If a person suffers from symptoms suchas skin rashes, swelling of tongue, unconditional sneezing, breathing problems, etc. it is generally assumed to be caused due to seasonal change or pollen allergy or sun allergy etc., without considering another common possibility i.e. response to food allergy or food hypersensitivity.

Commonly, allergies are associated with abnormal immune response to allergens (various substances or factors which triggers allergic reaction), in which immune system wrongly recognizes a substance as harmful (foreign) and tries to destroy it by launching a range of protective measures, including releasing chemicals like histamine, which causes inflammation, itchy hives, stomach upset, etc. In fact only just a handful of foods can cause 90% of the allergic reactions related to food and the most common allergen in food is proteins. Food allergies can develop at any age. Some can appear in childhood and disappear later in life, while some may last forever. Although most food allergies cause mild and minor symptoms, some can cause severe reactions. There is no cure for food allergies and also no food processing tool has been identified which completely eliminates the allergens, but certain measures can be taken to prevent serious health consequences such as strict avoidance, knowledge and awareness, labeling of possible allergen ingredient on the processed/packaged food, etc. In India, food allergies have been found to cause approximately 30,000 emergency cases, 100 to 200 deaths per year and up to 3million cases have been reported from peanut allergy alone.

More than 160 food materials are identified as allergenic. The most common allergenic foods and commonly referred to as “priority food allergens” are cow’s milk and dairy products, peanuts, nuts, hen’s egg, wheat, sesame, soybeans, fish, shellfish, etc. They account for over 90% of all food allergic reactions. Other less common allergenic foods include legumes, and some fruits and fruit juices (e.g., kiwifruit, apple, grape) and vegetables (e.g., celeriac, carrots, onions), etc.

The most common food allergy signs and symptoms include:

• Tingling or itching in the mouth
• Hives, rashes, itching or eczema
• Swelling of the lips, face, tongue and throat or other parts of the body
• Runny or congested nose, wheezing, trouble breathing, hoarse voice
• Abdominal pain, diarrhoea, nausea or vomiting
• Dizziness, lightheadedness or fainting
• Anaphylaxis (severe allergic reaction)-can cause life-threatening signs and symptoms, such as constriction and tightening of airways, swollen throat or the sensation of a lump in your throat that makes it difficult to breathe, shock with a severe drop in blood pressure(anaphylactic shock), rapid pulse, dizziness, lightheadedness or loss of consciousness. Emergency treatment is critical for anaphylaxis. Untreated, anaphylaxis can cause a coma or even death.

Below is a list of most common food allergens found in India, along with their common symptoms and possible food substitute:

1. Milk

Allergy to cows' milk is the most common food allergy in childhood. A reaction can be triggered by small amounts of milk, either passed to the baby through the mother's breast milk from dairy products she has eaten, or from feeding cows' milk to the baby. Children usually grow out of milk allergy but about one-fifth of children who have anallergy to cows' milk will still be allergic to it as adults, blood tests that measure the presence of milk antibodies can be used to check it. The allergy is usually directed against one or both major milk proteins, casein and whey. The sugar in milk, lactose, does not cause allergy, but can cause food intolerance.

Symptoms: Often mild symptoms can appear and can affect any part of the body. They can include ashes, stomach cramps, bloating, heaviness in the stomach, flatulence, diarrhoea, vomiting, etc. In very few cases, milk allergy can cause anaphylaxis.

Food substitutes: Almond milk, rice milk, soy milk, hemp milk, coconut milk are good substitutes to use in milkshakes, baking and with cereal. Calcium substitutes include leafy vegetables, chickpeas, eggs and seeds. Protein can be substituted with soy, pulses, meat or eggs.

2. Peanuts or groundnuts

 

Allergy to peanuts is often lifelong and can cause severe reactions, including anaphylaxis. Peanut allergy can be so severe that very tiny amounts can cause a reaction in people who are sensitive. They contain allergens that are not destroyed by cooking or roasting. Refined peanut oil is thought to be safe for people with peanut allergy, because the proteins that cause allergic reactions are removed during the manufacturing process. However, cold pressed, or unrefined peanut oil can contain small amounts of peanut allergens, which can cause a reaction in people who are sensitive.

