Do you experience undesirable symptoms after eating certain foods? You might be suffering from food intolerance. This is also known as non-IgE mediated food hypersensitivity or non-allergic food hypersensitivity. Food intolerance refers to difficulties in digesting certain foods. Food intolerance is not the same as a food allergy, which is much more severe.

If you have a food allergy, a certain food or group of foods sends the immune system into overdrive and can be fatal if the person is severely allergic. Food intolerances, on the other hand, do not trigger the immune system or cause the release of histamines. If you have a food intolerance, your digestive system will react to foodstuff and make you feel uncomfortable.

Several foods are commonly associated with food intolerances, such as gluten-containing grains, dairy products, and foods that cause intestinal gas to build up, such as cabbage, and beans. There are several causes of food intolerance. These include the presence of certain chemicals such as amines and caffeine, to which some people are more sensitive than others. Someone can also lack specific enzymes that are needed for digestion such as lactase. If so, they will be lactose intolerant and unable to break down milk sugars (lactose). Note that milk protein allergies present with similar symptoms leads to lactose intolerance, and many people get misdiagnosed.

Another cause is a sensitivity to naturally occurring histamines that occur in certain foods, especially if they have not been stored properly. Some foods contain chemicals that are toxic to humans, such as undercooked beans. Properly-cooked beans do not contain these toxins. Some people are intolerant of the salicylates that are present in many plant-based foods, including most fruits (especially citrus) and vegetables, tomato sauce, mint flavoring, herbs and spices, teas, and flavor additives, particularly in processed foods. Read on for some symptoms of food intolerance …

1. Fatigue

Feeling sleepy after eating can be caused by many things, one of which is food intolerance. This is because the body has to work harder at digesting a portion of the food to which it is intolerant. Because an intolerance causes inflammation, the body gets tired while it tries to digest foods to which it is sensitive. So rather than energizing you, certain foods cause you to feel tired. The body’s immune system is using a whole lot of energy to try and remove what it sees as an ‘invader.’ The result is severe tiredness. So, next time you get exhausted after eating, take note.

You might be suffering from food intolerance. Consider keeping a food diary to help identify any foods or ingredients that are impacting your energy levels. Write down everything you eat and drink, as well as how much. Also record how you feel, your energy levels, quality of sleep, mood, gastrointestinal activity, and any symptoms. This way you or your doctor might be able to link symptoms and energy levels to particular foods, drinks or ingredients. The problem might be as simple to treat as eliminating a particular food or ingredient from your diet.

2. Bloating

Bloating is another symptom that is associated with some food intolerances. The typical symptoms of bloating include a feeling that gas (wind) is ‘trapped’ in the stomach and a tight, distended, painful stomach (abdomen) after eating. Bloating is often caused by intestinal gases building up to an excessive degree, resulting in discomfort and sometimes embarrassment. Bacteria produce these gases in the digestive tract from food that hasn’t been adequately digested or absorbed. It could, also, be caused by a lack of enzymes. Enzymes are specialized proteins that work on specific foods to help break them down. In some people, there is a lack of specific enzymes needed to break down certain foods. If the body cannot properly break down certain foods, the result might be bloating and gas.

One of the more common intolerances to produce bloating is lactose intolerance. This intolerance occurs in people who are deficient in the enzyme lactase. Lactase is required to break down the sugars (lactose, a disaccharide) found in milk. When someone with lactose intolerance consumes milk or a product that includes milk as one of its ingredients, they are likely to feel bloated and uncomfortably gassy.

3. Cramping

Very closely related to the symptom of bloating is the symptom of cramping. If you experience mainly abdominal symptoms after eating certain foods, it might be because you are intolerant to something. That means your body is unable to digest that particular food or ingredient properly. If, on the other hand, you have a food allergy, the symptoms appear quickly and include hives or tongue or lip swelling. This takes place either immediately or within 10 to 15 minutes of consuming the food.

These symptoms do not occur in cases of food intolerance, whose symptoms often appear a while after consuming the food to which you are sensitive. The trouble is that food intolerances and food allergies are often misdiagnosed and confused with one another. Other common symptoms that appear in cases of proper food allergies include nausea after eating, vomiting, diarrhea, asthma, eczema (itchy, red, sometimes scaly patches on the skin), abdominal pain or cramping, and a rash on the skin around the mouth. If someone experiences these symptoms, especially if they are having difficulty in swallowing or breathing, seek immediate medical treatment. Food intolerances do not require emergency medical attention.

