Lactose Intolerance and Diarrhea

I know, I know. Oy with the poo already! But I swear, this is the last one (for now). Since I’ve talked about diarrhea due to gastrointestinal infections, I should probably explain why some people get diarrhea as a symptom to lactose intolerance.

Difference between diarrhea caused by GI infections and Lactose Intolerance

Last week, we learned that our bodies don’t absorb the water we ingest when there is a GI infection, which means we don’t gain any water in our systems. In contrast to diarrhea as a result of an infection, water is actually taken from the body and enters the intestinal tract; that means we actually lose water we already had. But why?

Diarrhea as a symptom of Lactose Intolerance

When you have lactose intolerance, you have a decreased efficiency in the digestion of lactose. While there are bacteria in your intestinal tract that are capable of digesting the lactose, they may not be able to digest all of the lactose you’ve consumed. This means that there is a concentration of lactose in your intestines that has not been taken up by your body. This is where the water loss comes in.

Remember that pesky biology lesson about Osmosis? Well, it’s actually applicable here (thank you, high school!). So, you have a high concentration of sugar (lactose) in your intestines and a lower concentration in the external environment of the intestine. Water likes to do this thing where it moves from areas of low concentrations of solutes, like sugars, to higher concentrations of solutes. Basically, water is a gold-digger and the more solutes an area has, the richer it is. So the water flows into your intestinal tract until the concentration of the sugars in your intestine is roughly the same as the concentration of the sugars outside of the intestine (this is called anĀ equilibrium). This increased volume of water in your intestines causes a watery stool (aka diarrhea!).

Always remember that it’s important to stay hydrated anytime you have diarrhea.

Lesson here is: don’t ingest crazy amounts of lactose, especially if you’re lactose intolerant… unless you’re taking lactase pills. If you’re taking lactase pills, you can eat all the poutine that your heart allows! (That reminds me, happy belated Canada day!)


Lactose Intolerance

So, one of my friends and I have recently discovered that we’re probably lactose intolerant after eating some sweet, delicious, pain-inducing ice cream. So I thought I’d talk a bit about it and explore how one can develop lactose intolerance.

What is Lactose Intolerance?

This is when an individual is unable to digest a particular sugar, lactose, that is found in dairy products. Lactose is a molecule that is made up of two smaller sugars: glucose and galactose. Your body prefers sugars in their simplest forms so that you can easily obtain energy from them.

To get sugars in their simplest forms, you require different enzymes (which are little protein superheros) that break the sugars. For lactose, you need a specific enzyme known as lactase to simplify it into glucose and galactose.

People who have lactose intolerance do not have much of this enzyme, resulting in their difficulty in digesting lactose.

So what happens to the lactose that they don’t break down? This lactose gets broken down by bacteria. Byproducts of this bacterial reaction are methane and hydrogen gases. The digestion of lactose via bacteria causes the symptoms of lactose intolerance: gassy-ness (due to the methane gas), bloating, cramps and diarrhea (sounds like the beginning of a Pepto Bismol commercial, I know).

Make sure you don’t confuse lactose intolerance with an allergy to milk. An allergy is different than the inability to digest something!

How can someone develop lactose intolerance?

Some researchers have found that we develop less enzyme levels as we grow older, including lactase levels. This is likely why I’m more sensitive to dairy now than I was when I was a youngin’ (when I used to eat blocks of cheese and drink cartons of milk). TMI maybe? Okay, sorry.

There are individuals who are lactose intolerant at a young age, which may be due to genetics, damage to the cells that produce lactase, or a premature birth of 6 weeks or greater. The latter reasoning is only a temporary state, however.

How common is lactose intolerance?

Lactose intolerance is actually viewed as a regularly occurring health issue and, therefore, normal. There are supplements available to those who require help digesting lactose, including lactase pills and drops that you take before eating dairy foods or put into your dairy drinks.

So don’t fret, my lactase-deficient friends! We’ve been saved. And now we can eat our ice cream with smiles all around.