Cow’s milk allergy vs. Lactose Intolerance

Lactose intolerance is not the same thing as an allergy to cows’ milk. Cow’s milk allergy refers to an immune response to the protein in milk and milk products. This is an allergic reaction to milk and is more often seen in childhood. You may have a quick reaction to even a tiny amount of that food (although some allergic reactions may occur up to 72 hours after having cows’ milk). Symptoms may include swelling of the eyes, lips, tongue and roof of the mouth, itchiness in the mouth, ears or throat, a red rash or eczema.

Lactose intolerance refers to the inability to digest the sugar in the milk called lactose. It is critical to get the correct diagnosis and the management of the two conditions is very different. Most people with lactose intolerance can still consume small amounts of dairy containing lactose with no symptoms whereas someone with an allergy to cow’s milk needs to follow a very strict diet and cannot have any cow’s milk.

The science

Lactose intolerance is a digestive problem where the body is unable to digest the sugar commonly found in dairy products called lactose. Normally the enzyme lactase is responsible for breaking down lactose into smaller compounds so our bodies can absorb it. In the case of lactose intolerance, there is absence or deficiency of lactase, so the lactose is not absorbed by the small intestine and bacteria in the colon end up breaking down the lactose which produce gases that build up. This causes symptoms such as bloating, wind and abdominal pain.

Lactose intolerance is rare in children, affecting mostly adults. It mostly develops later in life although there a few people that may have it from birth. It is also more common in those from an Asian or African-Caribbean background. You may develop lactose intolerance if you have had a gastrointestinal illness but it is usually temporary.