- Good evening, I'm Carol Shirk with the Dodge County Master
Gardener Association, and tonight our guest is Amy Freidig
with the Wisconsin Master Gardener Volunteer Program.
She's going to be talking to us about plant pigmentation,
where beauty meets science.
Plant colors are a vibrant part of gardening,
the gardening experience, and there's a fascinating science
behind that display.
We're gonna learn about five common plant pigments
in your garden, and I think there's something about lobsters
in there too.
Amy has a master's in horticulture and plant breeding,
where she researched her favorite
and very colorful plants: red beets.
Please join me in welcoming Amy.
[audience applauding]
- Well, thank you guys for having me out here tonight.
I actually do have a Dodge County connection.
I married a guy from Beaver Dam.
So I've spent a fair amount of time in this county,
so it's kind of cool to be able to talk to you all tonight.
So we're gonna be talking about plant pigments,
and when I create a talk, a lot of research goes into it.
So it's got to be something that I find interesting.
And I'm a very visual person.
I really love things that I find beautiful.
And besides plants, I also find science beautiful.
So, talking about plant pigments really holds my interest
because it kind of unites both science and beauty.
So you all have your set of, what is it, eight colors
in front of you.
You have your crayons and your coloring sheet,
and you're probably wondering, okay, why did she do this?
Well, I want you, today, to experience pigment firsthand.
So, throughout the course, I'm gonna be talking
to you for about 45 minutes, and that's a long time.
And I want you to be able to just doodle and color
and feel creative.
This isn't meant to make you feel childish or patronizing.
I really am a strong believer in that when your hands
are busy, then your mind is just kind of free
and better able to absorb information.
So I want you, as I'm talking and as you feel ready to,
take up whatever pigment stick you wish, color the rabbit,
color in the vegetables, or you can flip over your sheet
and it's a very, very open-ended note sheet.
So if I say anything that interests you that you want
to remember, draw a picture, doodle something, take notes.
It's very open-ended so that you can be as creative
as you want to be.
So tonight we're going to talk about color.
And my ultimate goal when you leave tonight is that when
you walk outside and it's still, you know,
it's still August, things aren't, it's not November.
We have vibrant colors surrounding us when we're outside,
and you're all gardeners, you all love plants,
so I want you to leave in more awe of plants
than when you came in, if that is possible.
And I want you to think about pigment, which is everywhere,
with a little bit more awe.
So, color.
In your garden, I mean when this picture pops up here,
maybe you noticed the design, maybe you noticed the texture,
but, wow, that color, it just pops.
And nowadays you're hearing it's recommended that you eat
a more colorful diet.
Now, that does not mean that you go out and you get
the green food dye and you turn your oatmeal green.
[audience laughing]
That means that you want to increase your consumption
of fruits and vegetables.
And here up on the screen are a series of plant colors
and health claims associated with eating that pigment
in a food.
And I'm not gonna go into detail about all of these
health claims associated with these plant pigments because
I am not a physician.
I'm a horticulturist so that's not in my wheelhouse.
But, tonight, we are going to first start out
by talking about four of these plant colors,
and I'm gonna tell you some of the really cool
science stories behind them.
And then, at the end, we're going to kind of pull back
and talk about the relationship between eating
a colorful diet and human health because I also have
a strong interest in plants and human health.
So, tonight, we're going to talk about the colors green,
red, orange, my favorite beet red,
and we don't have time to talk about blue tonight.
That'll take us into too long of a time.
We need to start out with kind of a baseline here
in talking about what gives a plant color.
And that's pigment.
So the definition of pigment is a compound that contains
a chromophore capable of harvesting light.
And to pick apart this definition a little bit,
we need to start by talking about light.
And to do that, you know, it's a little bit of physics.
So if that gives anybody heart palpitations, I'm sorry.
But here we go.
So how do things have color? Well, it has to do with light.
So light comes in, visible light comes in,
and the wavelengths of light that make up the visible light
spectrum are 400 to 700 nanometers.
So light comes in in waves.
Wavelength is the distance between the waves.
So, like, the bottom of one wave trough to the bottom
of the other.
That's a wavelength.
And the different widths or different wavelength correspond
to different colors of light.
So when light comes in, some of those wavelengths of light
are absorbed and some are reflected.
The wavelengths of light that are reflected are what we see
and perceive as color.
