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RD Andy Desantis, Toronto, Ontario

Educational video describing Lactose Intolerance Vs a Milk Protein Allergy

If you’re over 50, lactose intolerance and a milk-protein allergy can still occur, but they are quite different conditions.

Lactose intolerance Milk-protein allergy
What causes it? Difficulty digesting lactose (milk sugar) because of low lactase enzyme Immune reaction to milk proteins, mainly casein and whey
Typical symptoms Bloating, gas, cramps, diarrhea, urgency Hives, itching, swelling, vomiting, wheezing, throat symptoms, or sometimes GI symptoms
Timing Usually within a few hours of consuming lactose Often minutes to a couple of hours after exposure; can occasionally be delayed
Can you tolerate lactose-free milk? Usually yes No — lactose-free milk still contains milk proteins
Can you tolerate hard cheese/yogurt? Often better tolerated Still potentially problematic
Does it usually begin later in life? Yes, quite commonly

A particularly important distinction after 50

If your symptoms are primarily gas, bloating, abdominal rumbling, cramps or diarrhea, without hives, swelling, breathing problems, or repeated vomiting, lactose intolerance is generally more consistent with that pattern.

If you develop hives, facial/lip/tongue swelling, wheezing, difficulty breathing, throat tightness, dizziness, or fainting after milk, that raises concern for an allergic reaction and warrants medical evaluation. Breathing or throat symptoms or fainting after consuming milk should be treated as an emergency.

Also, milk allergy isn’t the same thing as sensitivity to lactose: switching from ordinary milk to lactose-free milk can help lactose intolerance, but it won’t make milk safe for someone allergic to milk proteins.

If you’re asking because you’ve recently started having symptoms after milk or dairy, tell me what happens, how soon after eating/drinking it starts, and which dairy products trigger it. I can help you distinguish the patterns.

RD Andy Desantis, Toronto, Ontario

Educational video describing shellfish Allergies

Shellfish isn’t one single allergy

There are two broad groups:

  • Crustaceans: shrimp, crab, lobster, crawfish

  • Mollusks: clams, mussels, oysters, scallops, squid, octopus

Someone can react to one group but tolerate another, although shrimp, crab, and lobster often cross-react because they share related proteins.

Also, shellfish allergy is different from an allergy to fish. Being allergic to shrimp, for example, doesn’t automatically mean you’re allergic to salmon or cod.

If this is a new reaction after 50

It’s worth seeing an allergist rather than simply assuming it’s an allergy. Reactions to shellfish can sometimes be caused or complicated by things such as food poisoning, toxins in contaminated shellfish, or other ingredients in the meal.

If you’ve had throat swelling, trouble breathing, fainting, or widespread hives after shellfish, don’t deliberately eat it again to “test” yourself. Seek medical evaluation; an allergist can determine whether testing and an epinephrine prescription are appropriate.

If you tell me what shellfish you ate, what symptoms you experienced, and how long afterward they started, I can help you understand whether the pattern sounds more like an allergy, intolerance, or food poisoning.

What a shellfish allergy can look like

Symptoms can occur within minutes to a few hours after eating shellfish and may include:

  • Hives, itching, or flushing

  • Swelling of the lips, face, tongue, or throat

  • Tingling or itching in the mouth

  • Abdominal cramps, vomiting, or diarrhea

  • Coughing, wheezing, or difficulty breathing

  • Dizziness, fainting, or a sudden drop in blood pressure

A serious reaction (anaphylaxis) can occur even if previous reactions were relatively mild.

RD Andy Desantis, Toronto, Ontario

Educational video describing Soy Food Allergies

Importantly, highly refined soybean oil and soy lecithin are tolerated by many people with soy allergy, but whether they’re safe depends on the individual and the severity of the allergy.

Allergy vs. intolerance

If you mainly experience gas, bloating, or digestive discomfort after soy without hives, swelling, breathing symptoms, or other allergic features, an intolerance or another gastrointestinal issue may be more likely than a classic IgE-mediated allergy.

If you’re developing reactions to soy, dairy, or shellfish for the first time after 50, it’s particularly useful to have an allergist evaluate the pattern rather than eliminating a large number of foods based solely on symptoms.

