Navigating Food Sensitivities: Understanding Lactose & Gluten Intolerance

Milk and wheat are two of the most common foods consumed in the world: from cheese and yogurt to breads and couscous, almost every culture includes these ingredients in their cuisines in some form. And that’s great because these two foods are full of nutrition. Milk is a complete food. It’s a good source of protein, carbohydrates, fats, vitamins A, D, E and K, and minerals like calcium, magnesium, sodium, potassium, phosphorus, iron, zinc, copper, and selenium. Wheat also contains carbohydrates, some protein and fat. It is also a great source of prebiotic fiber that feeds the gut microbiota. Plus, it also contains vitamins and minerals like thiamine (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), folate (B9), betaine, choline, and iron - although the amounts present depend on the particular wheat variety and whether the grain has been refined or not.

Milk and wheat are also two of the most common ingredients related to adverse food reactions - both allergies and intolerances. They are  often villainized on social media by wellness gurus and they’re also the two most common foods that our clients have removed from their diets. And while sometimes this may be warranted, it’s often not and can result in a person missing key vitamins and minerals in their diet. Keep reading to learn the differences between these different types of reactions and how they can be managed.

Let’s Talk Dairy

Milk Allergy

A cow’s milk allergy is one of the most common food allergies and it’s usually detected in babies, as this is often one of their first foods. A cow’s milk allergy is an immune-mediated reaction to the proteins found in the milk. There are two main components of milk protein- casein and whey. Whey is comprised of β-lactoglobulin, α-lactalbumin, serum albumin, and serum immunoglobulins. Of these, casein and β-lactoglobulin are thought to be the most allergenic, which is why there is now availability of A2 milk on the market. It should be noted that all components of milk proteins can lead to an allergic reaction.

For people with a milk allergy, the immune system mistakenly sees milk proteins as harmful compounds. This triggers the release of IgE antibodies, which bind to mast cells and basophils (white blood cells that play important roles in your immune system). When milk is consumed again, these cells release histamine and other inflammatory chemicals.

As an allergy, the reaction will occur every time that milk is ingested although the response can present differently depending on the person. Some will experience hives or itchy skin or gastrointestinal symptoms like diarrhea, cramping, or vomiting. Others will have respiratory symptoms like wheezing, sneezing, or, in severe cases, anaphylaxis.  

Symptoms of a milk allergy can occur within minutes or up to two hours after consumption. In some, it may take up to 48 hours to occur. For this reason, and because some allergic responses are similar to lactose intolerance, it’s best to meet with an allergist and be properly tested with a blood and skin-prick test and/or carry out an oral food challenge.

Lactose Intolerance

Lactose or dairy intolerance is different from a milk allergy. It is not an immune-mediated or inflammatory reaction to a protein found in milk, but occurs when the body is unable to digest and absorb lactose, the carbohydrate portion of milk. Lactose is a disaccharide made up of two monosaccharide sugars - glucose and galactose. When consumed, it travels to the small intestine where it is then hydrolyzed, or broken into its two monosaccharides, by an enzyme called lactase that is located on the microvillae of the small intestines. Glucose and galactose are then absorbed and used as energy throughout the body.

When there is not enough lactase or more lactose is ingested than a person has lactase, malabsorption can occur. The lactose isn’t broken down into glucose and galactose and remains as a disaccharide,which then continues to travel to the large intestine where it can draw in water and also be fermented by the microbes who reside there.

This water and fermentation can cause gas, cramping, pain, diarrhea, and, depending on the composition of a person’s microbiome, constipation (archaea, who ferment carbohydrates like lactose and produce methane, which can slow peristalsis, or the stomach contractions resulting in slower motility, gas and constipation). A small subset of people may experience non-gastointestinal symptoms like headaches, vertigo, and tiredness. The severity of the symptoms can depend on the amount of lactose ingested relative to the amount or activity of lactase available in the intestines.

