8 Most Common Food Intolerances You May Not Know You Have

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8 Most Common Food Intolerances You May Not Know You Have

Approximately one in five adults report having a food intolerance but, because they are so difficult to detect, the true figure may be much higher.

Unlike food allergies, intolerances are not life-threatening, but they can make life miserable for sufferers, particularly if they go undetected.

Read on to discover some of the more common foods associated with intolerance, so you can better identify the culprit behind your unpleasant symptoms.

Allergy versus Intolerance

Although many people use the words ‘allergy’ and ‘intolerance’ interchangeably in relation to food, there are differences between the two.

The symptoms of an allergy tend to come on quickly after eating a particular food, while those of an intolerance may not show up for several hours or days after consumption, making pinpointing the offending food difficult.

Food allergies also tend to be triggered by a small amount of food, and can be life-threatening. Those with intolerances may find they can consume certain amounts of the food without adverse reactions, only suffering side-effects once they reach a certain threshold. In addition, food intolerances are not life-threatening, although they can cause a huge array of uncomfortable symptoms, and have a big impact on the quality of life of the sufferer.

While allergic individuals can never reintroduce offending food items to their diet because their immune system will always respond in the same way, many people with food intolerance can enjoy moderate amounts of some foods in their diet after a period of elimination.


Signs that you may be suffering a food intolerance include:

  • Bloating
  • Digestive discomfort
  • Irritable bowel
  • Migraines or headaches
  • Fatigue
  • Skin rashes or hives
  • A cough
  • A stuffy or runny nose
  • A general feeling of unwellness without an apparent cause


Although the causes of food intolerance aren’t fully understood – or agreed upon within the medical community – it’s possible they stem from the absence of digestive enzymes, or sensitivities to natural or synthetic chemicals and compounds within the food, such as histamine and salicylates.

8 Most Common Food Intolerances

Although everyone is different, and it’s possible to be sensitive to almost any food, some foods are far more likely to cause an unpleasant reaction than others!

The following are the most common sources of food sensitivity:

1. Lactose (Dairy)

Lactose intolerance is characterized by the inability to digest the sugar in dairy, known as lactose. Up to 50 million Americans and approximately 65% of people worldwide are lactose intolerant, making it one of the most common food sensitivities around.

Normally, our bodies produce the enzyme lactase to break down lactose. However, some people experience a decline in lactase production. This happens naturally as we age, but it can also occur due to illness, injury or intestinal surgery. Ethnicity also plays a role in lactose intolerance – with those of African, Asian, Hispanic, and American Indian descent more likely to experience sensitivity to dairy.

Symptoms can appear between 30 minutes and several hours after dairy consumption and include bloating, gas, stomach gurgling, pain or cramps, diarrhea, or vomiting.

Many people with lactose intolerance can consume limited quantities of dairy, particularly if it is fermented (in the case of milk kefir and yogurt), or if it is organic. Goat milk can also be tolerated well by some sufferers.

2. Gluten

Those who are gluten sensitive – approximately 18 million Americans – cannot tolerate gluten, the protein found in wheat, rye, and barley.

Unlike those with Celiac disease, gluten does not damage the intestinal lining of those with a gluten intolerance, although it can cause significant gastrointestinal distress, among other symptoms.

Because gluten is so widespread, it can be difficult to avoid. It’s found in baked goods, cereals, processed meat and fish, spreads, canned foods, sauces and condiments, alcohol, many sweet treats, and even prescribed and over-the-counter drugs, along with certain vitamin supplements.

A myriad of gluten-free alternatives are available, but these should be used sparingly, as they contain several additives, are often high in calories, and can upset blood sugar balance.

Here are 16 surprising signs of gluten intolerance you should be looking out for.

3. Alcohol

Experiencing allergy-like symptoms (and not the usual hangover symptoms!) after alcohol consumption is pretty common. It can happen in reaction to a particular type of alcohol, or to several.

The intolerance can be to alcohol itself, or to the ingredients within the drink. For example, those with gluten intolerance may be unable to drink beer without adverse reactions. Other chemicals and ingredients in these drinks which may cause issues include histamine, yeast, flavorings, and other additives.

