Food Allergy or Food Intolerance?

Food sensitivity is an umbrella term for food intolerance, food allergy and other adverse reactions to food. Food allergies and food intolerances manifest themselves differently in different people; they may cause a skin rash or hives, a headache, a queasy stomach or trouble breathing. It is important to find out which foods are causing the reaction because in some people, eating even a small amount of the allergy inducing food can cause a life-threatening reaction.

The Difference Between a Food Allergy and Food Intolerance

Though they can cause the same symptoms, food allergies and food intolerance are different in their causes and how the body produces the reactions. A food allergy causes a sensitivity immune system response and tends to produce sudden, acute symptoms; a food intolerance may also be caused by a lack of enzymes the body requires to digest a certain food, which often leads to chronic symptoms.

While it is possible to be allergic or intolerant of any food, the most common foods that are known to account for 90 percent of all food reactions are:

• Milk and dairy products
• Eggs
• Wheat and other gluten containing products
• Peanuts
• Tree Nuts, such as walnuts and cashews
• Fish
• Shellfish
• Soy

Other trigger foods include tomatoes, corn, caffeine, spinach, strawberries, raspberries, oranges and other citrus fruits and mangoes.

Food Allergies

Food allergies occur when the body’s immune system determines that a food is ‘harmful’ and reacts to it by creating IgE (immunoglobin E) antibodies which mark and signal 'dangerous' substances in the body. When the same food is again ingested, these antibodies signal the immune system to release large amounts of chemicals, including histamine, which trigger a cascade of allergic reactions.

These autoimmune symptoms including asthma, skin rashes, itchiness, irritability, mood swings, puffiness around the eyes or elsewhere in the body, headaches, joint pain and heart palpitations. These heightened symptoms generally occur within minutes after eating the food. For some people, even touching foods they are allergic to can induce symptoms.

What is an Anaphylactic Reaction?

Food allergies can produce severe symptoms. The most severe type is an anaphylactic reaction. This potentially life-threatening reaction can occur within minutes after eating a food that causes a reaction, and effects several body systems. Symptoms may include hives, difficulty breathing, swelling of the tongue, mouth, lips or face and a loss of consciousness. Immediate medical attention is needed. Common foods that can cause anaphylaxis in individuals that are allergic to them are peanuts, nuts, eggs, and shellfish.

Food Intolerance

Food intolerance may not involve the immune system but it does produce similar symptoms, though it often has a delayed reaction with symptoms occurring hours to days after ingesting the culprit food. Many causes of food intolerance are caused by a lack of one or more digestive enzymes. This deficiency impairs the body’s ability to break down certain proteins in food, leading to ineffective digestion. For example, a person with lactose (the sugar found in milk) intolerance cannot produce any or enough of an enzyme called lactase that is needed to properly digest the milk sugar. Food intolerance can cause symptoms including gas, bloating, abdominal cramps and pain. Since symptoms often occur hours to days later, they can be difficult to link to the particular food.

Leading causes of food intolerance include lactose, sulfites, artificial colors, food additives such as monosodium glutamate (MSG, commonly used in Asian inspired cuisine) and histamines compounds in fermented foods such as cheese, sauerkraut, alcohol and vinegar. Other triggers include tyramine, an amino acid found in aged cheeses, yeast extract, alcohol, raspberries and bananas) and food preservatives like benzoic acid and sodium benzoate.