4. Migraines

Migraines are common symptoms of food intolerance. An intolerance to sulfites, which are preservatives found in products like dried fruit, wine, and in some pre-packaged foods and condiments, can be the cause. A migraine is an intense headache accompanied by painful throbbing, and often by light sensitivity, as well as sensitivity to smell or noise. They tend to last from 4 to 24 hours, or longer and are likely to reoccur. If you suffer from migraines or frequent headaches, it’s a good idea to have yourself checked out by your doctor to rule out any underlying medical conditions.

In the meantime, it’s well to take a look at your diet. People vary greatly in their reactions to foods and beverages. Something that causes a lot of problems in one person might do nothing to another person. If a food intolerance might be the cause of your migraines, keep a food diary for a few weeks as outlined above. This can help identify which foods or drinks are causing adverse effects on your health and well-being. By working with your doctor to identify and eliminate foods that trigger your migraines, you might be able to reduce the severity of the attacks, reduce their frequency, or even stop them altogether.

5. Gas

Along with bloating and abdominal cramps or pain, excessive amounts of intestinal gas can be caused by food intolerance. High FODMAP foods often produce high levels of gas. FODMAP is an acronym for fermentable oligo-, di-, monosaccharides and polyols. This is a group of carbohydrates that are difficult to digest and quickly start to ferment as a result of bacteria in the gut. This causes water to be drawn into the small intestine, causing uncomfortable symptoms like gas, bloating and bellyache. FODMAPs are little sugars and fibers that are found in lots of foods that we commonly consume. These include milk, apples, onions, garlic, wheat, and watermelon.

And that’s just a few of them. Intestinal bacteria particularly love to consume FODMAPs, and unfortunately, they’re mostly found in health-promoting foods rather than junk food. By keeping a food diary and detailing your symptoms after you eat foods and drink beverages, you can start to identify which foods are causing gas. Then, under your health practitioner’s advice, you might want to eliminate the offending foods. Sometimes, bacterial overgrowth is the cause and will need different treatment such as antibiotics.

6. Joint pain

Many millions of people around the world suffer from joint conditions such as arthritis, stiffness, pain, swelling, and reduced mobility. The underlying cause of these symptoms is inflammation, which is when the body’s immune system starts affecting the joints. The pain and swelling that occur as a result of this inflammation can cause severe debilitation. Typical symptoms include pain during movement, stiffness or swelling of the joints, and persistent aching in the joints such as the shoulders, back, knees, hips, wrists, or ankles. Many healthcare practitioners will recommend treatment that includes anti-inflammatory medications and analgesics to combat the pain. The trouble is, all medications have side effects, and in the case of these meds, you might suffer diarrhea, increased blood pressure, and a reduced ability to fight off infections.

After ruling out underlying medical conditions with your doctor, try examining what you eat more closely. Because we all react differently to the various foods and beverages that we consume, just about any ingredient could be causing or contributing to your joint pain. Once again, documenting what you eat and drink can allow you to work out what might be contributing to your symptoms. Then, it becomes a matter of eliminating the offending food or drink.

Check this out: 10 Superfoods To Fight Inflammation If Consumed Regularly.

7. Hives

If you develop hives shortly after eating or drinking something, you might be having a life-threatening allergic reaction to what you have consumed. In this instance, you need emergency medical treatment. Hives and other symptoms such as difficulty breathing, an itchy throat, swollen tongue or lips, swollen throat, or a rash around the mouth are manifestations of an anaphylactic reaction. This reaction is indicative of a severe allergy, and urgent medical treatment is required to prevent a possible fatality.

The symptoms of a food allergy vary from food to food. An allergy to foods such as fish, especially shellfish, and nuts can lead to an anaphylactic reaction within minutes or an hour of consuming the offending ingredient. Hives on the tongue usually indicate a severe reaction, but can also be caused by intolerances to vegetables from the nightshade family, including red peppers, eggplants, white potatoes, and tomatoes. If you do develop hives on the tongue without any of the other symptoms of anaphylactic shock, make a note of what you have eaten. You might have a food intolerance that you weren’t aware of. If it happens more than once without the development of other anaphylactic symptoms, you should probably eliminate that food item.