Types of Lactose Intolerance

There are several reasons why someone might malabsorb lactose, and it’s reported that nearly two thirds of the world’s population has difficulty digesting lactose. In fact, some groups of people are more prone to lactose intolerance. This includes people of West African, East Asian, Arab, Jewish, Greek, and Italian descent. Lactose malabsorption can be broken down into four categories:

1. Developmental lactase deficiency is seen in premature babies whose systems have not yet fully developed. This type of lactase deficiency is usually temporary and improves with age.
2. Congenital lactase deficiency, or alactasia, is a rare recessive genetic condition that’s due to a defect in the gene responsible for making the lactase enzyme. This condition is seen in infants who consume breast milk and/or lactose containing formula and presents with severe diarrhea. This is a life long deficiency.
3. Primary lactose intolerance, also known as Lactase non-persistence or hypolactasia, is the most common type of lactose intolerance and occurs when the lactase enzyme activity decreases to about 10% of what it was at birth, when it was needed to digest breast milk. This can be a result of normal aging or related to dietary changes and is irreversible.
4. Secondary lactase deficiency can happen as a result of damage to the small intestine and can be reversed once the damage is repaired. This type of lactose intolerance can be seen in those with conditions such as celiac disease, viral gastroenteritis, giardiasis, bacterial overgrowth (SIBO), Crohn’s disease, bowel resections, etc.

Diagnosing Lactose Intolerance

So how does one find out if they have a lactose intolerance? Well, there are a few diagnostic tests that your doctor can perform.  These include:

1. A breath test that measures the amount of hydrogen that is produced after consuming a lactose containing solution.
2. A blood test that measures blood glucose at different times after ingesting 50 grams of lactose.
3. Genetic testing that can identify common variants of the gene associated with primary lactose intolerance (although this will not tell you if a person will develop lactose intolerance over the course of their life).
4. A quick lactase test, which measures the amount of lactase activity after a sample is taken during an upper endoscopy/gastroduoendoscopy. This test is the most invasive, yet very easy for a gastroenterologist to complete if a patient is already being scoped.

How to Manage a Milk Allergy or Lactose Intolerance

Milk allergies and lactose intolerance can have many of the same symptoms like gas and diarrhea, but their mechanisms are very different. With an allergy, there is an immune reaction to the proteins in milk, while lactose intolerance is the inability to break down the carbohydrate lactose into usable sugars. Because of this, they should be handled differently.

Managing a Milk Allergy

For a milk allergy, all milk, milk products, and milk containing foods MUST be avoided. This includes milk, butter, ghee, yogurt, whey and casein protein hydrolysates, lactose, many baked goods, goat’s milk, etc. There is no enzyme that can help with this (or any) allergy.

However, some children can outgrow milk allergies (an allergist can help to determine if someone will outgrow), while others may deal with it for life. Fortunately, since milk is one of the top allergens, it is required by law to be listed on food packages if it contains or is manufactured in a place that processes milk or milk products. This, along with a rise in plant milks and vegan food in the marketplace make it a (tiny) bit more manageable for someone who has a milk allergy to navigate the food world.

Getting enough calcium in the diet can be challenging for those with a milk allergy, head to our blog on non-dairy sources of calcium for foods to include to ensure one's needs are being met.

Managing Lactose Intolerance

For those who have lactose intolerance, nutritional management should reduce the amount of lactose in the everyday diet. However, apart from someone with alactasia, lactose should NOT be completely excluded from the diet as this could lead to micronutrient deficiencies as dairy products are major sources of calcium, phosphorus, choline, riboflavin, vitamin B12, and vitamin A. In fact, according to research, most people with lactose intolerance can tolerate about 12 grams of lactose per day, which is equal to a cup of milk.

There are also many dairy products that are naturally low in lactose. Yogurt and kefir are usually well tolerated because the bacteria in them ferment and break the lactose down - they do the work for you! Butter and most hard cheeses are also very low in lactose. Some of our favorites include cheddar, parmesan, manchego, swiss, brie, havarti, and gouda.

