Kids can have reactions to food for many different reasons. They can be allergic, sensitive, intolerant, or have problems because the food contains poisons or has drug effects.

Food allergies are caused by a child’s immune system reacting to a food, similar to the way they can react to pollen or bug bites. Allergic reactions are usually to the protein in the food rather than the sugar or fat, and are usually immediate. The most common severe reactions are to tree nuts, peanuts, and shellfish. Less severe reactions are most common with cow’s milk, eggs, soy, wheat, and fish.

Celiac disease is in this category. People with celiac are allergic to the gluten protein in wheat and react with their immune system if they are exposed to even a tiny amount. Gluten allergy was worth a whole blog all by itself: A Gluten Free Blog.

80-90% of the time, kids will outgrow allergies to eggs, wheat, milk, and soy by 5 years of age. They outgrow peanut allergies only 20% of the time. (Do NOT experiment with this!) Fewer will outgrow allergies to tree nuts and seafood.

Symptoms of an allergic reaction include:

• Skin rashes. Hives, or whelps–itchy raised patches with pale centers and red rims. Hives move around, fading in one area to reappear in another. Antihistamines like Benadryl (diphenhydramine) help the symptoms.
• Breathing problems. Food reactions can make kids wheeze, make their throats feel tight, and give them sneezing fits.
• Gastrointestinal symptoms like nausea, vomiting, and  diarrhea.
• Circulatory symptoms like paleness, lightheadedness, and loss of consciousness.
• Severe reactions can involve several of these areas, and are called anaphylaxis.

Food sensitivities and intolerances are not allergies. Some children can be sensitive to the common effects of a food and react strongly. For example:

• Apples, pears and bananas contain pectin and can be constipating (useful if your child has diarrhea). Some children can get stopped up if they eat too many.
• Dairy products can also constipate–some kids will never poop again if they eat a lot of cheese. (This may be a slight exaggeration.)
• Sugar can cause diarrhea, so children may have problems if they drink a lot of juice. (Interestingly, we have never been able to prove that sugar makes kids hyper.)
• Kids can react to dyes and preservatives in foods–they will feel nauseated or tired, and we have proven that red dye can make them hyper.
• Lactose intolerance is an reaction to the sugar in milk. People who are lactose intolerant are missing the enzyme (lactase) that breaks down the sugar in milk (lactose). They get bloating, gas, and diarrhea.

There are certainly plants that contain toxins (poisons) in themselves–poisonous mushrooms, apple seeds, and belladonna are examples–but most poisonings are accidental, usually from foods that have spoiled:

• C. Botulinium bacteria grows in improperly canned food and in cans that have rusted through.When we used to give Karo syrup for constipation, the bacteria would grow in Karo left on a cupboard shelf and children would die, paralyzed by the neurotoxin (nerve poison) that the bacteria produced.
• Staph Aureus can grow in spoiled food and produce a toxin that is usually self limited in its effect, giving kids cramping, diarrhea, and vomiting.
• Clostridium perfringens produces a similar toxin, and is frequently the villain in cafeteria incidents and contaminations in soil and sewage.
• Salmonella can grow in spoiled meat, eggs, and milk and give your child diarrhea, vomiting and fever.
• E. coli is more likely to grow in beef, but can be found in mishandled produce. Same unpleasant symptoms.
• Shigella is common in daycare outbreaks. It causes the same nausea, vomiting, diarrhea, and fever, but has the added risk of seizures from the toxin it produces.

Foods can also have drug effects. The best examples of this are drinks (coffee, tea, energy drinks) and food (chocolate) that contain caffeine. Caffeine makes kids restless, shaky, and interferes with their sleep. In large doses, as with energy drinks, it can produce a rapid heartbeat, muscle tremors and seizures. There were 20,783 emergency room visits from energy drinks in 2011; 5 people died after consuming them. The youngest was a 14 year old girl.

Foods can also be irritants. For example, babies can get rashes around their mouths or diaper rashes from acidic foods.

People do not react to a food solely because it is a GMO (genetically modified organism)–GMOs are not something you need to avoid unless you have a reaction to the particular item. GMO wheat produces the same allergens as non-GMO wheat; if you are allergic to one, you will be allergic to the other. Also the subject of an entire blog: What’s the Deal with GMOs?

In conclusion, not every food reaction is a food allergy. Avoidance or treatment of the food reaction varies with the actual cause. If a child has an anaphylactic allergic reaction to peanuts, he or she never needs to be around peanuts again. They may outgrow other allergies. If they get gassy from a lactose intolerance, they can take lactase tablets when they eat dairy. Kids who become constipated with apples or cheese need to limit the number they eat. It is always important for every child to not be fed spoiled food or energy drinks.

Knowing in what way your child reacted to a food determines what you do about it in the future. Knowledge rules.