Food allergy is common in infant and young children. It can be frustrating for parents – colicky infants, vomiting and not tolerating formula or sometimes even breast milk. And for the child, the impact is even more so – failure to thrive is common, which may lead to developmental delay as poor nutrient intake or tolerance impairs achievement of developmental milestones. Thus, it is important for parents and pediatrician to diagnose food allergy in a timely manner to avoid long-term detrimental outcomes.
The good news is most of these allergies in young children will resolve by 4-5 years of age. However, before that happens, the child has to stay clear of the offending allergic foods as each accidental exposure to the offending will strengthen the immune reaction. Thus, the more a child is exposure to the offending before his outgrowing of the allergy, the immune response becomes stronger and stronger, which means it will take longer for the child to outgrow the allergy.
Children with ADHD frequently have hidden food allergy or intolerance. The reason why I use the word “hidden” is because these allergies or intolerances are difficult to identify. Most of the time we don’t even know they exist because when we think of food allergy we are thinking of the very obvious ones, like some who is allergy to seafood, and ate something with shrimp, and within minutes reacted with full body hives, facial swelling, itching mouth and throat, etc.
However, these are not what we’re seeing in children with ADHD or even autism. Their reactions are a lot more subtle and slow. In fact, the food reactions we frequently suspect in children with ADHD or autism are Food Intolerance. Food intolerance and food allergy shares many similar signs and symptoms, such as diarrhea, vomiting, runny nose, nasal congestions, hives, rash, etc. However, they are very different physiologically.
WHAT IS THE DIFFERENCE BETWEEN FOOD ALLERGY AND FOOD INTOLERANCE?
We frequently refer to any food reaction as food allergy. However, most of these reactions are food intolerances instead of allergies. Food reactions are common, but most are caused by a food intolerance rather than a food allergy. Food allergy and food intolerance share very similar signs and symptoms, which is why many people are confused between the two.
Food allergy triggers an immediate immune response, usually involving the immunoglobulin E (IgE). IgE-mediated response activates a cascade of systemic reactions, involving multiple organ systems. That is why this is the more severe form food intolerance. Fatal peanut allergy usually falls into this category. Even a tiny amount of the offending food can cause an immediate, severe reaction or anaphylactic shock, which is a life-threatening allergic reaction.
An anaphylaxis is characterized by systemic responses, such as difficulty breathing due to swelling of airway, hives along with itching, flushed or pale skin, weak and rapid pulse, dangerously low blood pressure, nausea/vomiting or diarrhea, dizziness or fainting.
An anaphylactic event requires emergent medical treatment, and delay of treatment may result in death. People with severe food allergies are usually prescribed and “epi” epinephrine pen that they carry around in case they consume or come in contact with their allergen by accident.
With a true allergy, the offending food needs to be avoided completely, especially in young children. Food allergies are common in the first years of life. With every repeated exposure to the offending food, the immune system becomes better in attacking that allergen, which means the response will become more and more intense each time the body is expose to the allergen. Children usually outgrow their allergies by 4 or 5 years of age. However, repeat exposure may prevent or delay the time to outgrow the allergy.
Food intolerance, on the other hand, usually does not involve the immune system, and reaction also comes on a lot slower – usually after two hours of ingestion of food, and up to 48 hours – and more subtle presentation. The individual usually is able to tolerate a small amount of the offending foods without much adverse effect.
Symptoms of food intolerance are generally less serious, less obvious and appear very subtly and slowly. That’s why that trouble food is seldom identified. Some common signs and symptoms include nausea, vomiting, abdominal cramps, constipation, diarrhea, asthma, eczema (atopic dermatitis), etc. Food intolerances may also result in behavioral symptoms frequently seen in ADHD and autism.
Causes of Food Intolerance
There are many causes of food intolerance or food allergy. There may be a lack of enzymes to fully and efficiently digest a nutrient, as in lactose intolerance, where the body does not produce enough lactase (enzyme that breaks down lactose into glucose and galactose). People frequent thought they are allergy to milk. If you are allergy to milk, you cannot have any diary product at all – milk, cheese, yogurt, and anything made with or contains dairy ingredient. If you are lactose intolerant, on the other hand, you can tolerate small amount of milk with your morning cereal or coffee, enjoy yogurt, cheese, or ice cream without problem. But you cannot tolerate drinking a lot of milk by itself.