Lactase enzyme supplements are also available and can be of great help to those with primary or secondary lactose intolerance. The research shows effectiveness with 3,000-11,250 international units (IU) of lactase. Lactase supplements should be taken with the first bite of the meal - not thirty minutes before or an hour after the meal. The enzyme has to come into physical contact with the food for it to work, if not it’ll be wasted and you’ll be more likely to experience unwanted symptoms. Additionally, if having a long drawn out meal, more enzyme may be required halfway through for it to be effective.

Lastly, there are many lactose- free products on the market like yogurt, milk, and cottage cheese, which have the lactase enzyme already added to them. Wondering how many IU of lactase would be effective for you? This is where individualized nutrition care shines bright! It depends on what you’re eating, how much, how often, etc. As GI dietitians, we can create tailored recommendations to you personally. Click the complimentary consultation button at the end of the blog to see how Amenta can help you!

Let’s Talk Wheat!

Wheat Allergy

Now that we’ve tackled dairy and lactose, let’s dive into wheat. A wheat allergy is an IgE-mediated allergic reaction to the protein components of wheat including gliadins, glutenins, albumins, and globulins. This is similar to a milk allergy as the immune system mistakenly identifies wheat proteins as harmful compounds, causing the production of IgE antibodies, which bind to mast cells and basophils.

The next time wheat is eaten, these immune cells release histamine and other inflammatory chemicals causing symptoms like hives, eczema, swelling, nausea, vomiting, diarrhea, abdominal pain, sneezing, wheezing, and difficulty breathing. Severe allergic reactions may cause anaphylaxis.

Unlike milk, a wheat allergy can also occur from inhaling wheat particles. This is known as baker’s asthma. Those with baker’s asthma do not usually have symptoms when they consume cooked wheat or products that contain cooked wheat, but will react after ingestion of products contaminated with raw wheat flour or inhaling flour particles. Like milk, testing for a milk allergy can be done via blood and skin-prick test and then an oral food challenge may be recommended.

Celiac Disease

Celiac disease is an autoimmune disorder that is triggered by ingestion of gluten, one of the proteins found in wheat, rye, and barley. Unlike a wheat allergy, celiac involves an abnormal T-cell (an immune cell) response that leads to intestinal damage and malabsorption.

When a person with celiac consumes food with gluten, the body initiates an immune response that mistakenly targets the small intestine. When you eat gluten, your body breaks it down into smaller pieces called gliadin peptides, but these aren’t fully digested. They sneak through the gut lining and activate an enzyme called tissue transglutaminase (tTG), which changes gliadin in a way that makes your immune system more likely to react. Since your gut is packed with immune cells, this sets off a chain reaction. In people with certain genes (HLA-DQ2 or HLA-DQ8), immune cells recognize the modified gliadin as a threat, triggering an intense inflammatory response that leads to tissue damage.

As this inflammation becomes chronic, the intestinal lining is damaged, blunting the intestinal villae, and impairing nutrient absorption. This can lead to the malabsorption of nutrients, vitamins and minerals, or conditions like sucrose or lactose intolerance. Patients with celiac can experience symptoms like pain, bloating, diarrhea, constipation, lethargy, headaches, reflux, skin rashes and brain fog.

Celiac disease can be diagnosed with a combination of serological tests and duodenal biopsies. For the serological tests, serum anti-tTG IgA antibodies are the most sensitive and specific test, while Anti-endomysial (EMA) antibodies and anti-deamidated gliadin peptide (DGP) antibodies may also be measured. During this process it is very important for the person being tested to NOT be on a gluten-free diet (they must have consumed about 1-2 pieces of bread per day for the past six weeks).

Depending on the results, this will then be followed by an endoscopy and duodenal biopsy to establish the diagnosis. Villous atrophy (blunted microvillae), hyperplasia, and increased intestinal intraepithelial lymphocytes on the duodenal biopsy together, along with positive serological results, can confirm a celiac disease diagnosis. Genetic testing can be done to identify the celiac genes (HLA-DQ2 or HLA-DQ8), although their presence will not confirm a diagnosis, but their absence can rule out a celiac diagnosis.

