What Causes Sudden Food Intolerance?

Have you ever experienced an upset stomach after eating or drinking your favourite foods or beverages? If your answer is yes, then you may have developed an intolerance to certain foods that you have been eating for years.

Fast Facts on Food Intolerance

Food intolerance — also referred to as food sensitivity — is a reaction of certain chemicals in your body to particular substances found in the foods you eat. This could result in your inability to digest these foods, leading to nutrient malabsorption, abdominal pains and other discomforts. Unlike food allergy—or IgE-mediated food hypersensitivity—food intolerance is not life-threatening. Symptoms of food intolerance may also take a longer time to appear, as this condition usually requires a certain threshold level to be attained.

Cracking the Common Types and Corresponding Causes of Food Intolerance

Food intolerance may be hereditary and detected during childhood, but it can also emerge later in life. It is possible for your body to develop an aversion to certain foods as you age or after a change in diet. A sudden sensitivity to certain foods can also occur as a result of taking medications (e.g. antibiotics) for a considerable time or due to a stressful life event like losing your job, going through a breakup or divorce, undergoing major surgery or battling a serious illness.

Below are the most common types of food intolerance and what causes each of them:

1. FODMAP Intolerance

FODMAPs (short for fermentable oligo-, di-, mono-saccharides and polyols) are short-chain carbohydrates found in a variety of foods like beans, honey, certain fruits and vegetables, and sweeteners.

If your body reacts negatively to foods that contain FODMAPs, it may be due to its inability to produce the enzymes required to metabolise FODMAPs. This causes the food to travel to your large intestine in an undissolved form. Here, it is fermented by gut bacteria, producing gas that results in bloating and other undesirable effects.

2. Lactose Intolerance

Lactose is a disaccharide found in milk and other dairy products. It is broken down by the enzyme lactase. When you were a baby, your body produces a large amount of lactase to help you digest the milk you consume. Once you start eating more solid foods and are weaned from milk, your body produces less lactase.

Symptoms of lactose intolerance may suddenly appear as you grow older and your production of lactase declines. As an adult, you may begin to experience flatulence and diarrhoea after consuming dairy products. But don’t fret as this is a relatively common condition. You may be one of the estimated 50% of the population who exhibit symptoms of lactose intolerance beyond infancy.

3. Gluten Intolerance

Similar to lactose intolerance, a study revealed that gluten sensitivity develops as people get older. There is an increase in the number of participants who had coeliac disease (an autoimmune disease triggered by gluten) after 15 years.

This phenomenon is linked to the change in the bacterial composition in the intestines of the subjects who were diagnosed with coeliac disease 15 years later. Since coeliac disease is a genetic disorder, the researchers concluded that the participants were already predisposed to this condition and that the altered composition of their gut bacteria triggered it. This change in bacterial composition may be caused by a stressful life event or medication.

If you exhibit signs of gluten sensitivity but test negative for coeliac disease, you may have non-coeliac gluten sensitivity (NCGS). Do not worry so much if you are diagnosed with NCGS. You may experience similar symptoms felt by those with coeliac disease, but NCGS will not cause permanent damage to your intestines.

4. Intolerance to Caffeine

Caffeine is a chemical present in chocolates, coffee, tea, soda and energy drinks. It stimulates a feeling of alertness and reduces fatigue by blocking adenosine receptors. Adenosine is a neurotransmitter that regulates your sleep-wake cycle and causes drowsiness.

Normally, adults can consume up to 400 mg of caffeine (about four cups of coffee) a day without experiencing adverse effects. However, if you are sensitive to caffeine, you may have negative reactions like palpitations, restlessness and insomnia even after taking just a small amount.

Caffeine intolerance may be a result of your body’s decreasing ability to digest caffeine as you age, or stress-related.

5. Intolerance to Amines

Amines are chemicals that can be found in different foods. They are a byproduct of bacteria during food storage and fermentation. Among the many types of amines, histamine is the one most frequently associated with food hypersensitivity.

Histamine is involved in various functions of your immune, digestive and nervous systems. It triggers an immediate inflammatory response such as sneezing, itching and watering of the eyes to help protect your body from infection by expelling allergens and other foreign elements.

If you have an intolerance to amines, it means your body is unable to properly metabolise them. Amines can then accumulate in your body and trigger symptoms like migraines, flushing and nasal congestion. Histamine intolerance can be attributed to a deficiency of diamine oxidase and N-methyltransferase—the enzymes responsible for breaking down histamine.

6. Intolerance to Food Additives

These days, almost all kinds of foods contain additives to enhance their taste, improve their appearance or help preserve them. Some examples of common food additives include:

  • Antioxidants
  • Artificial colourings
  • Artificial flavourings
  • Emulsifiers
  • Flavour enhancers
  • Preservatives
  • Sweeteners

Only a few types of food additives are believed to cause negative reactions in a very small population. These are:

  • Nitrates. Preservatives and colour fixatives present in processed meats that cause itching and skin rashes.
  • MSG (monosodium glutamate). Added as a flavour enhancer. Known to cause headaches.
  • Sulphites. Used to increase the shelf life of foods or enhance flavour. Commonly found in wines.
  • Some food colourings. Carmine (red) aggravates asthma and annatto (yellow) causes headaches.

Identifying Food Intolerances and Insights into Improvement

We recommend keeping a food diary to make the task of identifying the causes of your food intolerance easier. A food diary is where you will record the foods you eat, how they affect you and when. Use this data to identify the foods that trigger your symptoms.

You may be advised to undergo an elimination diet under the supervision of a medical practitioner or nutrition specialist. Professional supervision is very important so you won’t suffer from malnutrition when you restrict yourself from certain foods. In addition to an elimination diet, your doctor may also recommend a skin and/or blood test to rule out food allergy.

Working with your doctor or dietitian will help you figure out the causes of your food intolerance without jeopardising your health.

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