"Vinegar Mechanisms and Side Effects"
As I note in my chapter on greens in my book,
"How Not to Die",
vinegar may be one condiment that’s actually good for you,
though mustard could be another.
Randomized controlled trials involving both diabetic
and non-diabetic individuals found that adding two little teaspoons
of vinegar to a meal may improve blood sugar control,
effectively blunting the blood sugar spike
after a meal by about 20 percent.
But how?
Originally, we thought it was because vinegar
delayed the gastric emptying rate,
slowing the speed at which a meal leaves your stomach,
which makes sense, because there’s acid receptors
in the first part of the small intestine
where the stomach acid is neutralized,
and so if there is excess acid,
the body slows down stomach emptying
to give the intestine time to buffer it all.
So the acid in vinegar was thought to slow the rate
at which food leaves the stomach resulting in
a blunted sugar spike.
But then studies like this were published
where taking apple cider vinegar before bedtime
resulted in lower blood sugars the next day.
How does that work?
That’s obviously not some acid-induced stomach-slowing effect,
and indeed anyone who actually went to the trouble
of sticking an ultrasound probe on someone’s stomach
could have told you that—
no difference in stomach emptying times
comparing vinegar to neutralized vinegar.
So it’s not just an acid effect.
Back to square one.
Studies like this offered the next clue.
Vinegar appeared to have no effect on blood sugars,
but this was after giving people
straight glucose solution.
Glucose is a byproduct of sugar and starch digestion,
and so if vinegar blunts the blood sugar spike
from cotton candy and Wonderbread, but not glucose,
maybe it works by suppressing the enzymes
that digest sugars and starches.
And indeed vinegar appears to block the enzyme
that breaks down table sugar.
But it wasn’t just an acid effect,
there appears to be something unique
about acetic acid, the acid in vinegar.
But this was based on intestinal cells
in a petri dish.
What about in people?
Feed people some mashed potatoes
with and without vinegar,
and glucose flows into the bloodstream
at the same rate either way,
so that's another theory shot down.
Okay, so let’s figure this out.
If sugar enters the bloodstream at the same rate
with or without vinegar,
but vinegar leads to significantly less sugar
in the blood,
then logically it must be leaving the bloodstream faster,
and indeed vinegar ingestion appears to enhance sugar disposal
by lowering insulin resistance-
the cause of type 2 diabetes.
And indeed vinegar ingestion does appear to improve
the action of insulin in diabetics.
So the mystery of how vinegar works
appears to have been solved, at least in part.
So diabetics can add vinegar to their mashed potatoes,
or just not eat mashed potatoes.
If you add vinegar to a high fiber meal,
nothing happens, explaining results like this.
No effects of vinegar in diabetics in response to a meal.
No surprise, because the meal was mostly beans.
But if you are going to eat high glycemic index foods
like refined grains, vinegar can help,
though there are some caveats.
Don’t drink vinegar straight,
as it may cause intractable hiccups
and can burn your esophagus…
as can apple cider vinegar tablets,
if they get lodged in your throat,
not that apple cider vinegar tablets necessarily
actually have any apple cider vinegar in them at all.
Don’t pour it on your kid's head to treat head lice.
It’s not harmful—
except when it leaks on to the face
and penetrates the eyes,
and it turns out it doesn’t even work.
It can cause 3rd degree burns if you soak a bandage
with it and leave it on.
Though as many as a total of 6 tablespoons
a day of vinegar was not associated with any side-effects
in the short-term.
Until we know more maybe we’d want to stick
with more common culinary type doses,
like two tablespoons max a day.
For example, drinking a total of 2,000 cups of vinegar
was found to be a bad idea.