Lactose Intolerance Facts

Lactose is the most prevalent sugar found in cows’ milk and dairy products, making up approximately 4.8% of the average gross composition of milk.

Lactose can also be found in human breast milk and many baby milk formulas, but is not found naturally in any other foods, aside from dairy products. However, it is sometimes added to processed foods during the production stages.

Lactose intolerance is the inability or insufficient ability to digest lactose, a sugar found in milk and dairy products.

Lactase is an enzyme that is produced by the cells lining the small intestine. This enzyme’s role is to break down any ingested lactose into simpler forms. These simplified sugars are called galactose and glucose and are more easily absorbed into the bloodstream to be used as fuel by the body’s cells.

Lactose intolerance occurs when the body is not able to produce sufficient amounts of lactase to fulfill this task. While this intolerance can sometimes be found in infants, usually just for a few weeks after an upset tummy, it is more likely to develop later in life as the body’s lactase production slows down.
 
Very few people produce no lactase at all. Most people produce at least a small amount and therefore may be able to tolerate small amounts of lactose.

Lactose is the sugar naturally found in all cows’ milk and in mammalian milk, such as goats’ milk and human breast milk.

While lactose is not found naturally in any other foods, aside from dairy products, it is often added to many food items that one would not expect. It is useful to check the labels on products to establish which lactose foods to avoid.

Finding a complete list of lactose foods can be difficult, so it is worth knowing which types of food could have added lactose.

Processed foods often contain lactose as it is almost tasteless and offers a variety of functions from preventing caking to providing filler content. Lactose is also commonly added to tinned and frozen vegetables to prevent discolouration and can even be found in the coating of some medicinal tablets and capsules.

It is also worth bearing in mind that some foods labelled as non-dairy could still contain lactose in the form of whey or dry milk solids.

Individuals may be born lactose intolerant, however this is extremely rare. In most individuals, lactose intolerance develops over time as the body simply produces less lactase as it ages. Typically, lactase levels decline dramatically after weaning. Up to 95% of the lactase activity experienced at birth is lost by early childhood and then continues to decline with age.

In some cases, illness, infection or digestive disease can damage the small intestine and reduce its ability to produce the lactase enzyme, ultimately resulting in lactose intolerance. However, in the case of infection in the gut, such as gastroenteritis, this is reversible as the gut’s supply of lactase is replenished after about a month.

Research also shows that certain ethnic and racial populations are more likely to develop lactose intolerance. These include African-American, Native American, Asian, South American and African communities. This intolerance is least common amongst people of northern European descent.