So when all the visible light comes in and hits the apple,
some wavelengths of light are absorbed,
the red is reflected, and that's what we see and our brain
perceives as the color red.
So coming back to this definition,
a pigment is the compound
that contains a chromophore capable of harvesting light.
So it's really just a compound that has a part of it,
a chunk of it, called the chromophore,
that is responsible for harvesting that light.
So I think that it's really cool to think about color
and pigment, which is so bold and so vibrant,
is actually controlled kind of on a molecular level.
It's very, very small.
So that's our baseline just talking about
where color comes from.
And now we're going to launch into talking about
some specific plant pigment colors, starting with green.
And green is the pigment chlorophyll.
I'm sure you've all heard that name before.
And it's found in anything that's green.
So here are some edible crops.
Some leaf crops, broccoli, Brussels sprouts on the right,
and it's in fruits, like kiwi and lime.
That's chlorophyll.
And here is the structure of chlorophyll on the screen
And one thing that I want you to note, and I think
I'm supposed to stay here, but you can see the blue there.
Those are Ns.
Is there a, yep, okay. See, those Ns?
That stands for nitrogen.
So within the chlorophyll molecule there's nitrogen.
So when you're out there fertilizing with
a nitrogen-based fertilizer, you are providing some
of the nitrogen that goes into
manufacturing this chlorophyll.
So if you've got a plant that's yellowing,
that's why you need to add this nitrogen so it has some
of those raw materials so that it can
manufacture this molecule.
And it's obviously found in a lot of
above-ground structures,
like leaves, stems, and petioles,
and that makes sense because it has to
do with photosynthesis.
So, photosynthesis is a really, really super complex process
that I think is really, really fascinating,
but I'm not going to go into a lot of detail
about it tonight.
The 10 seconds elevator speech about photosynthesis
is that it takes in carbon dioxide and water
as raw materials, and energy from the sun and a series
of chemical reactions occur and out comes sugar,
which the plant uses for energy or for food,
you can think of it like that, and the byproduct of oxygen.
So what I want to talk to you about, though,
is were chlorophyll actually is in this.
So when you go outside and you look at that green grass
you're going to be able to remember and think back,
oh, yeah, that's where the chlorophyll actually is located.
So we're going to pretend like you have,
we're going to zoom in, okay?
So we have a plant.
We have our leaf here.
We're going to zoom into a cell,
and we're gonna look inside a plant cell right now.
So this structure right here is called a chloroplast.
And you're thinking, well, where's the green in this image?
This is an electron micrograph, and the nature
of these images is that they are black and white.
But this, we're going to hone in on where the chlorophyll
is in this chloroplast.
So that's the structure, and within the chloroplast
you see these lines going back and forth.
These are membranes called thylakoid membranes.
And they're a membrane that kind of weaves throughout
and forms also these little stacks called granum.
And in botany class they tell you to think about it
like they're kind of stacked like pancakes.
So we need to go inside these membranes
to continue our hunt for the chlorophyll.
So here, on this slide, it's really,
really complicated slide, but I don't want you
to worry about too much on it.
So here, you see those little yellow circles
on top and bottom?
That is the membrane, okay?
So we've cut it in half, and we're looking inside,
and embedded within those membranes
are these two structures.
They're called PSII and PSI, which stands
for Photosystem II and Photosystem I.
So those are embedded within those thylakoid membranes.
And, finally, now, we have zoomed in far enough that we can
finally find the chlorophyll pigment molecules.
So that's pretty far.
We've gone from leaf to cell to chloroplast to the membrane,
cut the membrane in half, and with, you know,
look in there for the photosystems, and those are where
the pigment molecules are.
And what happens is the light comes in, indicated
by that arrow, and, remember, pigment molecules contain
that chromophore which is capable of harvesting the light.
So they're harvesting that light coming in.
They're bouncing it around, kind of like a pinball machine,
to various pigment molecules until it hits
the reaction center.
And the reaction center is a special place where
an electron is hanging out.
An electron is the negatively charged particle.
And what happens is the energy, just think of it kind
of like a packet of energy is given to that electron,
and that elevates the energy status of that electron,
which really what it does is it starts a chain reaction
of chemical reactions that cascade down and eventually
produce the end product of photosynthesis: sugar.
So this is kind of like the very start of everything,
and chlorophyll is right there facilitating this.
