"Are Green Smoothies Good for You?"
Unhealthy lifestyle behaviors associated with increased
risk of premature death, include things like smoking
and excessive drinking and not eating enough greens.
The best way to get your greens
is in whichever way you’ll eat the most of them,
and one way to sneak extra greens into your daily diet
is with whole food smoothies,
a potent blend of good nutrition
in a quick, portable, delicious form.
The Mayo Clinic offers this as a basic green smoothie recipe,
combining the healthiest of fruits, berries,
with the healthiest of vegetables, dark green leafies.
Two ounces of baby spinach is about a cup and a half.
Curly parsley is another mild beginner green to start with.
Surprisingly, the sweetness of the fruit
masks the bitterness of the greens,
such that the pickiest of children love them,
along with any adults who would otherwise not be consuming
dark green leafy vegetables for breakfast...
or even fruit for that matter.
The average teen may be only getting about 1/20
of a serving of fruit, otherwise—
and loops don't count...
But offering smoothies can have a dramatic effect on fruit consumption,
for students who do not want to take time peeling or chewing fruits—
who doesn’t have time to chew a fruit?
But the milkshake-y texture of smoothies may not
just boost the quantity of fruit and vegetable consumption,
but also the quality.
Carotenoid phytonutrients like beta carotene and lycopene
can exist as microscopic crystals trapped within the cell walls
of fruits and vegetables and they’re only released
when the cells are disrupted;
that’s why we need to chew really well.
(“Mastication” is doctor- speak for chewing).
We either have to chew better or choose plants that are easier to chew.
For example, while tomatoes have more β-carotene than watermelon does,
the watermelon’s β-carotene is more bioaccessible,
because it has kind of whimpy cell walls,
but the cells of other fruits and vegetables
are smaller and tougher.
To maximize nutrient release, food particle size would
ideally be reduced down to smaller than the width
of the individual plant cells,
but you can’t do that with chewing.
Most vegetable particles end up greater than
two millimeters when you chew them,
which corresponds to way up here,
whereas if we broke open all the cells we could release much more nutritrion.
We can never chew as well as a blender.
The particle size distribution from chewing is about what you’d get
blending in a food processor for about five seconds,
or one of those high speed blenders for maybe half a second.
40 seconds in a blender and you can break spinach down
to a subcellular level.
Why does that matter?
Take folate for example, the B vitamin in greens
that is especially important for women of child-bearing age.
Feed people a cup of spinach a day for three weeks
and their folate goes up compared to control,
but even just chop it up finely with a knife first before chewing it
and you end up with more than twice as much ending up in your bloodstream.
And the same absorption boosting effect with lutein,
the greens nutrient so important for our eyesight.
It’s not what you eat; it’s what you absorb.
But for lutein, the boost was only 14%,
so a few extra bites of the whole leafy greens
would have gotten you just as much,
and some other nutrients, such as vitamin C
aren’t affected by prechopping.
And this is less of an issue with cooked vegetables.
This is for raw carrots.
Boil the carrots for 3 minutes first and even just regular chewing
can release about 10 times more,
but not as much as blended.
Intense cooking, boiling for 25 minutes,
so damages the cell walls, that even gulping down
large particles can result in significant absorption,
but even then blending may double carotenoid availability,
explaining why we may be able to absorb
3 times the alpha and beta carotene from pureed cooked carrots
compared to mashed cooked carrots.
So, blending vegetables— raw or cooked—
into soups, sauces or smoothies can maximize nutrient absorption.
You went to the store and bought it
or toiled in your garden to grow it,
you might as well take full advantage of it.
Might there be a downside to enhanced absorption, though?
We’ll find out, next...