Flashback Friday: Green Smoothies – What Does the Science Say?

September 29, 2019 0 By Ewald Bahringer


“Green Smoothies:
What Does the Science Say?” As I’ve explored previously,
drinking sugar water is bad for you. If you have people drink
a glass of water with 3 tablespoons of table sugar in it,
which is like a can of soda, this is the big spike in blood sugar
you get within the first hour. Our body freaks out and
releases so much insulin we actually overshoot,
and by the second hour we’re relatively hypoglycemic,
dropping our blood sugar below where it was when
we started our fasting. In response, our
body dumps fat into our blood stream
as if we’re starving, because our blood sugars
just dropped so low. And the same thing happens
after drinking apple juice. Here’s what happens to your
blood sugar in the 3 hours after eating 4 1/2 cups
of apple slices: It goes up and
comes down. But if you eat the same amount
of sugar in apple juice form, about 2 cups, your body overreacts,
releasing too much insulin and you end up dipping
below where you started. The removal of fiber in the
production of fruit juice can enhance the
insulin response and result in this
“rebound hypoglycemia.” What would happen though if you stuck
those 4 1/2 cups of sliced apples in a blender with some water and
pureed them into an apple smoothie? It would still have
all it’s fiber, yet it still caused that
hypoglycemic dip. The rebound fall
in blood sugars which occurred during the
second and third hours after juice and puree
was in striking contrast to the practically steady
level after apples. This finding not only indicates how
important the presence of fiber is, but also perhaps
whether or not the fiber is physically disrupted,
like in the blender. Let’s play devil’s
advocate, though. Eating 4 1/2 cups of
apples took 17 minutes, but to drink 4 1/2 cups of
apples in smoothie form only took about
6 minutes and you can down 2 cups of
juice in like 90 seconds. So maybe these dramatic differences
have more to do with how fast the fruit entered into our system
rather than its physical form. If it’s just the speed we
can instead sip a smoothie over 17 minutes and
it would be the same. Right? So they put it
to the test. Fast juice was drinking
it in 90 seconds, but what if you instead sipped
the juice over 17 minutes? Same problem—so it
wasn’t the speed, it was the lack
of fiber. What if you disrupt that
fiber with blending, but sip it as slowly
as the whole apple eating? A little better, but not as
good as just eating the apple. So eating apples is better
than drinking apple smoothies, but who drinks
apple smoothies? What about bananas,
mangoes, or berries? There was a study that
compared whole bananas to blended bananas and
didn’t see any difference, but they only
looked for an hour and it was while they
were exercising. Bananas in general, though,
may actually improve blood sugars
over time. The same thing with mangoes—
and this was with powdered mango— can’t get any more fiber
disrupted than that. It may be due to a
phytonutrient called mangiferin, which may slow sugar absorption
through the intestinal wall. Berries help control
blood sugar so well they can counter the
effects of the sugar water even when they’re
pureed in a blender. Adding blended berries in
addition to the sugar water, and you don’t get the
hypoglycemic dip; you don’t get that burst
of fat in the blood. Drinking blended berries
isn’t just neutral, but improves blood
sugar control. Again thought to be due
to special phytonutrients that may slow sugar uptake
into the bloodstream. Indeed six weeks of blueberry
smoothie consumption may actually improve whole
body insulin sensitivity. So while apple smoothies
may be questionable, a recipe like Mayo’s basic
green smoothie recipe packed with berries and greens
would be expected to deliver the best of both worlds,
maximum nutrient absorption without risking overly
rapid sugar absorption.