It is very common nowadays that people feel discomfort eating a specific food. Artificial sugar, food thickeners, dairy substitutes can make our bodies feel very uncomfortable in the most inappropriate situations. What is this? If it is just a quality of food we have now or the body reaction to specific food components? In the following article, I will try to explain the difference between food allergy and food intolerance.
Digestive System vs Immune System
Food allergy and food intolerance are commonly confused, as symptoms of food intolerance occasionally resemble those of food allergy. However, food intolerance does not involve the immune system and does not cause severe allergic reactions, known as anaphylaxis. Food intolerance also does not show on allergy testing.
Food intolerance can be a difficult concept to understand and even doctors can´t understand it well. Sometimes, substances within foods can increase the frequency and severity of migraine headaches, rashes (such as hives) or the stomach upset of irritable bowel.
Food allergy is described as an increasing disease over time. It is generally accepted that food allergy affects approximately 2.5% of the general population, but the spread of prevalence data is wide, ranging from 1% to 10%.
A food allergic reaction involves the immune system. Your immune system controls how your body defends itself. For instance, if you have an allergy to cow’s milk, your immune system identifies cow’s milk as an invader or allergen. Your immune system overreacts by producing antibodies called Immunoglobulin E (IgE). These antibodies travel to cells that release chemicals, causing an allergic reaction. Each type of IgE has a specific “radar” for each type of allergen.
A food intolerance response takes place in the digestive system. It occurs when you are unable to properly breakdown the food. This could be due to enzyme deficiencies, sensitivity to food additives or reactions to naturally occurring chemicals in foods. Often, people can eat small amounts of food without causing problems.
If you have a food intolerance, you may be able to eat small amounts of the offending food without trouble. You may also be able to prevent a reaction. For example, if you have lactose intolerance, you may be able to drink lactose-free milk or take lactase enzyme pills to aid digestion.
Causes of food intolerance include:
- Absence of an enzyme needed to fully digest food. Lactose intolerance is a common example.
- Irritable bowel syndrome. This chronic condition can cause cramping, constipation, and diarrhea.
- Sensitivity to food additives. For example, sulfites used to preserve dried fruit, canned goods, and wine can trigger asthma attacks in sensitive people.
- Recurring stress or psychological factors. Sometimes the mere thought of a food may make you sick.
- Celiac disease. Celiac disease has some features of a true food allergy because it involves the immune system. Symptoms often include gastrointestinal issues as well as those unrelated to the digestive system, such as joint pain and headaches. However, people with celiac disease are not at risk of anaphylaxis. This chronic digestive condition is triggered by eating gluten.
Symptoms Of Food Intolerance
Symptoms usually happen a few hours after eating the food. It can be difficult to know whether you have a food intolerance as these are general symptoms that are typical of many other conditions.
In general, people who have food intolerance tend to experience:
- bloating, stomach pain
- rapid breathing
- headache, migraine
- burning sensations on the skin
- tightness across the face and chest
- breathing problems – asthma-like symptoms
- allergy-like reactions.
A food allergy is a medical condition in which exposure to food triggers a harmful immune response. The immune response called an allergic reaction occurs because the immune system attacks proteins in the food that are normally harmless. The proteins that trigger the reaction are allergens. Unlike an intolerance to food, a food allergy can cause a serious or even life-threatening reaction by eating a very little amount, touching or inhaling the food.
Symptoms Of Food Allergy
The clinical symptoms of food allergies range from mild discomfort to severe or life-threatening reactions, which require immediate medical intervention.
Symptoms of allergic reactions to foods are generally:
- swelling of the skin.
- vomiting and diarrhea.
8 foods cause 90% of all food allergies. These include milk, eggs, peanuts, tree nuts, soy, wheat, fish, and shellfish. But over 170 foods can cause allergic reactions.
- Anaphylaxis. Symptoms of anaphylaxis may include difficulty breathing, dizziness or loss of consciousness. Without immediate treatment—an injection of epinephrine (adrenalin) and expert care—anaphylaxis can be fatal.