Symptoms:Runny nose, skin reactions, such as hives, redness or swelling, itching or tingling in  or around the mouth and throat, digestive problems, such as diarrhoea, stomach cramps, nausea or vomiting, tightening of the throat, shortness of breath or wheezing, anaphylaxis,etc.

Food substitutes: The easiest and the most common peanut butter alternative is almond butter and sunflower seed butter is also a great substitute for peanut butter and contains healthy fats and proteins.

3. Eggs

Egg allergy is more common in childhood and is often outgrown. Trigger is mostly egg proteins: ovomucoid, ovalbumin and conalbumin. Mostly children grow out of it by the age of 3. In a few cases, egg allergy can cause anaphylaxis. Cooking can destroy some of these allergens. So, some people might react to cooked eggs, as well as raw eggs. Some children are allergic to this protein rich food and can’t take it at all, while others might be allergic to either egg white or the yolk.

Symptoms: Skin reactions like red patches or rashes all over the body, stomach aches, diarrhoea,wheezing or shortness of breath, sneezing and nasal congestion, nausea and vomiting, anaphylaxis – in some casesetc.

Food substitutes: Eggs are widely used for baking and can be replaced with yoghurt or plant alternatives or egg substitutes. The protein content can be obtained from milk, pulses or meat.

4. Fish

Fish allergy can often cause severe reactions, including anaphylaxis. Trigger is fish proteins. Cooking doesn't destroy fish allergens. In fact, some people with a fish allergy can be allergic to cooked but not raw fish.

Symptoms: Skinirritations, swelling of the throat, mouth and nose, vomiting and diarrhoea, breathing difficulties, a severe drop in blood pressure, anaphylaxis in some cases, etc.

Food substitutes: Daily dose of protein can be obtained from eggs, dairy products, meat, poultry, pulses, lentils, black beans, etc.

5. Tree Nuts

Allergy to nuts from trees (e.g. walnuts, hazelnuts, almonds, cashew, pistachio, coconut etc.) is usually lifelong. On rare occasions, all these nuts can cause anaphylaxis in people who are sensitive. Sometimes, people with an allergy to one type of nut will also react to other nuts.

Symptoms: Mild swelling of tongue, lips and eyes, itchy mouth, throat or eyes, shortness of breath, nausea and vomiting, skin irritations and rashes, abdominal pain, anaphylactic reactions in severe casesetc.

Food substitutes: Seeds are the best replacement for nuts nutritionally. Omega 3 can be obtained from egg yolk and the protein can be obtained from milk.

6. Shellfish

 

Shellfish (e.g. shrimp, lobster, crab, oysters, scallops, mussels, clams, etc.) allergy can often cause severe reactions, and some people can even react to the vapors from cooking shellfish.

Symptoms: Tingling in the mouth, nausea, vomiting and diarrhoea, skin irritations, dizziness and fainting, throat swelling and breathing difficulty, drop in blood pressure and rapid pulse, anaphylaxis, etc.

Food substitutes: Daily dose of protein can be obtained from eggs, dairy products, meat, poultry, pulses, lentils, black beans, etc.

7. Soybean

It is a common childhood allergy. Most people grow out of it by the age of two, but occasionally adults are allergic to soybean. It is known as a potent food that leads to hormonal imbalances; it isn’t easy to digest for some kids.

Symptoms: They are similar to milk allergy and include ashes, diarrhoea, vomiting and stomach cramps. Also includes swelling on the hand and feet, tongue and lips, puffed eyes, flatulence and bloating Very rarely, it can cause anaphylaxis.

Food substitutes: Since soy is mainly eaten for its complete protein content, any animal foods like milk, eggs or meat can be a good replacement. Alternatively, pulses, beans, grains (e.g. quinoa) and sprouts are good substitutes too.

8. Wheat

Wheat allergy is common, particularly among babiesand is usually outgrown byage three. It is sometimes confused with celiac disease, which is a digestive disorder that creates an adverse reaction to gluten (Gluten intolerance). Individuals with celiac disease must avoid gluten, found in wheat, rye, barley, and sometimes oats. While, people who are allergic to wheat have an immune mediated response to wheat protein and may tolerate other grains.