8. Diarrhea and constipation

There’s been a lot of talk about gluten and whether or not we should be eating it, but some people are definitely gluten intolerant. The most severe form of gluten intolerance is known as celiac disease, an autoimmune disorder in which the body attacks its small intestine when gluten has been consumed. Gluten is a protein that is found in wheat, rye, barley, and some oats. Many manufacturers are producing gluten-free products these days in response to what seems to be a growing problem. Celiac disease causes many health problems, including diarrhea and constipation, as well as headaches and migraines, skin rashes, chronic fatigue or weight loss, oily stool (steatorrhea), and the inability to properly absorb vital nutrients such as vitamins B12 and D, as well as iron.

But you don’t have to suffer from celiac disease to be sensitive to gluten. In non-celiac gluten sensitivity or intolerance, the body doesn’t react well to gluten, but the autoimmune symptoms of celiac disease are not present. Scientists have studied the phenomenon and found that 50% of people who are gluten sensitive experience diarrhea, while 25% suffer from constipation. But diarrhea and constipation can be caused by a multitude of factors, not just food intolerance.

9. Arthritis

There are over 100 different kinds of arthritis and diseases related to arthritis. The most common types of arthritis are osteoarthritis and rheumatoid arthritis, both of which involve inflammation of one or more joints in the body. The significant symptoms of arthritis are stiffness and joint pain, which usually worsens with age. In osteoarthritis, the cartilage that cushions the joints between bones breaks down. In rheumatoid arthritis, the lining of the joints (synovium) is attacked by the body’s immune system, making it an autoimmune disease. Other kinds of arthritis might be caused by diseases like lupus or psoriasis, or by the presence of uric acid crystals in the joints, or by infection.

Different kinds of arthritis require different kinds of treatment to allow the sufferer to live a better life, with fewer symptoms. The two most common forms of arthritis, osteoarthritis and rheumatoid arthritis, cause damage to the joints in different ways and have different causes. It is interesting to note that most scientific studies have found that between 30% and 40% of people with rheumatoid arthritis can improve their condition substantially if they use an elimination diet to identify foods that precipitate symptoms and avoid these foods.

10. Acid Reflux & Heartburn

If you often suffer from heartburn or acid reflux after eating or drinking, you might have an undiagnosed food intolerance. Acid reflux is when the naturally-occurring acids in your stomach, as well as other stomach contents, move back up into the esophagus. They pass through the lower esophageal sphincter (LES), a ring of muscle where the esophagus and the stomach meet. Usually, the LES opens to allow food into the stomach when you have swallowed. It then closes to stop the food from coming back up. However, if the LES is damaged or weak, it might not close completely. That’s when stomach contents and acids can move back up into the esophagus. This is acid reflux, which is estimated to affect around 20 percent of Americans.

Gastroesophageal reflux disease, or GERD, is a severe, chronic form of acid reflux, and can lead to serious health problems if untreated. The symptoms of acid reflux different in form and severity in different individuals. They include experiencing symptoms after a fatty or spicy meal, after a heavy meal, or when lying down or bending over. Heartburn is the most common symptom of acid reflux. Heartburn is painful, burning in your chest caused by stomach acids leaking from the stomach into the esophagus.

11. A runny nose

If you have a runny nose after eating, it could be caused by many factors. The medical term for a runny nose is rhinitis, and it can be allergic rhinitis or non-allergic rhinitis. If you have a food allergy, your nose might run within two hours of eating a particular ingredient, and will probably be accompanied by other symptoms. As we said earlier, anaphylactic symptoms require urgent treatment. However, if your nose runs within a couple of hours of eating and you have other, less severe symptoms, your runny nose might be a sign of food intolerance. The reason the nose runs is that it is attempting to cleanse itself.

