Welcome to the Nutrition Facts Podcast. I’m your host Dr. Michael Greger.
The coronavirus pandemic has made many of us very aware
of the importance of maintaining and improving our health.
Make that your silver living.
Because the more positive change we can make to our diet and lifestyle, the better.
Today we experience the glory –
of cabbage – a multi talented vegetable that’s good for much more than coleslaw.
In fact it is packed with nutrients and may also be useful applied topically.
Cabbage is one of the most healthy and cost-effective ways to improve your diet.
A few years ago, in an analysis of antioxidants per unit cost,
I concluded that red cabbage — purple cabbage — was the most
nutrition you could get for your money.
Yes, there are healthier foods out there, but not healthier foods
for the same amount of money.
I encouraged everyone to always make sure they have a purple cabbage
in their crisper, to slice off shreds to put in whatever they could.
It lasts for weeks, is cheap, convenient, and one of the
healthiest things on the planet.
All still absolutely true.
My new calculations, though, suggest they just got one-upped
by DIY broccoli sprouts; do it yourself.
Broccoli sprout seeds start out like this.
You can buy them online, or at your local health food store in bulk,
for about 20 bucks a pound.
But that makes about 75 cups of sprouts, so it comes out to be
about 25 cents per cup.
And as we saw before, in terms of sulforaphane content, that’s
equivalent to eating about 27 cups of broccoli.
So, that’s like going to the store and buying broccoli for a penny a cup.
Even purple cabbage has got to give it up for broccoli sprouts.
Start out with a mason jar with some kind of screen top.
Tablespoon of seeds, soak them overnight, drain in the morning,
and then rinse twice daily.
So day two, day three, day four, and then you can enjoy the bounty.
One tablespoon of seeds makes about two cups of sprouts.
Since it takes four or five days, though, sometimes I’ll have five jars
in constant rotation.
Can be in the middle of winter, and I’m growing my own salad.
Every day, you get cups of fresh produce, for pennies,
without ever having to go to the store.
In our next story - dinosaur kale and red cabbage are put to the test.
LDL “bad” cholesterol is bad, but oxidized LDL may be worse.
What role might our diet play?
Increased fruit and vegetable consumption
has been reported to reduce the risk
of developing cardiovascular disease, heart attacks, and strokes.
Well, maybe it’s in part because of all the antioxidants in healthy plant foods
preventing the oxidation of LDL cholesterol.
And, indeed, the LDL oxidation resistance was found to be greatest among those
eating more plant-based.
So, that would be in addition to the
decreased blood pressure and lower LDL overall
in terms of beneficial effects.
But, you don’t know if it’s cause-and-effect...
until you put it to the test.
Put people on a whole food plant-based diet for just 3 weeks,
and rates and extent of LDL oxidation drop.
The effects of kale on LDL oxidation were put to the test.
Kale is a best-of-all-worlds food, low in calories and packed to the hilt
with nutrition—vitamins, minerals, anti-inflammatory compounds,
antioxidant phytonutrients, you name it.
No surprise, then, given its high antioxidant capacity,
kale showed a protective effect on the oxidation of LDL
even at low concentrations.
But, this was in vitro, in a test tube.
Kale was also put to the test in mice, but what about people?
I did a video on this study, on how kale juice improves
coronary artery disease risk factors in men with high cholesterol.
Extraordinary results, a 20% drop in LDL among the nonsmokers;
but they were drinking the equivalent of about 10 cups of kale a day.
Still, the fact that they were able to see such an improvement, even though
nearly all the fiber was removed, because it was just juice,
shows there does seem to be something special in the plant.
But, can you get the benefit just eating the stuff?
Let’s find out.
The effect of black and red cabbage on oxidized LDL,
and by black cabbage, they mean lacinato kale, also known as dinosaur or Tuscan kale.
They had people eat a bag of frozen kale and cabbage a day for just 2 weeks,
which is great because you just keep it in the freezer, prewashed, pre-chopped—
just throw it in any meal you are making—
and got significant reductions of total cholesterol, LDL cholesterol,
and even blood sugar levels,
and the antioxidant capacity of their blood went up;
so, no surprise they demonstrated a significant decrease
in oxidized LDL too.
Would it have been better to take that red cabbage
and ferment it into sauerkraut?
Red or purple cabbage is one of my favorite vegetables,
packed with antioxidants, yet dirt cheap and seems to last forever in the fridge,
and it’s pretty, and juicy, and tasty—
I try to slice shreds off into any meal I’m making.
But, when you ferment it, not only do you add way too much salt,
but you end up wiping out some of the nutrition.
Here’s the big spike in antioxidant capacity
of your bloodstream in the hours after eating fresh red cabbage,
cut down by almost 30% if you ate the same amount
in fermented form.
Does cabbage have to be raw though?
No, some cooking techniques may improve
the antioxidant activity in kale and red cabbage.
The effects of the cooking process can be positive,
since cooking softens the vegetable tissues,
helping your body extract the active compounds.
However, cooking can also be negative,
because heat treatment can degrade some of the compounds.
They looked at a variety of different cooking methods
and concluded steaming may be
considered to be the best home cooking technique
to prepare kale and red cabbage.