Your child may be sensitive to food additives, such as preservatives, food coloring, etc, which is basis of the Feingold diet, introduced by Dr. Benjamin Feingold in 1975 to treat children with ADHD. Autoimmune conditions, such as Celiac disease, may trigger adverse reaction to foods.
Milk protein allergy, common in infants and young children, may cause projectile vomiting, constipation, blood in stool and failure to thrive in young children.
FOOD ALLERGY VS FOOD INTOLERANCE
Food Allergy (IgE) – Immediate Response
1. Usually only allergic to one to two offending foods.
2. Only trace amounts of offending food is enough to trigger an immediate intense allergic reaction.
3. Allergic reactions usually appear within minutes up to two hours of ingesting offending foods.
4. Primarily affects multiple systems, such as the skin (hives, rashes, and eczema), respiratory (asthma, throat swelling, and runny nose) and digestive tract (vomiting, diarrhea or constipation).
5. More common in children, rare in adults. But we’re seeing more adults developing new allergies as they age.
6. Children tend to avoid these foods on their own. Addictive cravings and withdrawal symptoms are rare.
7. Offending food is self-diagnosed due to the immediate appearance of allergic reactions.
8. A few food allergy may not be outgrown, especially peanut allergy, which is the more fatal allergy.
Food Intolerance (IgG) – Delayed Response
1. More food may be involved.
2. Accumulation of the offending foods over a period of time to trigger a reaction.
3. Reaction usually appears at least two hours after ingesting offending food, and up to 24-48 hours
4. The tissue organ affected depends on the cause of food intolerance.
5. Very common in both young children and adults.
6. Addictive craving and withdrawal symptoms are common.
7. The offending food is difficult to identify due to involvement of multiple foods and delayed onset of symptoms.
8. Allergic foods are frequently favorite eaten foods in larger amounts, such as milk and wheat.
9. The food intolerance may be resolved after three to six months of complete elimination.
FOOD ALLERGY AND CHILDREN WITH ADHD
So now we know your child most likely have food intolerance and not food allergy. This explains why the food allergy test usually comes back clean. The allergy tests that your pediatrician use – RadioAllergoSorbent Testing (RAST) and skin prick – only identify allergic reaction caused by the immunoglobulin E (IgE). Remember, the reactions we see in food intolerance do not involve the immune system, thus, RAST and skin prick will pick up nothing.
The focus of food allergy has always been on the physical manifestations. We frequently forget about that fact that the intestine is our biggest immune organ, blocking all kinds of foreign substances from entering our body. However, when our body is reacting to certain foods or chemicals in the foods we eat, and is showing associated GI symptoms, that means the GI tract is being attack. Chronic exposures to these insults may weaken the gut barrier that is supposed to be selective. Over time, this lead to leaky gut, where the intestine being so permeable and porous that it is allowed more foreign substances and semi-digested protein to enter the blood steam.
This feeds into a vicious cycle of offending food irritating the intestinal wall, the intestinal become porous and allowing undigested food particles (from poor digestion) into the blood stream, triggering allergic reaction. Along with all these, the undigested food, especially carbohydrates, creates an ideal environment for the yeast and bad bacterial to thrive, making the intestinal more susceptible to insults.
The best we have is observation and keeping a food and behavior log. Sometimes you maybe able to pinpoint a few food that your child reacts to. Some parents would swear that every time their child eats or drinks anything with red coloring, will act up after. You’ll probably notice when your child’s eczema worsens with eating dairy products. Or your child starts acting silly and not able to focus after eating a lot of wheat product.
There is another interesting point to make – many children with ADHD or autism, crave foods that they are intolerant to, such as dairy and gluten. They are the ones who are usually big milk drinker and eats mainly bread and crackers, and love mac n’ cheese.