But, for something that is so vital to the plant,
to plant life, chlorophyll can actually kind of
be a liability for the plant, and here's how.
So this is our pretend chlorophyll molecule.
So when light comes in and elevates that electron,
remember it elevated the energy status of that electron,
sometimes things don't go as planned.
So, in theory, the electron gets its energy and it causes
the right chemical reactions to occur.
But sometimes that doesn't happen, and the electron reacts
with some that it's not supposed to.
For example, oxygen.
And when that happens, that creates something called
a free radical molecule.
Has anybody heard that before?
Free radicals, yep.
So these are molecules that can cause damage
within a cell because they're highly reactive.
And so when that happens within a plant,
that problem is called phytotoxicity.
When those free radical molecules are reacted with things
that they aren't supposed to be and are causing damage.
And they cause damage on a cellular level.
Like they react with nucleic acids, with proteins,
with membranes.
That's the level at which they do their damage.
And in a minute, we're going to talk about kind of
what I consider the elegant ways that plants have
of dealing with this problem because it's a big problem
if you think about it, that your green blade of grass,
that's a lot of chlorophyll and that's a lot
of phytotoxicity issues that could be going on.
A cool story about chlorophyll has to do with purple plants.
And I don't know if any of you have
personal experience with this.
I'd be interested to hear.
So this is a sweet potato vine.
A really pretty purple one.
So it's a sun-loving plant.
When it's grown in the proper light conditions, looks great.
You take that plant and you move it to the shade.
It's going to turn kind of a browner, muddier color.
Not that really true purple color.
And that's because it's upping its level
of chlorophyll production.
You take that sun-loving plant, you put it in the shade,
it needs to increase the amount of chlorophyll
it's producing so that it can kind of compensate
for how it's not...
Compensate so that it's harvesting enough light
to get enough energy to perform photosynthesis
the way that it needs to.
So I don't know, has anybody ever experienced that?
Off the top of their head, no?
It's something worth experimenting with to see if
the color change does happen.
And, of course, we talked about how chlorophyll
can be produced by plants.
It can also be degraded.
So in a little while we're going to start to see this,
and that's because as trees start to go dormant,
they are starting to break down their chlorophyll
for the season.
That's part of the going dormant process,
and we'll start to see other pigment shining through.
Okay, our next pigment, our next color is orange.
Orange is the family of compounds called carotenoids.
You may have heard of beta carotene.
This is a member of this large family of compounds.
There's over 600 compounds are in the carotenoid family.
And there are two big groups, the orange carotenes
and the yellow xanthophylls.
And these type of molecules are lipid soluble.
That means they don't like to be free-floating in water.
They want to be surrounded by a lipid or a fat kind
of protective bubble.
And these molecules, carotenoid molecules,
will occur a lot of times as something else,
like in a crystal form surrounded by lipids
or fats or in association with other proteins.
And now here comes the lobster story.
So, lobsters really illustrate this well.
How carotenoids don't like to just hang out by themselves.
They like to be in association with something else.
So when you have a live lobster like this, its shell
is kind of a darker color.
Alright, a variation on this type of color.
But their shells are still really high in carotenoids.
So I like to think of it like this.
You have the carotenoid and you have the protein that
it's in association with, but then, when you cook it,
you heat the lobster shell and protein doesn't like heat.
It gets destroyed by heat.
So you take away that protein and all that's left
is the carotenoid shining through in this,
Oops, sorry, wrong button.
In this shell.
So that's why shells of lobsters change color
when they're cooked because the carotenoid
is shining through because you took away the protein.
Carotenoids are found in a lot of flower petals,
like those lilies, marigolds, also dandelions.
They have those luteins in them.
We already talked how they're found in the shells
of crustaceans, but shrimp also have it, salmon,
and the feathers of flamingos contain carotenoids.
And, talking about human health,
here are some healthy carotenoid-containing foods,
sweet potatoes, carrots, and squash.
And now, here are some green things that actually
contain carotenoids: collard greens, spinach, and kale.
And there is...
So you're thinking, we're talking about orange.
Why are we talking about green now?
Well, the reason why is that carotenoids actually
have something in common with chlorophyll,
and it has to do with what they do for the plant.
So one reason plants have carotenoids is that they
also play a role in photosynthesis.
They're an accessory pigment.
So, while chlorophyll is doing the heavy lifting
of the light absorption for the photosynthesis,
carotenoids can also do that.
