It's estimated that 65% of the worlds population are lactose intolerant.
However, that doesn't mean that 65% of humans categorically can't digest cows milk or dairy products. It just means that we all have a varying tolerance of lactose.
A very important thing to remember here is that, if 65% of people can't handle lactose, that still leaves 35% of the world's population perfectly capable of digesting milk into adulthood.
What are the symptoms of lactose intolerance?
Symptoms of lactose intolerance may include:
- Stomach cramps
- Stomach rumbling
Why can't some people digest lactose?
In short, as infants, humans produce an ample amount of lactase to enable them to break down all the lactose in the milk they consume.
What is the difference between lactose and lactase?
- Lactose - a sugar present in animal milk. It is found in mammal's milk including cows, horses, dogs and humans.
- Lactase - the enzyme capable of processing and breaking down lactose.
As we grow older, the production of this enzyme diminishes. We don’t consume as much milk as we did as infants so we produce less lactase. The amount we produce varies greatly between individuals, and indeed populations. There is a strong genetic component to how persistent this is and depends on ancestral geographical location (Hollox, 2005).
What happens when we stop producing lactase?
Our ability to digest foods containing lactose will therefore suffer. When we drink a lot of milk (or eat a hefty dose of ice-cream) in one go, we push our body’s limit to produce enough of the enzyme to help us fully break down and digest the lactose present (Gerbault et al, 2011).
The result? We experience symptoms of lactose intolerance - bloating, gas and general discomfort. Why? We probably don't have adequate amount of lactase to digest that much dairy in one sitting.
'But I gave up milk and now I can't handle even a drop.'
Yes, this is a keen observation that warrants a deeper look. The lactase enzyme, if not needed, won't stick around for the no-lactose party. The body will stop expressing it.
When we 'give up' milk or lactose containing products there is no need for lactase to be there. When we break our lactose exile and have a glass or two, there is no enzyme present to help. Again, we experience symptoms akin to lactose intolerance.
That explains why some parts of the world, where they have a history of very low dairy consumption (for example Asia and Africa), there is a much higher prevalence of lactose intolerance.
As human adults, we all have a varying tolerance of lactose found in milk and dairy products. That doesn't mean we should all avoid dairy. Just be mindful of how much your body feels comfortable consuming and adjust your diet accordingly.
If you think you might be lactose intolerant, take a trip to your GP for a diagnosis before removing milk and dairy products from your diet.