Gluten Intolerance/Non-celiac gluten sensitivity/non-celiac wheat sensitivity

Gluten intolerance, non-celiac gluten sensitivity (NCGS), or non-celiac wheat sensitivity (NCWS) are three terms that are often used interchangeably to describe a syndrome that occurs after a person eats wheat, gluten, and other grain components such as fructans and amylase-trypsin inhibitors (ATIs). Because there is uncertainty in which component of wheat is actually causing symptoms, NCWS is currently the most widely accepted name. With NCWS, a person will eat wheat or other gluten containing grains and experience symptoms such as abdominal pain, distension, gas, diarrhea, constipation, fatigue, headache, pain in muscles and joints, eczema,and more.

Unlike celiac disease or a wheat allergy, there is no autoimmunity nor IgE-mediated allergy reaction in the body. However, there is newer evidence in some with IBS showing that there is inflammation in the small intestine (without having blunted microvillae like celiac) and an increased presence of immune cells in the intestines. The data is inconclusive though, and there are other autoimmune diseases that can also present this way including Hashimoto thyroiditis, Graves’ disease, psoriasis, rheumatoid arthritis, and multiple sclerosis. It’s also important to emphasize that wheat contains many potentially immunogenic proteins in addition to gluten, and also nonprotein fractions like fructans that could trigger symptoms in patients with disorders like IBS.

Currently, there is no diagnostic test to determine if someone has NCWS. To be diagnosed, one has to be experiencing symptoms after eating wheat containing foods and be ruled out for celiac and a wheat allergy. Then, a person will begin a gluten-free diet for six-weeks. If all symptoms resolve after six weeks, then a doctor can give a diagnosis of NCWS. If a patient is still experiencing any symptoms, additional testing will need to occur and it is most likely not related to wheat.

Managing a Wheat Allergy, Celiac, & Non-Celiac Wheat Sensitivity

Wheat allergies require a strict avoidance of all wheat products and for many, the easiest way to accomplish this is by using certified gluten-fee products. It should be noted that re-testing should occur for this allergy as many children usually outgrow it by school age.

Celiac disease requires a strict gluten-free diet for life. This includes gluten and gluten-related proteins found in rye, barley, and all types of wheat. Currently, there is no enzyme, pill, or other miracle drug that can help someone with celiac be able to tolerate any gluten-containing foods.

NCWS also requires a wheat or gluten-free diet although some people may be able to tolerate small amounts or be less strict than someone with celiac. However, it’s important to be properly diagnosed by a doctor as self-diagnosis could remove healthy grains full of fiber, vitamins, and minerals from the diet. For instance, someone with IBS might be sensitive to fructans, one of the carbohydrates in wheat and not gluten, the protein. In this case, they may be able to tolerate sourdough bread or use an enzyme to help break down the fructans for easier digestion, which will allow them to have a more varied, more nutritious diet.

Navigating Dairy and Wheat Intolerances with Confidence

Understanding the differences between milk allergies, lactose intolerance, wheat allergies, celiac disease, and non-celiac wheat sensitivity (NCWS) is essential for making informed dietary choices. While these conditions may share some overlapping symptoms, their underlying mechanisms are distinct—ranging from immune-mediated allergic reactions to enzyme deficiencies and autoimmune responses.

For those with milk or wheat allergies, complete avoidance is necessary to prevent severe reactions. However, individuals with lactose intolerance can often tolerate small amounts of dairy or use lactase enzymes to aid digestion. In contrast, celiac disease requires lifelong gluten avoidance, while NCWS may vary in severity and dietary restrictions.

Rather than following food trends or unnecessary eliminations, it's vital to get a proper diagnosis and work with healthcare professionals (like Amenta!) to develop a personalized approach. By understanding how these food sensitivities impact the body, individuals can manage their diets effectively while still maintaining optimal nutrition.

Have you experienced a food intolerance or allergy? We want to hear from you! Message us on social media @amentanutrition and we may feature you in one of our posts.

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