Alcohol can also exacerbate underlying conditions, particularly asthma, migraine, and rosacea. In situations like this, the alcohol is merely a trigger and not a true intolerance.

Another way in which alcohol causes distress is through its ability to increase the permeability of the gut, allowing more food molecules into the body. In cases like this, it may be the food you ate with the alcohol – and not the alcohol itself – that is the cause of your problems. However, you may only notice the effects because the alcohol magnifies or facilitates them!

Some of the worst offenders include red wine, beer, and darker colored liquors like whiskey and brandy.

If you can’t handle any alcohol at all, just look at all the fantastic things that will happen your body when you stop drinking!

4. Eggs

A common sensitivity, egg intolerance or allergy affects nearly 1.5% of children. In most cases, the intolerance will disappear as they age.

Interestingly, most people that suffer from the intolerance cannot handle the egg white, while they may have no issues with the yolk. Intolerance to egg yolk is much rarer, but is still possible.

Those with an egg intolerance should also be aware that most chickens are fed a soy-based diet, so you may be sensitive to soy, rather than eggs. Choosing eggs from grass-fed, free range and organic animals will help you determine the true nature of your sensitivity.

Hidden sources of egg include baked goods, pasta, some commercial egg substitutes, and the foam toppings on desserts and specialty drinks.

5. Soy

With soy and its derivatives found in 75% of products on supermarket shelves and in almost 100% of fast food, it’s not surprising it’s one of the top causes of food sensitivities.

Soy can cause gastrointestinal irritation in those who are sensitive, such as gas, bloating, vomiting, nausea, and heartburn. However, it can also cause irritability or depressed mood, along with headaches. Infants who are soy intolerant can experience reflux caused by soy-based formula or foods.

Avoiding soy is difficult, especially if you buy a lot of processed or pre-made foods such as baked goods, cookies and chips, canned meats and fish, infant formula, and lots more. Check labels for terms like hydrogenated oils, vegetable starch, lecithin, emulsifiers, and hydrolyzed plant protein.

As almost 95% of soy beans are genetically modified, some people believe it’s this engineered version of soy that causes issues. Some people may be able to tolerate organic soy better.

Consider trying fermented soy foods too – such as miso, tempeh, and natto – as at least two studies from Spanish and American scientists have found that people with soy allergies don’t react to fermented soy!

6. Corn

Similar to soy and gluten, corn is in everything from medications to make-up – increasing its risk of causing symptoms of intolerance.

Corn’s proteins can irritate the gastrointestinal tract of people who are also intolerant to gluten and other grains, so if your symptoms haven’t abated after cutting out wheat and/or all gluten, consider ditching corn for a while too.

It doesn’t help matters that over 90% of corn is genetically engineered, and is one of the biggest components of commercial animal feed. Remember, ‘you are what you eat’ – and this goes for your food sources too!

Look out for corn under names like corn starch, corn syrup, and high-fructose corn syrup which are added to processed foods, sodas, condiments, bread, and many gluten-free replacement foods.

7. Yeast

Yeast can be a surprising cause of food sensitivity, with some experts even believing that yeast, rather than wheat, may the culprit for the plethora of symptoms many suffer after indulging in a pizza or bowl of pasta.

Yeast intolerance can cause a wide variety of symptoms, including yeast infections, joint pain, and fatigue after eating a product containing yeast.

Any food or drink that is aged or undergoes a fermentation process will contain yeast. You’ll find it in many baked goods, alcoholic drinks, stock cubes, vinegar and salad dressings, pickles, overripe or dried fruit, malt, sour cream or ripe cheese, soy sauce, B vitamin supplements, and much more. Leftover food can also develop yeast on its surface.

8. Chemicals, Pesticides and Additives in Foods

Because much of the food we consume today has been treated with pesticides and other chemicals, or is loaded with artificial flavorings, colorings, and sweeteners, it’s difficult to pinpoint the source of intolerance.

Some people who seemingly have lactose or gluten intolerance can handle organic products, leading many to suspect it’s the chemical additives, rather than the food itself, that are the problem.

The only way to know for sure is to keep a food diary, and note what causes your symptoms. If consuming homegrown or organic versions of the products cause you no ill-effects, it may well be a chemical sensitivity, rather than a food intolerance, you are suffering.