What can mice tell us about behavior?
The world of academic medicine puts out a lot of really great stuff every year. The problem is that either it’s really difficult to read it (it’s written like the instruction manual for your leaf blower) or it’s so sensationalized that you discount it as media hype and you ignore it. We as a profession have to do better! Thankfully, there are a few people out there that do a great job of turning the drudgery into something that the rest of us can read and understand. I spend a lot of time listening to podcasts and because of sheer information overload, I can’t even remember who translated this study into “real-people speak”. That means I can’t give credit where it’s due, which is sad, but clearly a first-world problem.
This article released in Endocrinology and Metabolism deserves a few minutes of our attention. The authors demonstrated that we can knock out mice’s ability to taste sweet things (genetically modify them to have no sweet receptors) and even without the ability to taste sweet, these mice preferentially choose sweetened water over plain water. Despite being unable to actually taste the sugary water, these mice choose it over plain water and eventually develop severe features of metabolic syndrome due to reduced sensitivity to leptin, reduced ability to mobilize and oxidize fats, and increased hepatic de novo lipogenesis. This means that sugar can induce metabolic syndrome in mice independently of its sweet properties. This raises the question – can sugar affects our human brains and our human actions – even when we don’t taste it? Can the presence of sugar in foods (even when we can’t taste it – for example, in pasta sauce or salad dressing, or hamburger buns) cause us to consume it over healthier foods?
I agree that it’s a leap from mice to humans, but in reality, it’s how many drug trials and medical interventions begin. The beautiful thing about mice is that they don’t have an underlying agenda that drives them. They are simple. They do what they want. They don’t have preconceived notions about what is proper or embarrassing. If they prefer sugary water, they drink it. If they eat so much that they can’t move, they quit moving. They can’t talk, so they can’t stretch the truth to make themselves sound better. And despite the obvious differences between mice and people, most of the time we are eerily similar in the way we react to drugs and interventions. However, despite our similarities, the lifespan of a mouse is much shorter than ours – so we get to see the long-term effects of interventions much sooner than we can see them in humans.
We know that fructose consumption causes metabolic syndrome in mice. It’s easy to prove. We see the same thing in humans. We’ve shown it over and over again. We as a population just don’t want to hear it. We don’t want to accept that eating fructose is bad for us. Not fructose in the form of fruit, but fructose as part of sucrose – or table sugar. We don’t want to think of table sugar as dangerous. After all, we all have fond memories of eating sugar and being happy. We all associate sugar with happiness. We associate sugar with love. Logically, we don’t want to associate something that brings us so much happiness with metabolic derangement and chronic disease and early death?
It’s time to start opening our eyes and acknowledging what is so clear in the medical research. Not wanting to hear something is not a reason to ignore something.
Acknowledging the truth doesn’t mean that we need to live like martyrs, foregoing all things that contain sugar. Sometimes sugar is fun. Sometimes having a sparkly, decadent cupcake on your birthday is a good thing. But having sugar added to your salad dressing, your hamburger meat, your pasta sauce and your bread is too much. There’s no reason it should be there – other than because it will keep you coming back over and over again.
Just like the mice that keep coming back and drinking the sugar-sweetened water – even though they can’t taste it. They (and we) do it because it feels good inside. Because it does something pleasurable for us – not always on our taste buds, but deep inside. But that pleasure leads to metabolic syndrome – which means that it isn’t benign. That thing that we seek (even when we don’t know we are seeking it) is making us sicker. It’s costing us health and happiness.
We are smarter than mice. We can choose the regular water. It’s not easy to make that choice, but it can be done. However, knowing what choice to make and actually making the choice are two different things. They require two different skill sets. This is where the real work of Obesity Medicine begins!
