Health & Medicine

The docs offer advice: The mouse and the fruit fly

Q: Why do scientists use mice and fruit flies in lab experiments for testing toxins, drugs and other things? Rodents and insects are so different from humans!

Jeremy R., Bellevue, Washington

A: Mice and other rodents are mammals and they share behavioral as well as genetic and biological characteristics with humans. And they are much easier to understand, scientifically speaking. Plus, we know so much about their biology and genetics that we can now switch their genes on and off, and see how their various internal systems respond. For instance, there is a genetically engineered mouse with an inactive immune system. That helps scientists develop treatments for HIV, anti-rejection meds for organ transplant patients and new cancer treatments. While a lot of the investigations apply only to mice (so far), whole organ and stem-cell transplants and even limb-grafting and cloning are becoming realities because of work done with rodents.

Mice also breed well and have a relatively short life span (two to five years, depending), so scientists can easily study their complete life cycle. And that brings us to another even less-expensive test subject with an even shorter life span (two weeks): Drosophila melanogaster, the fruit fly.

It might seem unlikely, but fruit flies can tell us a lot about human biology and what’s common to all biological organisms. They have a simple chromosomal organization, but nonetheless around 75 percent of genes we humans use to fight disease have counterparts in the fruit fly. In Fruit Fly Lab-01, NASA is studying how space flight affects the fly’s innate immune system. What they discover will help prepare astronauts for extended space travel. And closer to home, studying the so-called hedgehog gene in the fruit fly led to the development of a recently approved drug to treat advanced basal-cell carcinoma. So, the simple fruit fly and a mouse teach us how connected all life forms are and just how much we can learn from every one.

Q: I believe comfort foods exist for a reason; they give you comfort! What’s so bad about a bowl of mac and cheese or a slice of pie every once in a while if you want a little taste of happiness?

Gladys F., Franklin, Tennessee

A: Glad you brought this up, because we aren’t against true comfort foods. In fact, we believe food should provide the ultimate comfort: good health! But the notion that you can get comfort from a load of added sugar or fat is like saying you can get true happiness from an addictive drug. Not really. There may be a temporary lift, but the burden of addiction certainly erases any of that pleasure, and then you’re stuck! The same is true for a whole range of processed foods that are sugar- and syrup-added and saturated- and trans-fat-laden. They may give you a dopamine rush -- that pleasure hormone -- but then they let you down hard.

In fact, the latest research shows that high glycemic index foods, like white rice, soda and baked goods, that are rapidly converted to sugar (and spike blood sugar levels) fuel depression. So that hot fudge sundae or plate of pasta that you gobble down when you’re blue feels good in the short term (like cocaine), but ultimately betrays you and makes you feel worse.

Want to feel happier? The researchers found high-fiber foods like fruits and veggies, 100 percent whole grains and lactose in low-fat or nonfat dairy improve the mix of bacteria in your gut. And that seems to protect you from depression. So here’s our proposal for true comfort food: a bowl of hot oatmeal with nonfat, no-sugar-added Greek yogurt, a handful of blueberries and six walnut halves. Or how about a plate of oven-roasted veggies coated with a dash of olive oil and garlic and a hummus dip? And try a summer smoothie whipped up with fresh fruit, tasty greens (kale? spinach?) and kefir. Now, that’s comfort.

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