Protein Intolerance

What is Protein Intolerance?

Protein intolerance is a condition where your body reacts negatively to proteins you consume in your diet. This can happen due to various reasons including immune system responses, non-immune related issues, metabolic conditions, genetic factors, and reaction to certain medications. Usually, this disorder comes with symptoms related to your digestive system. If diagnosed early and treated appropriately, protein intolerance can be kept under control, and the likely outcome of the condition is generally positive.

What Causes Protein Intolerance?

Protein intolerance happens when someone can’t properly break down the amino acids in proteins. When these proteins aren’t broken down well, they can cause food protein allergies. Often, this intolerance is due to proteins found in cow’s milk and is most common in infants. The symptoms include diarrhea, swelling, and lower levels of a protein called albumin in the blood. As individuals grow older and start eating more diverse foods, intolerance to egg protein, soy, and peanuts can become more common.

Protein intolerance can occur due to various conditions such as:

Immunological food protein intolerance: This is your body’s immune system response to certain proteins and can be split into two categories:

IgE mediated conditions are allergic reactions where your body produces a certain type of antibody known as IgE when you consume certain proteins. Conditions that fall into this category include:

• Cow’s milk allergy
• Oral allergy syndrome or allergies affecting the mouth
• Immediate GI hypersensitivity or sudden upset stomach after eating certain food
• Eosinophilic esophagitis, gastritis, or gastroenteritis, which causes inflammation in various parts of the digestive system

Non-IgE mediated conditions don’t involve the IgE antibodies but are still a reaction to certain foods that causes discomfort and inflammation. They include:

• Food protein-induced enterocolitis or inflammation in the gut
• Food protein-induced enteropathy or digestive system disease caused by food
• Food protein-induced allergic proctocolitis or inflammation of the rectum and colon due to food allergy

Autoimmune reactions: In some cases, the body’s immune system mistakenly attacks gluten proteins resulting in conditions like celiac disease, non-celiac gluten sensitivity, wheat allergy, gluten ataxia, and dermatitis herpetiformis, which is a skin condition.

Enzyme deficiency: Conditions like enterokinase (enteropeptidase) deficiency, which is a state where the body lacks a necessary digestive enzyme, can cause protein intolerance.

Metabolic disorders: These include phenylketonuria (PKU), maple syrup urine disease (MSUD), tyrosinemia, and homocystinuria, which are all conditions where the body has difficulty processing certain types of amino acids.

Genetic disorders: Urea cycle disorders and lysinuric protein intolerance are inherited genetic conditions which affects the body’s ability to process proteins.

Pharmacological: Chronic use of medications to suppress stomach acid production can cause protein intolerance.

Toxic reactions to biogenic amines: Some people might have reactions to tyramine found in aged cheeses or histamine.

Undefined: Conditions like irritable bowel syndrome can sometimes cause symptoms of protein intolerance without a clearly defined cause.

Risk Factors and Frequency for Protein Intolerance

Food intolerance affects approximately 15% to 20% of people. An allergy to cow’s milk, or cow’s milk allergy (CMA), is the leading food allergy found in early life. It affects between 0.5% to 3% of 1-year-olds but typically becomes less prevalent as people grow older.

According to a study in Australia, one in every 10,000 infants younger than 2 years old was found to have a condition called food protein-induced enterocolitis syndrome (FPIES). FPIES mostly affects infants and is triggered by certain proteins found in common foods like cow milk, soy, rice, oats, and eggs. However, there still isn’t enough data to fully understand how common it is.

Celiac disease, which affects people all around the globe, is particularly widespread in Western Europe and the United States. Despite its prevalence, it often goes undiagnosed in most sufferers. A comprehensive analysis conducted in 2018 found that about 1.4% of people have celiac disease according to blood tests, while 0.7% showed evidence of the disease in tissue samples studied under a microscope.

