In recent years, Pediatrician William Sears has seen many more cases of asthma and eczema in his San Clemente, California, office. Dairy and wheat remain the biggest culprits, but experts believe new factors may be contributing to the rise in food sensitivities, including synthetic additives like partially hydrogenated oils, artificial colors and flavors and sweeteners, plus genetically modified ingredients.

Often undiagnosed and untreated, food intolerances can cause long-term tissue damage, warns Sears, author of The NDD Book, which addresses what he calls nutrient deficit disorder without resorting to drugs. Increasingly, kids are developing formerly adult-onset diseases, such as Type 2 diabetes, obesity, depression, cardiovascular disease and acid reflux, he says.

If it seems that a child is having a dietary reaction, first look for clues. “A lot of parents already suspect the answer,” says Kelly Dorfman, a licensed nutritionist dietitian and author of What’s Eating Your Child? Become a “nutrition detective”, she suggests. Here’s how to assess conditions and find solutions.

Spitting Up

Suspects: Intolerance to casein—a protein prevalent in dairy cow milk different from its form in breast milk that can get into mothers’ milk or formula—tends to irritate an infant’s gut lining, causing gastroesophageal reflux disease (GERD) and then chronic ear infections or constipation, says Dorfman.

Action: Remove dairy from the baby’s and nursing mom’s diet for at least a week. For formula feeding, choose a brand made with predigested casein or whey. To heal baby’s damaged intestinal lining, give 10 billion CFU (colony forming units) daily of probiotic bacteria, mixed in a bottle or sprinkled on food.

Chronic Diarrhea

Suspects: Intolerance to gluten (a protein in wheat and other grains) or lactose (dairy sugar). Diarrhea, the gastrointestinal tract’s way of eliminating problematic substances, plus gas and bloating, often accompany these intolerances. Lactose intolerance is usually a root cause and is present in nearly everyone that’s gluten intolerant, Dorfman says.

Action: Get a blood test to check for celiac disease, then eliminate gluten for at least a month. Although the diarrhea could end within a week, “You need a few weeks to see a trend,” counsels Dorfman. Consume fermented dairy products like cheese and yogurt, which have low lactose levels; cream dairy products may also test OK.

Chronic Ear Infections

Suspects: Dairy intolerance and for many, soy sensitivity. Some research has shown that 90 percent of kids with recurring ear infections or ear fluid have food reactions, corroborated by Dorfman’s patients.

Action: Quit dairy and soy for several months to verify a correlation. Dorfman recommends eliminating soy milk, soy yogurt and tofu, adding that ultrasensitive individuals may need to avoid processed foods that contain soy byproducts.

Itchy Skin

Suspects: Reaction to gluten, casein (in dairy products) and eggs plus oranges, grapefruit, tangerines, lemons, strawberries and pineapple.

Action: Because itchiness can suggest a histamine response, ask an allergist for an IgE radioallergosorbent (RAST) blood test to detect food sensitivities.

Hyperactivity

Suspects: Sensitivity to artificial colors or sugar. According to Sears, children’s underdeveloped blood-brain barrier increases vulnerability to the neurotoxic effects of chemical food additives, including artificial colors and monosodium glutamate (MSG).

Action: When possible, buy organic foods certified to contain no artificial colors. Otherwise, scrutinize food labels for the nine petroleum-based synthetic dyes in U.S. foods: Blue 1 and 2, Citrus Red 2, Green 3, Orange B, Red 3 and 40, Yellow 5 and 6. Avoid ingredients like high-fructose corn syrup, sucrose, glucose, fructose, cane sugar and syrup—all added sugars.

Crankiness

Suspects: Gluten sensitivity is traditionally associated exclusively with digestive disturbances, but some recent studies have linked it to neurological symptoms, from moodiness and chronic headaches to ADHD and coordination loss.

Action: Eliminate gluten for a month to assess a potential connection between mood and food, possibly signaled by excessive eating of a certain food.

Stunted Growth

Suspects: Gluten sensitivity or zinc deficiency. Because gluten intolerance interferes with nutrient absorption, suffering kids often fail to thrive. “Small size—height or weight—is a classic symptom of celiac disease,” Dorfman advises.

Zinc could be another factor; it normalizes appetite and through its relationship with growth hormones, helps the body develop. If levels are too low, growth will be abnormally stunted. In such cases, a child may rarely be hungry, be a picky eater or complain that food smells or tastes funny, Dorfman says.

Action: Eliminate gluten consumption for a month. A blood test by a pediatrician can determine serum zinc levels, or buy a zinc sulfate taste test online. After sipping a zinc sulfate solution, the child will report either tasting nothing (indicating deficiency) or a bad flavor (no deficiency). Zinc-rich foods include beef, chicken, beans, pumpkin seeds, cashews and chickpeas. To counter a deficiency, ask a family healthcare provider for an age-appropriate supplement dose.

Pamela Bond is the managing editor of Natural Foods Merchandiser.