And the other really fascinating thing that they do is
they behave as an antioxidant, and this is getting back
to earlier when I said we're gonna kind of
talk about that elegant way that plants have of dealing
with that phytotoxicity problem with those
free radical molecules.
We're going to talk about that now.
But first of all, what is an antioxidant?
So, we have to go back to free radical molecules
to explain what an antioxidant is.
This is a generic molecule that I invented,
here on the screen.
And the thing about molecules or atoms
is that they don't like to have unpaired electrons.
They always want to have a pair. They always want to be in two.
So this unpaired electron is what makes this really
highly reactive and causes that damage.
It's called oxidative damage.
But I just want you to really focus on the word damage.
Remember that.
So an antioxidant molecule is able to come over
and donate one of its electrons to the free radical,
so now it's a pair.
It's neutralized it.
It's not gonna react and cause that damage.
And the antioxidant also, even though it now has
an unpaired electron, it's not going to be reactive
and damaging like a free radical molecule can be just by
nature of its chemistry.
So, what's some oxidative damage you see every day?
- [Audience Member] Rust.
- Rust.
And I like this picture because it makes me think, okay,
oxidative damage caused by free radicals, you know,
maybe within one cell, maybe it's bad news
for that one cell, but you think collectively, well,
it's bad news for that car.
So it's a good example of types of oxidative damage.
But back to that phytotoxicity problem.
So plants have carotenoids and they have chlorophyll.
And the chlorophyll is causing this problem ultimately,
in a way, by creating these free radical molecules,
but it's got another pigment in it that's able to act
as an antioxidant and give those electrons
to the free radical molecules it's created
and neutralize the problem.
So that's why we don't always sit here, you know,
in Master Gardener training or plant
health adviser training, you're not talking about
phytotoxicity issues because the plant
can solve it for itself.
So, in the fall we talked about how chlorophyll degrades.
Carotenoids one of the colors that you are gonna see
coming through in just a little while.
Those yellows and those oranges are gonna be
due to carotenoids.
So sycamores, buckeyes, birches, all those and many more
are caused by carotenoids.
And to talk a little bit again about carotenoids
in our diet.
Carotenoids are precursors to vitamin A,
which is an essential nutrient for immune health,
normal growth and development, and vision.
And so when you eat a dose of carotenoids,
it's a good idea to eat it with a little bit
of fat, actually.
It can be as low as three grams of fat per serving
of your carotenoid-containing food.
Because remember, carotenoids are lipid soluble
or fat soluble.
They want to be safe in their little, surrounded by a lipid.
And that's how your body can properly absorb it as well.
So you eat your carrot with your little olive oil dose,
it's absorbed into your body, and inside your body
is where your body can convert that carotenoid
or that pro vitamin A.
It converts it into the active form of the vitamin,
vitamin A or retinol, which your body uses
for all those things.
And this pigment has actually taken,
plays a role in humanitarian efforts worldwide.
So I want to introduce you to biofortification.
Has anyone ever heard of this term before?
Maybe?
So biofortification is where you're taking a crop
and you are creating it so that it has a nutrient
where it never had it before, or you are increasing
the level of a nutrient inside that crop.
Ramping it up.
And it can use either traditional plant breeding techniques
or transgenic methods in order to achieve that end.
And one really well known example is golden rice.
And this is-- I'm gonna give you the very bare bones
story about this.
This is a very fascinating, complex story,
but this is just the Reader's Digest version.
So here is regular rice and unbiofortified regular rice.
And carotenoids do not naturally accumulate in the grain.
Carotenoids are in the rice plant, like the leaves
of the rice plant, but not in the grain.
So it is not a good source of vitamin A.
So, two European scientists
went about biofortification efforts using transgenes.
So they took a gene from a plant and a gene
from a bacterium, and they inserted it into the rice plant.
And they were able to get the rice plant to produce
and accumulate carotenoids in the rice grain
with the hope that this would be a source of vitamin A
in places where rice is a staple crop and where vitamin A
deficiency is an issue.
So if this is of interest to you, I really encourage you
just, you know, Google it.
Find out more information and read about it because it's
a really, really interesting complex story.
And biofortification efforts are not just done on rice.
Other staple crops are done as well.
This is a biofortified maize,
biofortified for carotenoids.
Sweet potatoes actually have been bred
to have higher levels of carotenoids in them.