• Food intolerance impacts 15% to 20% of the population.
• The most common food allergy in early life is cow’s milk allergy, affecting 0.5% to 3% of 1-year-olds. However, this allergy tends to become less common in adults.
• An Australian study found that one in 10,000 infants under two years old suffer from food protein-induced enterocolitis syndrome, typically caused by proteins in foods such as cow milk, soy, rice, oats, and eggs.
• Celiac disease is a significant public health problem worldwide, particularly in Western Europe and the United States. It often remains undiagnosed despite an estimated prevalence of 1.4% based on blood tests and 0.7% based on biopsy.

It’s interesting to note that while no particular gender seems more prone to food intolerance, FPIES and a condition called eosinophilic gastroenteritis tend to slightly affect more males. In contrast, celiac disease is slightly more common in females.

Signs and Symptoms of Protein Intolerance

Food protein intolerance is a condition that affects various body systems in different ways. However, the most common symptoms are related to the digestive system. In non-immunological food protein intolerances, the severity of the symptoms usually matches the amount of the food ingested. Common symptoms include excess gas, bloating, stomach pain, and diarrhea. On the other hand, immunological food allergies can cause severe reactions to even tiny amounts of the food protein, and may also affect the skin and blood vessels.

Infants with food protein intolerance often begin to show symptoms before they reach six months of age, frequently developing diarrhea and eventually vomiting after being fed with certain types of baby formula. In some cases, babies will have diarrhea but still maintain a healthy weight. On the other hand, some infants may experience dehydration and weight loss.

Food protein intolerance can lead to varying symptoms among different disorders:

• Oral allergy syndrome: Those with this will experience symptoms prominently around the mouth, such as itching and burning in the lips, tongue, roof of the mouth, and throat. Swelling and vomiting can also occur.
• Immediate GI hypersensitivity: Symptoms here include nausea, stomach pain, and vomiting occurring 1 to 2 hours after eating the food protein. This is also often followed by diarrhea.
• Eosinophilic esophagitis (EoE): Symptoms include difficulty swallowing, stomach pain, vomiting, and lack of appetite. Children with this condition may experience difficulty feeding and poor weight gain.
• Eosinophilic gastritis: This usually exhibits symptoms of gastritis such as stomach pain, vomiting after meals, early fullness, lack of appetite, and failure to flourish.
• Eosinophilic gastroenteritis: This uncommon condition is characterized by symptoms such as stomach pain, difficulty swallowing, diarrhea, and can also cause protein loss, GI bleeding, or malabsorption.
• Food protein-induced enterocolitis syndrome (FPIES): This can cause vomiting, bloating, bloody diarrhea, anemia, and weight loss. Symptoms are often triggered by cow’s milk or soy protein-based formulas.
• Food protein-induced enteropathy: Symptoms include fatty diarrhea and failure to thrive during early life.
• Food protein-induced allergic proctocolitis: Usually seen in healthy breast-fed infants, it causes symptoms of blood-streaked stools.
• Celiac disease: This can lead to symptoms of diarrhea, foul-smelling stool, fat in the stool, stomach rumbles, gas, and weight loss, with signs of anemia possibly also being evident.
• Enterokinase deficiency: This can cause diarrhea, failure to thrive, and is prone to develop edema due to protein malabsorption.
• Inborn problems of metabolism: The symptoms of these vary based on which enzymes are affected.
• Toxic reactions to biogenic amines: Symptoms here include headache, palpitations, vomiting, diarrhea, and allergies.

Protein intolerance is frequently associated with skin conditions. These skin symptoms can include rashes, hives, and swelling.

Testing for Protein Intolerance

There isn’t a single test that can definitely diagnose food protein intolerance. Instead, it’s figured out mainly through a thorough review of your personal health history and a physical exam. The goal is to identify whether the intolerance is due to an immune response or not, as this helps to guide treatment. For example, if you have an allergic reaction involving an antibody called IgE to certain foods, skin prick tests and specific blood tests can often detect these antibodies. However, many food protein intolerances do not involve IgE antibodies.