But with foods that healthy, the truly best way to prepare them
is whatever way will get you to eat the most of them.
Next up - we discover some of the topical benefits of cabbage leaves.
In response to a photo showing a woman taping a cabbage leaf onto her knee
to help with her osteoarthritis,
doctors wrote in asserting that cabbage leaves
can help inflammation of any body part.
You may even find that there is a cache of cabbage in the fridge
of your local maternity unit.
Why?
Well, not only is cabbage cheaper than gel packs,
but knees are not the only anatomical shapes
that the leaves conform well to.
Breast engorgement, when the breasts become
overfilled with milk during breastfeeding, becoming hard, tight, and painful,
can negatively impact both mother and infant alike.
So, why not put cabbage leaves on them?
A lactation consultant in a breastfeeding journal suggests wearing
cabbage leaves.
Evidently works like a charm, and once the swelling goes down,
frequent breastfeeding should help them from refilling too much.
Where did she even get the idea for this?
Well, her son got in a car accident,
she wrapped his leg in cabbage, and the rest is history.
The only adverse side effect identified was a complaint from the son
who felt “like a vegetable.”
Based on the information she collected, she concluded that cool green cabbage
compresses have anti-inflammatory, anti-edema—anti-swelling,
and anti-infectious properties, but you don’t really know, until you…
put it to the test.
Yeah, but who's going to do a randomized, controlled study of cabbage leaves?
Scientists, that’s who.
Do cabbage leaves prevent breast engorgement?
Let’s find out.
120 women randomized to apply cabbage leaves
to their breasts or not, and...
Though the cabbage group tended to report
less breast engorgement, the trend was not statistically significant,
though one of the big things you care about
is premature weaning, and the cabbage group did seem to
be able to extend the time they were exclusively breastfeeding.
So, while they couldn’t rule out the possibility that cabbage leaves
had a direct effect on breast engorgement that may have contributed to the
increased breastfeeding success in the experimental group.
They consider the positive effect to be more likely due to
psychological mechanisms, in other words, the placebo effect.
They did weed out some of the true believers,
though, as some women refused to join the study out of fear they might end up
in the control group and not be able to use them.
A similar study performed recently found that, while adding cabbage leaves to early
breast care didn’t significantly reduce pain, it did seem to significantly reduce
breast hardness.
Since it probably can’t hurt,
some women might want to just give it a try,
but it would be nice to get some more concrete answers.
Like, how about a treatment trial instead of just prevention?
You could try hot cabbage leaves versus cold cabbage leaves.
To control for the placebo effect, you could use placebo cabbage,
like iceberg lettuce leaves or something?
In fact, since both breasts are affected, women could act as their own controls,
with cabbage on one breast and turning over a new leaf on the other.
How about a comparison of chilled cabbage leaves versus chilled gel packs?
Just cold alone decreases blood flow
and might, therefore, decrease engorgement.
On the other hand, maybe cabbage leaves contain some component
that the mother’s skin absorbs that somehow helps?
You don’t know, until you… put it to the test.
Thirty-four lactating women with breast engorgement:
one breast got the cabbage; one breast got the gel pack.
Their pain levels were established before and after, and there was
no difference.
They both appeared to work about just as well,
with two thirds reporting relief within hours, either way, though interestingly the majority
of mothers preferred the cabbage leaves.
The similarity in the effect may have been caused by the fact that both applied cold,
although you’d think the effects of the cold
of the cabbage leaves would have been transitory.
So, hey, maybe there is something special in cabbage leaves after all.
What you’d have to do is like a comparison of chilled versus room temperature cabbage.
OK, here you go!
One breast gets the chilled cabbage leaf,
and the other gets a room temperature cabbage leaf, and...
there was no difference between the two;
they both seemed to work,
suggesting that it’s not the cold itself that’s doing it.
But, we still don’t know what the role the placebo effect is playing.
If you were going to design a study to determine if there was some special
compound in cabbage that could decrease breast engorgement, what would you do?
You could try the iceberg lettuce,
but if women heard about the cabbage effect,
they might have an expectation bias in favor of the cabbage.
Aha!
How about using a cabbage leaf extract?
Then, you can finally do a double-blind experiment
where women don’t know which breasts
are exposed to the cabbage by asking them
to rub on a cream containing a cabbage leaf
extract versus a placebo cream.
They added some rosewater to both creams
to try to camouflage any residual cabbage odor, and...
no difference in relief.
Now, the decrease in discomfort produced by the cream was not as strong as that
produced by the real cabbage leaves in the previous studies.
The superiority of the whole leaves might be explained by a failure
of the extract to contain the potentially active chemical, or maybe the chemical
broke down, or maybe it wasn’t concentrated enough,
or maybe there was just a powerful placebo effect of wearing cabbage leaves.
The bottom line is that, even though no active pharmacological substances
in cabbage leaves have been identified, the convenient shape of cabbage leaves,
their low cost, wide availability, and purported soothing effect
make it a sought-after treatment.
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To see any graphs charts, graphics, images or studies mentioned here,
please go to the Nutrition Facts Podcast landing page.
There you’ll find all the detailed information you need –
plus links to all of the sources we cite for each of these topics.
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