If you tell me which soy food caused the reaction and exactly what happened afterward, I can help you sort out whether the pattern is more suggestive of soy allergy, intolerance, or something else.

A soy allergy can develop in adulthood, including after age 50, although soy allergy is more commonly diagnosed in children. It’s an immune reaction to soy proteins, not an intolerance to a particular carbohydrate.

What a soy allergy can cause

Symptoms typically appear within minutes to a few hours after eating soy and can include:

  • Hives, itching, or flushing

  • Tingling or itching in the mouth

  • Swelling of the lips, tongue, face, or throat

  • Nausea, vomiting, stomach cramps, or diarrhea

  • Coughing, wheezing, or difficulty breathing

  • Dizziness or fainting

A severe reaction can cause anaphylaxis.

Foods that may contain soy

Soy is found in more foods than just tofu and soy milk. Examples include:

  • Tofu and tempeh

  • Soy milk and soy yogurt

  • Edamame

  • Miso and many soy sauces

  • Some protein bars and meal-replacement products

  • Some processed meats and packaged foods

  • Foods containing soybean oil or soy lecithin

RD Andy Desantis, Toronto, Ontario

Educational video describing Understanding Egg Protein Allergies

Egg intolerance or sensitivity is different. It may cause primarily digestive symptoms such as bloating, gas, nausea, or diarrhea without the typical allergic symptoms.

One useful clue

Some people who react to raw or lightly cooked egg can tolerate thoroughly cooked egg because heating changes some of the proteins. However, don’t deliberately test this yourself if you’ve previously had an allergic-type reaction.

Egg can also be hidden in foods such as baked goods, mayonnaise, pasta, sauces, and some prepared foods.

If this is new after 50

Because new food reactions later in life can have several causes, an allergist can distinguish an actual egg allergy from intolerance or another reaction using your history and, when appropriate, skin-prick or blood testing.

If you’ve had throat/tongue swelling, difficulty breathing, fainting, or widespread hives after eating egg, avoid further exposure and seek prompt medical evaluation. If those symptoms are happening now, seek emergency care.

Egg allergy can occur after age 50, although new-onset egg allergy in adults is relatively uncommon compared with childhood allergy.

Egg allergy vs. egg intolerance

Egg allergy is an immune reaction to egg proteins, particularly proteins in the egg white. Symptoms can include:

  • Hives or itching

  • Swelling of the lips, face, or throat

  • Tingling/itching in the mouth

  • Vomiting, abdominal cramps, or diarrhea

  • Coughing, wheezing, or difficulty breathing

  • Dizziness or fainting

RD Andy Desantis, Toronto, Ontario

Educational video describing Wheat and Gluten Allergies

After 50, celiac disease is particularly worth considering

Celiac disease can be diagnosed at any age, including later adulthood. It doesn’t necessarily cause dramatic digestive symptoms. Unexplained iron-deficiency anemia, osteoporosis, chronic diarrhea, weight loss, or nutritional deficiencies can sometimes be clues.

One important point: don’t start a strict gluten-free diet before being tested for celiac disease if celiac is a possibility. Removing gluten can make the blood tests—and sometimes the subsequent evaluation—less informative.

What about ordinary wheat allergy?

A true wheat allergy can also occur in adults, but its symptoms tend to resemble other immediate food allergies: hives, swelling, vomiting, wheezing, or anaphylaxis shortly after eating wheat.

If your reaction is primarily bloating, gas, abdominal discomfort, or changes in bowel movements, that pattern doesn’t by itself establish a wheat or gluten allergy.

wheat and gluten-related conditions can become apparent after age 50, but “wheat allergy” and “gluten intolerance” are not the same thing.

Wheat allergy vs. celiac disease vs. gluten sensitivity

Condition What triggers it? Typical symptoms
Wheat allergy Immune reaction to wheat proteins Hives, itching, swelling, vomiting, wheezing, breathing difficulty; sometimes anaphylaxis
Celiac disease Immune reaction to gluten (in wheat, barley, rye) that damages the small intestine Diarrhea, bloating, abdominal pain, weight loss, fatigue, anemia; sometimes few or no digestive symptoms
Non-celiac gluten sensitivity Symptoms associated with gluten/wheat without evidence of celiac disease or wheat a