And other staple crops as well, but like maize,
I can't think of the other ones right now,
but including other minerals in these types of staple crops,
like zinc or iron for example.
So biofortification efforts are happening
in many different types of crops.
And I've kind of touched on this, but why does this matter
that people are working in these efforts?
And that's because of deficiency.
Vitamin A deficiency is a humongous problem worldwide,
especially for children.
It affects over, I have the exact numbers here.
Over 100 million children, which is an astounding number,
are vitamin A deficient worldwide.
And you can see, on this map here, in the darker green,
these are the areas of the world where
the largest populations of vitamin A deficient children are.
And up here on the screen, it says the severity of what this
deficiency can cause.
I'll read it for you.
It says-- This is from the World Health Organization,
"Vitamin A deficiency can cause severe visual impairment
and blindness and significantly increases the risk
of illness and even death from common childhood infections
as diarrheal disease and measles."
And there have been other efforts
to combat this deficiency,
for example, using vitamin A supplementation,
which has been very successful.
But even the World Health Organization still notes
the value of eating a carotenoid-rich diet and using
the family garden to do so, or attempt to do so,
especially in rural areas.
So our next color that we're going to talk about,
I'm sure a lot of you are probably seeing a lot
of this color in your gardens right now, is red.
Red is the pigment lycopene.
And there's the molecule there.
And why this is kind of a cool molecules is--
Well, first of all, it is actually a member
of the carotenoid family, which we were just talking about.
But with lycopene, there is a distinction because
it's kind of...
So when plants manufacture compounds
or molecules inside them,
you know, they have a compound
but they rearrange it.
They take things off.
They add things, they join things.
They rearrange things.
And that whole process is called a biosynthetic pathway.
And so you kind of got to start with something
and then build from it.
So lycopene is a molecule that kind of starts a lot
of biosynthetic pathways,
and a lot of other different types
of molecules are made from that.
So it's an important and kind of cool molecule of note.
It's actually in watermelon, apricot, grapefruit,
pink guava, and of course tomatoes.
And here are some flower parts it's in.
Damask rose, calendula, and actually in saffron.
And now's a good time to talk about one
really big reason why plants have pigment at all
in the first place, and that has to do with reproduction.
So, you know, that's what it's all about for the plant
is reproducing so that your genetic material makes it
into the next generation.
And so you need to have a really good advertisement
for your pollinators to come and visit you.
And pigmentation, I'm sure you can all think
of an example in your garden of a plant
with unique pigmentation.
It's just an advertisement to get pollinators to come.
And there are really cool stories about how
different pollinators have evolved with different styles
and colors of flowers.
They have special relationships.
It's kind of a, there are so many different stories,
and I'm only going to share one with you to show you how
dynamic pigmentation can actually be within a plant,
and it's lantana.
And what this plant does is it changes the pigmentation
of the flower based on when it's ready to pollinate.
So if you're the pollinator, you're flying around,
you can distinguish, based on what color it is,
what flower's too old, what one is too young,
and what is ready to go.
Now, the place where plants store pigment is called,
the cellular structure is called the chromoplast.
And right here, these are cells from a red pepper fruit,
and you can see all these little dots.
That's pigment contained in chromoplasts.
And its sole job is to just pack in the pigment
that the plant makes.
And plants can actually turn chloroplasts,
they can morph them into chromoplasts.
And, again, the tomato gets picked on here again.
That's kind of a bad pun.
[audience laughing]
So here we have a green chlorophyll filled tomato.
And as it's ripening, the tomato, the plant is converting
its chloroplasts, which contain chlorophyll,
into chromoplasts and stuffing it full of that red lycopene.
Why would the plant bother to do that in the first place?
Well, does that look particularly appetizing?
Compared to that lush, beautiful red fruit that you or I,
as a potential seed dispersal agent, might come and,
you know, pick that tomato off, eat it,
maybe I drop some seeds over here or excrete them
in other ways.
So it's all about reproduction.
And I eat a lot of spaghetti sauce.
I have small children at home, so this is a staple
in our diet.
And something interesting to share about consuming lycopene
in your diet is that, and it's good news.
When you cook a lot of plant products,
like boiling or steaming, you're usually losing a percentage
of the nutrition in the cooking water
or it's breaking down due to cooking.
With lycopene, found in tomatoes, the opposite is true.