If a runny nose plagues you after eating, try keeping a food journal in which you note everything you eat and drink, as well as how you feel and any symptoms you may be experiencing. This way, you might be able to narrow down or find out exactly what foods or beverages are triggering your symptoms if any. Then, eliminating the food will alleviate the symptoms. In the meantime, your doctor might prescribe medication to deal with your runny nose and any accompanying cough or sneezing symptoms.

12. Acne and rosacea

Although food allergies and food intolerances are not the same, if you are intolerant to some food or beverage, you should avoid them. Food allergies can show up in various skin conditions, including rashes, hives, eczema, rosacea, acne, puffiness, and itchiness. This is because the immune system is overreacting to a particular allergen that the body views as harmful, even if it isn’t. The immune system summons up disease fighters called immunoglobulin E (IgE) antibodies. When you eat a portion of food that contains that particular protein, the body releases IgE antibodies and other chemicals, including histamine in an attempt to get rid of the ‘invader’ protein.

Histamine is a powerful substance that causes allergic symptoms in various parts of the body, depending on where in the body the histamine has been released. If released in the skin, you could experience one or more of the skin problems mentioned above. If you have any of these skin problems, you might be suffering from a food allergy or an intolerance to a particular ingredient. Keeping a food diary that matches symptoms to foods consumed will allow you to narrow down the ingredients that might be causing your symptoms. Then avoiding them should help alleviate symptoms.

13. General malaise

If you’re generally feeling under the weather, the cause might be food intolerance. If you are regularly consuming foods or beverages that contain ingredients to which your body is over-sensitive, your body is being put under strain. Rather than any specific symptom, you might just be feeling off-color. If you’re sure you’re leading a healthy lifestyle with a balanced diet, adequate water and sleep, and reasonable levels of exercise, yet still feel generally unwell, it’s time to visit your doctor.

Your doctor might want to do one of a number of tests on you to find out if any underlying conditions might not be immediately apparent. But sometimes, no problems can be found, and you’re left still feeling off-color. That’s when taking a closer look at your diet might be the next logical step. After all, as the saying goes, we are what we eat. And we might not be feeling all that if we eat certain things. Start by keeping a food diary. Every day, write down every single thing that you drink and eat and any symptoms you have. Then, when you find out what foods you are sensitive to, you can eliminate them from your diet.

14. Mouth ulcers

Do mouth ulcers plague you? Also known as canker sores, mouth ulcers are usually small, painful lesions in the mouth or at the base of the gums. They can make everyday activities like eating, drinking, and talking uncomfortable. They aren’t contagious and usually go away within a week or two. If you get a large sore that doesn’t heal or is very painful, you should consult your doctor. While no definitive cause for mouth ulcers has been found, certain triggers and factors have been identified. These include food sensitivities, especially to acidic foods like citrus fruits, pineapple, and strawberries, as well as other foods like coffee and chocolate.

Some mouthwash and toothpaste that contain sodium lauryl sulfate can cause canker sores, as can a lack of nutrients like vitamin B-12, folate, iron, and zinc. The hormonal changes that accompany menstruation can also cause mouth ulcers, as can various viral, fungal, and bacterial infections. Mouth ulcers can sometimes be signs of severe conditions, including diabetes, Bechet’s disease, HIV/AIDS, celiac disease, and inflammatory bowel disease. These require medical treatment. See your doctor if you have large ulcers, recurring ulcers, ulcers that last more than three weeks, painless ulcers, uncontrollable pain, severe problems with eating and drinking, and fever or diarrhea when the ulcers appear.

15. Respiratory problems

If you experience a runny nose (rhinitis) or sinusitis on a recurring basis due to food intolerance, it might be accompanied by respiratory problems such as shortness of breath. Although rhinitis can be treated with various medications, these come with undesirable side effects and don’t get to the cause of the issue. If you are having problems breathing without an apparent reason such as the common cold or flu, visit your healthcare provider to rule out any underlying medical conditions that might be causing your symptoms.

If you keep getting rhinitis or sinusitis that are causing shortness of breath, it’s time to take a look at your eating habits. This is where following an elimination diet under the guidance of your doctor can be highly beneficial in relieving symptoms. For example, one study showed that eliminating so-called ‘trigger’ foods alleviated sinusitis in 89% of participants and asthma and rhinitis in 72% of participants. To follow an elimination diet, it’s necessary to keep a food journal in which you record everything you consume and what symptoms you experience. If you have a food intolerance, a link will show up between an ingredient and one or more symptoms.

