Food Sensitivity
What is Food Sensitivity?
Food sensitivity includes many different types of sensitivities to food which may arise for a wide variety of reasons making it a complex, oftentimes confusing and not easily defined as an aread of stufy. Diagnosis can also be difficult because symptoms may be delayed for up to two days after a food has been consumed.
In general, food sensitivities are the result of toxic responses to food and are divided into two categories:
- Allergic Responses (Food Allergies)
- Food Intolerances
Food Allergies Involve the Immune System
Food allergies are defined as toxic clinical reactions to food or food additives that involve the immune system. The immune system is a complex system whose cells and molecules are found throughout your body to protect it from potentially harmful foreign molecules. It is most active in the areas of the body which have some direct contact with the outside world such as the skin, lungs, nose and gastrointestinal tract. The majority of potentially harmful molecules enter your body through your intestinal tract therefore, it is not surprising that over 60% of immune activity occurs in this area. The immune system is made up of a team of different types of cells that, while each having their own specific function, work together to protect the body from foreign invaders: B-cells produce antibodies; T-cells conduct surveillance for potentially dangerous molecules and kills dangerous cells such as disease-causing bacteria; and macrophages are the scavenger cells of your body acting like garbage trucks, cleaning up residue and removing potentially dangerous substances.
A surveillance team of cells determines whether newly introduced molecules pose a threat to your system. New molecules are constantly being introduced into the intestinal tract by the food that we eat. An allergic reaction occurs when your body identifies molecules as potentially harmful and toxic; these molecules are called antigens. The surveillance cells bind to the antigens activating the immune cells to release histamine and other chemicals which then signals the scavenger macrophages to come to the site and destroy them. Allergic reactions involving excessive histamine release can cause anaphylactic reactions (difficulty in breathing) which are responsible for 29,000 people in the United States ending up in the emergency ward each year. When the surveillance immune cells bind to an antigen and send out chemical messengers, they also communicate to other immune cells, the B-cells, which are instructed to make antibodies to the antigen
Antibodies are long, branched molecules that have places for recognition and binding (attachment) of the antigen on one side, and a site on the other end that can call into action other immune responses.
An antibody will only bind one specific antigen and nothing else. When the antibody binds, or sticks, to the dangerous molecule it is acts like a red flag identifying the molecule as something potentially damaging that should be removed. Your macrophage cells are often called the scavenger cells of the immune system and are specifically designed to remove damaging molecules from the body. After the antibody binds to a dangerous molecule the macrophages consume the molecule, taking it out of circulation and destroying it.
Symptoms of Food Allergies
The most common symptoms for food allergies include vomiting, diarrhea, blood in stools, eczema, hives, skin rashes, wheezing and a runny nose. Symptoms can vary depending upon a number of variables including age, the type of allergen (antigen), and the amount of food consumed. It may be difficult to associate the symptoms of an allergic reaction to a particular food because the response time can be highly variable. For example, an allergic response to eating fish will usually occur within minutes after consumption in the form of a rash, hives or asthma or a combination of these symptoms. However, the symptoms of an allergic reaction to cow’s milk may be delayed for 24 to 48 hours after consuming the milk; these symptoms may also be low-grade and last for several days. If this does not make diagnosis difficult enough, reactions to foods made from cow’s milk may also vary depending on how it was produced and the portion of the milk to which you are allergic. Delayed allergic reactions to foods are difficult to identify without eliminating the food from your diet for at least several weeks and slowly reintroducing it while taking note of any physical, emotional or mental changes as it is being reintroduced.
Foods That Cause Allergic Reactions
Over 140 different foods have been identified as causes of allergic reactions. According to a recent report by the U.S. Centers for Disease Control, 90% of food allergies are associated with 8 food types:
- Cow’s milk
- Hen’s eggs
- Peanuts
- Soy foods
- Wheat
- Fish
- Crustacean shellfish (such shrimp, prawns, lobster, and crab)
- Tree nuts (such as almonds, cashews, walnuts, pecans, pistachios, Brazil nuts, hazelnuts, and chestnuts)
Cow’s milk is one of the first foods to consider eliminating from your diet when attempting to determine the foods to which you may be allergic. It contains over 25 different molecules which have been identified by scientists as having the potential to elicit an allergic food response. One of the most common allergens in cow’s milk is a protein called casein which is used in many products and is even found in soy based foods to boost their protein content. If you suspect an allergy to cow’s milk you should also avoid other products made from or containing milk including cream, creamy sauces, ice cream and milk chocolate.
How a food has been prepared, processed, handled and stored can also have an effect on whether a food will cause an allergic reaction. For example, some molecules responsible for allergic reactions can be destroyed by heat. Individuals with allergies to cow�s milk have reported that drinking heated milk does not cause the symptoms associated with their milk allergies suggesting that the molecules that are toxic to these individuals have been destroyed by the heating process. However, the molecules in peanuts that can cause highly toxic responses in people allergic to peanuts are known to be very stable and unaffected by even long periods of heating.
Food Intolerance Does Not Involve the Immune System
The majority of toxic responses to food is a result of food intolerance rather than food allergy. A food intolerance response is defined as any reproducible, toxic response to food that does not involve the immune system. Food intolerance responses can occur for many different reasons. A food can contain a molecule that your body has difficulty breaking down or digesting causing an intolerance response as that molecule is allowed to continue down your intestinal tract. Lactose intolerance is an example of this type of toxic food response. Food intolerances can also be caused by food additives such as sulfites which are added to processed foods to extend their shelf life.
Government agencies often include food poisoning as a food intolerance, but in this case, the part of food that is reacted to is not a deliberately added component during processing, but a naturally occurring toxin or an unintentionally added toxin (like the mercury in mercury-contaminated oceans that can end up in tuna), so an adverse reaction to this food would not be expected to occur every time you ate that particular type food. For this reason, most research scientists do not consider food poisoning to be a true food intolerance.
There are many types of food intolerances. The most common are intolerances to:
- Lactose
- Tyrosine
- Preservatives and Additives
- Gluten