Image is courtesy of UnlockFood.ca.
What is Lactose?
Lactose, also known as “milk sugar,” is a type of sugar that is found naturally in the milk of mammals like cows and goats. It is a disaccharide, which is the sugar formed from the link between two monosaccharides, or single units of sugar molecules. Common monosaccharides include fructose, galactose, and glucose; those combine together in various pairs to form the three most important disaccharides for human nutrition: lactose, maltose, and sucrose.
Digesting Lactose
As Food Insight explains, the digestion of lactose occurs in the small intestine. It requires an enzyme called lactase to help break it down into its glucose and galactose components to be available for absorption. Glucose gets absorbed by our cells with the help of insulin, while galactose travels to the liver to be turned into glucose to provide energy for our body. According to PennState Extension, if lactose digestion does not complete within the small intestine, it continues to travel into the large intestine/colon, causing the digestion comfort level to decrease. Not fully digested lactose can be fermented by resident bacteria, producing lactate (small chain fatty acids) and gases like hydrogen.
Us humans are born with a lactase production ability, and infants rarely have a disorder called congenital alactasia, or in other words, lactase deficiency. Our infancy stage allows us to have the highest lactase production; however, the production amount diminishes with age. Almost ¾ of the population’s lactase production drops by approximately 10%. This can cause difficulty breaking down and absorbing lactose, which leads us to what lactose intolerance is.
Image is courtesy of PennState Extension.
Lactose Intolerance
As you can probably already guess, lactose intolerance is a condition in which one cannot produce enough lactase, so lactose cannot be broken down. As outlined by WebMD, it continues to travel to the colon and combines with bacteria and ferments, causing things like gas, cramps, bloating and diarrhea. This is not a dangerous condition, as about two-thirds of the world’s population does not produce enough lactase to sufficiently digest lactose, according to a study published in the National Library of Medicine.
Types of Lactose Intolerance
There are various types of lactose intolerance, as described by Luna.
Primary Lactose Intolerance
This is the most common type of lactose intolerance, and occurs as a result of a decrease in lactase production due to aging.
Secondary Lactose Intolerance
This condition is caused by an injury or illness that negatively impacts the small intestine, causing a decline in lactase production temporarily or permanently. Some examples include Crohn’s and celiac diseases, or certain surgeries, medications and chemotherapies.
Developmental Lactose Intolerance
Babies who are born prematurely before their digestive system is fully developed often experience developmental lactose intolerance, however, it usually only lasts for a temporary period of time.
Congenital Lactose Intolerance
As the rarest type of lactose intolerance, congenital lactose intolerance is a lifelong condition that occurs to infants who were born with little to no lactase production. It is when both parents possess a particular gene mutation for this condition.
Genetics Play an Important Role
For developing lactose intolerance, one’s genetic makeup is an important factor. Some ethnic groups are shown to be more prone to this condition compared to others. Statistics show that “in Southeast Asia, more than 95% of adults are deficient in lactase, whereas deficiency is only found in about 10% of adults in Scandinavia. Lactose intolerance was found in only 1% of Dutch people, but it was prevalent in 100% of Native Americans. Given the ethnic composition of the U.S. population, roughly 35% of adolescents and adults in the U.S. are lactase non-persistent, meaning they do not continue producing the lactase enzyme into adulthood.” All in all, as WebMD suggests, lactose intolerance is found most prone in Asian, African, Mexican, and Native Americans.
How is it Diagnosed?
Johns Hopkins Medicine explains three common ways lactose intolerance is diagnosed.
Lactose Intolerance Test
This test checks for the rise in sugar levels in your bloodstream. After two hours of drinking a liquid that contains lactose, blood samples will be taken; if the amount of glucose does not rise, there may be a chance of lactose intolerance.
Hydrogen Breath Test
The patient will need to drink a high-lactose beverage, and their breath will be checked for the presence of hydrogen. As mentioned previously, undigested lactose in the colon produces gases like hydrogen, thus the rise in hydrogen level can indicate lactose intolerance.
Stool Acidity Test
This test is used for infants and young children to check how much acid is in the stool. The undigested lactose reaches the bacteria in the colon where it becomes acidic, and if detected, acidic levels will rise.
Treatment
Even though there are no actual treatments for lactose intolerance, the issue won’t be a huge deal if you change up your diet slightly. You may choose to avoid dairy products completely and get your nutrients from other substitutes, or you can try various dairy products to find a suitable one that causes fewer symptoms. There is also the option of taking supplements like Lactaid to help break down the sugar if you still want to enjoy regular dairy products. It is essential to look out for what you eat when you have lactose intolerance, but otherwise, this is not a dangerous condition, so there is no need to stress!
Article Author: Kacy Zhao
Article Editors: Victoria Huang, Stephanie Sahadeo