Food allergies occur when the immune system produces IgE antibodies against specific foods causing allergic reactions that range from a mild rash to anaphylaxis and death. Reactions can occur minutes to hours after breathing, touching or eating the allergenic food. Signs and symptoms can involve the skin, respiratory, gastrointestinal, and cardiovascular systems. Food sensitivities differ from food allergies in that the body produces IgG or IgA antibodies against specific foods which manifests as sub-acute or chronic symptoms that generally affect the skin or gastrointestinal tract. Food intolerances are not mediated by the immune system and can occur due to chemicals found in the food, an inability to absorb nutrients or lack of certain enzymes to digest food.
Food allergies are more prevalent in children than adults, but there is an increasing rate of new onset allergies in adults. Childhood food allergies tend to wane or resolve over the years but may persist into adulthood. From 1997 to 2007, the prevalence of food allergies increased 18% for children under the age of 18, with 3 million children reporting some type of allergy. Eight foods accounted for 90% of food allergies: milk, eggs, peanuts, tree nuts, fish, shellfish, soy, and wheat.1
Symptoms vary among each person. Mild symptoms of food allergies include:
Severe symptoms that are known as anaphylaxis include:
The main contributor to food allergies is a poor diet that results in increased intestinal permeability. The development and production of the immune protecting interstitial lymphocytes is dependent on phytonutrients in green vegetables and other natural plant foods. Without exposure to colorful plant compounds, particularly greens, during pregnancy and in the mother’s diet during breast feeding, as well as in early life, decreased digestive track immunity and integrity is likely. With increased intestinal permeability, consumed protein fragments (called peptides) are absorbed and recognized as foreign by the immune system. This results in antibody formation against that specific food. Every time the food is consumed in the future, more antibodies are produced, manifesting in various symptoms. Consumption of a low-nutrient, high-inflammatory diet damages the gut lining further and increases the risk of food allergies. Lack of exclusive breastfeeding until the age of 6 months and not breastfeeding long enough increases the risk of food allergies. Breastfeeding decreases intestinal permeability and colonizes the infant's gut with beneficial, immune-regulating probiotics.2 Medications that decrease stomach acid production also increase the risk of developing food allergies as these prevent the complete digestion of proteins, leaving behind an intact form that is more allergenic. Vitamin D and omega-3 fatty acid deficiencies affect the immune system and may contribute to food allergies.
The following are sample questions from the Ask the Doctor Community Platinum and higher members can post their health questions directly to Dr. Fuhrman. (All members can browse questions and answers.)
What causes an adult to become allergic to foods mid-life? Within this past year, I have developed food allergies to oats, peaches, cantaloupe, turnips, walnuts, cashews, and eggs. I used to be able to eat these foods without a problem, but now I can no longer eat them. They cause my eyelids to swell. What causes this, and is there anything I can do/take?
My procedure is to get the immune system back to normal, check for fatty acid imbalances and Vitamin D deficiency, supplement appropriately (with borage oil and DHA/EPA Purity), and institute excellent nutrition. After a while, usually more than a year, the allergies can lessen if you build up your immune system with lots of raw greens and other G-BOMBS (Greens, beans, onions, mushrooms, berries, and seeds). Once a year goes by, you could also do oral challenges with a microscopic amount of the food in question, and then increase the amount very gradually to build up tolerance.
My son was recently retested for allergies. He has tested positive for hazelnut, peanut, sesame seed, macadamia, and chestnut allergies. He eats almonds, Brazil nuts, and cashews regularly. I have been extremely diligent about feeding him a Nutritarian diet. We provide very little dairy and animal products. He eats some grains, mostly oatmeal and Ezekiel sprouted grain bread. Could these results be false (or falsely elevated)? Does exposure to allergens increase the allergic response in the body? Can he outgrow this with excellent nutrition? Should I try to avoid trace exposures (i.e. produced in a factory that processes tree nuts)? What about wheat? Should I completely restrict dairy (he has the occasional ice cream and may have a food with dairy in it on special occasions)?
The allergy (IgE/RAST) tests give a guide, but are not foolproof. IgG and other food intolerance testing is more inaccurate, and the findings are inconsequential in most cases. Lots of cross-reactions occur, and some 1-2 results may be false positive. If no reaction occurs with eating those foods, it is neither healthier to avoid them, nor harmful if they are eaten. His allergies could still improve in the years ahead as he matures, however, it sounds like he does not have a history of severe reactions to specific foods. It seems that allergy testing was not needed and should not influence his food choices. You should test those foods that he may be sensitive too and that the tests indicate are of concern, but if he tolerates them well without experiencing any symptoms, there is no reason for you to avoid them. Plus, exposure to small amounts of mildly allergic foods may actually aid his recovery and help build tolerance to those foods. I also don’t think the occasional dairy or wheat on special occasions will be significant, unless it is determined to be celiac, allergic or wheat intolerant. If he is already consuming the Ezekiel bread without difficulty it sounds like none of these problems exist.
My one-year-old hasn’t tried any nuts, and I am scared to give them to him. At his 12-month check-up, our doctor told us to avoid all nuts and almond milk until two years old.
Avoiding nuts until age two increases, not decreases, the risk of developing allergies. There is no reason to avoid seeds and nuts, and avoiding them will decrease the health of your child. In fact, eating a variety of foods including seeds and nuts while breast milk is still coming in and the mom is eating the same foods offers the best protection against developing allergies.