For children with aggression, I always explore the possible role of salicylates, amines, and glutamates for causing or contributing to the reaction, as I have seen many times in my practice that removing these foods reduces aggression for those that don’t tolerate them.
Before we wrap up this conversation about food and aggression, let’s discuss how not only food reactions can cause aggression, but nutrient deficiencies as well.
Nutrients are important for building neurotransmitters, as well as hundreds, if not, thousands of functions in the body and brain. And certain deficiencies have been associated with aggression.
Serotonin is the feel good brain chemical that when in low supply not only can cause depression but aggression as well. The amino acid tryptophan converts to serotonin, and low levels of tryptophan are associated with aggression in rat-mouse studies (4).
Also, vitamin B6, zinc, magnesium, and iron are all important for the production of serotonin – and all of these vitamins and minerals have been showing in studies to cause aggression when low.
Lithium is another important mineral. A well known study showed how areas with little to no lithium in their drinking water had significantly higher rates of violent crime than those with more adequate levels. (5) contains lithium (in low doses) is beneficial. And I’ve heard Dr. James Greenblatt speak on the benefits of low dose lithium at the Integrative Medicine for Mental Health conference and the benefits are quite amazing. (6)
There are more nutrients as well that can be helpful with aggression such as vitamins B1, B3, B5, niacin, and vitamin C.
A healthy nutrient dense diet and a multivitamin/mineral formula can help supply the nutrients we need for many everyday functions, including more stable mood.
World of Difference
Aggression can have so many various causes, and food is not the cause for everyone. However, what is clear is that if foods are triggering aggression for a child, removal of those foods can make a world of difference in decreasing aggression, and huge improvements in the quality of everyone’s life.
For more on common reactions and symptoms from these foods, when and how to implement these special diets, lists of foods containing salicylates, amines, and glutamates, and how to create a personalized nutrition plan for your child, check out my nutrition program for parents, Nourishing Hope for Healing Kids.