When your doctor thinks that you might have food protein intolerance, they may recommend the following steps and tests to help them make a diagnosis:

1. Food diary: Keeping a record of what you eat can help your doctor relate your symptoms to the food you consume.
2. Skin prick test: This test is used to identify food allergies that involve IgE antibodies. A positive result might indicate you have these antibodies, but it doesn’t necessarily mean you have an allergy. On the other hand, a negative result strongly suggests you don’t have this kind of food allergy.
3. Atopic patch test: This test is useful for identifying delayed reactions to food proteins, which are driven by immune cells rather than IgE antibodies.
4. Specific IgE blood test: This blood test looks for specific IgE antibodies that react to certain foods.

If your doctor suspects you have a food protein intolerance or allergy, they might ask you to follow a diet that avoids the suspected food for 2-4 weeks. If your symptoms improve during this time, you might then be given an oral food challenge. This involves eating the food under medical supervision to see if symptoms return. Food protein intolerance is diagnosed if symptoms disappear during the elimination diet and return after the food challenge. Some symptoms may appear hours or days after eating the food, so you might need to repeat the diet elimination and food challenge to be sure.

Additional tests may include:

1. RAST (Radioallergosorbent) test: This test identifies IgE antibodies linked to allergies and is often positive in immediate gastrointestinal hypersensitivity.
2. Differential leukocyte count: This blood test checks for types of white blood cells called eosinophils. High levels can indicate allergic conditions like eosinophilic gastritis and gastroenteritis.
3. Stool test: This test checks for blood and immune cells in the stool, which can indicate inflammation.
4. Biopsy: This test involves taking a small sample of the stomach lining or small intestine to check for immune cells like eosinophils appearing where they shouldn’t be, or damage to part of the small intestine in conditions like celiac disease.

Keep in mind, diagnosing food protein intolerance can be complex and may involve several steps. Always make sure to reach out to your healthcare provider for guidance and support.

Treatment Options for Protein Intolerance

If you have food protein intolerance, the only sure-fire way to manage this condition is to completely remove the offending food from your diet. It’s important to check the labels of the food you buy to make sure they don’t contain the problematic ingredient. If you’re following a long-term elimination diet, you might want to consider seeking advice from a nutritionist or dietitian to make sure your diet remains balanced. It’s also essential to regularly check your growth, especially in kids.

For breastfeeding moms, if your child has an adverse reaction to cow’s milk, you may need to avoid milk and dairy products in your diet. However, for bottle-fed babies or young children allergic to cow’s milk, extensively hydrolyzed formulae – milk where the protein has been broken down into smaller parts – are often recommended as a safer alternative. If the child has severe symptoms, formulas made from amino acids might be a better option.

Steroids are generally used to handle food protein intolerance that involves your immune system. This includes disorders where your body’s white blood cells, like eosinophils, cause damage to your digestive tract.

If a baby with food protein intolerance (FPIES) shows mild symptoms, such as listlessness or pallor (paleness), they can be rehydrated at home using an oral rehydration solution. However, if the baby’s symptoms are severe, they must be taken to a medical facility for treatment with IV fluids. The treatments given for an allergic reaction (epinephrine and antihistamines) are not usually used in the management of FPIES reactions.

If you suspect food is causing acute allergic reactions or anaphylactic shock (a severe allergic reaction), you must immediately stop eating the food and seek emergency medical help. You might also be given a prescription for a device that can inject epinephrine (a medication that can save your life during a severe allergic reaction), and taught how to use it correctly.

What else can Protein Intolerance be?