Common Food Intolerances
When you have a food intolerance, symptoms usually begin within a few hours of eating the food that you are intolerant to. Yet, symptoms can be delayed by up to 48 hours and last for hours or even days, making the offending food especially difficult to pinpoint. What’s more, if you frequently consume foods that you are intolerant to, it may be difficult to correlate symptoms to a specific food.
Lactose is a sugar we can find in milk and dairy products. It is broken down in the body by the enzyme lactase, which is necessary in order for lactose to be properly digested and absorbed. Lactose intolerance is caused by a shortage of lactase enzymes, which causes an inability to digest lactose and results in digestive symptoms.
Gluten is the general name of proteins found in wheat, barley, rye and triticale. Several conditions related to gluten, including celiac disease, non-celiac gluten sensitivity, and wheat allergy. Celiac disease involves an immune response, which is why it is classified as an autoimmune disease. When people with celiac disease eat gluten, the immune system attacks the small intestine and can cause serious harm to the digestive system.
Wheat allergies are often confused with celiac disease due to their similar symptoms. They differ in that wheat allergies generate an allergy-producing antibody to proteins in wheat, while celiac disease is caused by an abnormal immune reaction to gluten in particular.
Caffeine is a bitter chemical that is found in a wide variety of beverages, including coffee, soda, tea and energy drinks. It’s a stimulant, meaning it reduces fatigue and increases alertness when consumed. Most adults can safely consume up to 400 mg of caffeine a day without any side effects. However, some people are more sensitive to caffeine and experience reactions even after consuming a small amount. This hypersensitivity to caffeine has been linked to genetics, as well as a decreased ability to metabolize and excrete caffeine
FODMAPs is an abbreviation that stands for fermentable oligo-, di-, mono-saccharides and polyols. They are a group of short-chain carbohydrates found naturally in many foods that can cause digestive distress. FODMAPs are poorly absorbed in the small intestine and travel to the large intestine, where they are used as fuel for the gut bacteria there. The bacteria break down or “ferment” the FODMAPs, which produces gas and causes bloating and discomfort.
Fructose, which is a type of FODMAP, is a simple sugar found in fruits and vegetables, as well as sweeteners like honey, agave and high-fructose corn syrup. Aside from a rise in fructose-related diseases, there has also been a surge in fructose malabsorption and intolerance.
In people with fructose intolerance, fructose isn’t efficiently absorbed into the blood. Instead, the malabsorbed fructose travels to the large intestine, where it is fermented by gut bacteria, causing digestive distress.
Common Food Allergies
Food allergies are extremely common. In fact, they affect around 5% of adults and 8% of children — and these percentages are rising. Interestingly, although it’s possible for any food to cause an allergy, most food allergies are caused by just eight foods. For people who have a food allergy, even exposure to very small amounts of the problem food can cause an allergic reaction. Symptoms can occur anywhere from a few minutes after exposure to a few hours.
An allergy to cow’s milk is most often seen in babies and young children, especially when they have been exposed to cow’s milk protein before they are six months old. It’s one of the most common childhood allergies, affecting 2–3% of babies and toddlers. However, around 90% of children will outgrow the condition by the time they’re three, making it much less common in adults.
Milk allergy can be either immunoglobulin E (IgE) or non-IgE mediated. IgE-mediated reactions typically occur immediately after ingestion whereas non-IgE mediated are delayed and take up to 48 hours to develop but still involve the immune system. Children or adults with an IgE allergy tend to have a reaction within 5–30 minutes of ingesting cow’s milk. They experience symptoms like swelling, rashes, hives, vomiting and, in rare cases, anaphylaxis.
A non-IgE milk allergy can be quite difficult to diagnose. This is because sometimes the symptoms can suggest an intolerance and there is no blood test for it. If a diagnosis of a cow’s milk allergy is made, the only treatment is to avoid cow’s milk and foods that contain it. This includes any foods or drinks that contain:
- Milk powder
- Ice cream
An egg allergy is the second most common cause of food allergy in children. However, 68% of children who are allergic to eggs will outgrow their allergy by the time they’re 16. Interestingly, it’s possible to be allergic to egg whites, but not the yolks, and vice versa. This is because the proteins in egg whites and egg yolks differ slightly. Like other allergies, the treatment for an egg allergy is an egg-free diet. However, you may not have to avoid all egg-related foods, as heating eggs can change the shape of the allergy-causing proteins.
