Smoothies: Another Kind of Sugar Water

We’ve talked about fruit, juice and smoothies before, but there’s more to say. Much more.

We all know that sugar water (soda, in other words) is bad for us. Test subjects given water mixed with three tablespoons of sugar experienced a massive blood sugar spike within the hour, followed by a hypoglycemic drop.

When that happens, our bodies kick into crisis mode and dump fat into our bloodstream—because they think we’re going to die of starvation!

Interestingly, a glass of apple juice causes a similar response.

If you eat a bunch of apple slices, your blood sugar gradually rises and falls over the course of a few hours. But if you consume the same amount (of sugar) in juice form (around two cups of apple juice), your body freaks out—just like it does with sugar water.

Fiber seems to be the missing link here. Take it out of the apples (leaving the juice), and the body’s insulin response amplifies.

Yet, blending apples instead doesn’t seem to fix the problem. Making an apple smoothie, which keeps all the fiber, won’t prevent the hypoglycemic dip caused by both sugar water and juice. Hmmm, right?

Why are apple slices totally fine, but pureed apples cause this rebound?

There are a couple possibilities. It could be that blending alters the physical composition of the fiber—and how our bodies absorb it.

Or, it could be that we tend to drink fluids much faster than we eat solid foods. It might take us a quarter hour to eat four cups of apples, but less than a couple minutes to drink the same quantity in juice or smoothie form.

Researchers considered just that, and found that drinking apple juice slowly didn’t change the body’s reaction at all, and had only limited effects when it came to the blended apples.

A study comparing whole bananas to blended bananas, on the other hand, didn’t find any difference between the two. The study was incomplete (they only looked at participants for one hour after eating), but it’s worth noting that it could just as well be the type of fruit as the mode of consuming it that affects blood sugar so strongly.

Mangos, by the way, had the same results as bananas—no difference between blended, powdered and whole—and scientists think a certain phytonutrient called mangiferin may have something to do with it. They hypothesize that this special phytonutrient could slow our absorption of sugar through the intestines.

Berries, as discussed in another blog, seem to slow sugar absorption as well—whole or blended. In fact, adding blended berries to sweet beverages actually helps control blood sugar levels! Again, scientists think it has something to do with the phytonutrients in berries slowing our absorption of sugar into our bloodstream.

Sign us up, right?!

So, as long as they’re packed with phytonutrient-rich fruits, like this, smoothies are a great source of nutrition. Maybe just go easy on the apple juice.