16. Anxiety and depression

Millions of people around the world suffer from anxiety or depression, and the causes vary from situational to chemical. The role of diet in our health cannot be underestimated. In recent times, science has been paying closer attention to the relationship between the brain and the digestive system. It turns out that the digestive system produces 90% of the serotonin the body produces. Serotonin is a hormone that makes us feel happy, and many anti-depressant medications focus on restoring the balance of serotonin in the brain. But what about the role of the gut?

Another fascinating finding is that the brain and the gut contain 30 identical neurotransmitters. These chemicals, of which serotonin is just one example, carry messages around the brain and the body. They are also responsible for how we feel. It follows, then, that if we have an unhappy digestive system, we’re likely to feel depressed. Interestingly, scientific studies have found gastrointestinal inflammation in a large number of people suffering from depression.

Given that this inflammation is one of the main overarching symptoms of food intolerance, it appears that food intolerances are linked to depression. And the relationship goes both ways. A depressed mind influences the gut and vice versa.

17. Irritable bowel syndrome

Although people with Irritable Bowel Syndrome (IBS) are sensitive to food, few people with this disorder have a food allergy. Between 3 and 20 percent of people in the U.S. suffer from IBS symptoms, women more than men. Some people experience minor symptoms, but others’ symptoms are so severe that they disrupt daily life. Also known as spastic colon, irritable colon, mucous colitis, and spastic colitis, IBS is not the same as inflammatory bowel disease and is not related to other conditions of the bowel.

IBS is a cluster of symptoms that usually occur together, and which vary in duration and severity from person to person. IBS symptoms include diarrhea, constipation (often alternating), bloating, gas, abdominal pain, cramping, and discomfort. Food intolerances linked to IBS include dairy foods, beans and pulses, sugars that are indigestible, fried foods, processed foods, and cabbage. Sometimes, chamomile, peppermint, and ginger can help to reduce symptoms.

18. Food aversion

People with an aversion to a particular food or drink might feel ill if they think about consuming the substance and might find it virtually impossible to take a mouthful of it as they believe it will make them sick. But the problem is psychological. The person believes that a particular food will make them ill, causing them to develop actual physical symptoms.

Food aversion is a psychological food intolerance where there is a negative physical reaction associated with ingesting food, or there is food avoidance. A psychological food intolerance displays symptoms similar to real food intolerance, but the reactions are psychosomatic and don’t happen if the specific food is consumed in a disguised form. Some people with food aversion might develop hyperventilation syndrome in response to food to the extent that they hyperventilate so much that they lose consciousness.

19. Milk and yogurt upset your stomach

If you experience gastrointestinal or other symptoms when you’ve drunk milk or eaten yogurt, you might be lactose intolerant. Lactose is the natural sugar found in milk. To digest lactose, we require adequate quantities of the enzyme Lactase. The trouble is, early humans lacked this enzyme and were unable to digest milk products. To this day, it is estimated that 65% of human beings experience some difficulty in digesting lactose and milk products after infancy. This rate of intolerance is much higher in some areas of the world, with the rate as high as 90% in people of East Asian descent.

Symptoms differ in severity from person to person, but lactose intolerance usually manifests as gastrointestinal symptoms that are similar to those of IBS, namely cramping gas, bloating, diarrhea or constipation, and abdominal pain. The most obvious solution is to avoid milk products but reads product labels carefully as milk sneaks into thousands of products.

20. Underactive thyroid (hypothyroidism)

The thyroid gland, which is butterfly-shaped and lies at the front of the neck, is a vital hormone gland. It places an essential role in the development of the human body, in bodily growth, and in metabolism. It helps to regulate many of the body’s vital functions by releasing a steady stream of hormones into the bloodstream. Thyroid hormones are wholly or partially responsible for body temperature, moods, and energy levels.

When your thyroid gland is not producing enough hormones, you develop hypothyroidism. This leads to various symptoms, such as sleeping problems, fatigue, depression, cold sensitivity, and constipation. Sometimes, food intolerances can play a role in an underactive thyroid. Finding out if you have a food intolerance if you have hypothyroidism can be severe because symptoms can be similar. For example, if you have a gluten intolerance, you might experience bloating, fatigue and depression, which mimic hypothyroidism.