Peanut allergies are very common and can cause severe and potentially fatal allergic reactions. However, the two conditions are considered distinct, as a peanut is a legume. Nevertheless, those with peanut allergies are often also allergic to tree nuts. Peanut allergies affect around 4–8% of children and 1–2% of adults. Around 15–22% of children who develop a peanut allergy will find it resolves as they move into their teenage years.
Like other allergies, a peanut allergy is diagnosed using a combination of patient history, skin prick testing, blood tests and food challenges. At the moment, the only effective treatment is complete avoidance of peanuts and peanut-containing products.
A shellfish allergy is caused by your body attacking proteins from the crustacean and mollusk families of fish, which are known as shellfish.
Examples of shellfish include:
The most common trigger of a seafood allergy is a protein called tropomyosin. Symptoms of a shellfish allergy usually come on quickly and are similar to other IgE food allergies.
However, a true seafood allergy can sometimes be hard to distinguish from an adverse reaction to a contaminant of seafood, such as bacteria, viruses or parasites. Symptoms can be similar, as both can cause digestive issues like vomiting, diarrhea and stomach pain. A shellfish allergy doesn’t tend to resolve over time, so most people with the condition must exclude all shellfish from their diet to avoid having an allergic reaction.
A wheat allergy is an allergic response to one of the proteins found in wheat. It tends to affect children the most. Although, children with a wheat allergy often outgrow it by the time they reach 10 years. Like other allergies, a wheat allergy can result in digestive distress, hives, vomiting, rashes, swelling and, in severe cases, anaphylaxis.
It is often confused with celiac disease and non-celiac gluten sensitivity, which can have similar digestive symptoms. A true wheat allergy causes an immune response to one of the hundreds of proteins found in wheat. This reaction can be severe and sometimes even fatal.
People with a wheat allergy only need to avoid wheat and can tolerate gluten from grains that don’t contain wheat. A wheat allergy is often diagnosed through skin prick testing. The only treatment is to avoid wheat and wheat-containing products.
Soy allergies affect around 0.4% of children and are most commonly seen in infants and children under three. They are triggered by a protein in soybeans or soybean-containing products. However, around 70% of children who are allergic to soy outgrow the allergy.
The symptoms can range from an itchy, tingly mouth and runny nose to a rash and asthma or breathing difficulties. In rare cases, a soy allergy can also cause anaphylaxis. Common food triggers of soy allergy include soybeans and soy products like soy milk or soy sauce. Since soy is found in many foods, it’s important to read food labels.
Like other allergies, the only treatment for soy allergy is the avoidance of soy.
Fish allergies are common, affecting up to around 2% of adults. Unlike other allergies, it’s not uncommon for a fish allergy to surface later in life, with 40% of people developing the allergy as an adult.Like a shellfish allergy, a fish allergy can cause a serious and potentially fatal allergic reaction. The main symptoms are vomiting and diarrhea, but, in rare cases, anaphylaxis can also occur.
Because the symptoms can be similar, a fish allergy is sometimes confused for a reaction to a contaminant in fish, such as bacteria, viruses or toxins What’s more, since shellfish and fish with fins don’t carry the same proteins, people who are allergic to shellfish may not be allergic to fish.
Sometimes it can be difficult to recognize if you have a food allergy or food intolerance. If you suspect you have a food allergy, it’s important to speak to your doctor. To find out whether you have an allergy or intolerance, your doctor will probably carry out a number of diagnostic tests.
- Dietary review: A detailed review of foods eaten, including timing and symptoms.
- Skin prick testing: A small amount of food is “pricked” into the skin using a tiny needle. The skin is then monitored for a reaction.
- Oral food challenges: The problem food is eaten in a controlled environment under medical supervision in gradually increasing amounts.
- Blood tests: In some circumstances, blood will be drawn and the level of IgE antibodies measured.
If you are allergic to a food, your doctor will advise you on how to manage it. Your doctor may also refer you to a registered dietitian to help with managing your diet. Don´t forget to read labels to avoid potentially harmful food for you.