Symptoms: Watery diarrhoea, bloating and cramping, indigestion that could lead to nausea, headache, excessive burping, stomach aches due to swelling of the intestinal wall, mouth ulcers, muscle pains, skin irritations,etc.

Food substitutes: Wheat can be substituted by a number of flours like millets (jowar, ragi, bajra), rice, maize, amaranth, etc. These substitutes can be used in breads and pancakes. Alternatively, potato starch and tapioca can be used as baking agents for muffins and cakes.

9. Sesame (Til)

Sesame allergy is increasing, possibly because it's now more commonly used. Sesame seeds, sesame oil, and other sesame products, can cause anaphylaxis.An allergy to sesame seeds is also particularly difficult to control as the food label does not always specially say sesame seeds. Other names indicate the presence of sesame seeds; for example, sim sim, benne, gingelly seeds, etc. Both the people suffering from sesame seed allergies and food handlers need to be aware of each different name that can indicate the presence of sesame seeds. Sesame seeds are tiny and it doesn’t take many to cause and allergic reaction.

Symptoms: Skin irritations and rashes, abdominal pain, nausea, vomiting and diarrhoea, itchy mouth, throat or eyes, swelling of the face, nose or mouth, shortness of breath, anaphylactic reactions in severe cases, etc.

Food substitutes: Sesame oil can be substituted with roasted peanut oil, nut oil such as walnut oil, olive oil, perilla oil, avocado oil, canola oil, grape seed oil, etc. Also instead of sesame seed one can use sunflower seed, perilla seed, pumpkin seed, etc.

10. Corn

Allergic symptoms of a corn allergy develop when a person’s immune system becomes sensitized and overreacts after eating corn or foods containing corn-based ingredients, or after being exposed to corn pollen. Corn and corn-derived products (includes baking powder, caramel, cellulose, citric acid, dextrin, dextrose, inositol, malt, maltodextrin, monosodium glutamate (MSG), semolina, sodium erythorbate, sorbitol, starch, vanilla extract, xanthan gum, xylitol, etc.) are used in many processed foods, as well as in many other everyday items.

Symptoms: Hives or a skin rash, nausea, stomach cramps, indigestion, vomiting or diarrhoea, stuffy or runny nose, sneezing, headaches, asthma, anaphylaxis (less common), etc.

Food substitutes: A substitute for corn or its product can be used depending upon its function or flavor. Corn oil can be substituted with another oil e.g. canola oil has a mild flavor and is a good substitute for baked goods or desserts, while oils with a distinct flavor such as grapeseed oil or olive oil can be substituted in savory dishes. Other options include sunflower oil, rice bran oil, soybean oil, etc. Similarly instead of using baking powder which contains corn starch, can replace it with soda and other leavening agents. Instead of using corn starch as thickener, can replace it with arrowroot starch, wheat starch, tapioca starch, potato starch, xanthan gum, etc. Corn syrup can be substituted with other liquid sweeteners such as honey, nectar, etc.

11. Spices

Spices are commonly used in Indian diet and allergen city to it can be problematic. Reactions to spices are usually mild, but severe reactions can happen occasionally. Some people react to mustard, coriander, caraway, fennel, paprika, saffron, ginger, garlic, etc..

Symptoms: Stomach problems, sneezing,anaphylaxis, etc.

Food substitutes: One can avoid that particular spice and substitute it with herb or spice with similar flavor and aroma.

12. Fruits and Vegetables

People with fruit and vegetable allergies generally also have hay fever because some tree and weed pollens share characteristics with certain fruit and vegetable proteins. Such allergies often develop in adulthood.

Symptoms: These allergies are usually mild, with symptoms like an itchy mouth or throat, and can be addressed by heating fruits and vegetables prior to consumption.

Food substitutes: Vinegar, tomato juice and apple cider vinegar are good substitutes for citrus fruits.

Source: https://www.medicalnewstoday.com/articles/8624.php, https://www.mensjournal.com/health-fitness/10-most-common-food-allergies-20140429/milk/, https://www.medicalnewstoday.com/articles/8624.php, https://firstmomsclub.in/dealing-with-common-food-allergies-among-indian-children/, https://acaai.org/allergies/types/food-allergies/types-food-allergy