People suffering from food protein intolerance may be displaying symptoms of other health conditions as well. Some common ones are:

• Intestinal infections: They share similar symptoms with protein intolerance. Here, the patient often shows signs of infection and can be treated with antimicrobials.
• Celiac disease: This disease has a strong genetic component and is linked to certain genes (DQ2 and DQ8). This confronts your body with an immune response to gluten, a protein found in certain foods. Testing for certain antibodies (anti-tTG IgA) in the blood can help diagnose or exclude celiac disease as a cause of protein intolerance.
• Gastroesophageal reflux disease (GERD): In children, this health condition may result in troubled sleep, vomiting, poor appetite, slow growth, wheezing and stridor. Adults may experience heartburn, vomiting, and regurgitation. The condition can be treated with medication, lifestyle changes or surgery. The symptoms though, are not associated with a specific food protein.
• Inflammatory bowel disease (IBD): This includes diseases like Crohn’s disease and ulcerative colitis that can cause common digestive symptoms like diarrhea, rectal bleeding, and abdominal pain. However, it’s essential to exclude IBD as a possible diagnosis, as these are chronic diseases that affect the entire body and require thorough treatment.

Therefore, it’s crucial for medical professionals to accurately pinpoint the cause of the symptoms to provide the correct treatment.

What to expect with Protein Intolerance

The outlook for many protein intolerances is positive as long as a strict dietary elimination is followed. Research has shown that for a lot of people who are allergic to cow’s milk protein, their allergies lessen or go away as they become older, usually in their adolescent years. However, it’s important to note that some children with a particular type of protein intolerance that triggers the immune system, known as IgE-mediated protein intolerance, may go on to develop conditions like allergic rhinoconjunctivitis (allergies affecting the nose and eyes) and asthma.

Possible Complications When Diagnosed with Protein Intolerance

Protein is a vital nutrient for the growth and health of our bodies. Protein deficiency due to tolerances can lead to several complications such as shrinking muscle mass, suppressed growth, failure to flourish properly, and a weak immune system. Some of the symptoms experienced by people with protein deficiency are swelling in the legs, face and other body parts, dry and brittle hair, constant tiredness, and regular infections.

In adults, allergic reactions to proteins found in cow’s milk can become worse with lactose intolerance, a condition that becomes more common as we age. These allergies may cause quick-onset allergic reactions and swelling in the deeper layers of the skin, which can become life-threatening if not treated. Diarrhea and vomiting caused by Food Protein-Induced Enterocolitis Syndrome (FPIES) and a disorder called eosinophilic gastroenteritis can lead to serious complications such as extreme dehydration and a drop in blood volume that can cause shock.

Common Complications of Protein Deficiency:

• Loss of muscle mass
• Delay in growth
• Failure to thrive
• Weakened immune system
• Swelling in the body, face, and legs
• Dry and brittle hair
• Fatigue
• Frequent infections
• Severe dehydration
• Drop in blood volume
• Lactose intolerance with allergic reactions to cow’s milk proteins
• Anaphylactic reactions
• Swelling in the deeper layers of the skin
• Potentially life-threatening conditions if not managed properly

Preventing Protein Intolerance

For healthy babies, it’s generally recommended to exclusively breastfeed for the first six months of life. Afterwards, introducing solid foods gradually can help to possibly avoid food allergies or intolerance. Babies who are allergic to cow’s milk should steer clear from formula milk and should continue to be breastfed. The mothers who are breastfeeding these infants are advised to avoid eating dairy products.

If breastfeeding isn’t possible, there are alternative options, such as a special kind of formula known as extensively hydrolyzed formula. This formula is developed in a way that makes it easier for babies to digest.

Healthcare professionals should ensure parents are aware of the significance of removing certain foods from the diet if a protein intolerance or allergy is suspected. This means they have to be mindful of the ingredients in the foods they buy. Importantly, families who have to eliminate certain foods from their diets should receive guidance from a proficient dietitian or nutritionist, who can give them advice and make sure the diet is balanced and healthy.

Furthermore, people who have had severe allergic reactions to food proteins in the past should be prescribed an epinephrine injection pen. This is a device that they can use to inject medicine in case they accidentally consume a food they are allergic to, helping them to prevent or treat severe allergic reactions.