One study I looked at looked at cooked tomatoes
and heating them for the amount of time that's akin
to like processing for tomato sauce and heating
or cooking tomato sauce that you would eat.
And they found that lycopene level,
bioavailable lycopene levels increased with heating.
Bioavailable is a fancy way of saying what your body
can actually absorb.
So it's good news that more lycopene is available
to you if you heat it.
And they think this is because, as you heat things,
cellular structures are breaking apart.
More is just like physically accessible and coming out
of the cell.
So the last color we're going to talk about tonight
is my personal favorite, beet red.
Does everybody like beets in the audience?
I should see, yes, yes, good.
Head nodding.
So, beet red color is caused by-- It's the betalain family.
And right here, betacyanin is the actual compound
that is the beet red color, and there's also
a yellow compound betaxanthin, in this family as well.
Unlike the carotenoids we talked about earlier,
betalains like to be in water.
They're water soluble.
So you're looking at a cell here,
another electron micrograph, and this big area right here
that looks like there's nothing in it is the vacuole
And that's a membrane-bound area, and inside it
it's filled with water.
But that's a good place for the plant to put things
like toxins, waste products,
as well as small molecules or things like betalain pigment.
And something that's just kind of a mystery still
and really cool is that these betalain pigments
are only found in one order in the plant world.
So, remember, you have kingdom, phylum, order.
So it's a big group.
But that word, how you say that is caryophyllales.
Pretty cool word.
So that is the only order that contains these pigments.
So when you think about that, you know,
all the other plant orders they kind of,
they share pigments.
They have that in common.
This is the only one with betalain.
So that's a very interesting thing
from an evolutionary perspective.
How did that happen, why did that happen?
Why is it nowhere else, I don't know.
It's a mystery, but it's really neat.
So I'm glad that this screen shows this color well
because you can see, like, pop, wow.
These are flowers that contain betalains.
Celosia, four o'clocks, moss flower, and bougainvillea.
And, of course, it's in beets, a member of the beet family,
like a Swiss chard here in petioles and the midvein.
That's all betalains.
So you might be thinking red beet, red pigment,
that's that betacyanin one on the left
that she was talking about earlier.
Well, actually, red beets contain both of the pigments,
in a ratio of about three to one.
And when you have a yellow beet,
that beet has the genes turned off that manufacture
the red pigment.
It just makes the yellow pigment.
And then the white beet, which I hope you all feel
a little bit sad when you think about the white beet.
[audience laughing]
That has no pigmentation in it whatsoever because the genes
to make pigment have been bred--
They've bred it so it's shut off.
It does not produce anything.
And beet pigment actually
is an important food colorant.
So, in the 1970s,
interests arose in creating
a natural alternative to petroleum-based food dyes.
And so they started looking at these betalain pigments.
But the problem was it was very costly to create them
because in the beet root you've got sugar and water,
you have to concentrate it down.
It was very expensive.
So at UW-Madison, breeding efforts started.
And what they were able to do over decades was create lines
of beets that had very concentrated pigment.
I was actually luck enough to work as a student hourly
on the tail end of this project.
And those breeding lines are still in use today.
And it was very successful, so much so that in 2008
it was only two-and-a-half times more expensive
to manufacture a beet food dye than it was
synthetic food dye.
And you may know this from firsthand experience,
you go in the yogurt aisle and you're looking at, like,
the strawberry yogurt you may see, you know,
colored with beet juice or something like that.
You may have already seen that.
And one thing to note is that these food dyes,
betalain food dyes, are only in things that are kept cool.
They're degrade when they're heated.
So they're going to be found in things like ice cream
and yogurt, cosmetics and meat products,
powdered drink mixes, for example.
So in encourage you to go home and take a look.
It's cropping up more and more.
I mean, they're even using it in my kid's Goldfish crackers,
I think, or maybe some other vegetable dyes.
But it's really cool.
So now we've talked about our four colors tonight
and some of the really neat science stories behind it.
And now I want to kind of pull back and talk to you guys
about plant pigments and health, human health.
So here's this slide again with the individual plant colors
and the various health claims associated with eating them.
And I don't want to talk about,
focus on these individually right now.
I want to think of them as a whole.
So I'm gonna talk about plant pigments in terms
of eating a more colorful diet.
A diet rich in fruits and vegetables.
And so there's a lot of research that goes on
today looking at these types of things.
So I have an example on the board for you right now.
In 2010, the USDA published this information.
