Lactose Intolerance vs. Milk Allergy?

What is Lactose Intolerance

A food intolerance is different than a food allergy. It can be confusing, but it helps to know what’s what in order to healthfully navigate food choices. When it comes to milk, here’s the difference:

Lactose Intolerance:

Lactose Intolerance (LI) refers to the body’s physical response to the sugar found in milk. While its symptoms can be really uncomfortable, there are no lasting, harmful consequences. Here’s the quick 411 on how dairy digestion works:

  • Lactose is the simple sugar found in milk, comprised of two sugar molecules – glucose and galactose.
  • In the intestine, the enzyme lactase breaks lactose into its component sugar molecules for complete digestion and absorption.
  • As people age, the amount of lactase in the body slowly declines, a term called lactase non-persistence.
  • Without enough lactase, the undigested sugar moves further along the intestinal tract into the colon, where bacteria break it down. This process is called lactose maldigestion since the milk sugar is not digested in the proper part of the intestine by the enzyme lactase.
  • If the byproducts of bacterial digestion cause physical symptoms (individual reactions can be different), such as gastrointestinal distress, the consequence is lactose intolerance. Many people have maldigestion without physical symptoms.

A Milk Allergy:

An allergy to milk is a different beast all together. When someone suffers a cow’s milk allergy, the body actually mounts an immune response to one or more of the proteins found in milk – reactions to b-lactoglobulin, casein,  a-lactalbumin, and bovine serum albumin are the most common. As is the case with all food allergies, the reasons why the body treats these benign proteins as foreign invaders is unclear. Milk allergy is most common in infants and young children – approximately 2.5% of children experience this in the first three years of life. Most of these children – about 80% – outgrow the allergy and can tolerate milk by age 4.

Symptoms associated with milk allergy vary from individual to individual but can include hives, wheezing or vomiting and in severe cases, anaphylaxis. In some people, symptoms can be similar to those associated with lactose intolerance – loose stool, diarrhea, or abdominal cramping.

For those with a milk protein allergy, the solution is avoidance.

So to recap:

Lactose intolerance refers to the body’s inability to digest the sugar found in milk. Those with LI can still enjoy dairy, by opting for lactose-free milk products or by choosing dairy foods that are naturally low in lactose or lactose-free like aged, natural cheeses, and fermented dairy products like yogurt and kefir.

When the immune system gets involved, the body has an allergic reaction to one or more of the proteins found in milk. It is likely that most children with the condition will outgrow it, but while symptoms persist, avoidance is the solution.

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