21. Caffeine sends your system into overdrive

We all know caffeine is a stimulant. That’s probably why it’s one of the world’s most popular beverages. But caffeine is not everybody’s cup of tea. Being caffeine intolerant is possible. How your body reacts to caffeine differs from person to person, and one of the primary reasons for that comes down to your genes.

These days you can even be tested for caffeine sensitivity by a health practitioner who conducts genetic testing. If, for example, your body metabolizes caffeine slowly, you might experience significant discomfort if you drink a strong cup of coffee. Symptoms can include sweating, increase in blood pressure, and digestive distress. With regular consumption, there is an increased risk of heart disease. So, if your system goes into overdrive if you consume something with caffeine in it, try choosing herbal teas that are naturally caffeine-free.

22. You always feel exhausted in spite of sleeping well

If you are still exhausted, both mentally/emotionally and physically, you might be suffering from a condition called chronic fatigue syndrome. This disorder involves severe, long-term fatigue that negatively impacts on the person’s ability to function in everyday life. It has been estimated that between 1 and 4 million Americans suffer from the condition, but fewer than 20% of them have been diagnosed. The trouble is that the scientific community does not fully understand the causes of chronic fatigue syndrome.

That said, food intolerance has been a suspect for a long time. Some believe that food intolerance acts as a trigger for the disorder, along with other triggers such as genetics, stress, inflammation, and others. There isn’t a list of specific foods that are suspected to be related to chronic fatigue syndrome. And to make matters worse, foods that might give you a temporary ‘lift’ might be the very ones that cause the fatigue a day later.

23. You run to the bathroom all-day

If you avoid certain events or places because the bathrooms aren’t great, you might be suffering from food intolerance. This kind of thinking is relatively common in someone with strong food intolerance because the first symptom to strike after ingesting the offending ingredient comes in the form of digestive distress. Rushing to the bathroom several times a day is common in people with food intolerances. Symptoms include bloating and gas, diarrhea, abdominal pain, all symptoms associated with irritable bowel syndrome (IBS).

One of the culprits responsible for this condition is FODMAP foods. FODMAP is short for Fermentable Oligo-, Di-, Mono-saccharides And Polyols. This is a collection of short-chain carbohydrate molecules that the body cannot absorb well. If you have gastrointestinal symptoms, FODMAPs can bring on diarrhea or constipation, wind, bloating, and abdominal pain. A Low FODMAP diet has been shown to be successful in relieving gastrointestinal symptoms in a majority of IBS sufferers.

24. Enzyme deficiencies

If we don’t have the right digestive enzymes in the right quantities, we might develop a food intolerance. After we have chewed our food, digestive enzymes break down the larger food particles into smaller molecules. This process begins taking place in the mouth while we are chewing our food. It then continues in the stomach, where stomach acids and enzymes act upon the smaller pieces of food.

It continues in the small intestine, where tiny pieces of food can pass through the lining of the gut wall and enter the bloodstream to nourish the body. The food we eat contains three macro-nutrients: proteins, carbohydrates, and fats. Milk contains all three. In people who are lactose intolerant, the enzyme lactase is not present. The result is that milk sugars (lactose) cannot be absorbed and end up fermenting in the gut. This produces gas, cramping, diarrhea, constipation, and bloating.

25. Itchy skin

A familiar sensation many people feel when they eat food they’re intolerant to is itchy skin. This can also be a sign of many other conditions, such as eczema or hormonal changes. To differentiate different types of itches, you have to check how your skin responds to scratching. If the itch feels like it’s under the skin and it won’t subside, there’s a high chance that food intolerance is the cause of your problems. The important thing is to stay calm and not panic.

Be sure to alert your doctor if you can’t get rid of the itch. Before you do anything, it’s important to know that scratching too much won’t make matters any more comfortable. Control yourself and be sure not to injure yourself. A mild or cold shower can reinvigorate you and allow other sensations to overshadow the itching feeling. Wait for a day or two and think about what could have possibly caused the itch. Experiment and conclude.