They published the ORAC database, which ORAC stands for
Oxygen Radical Absorbance Capacity.
And what they did was they looked at a bunch of different
foods and they, in the laboratory, they subjected them
to a lab test to see how they behaved as an antioxidant.
And they got these numbers, and here are some of the values
for just some vegetables that I picked out here.
So this is one example of some of the research
that's going on.
And that's a type of in vitro or research which means like
in a test tube, in a lab, in a Petri dish.
Other types of research that go on are in vivo,
meaning in a body system, like in mammal or in a human,
and then there's also epidemiological research,
which is more at the population level.
But the trouble with studying plant pigments is it's really
hard to attribute a particular health function to a pigment.
Because these are very large, complex molecules,
they break down during analysis, they're highly metabolized
by your body, and they're often acting in concert with
another molecule found in the food matrix where
that pigment originated.
So there's a lot of research going out there,
and there's a lot of misuse of research going out there
to make health claims.
So much so that, in 2012, the USDA took
that ORAC database information down.
And I'll read this to you.
So, on their website here, you can't read that because
it's too small, they said,
"The data for antioxidant capacity of foods generated
by in vitro or test tube methods cannot be extrapolated
in vivo or human effects, and the clinical trials
to test benefits of dietary antioxidants
have produced mixed results."
So they're saying there that the--
They're saying that the data on how antioxidants
affect your health, there's information for and against it.
But still they noted that "there are a number of bioactive
compounds which are theorized to have a role in preventing
or ameliorating various chronic diseases, such as cancer,
coronary vascular disease, Alzheimer's, and diabetes.
However, the associated metabolic pathways
are not completely understood, and non-antioxidant
mechanisms still undefined may be responsible."
Which is a long way of saying, like, we think these types
of compounds may have a human health benefit,
but we don't really know how it works.
And here's another example of some research.
This is a citation up here for a study that was released
in 2010, and it was published in the Journal
of the National Cancer Institute.
It did receive some popular press, so you may remember it.
It's fruit and vegetable intake and overall cancer risk in
the European perspective investigation
into cancer and nutrition.
So the story behind this is in the '90s,
recommendations started to come out,
that to eat a diet high in fruits and vegetables
in the hopes that it would lead
to a decrease in overall cancer risk.
And since then, institutions have really backed off of that.
And this study was kind of addressing that.
So they looked at the relationship between eating
a diet high in fruits and vegetables
with overall cancer risk.
And it's important to note it's overall cancer risk.
Not saying, you know, associating eating one particular type
of food with a health effect on a particular type of cancer.
This is overall.
So they--
This was a huge study.
Over 400,000 participants across 10 countries in Europe.
From-- It was 1992 to 2000.
It was very, very large.
So, what they found was that eating a high amount
of fruits and vegetables only contributed to a modest
preventative effect toward decreasing overall cancer risk.
And there was a very weak association between
overall cancer risk and high fruit
and vegetable consumption.
So that's kind of a bummer, huh?
[audience chuckling]
So...
I'm sharing with you that there's lots
of research out there,
with results that go in both directions.
And you might sit there and say, well,
there's all this research.
Some of this research is being misused
by certain companies for, you know, to sell a product.
It's all kind of a downer.
What can we say? What can we say?
We're still saying eat a colorful diet.
We are still recommending that because
of the vast potential benefits.
A diet high, fruits and vegetables are low in calories,
high in fiber, low in cholesterol
They're very nutrient-dense.
Eating a diet high in fruits and vegetables may reduce
the risk for heart disease,
including heart attack and stroke.
It may protect against certain types of cancers.
It may reduce the risk of heart disease, obesity,
and Type 2 diabetes.
It may lower blood pressure and may also reduce the risk
of developing kidney stones, may help to decrease bone loss.
So you may have noticed a lot of "may contribute"
type of language there.
And I think that really highlights that we don't know
a lot for certain but due to the vast potential benefits,
we are still recommending it, and it is still important.
And it's also really important to mention that a lot
of these benefits due to various compounds are
because you're eating the compound in the food matrix
in which it occurs.
That means, like, eating the broccoli as opposed
to taking a broccoli supplement.
Okay?
So I share that with you just so
that you're aware of that,
because there are many health claims out there,
and it's important to do your research
and understand that concept.
So to kind of wrap things up,
I really like these words on the board in terms
of eating a colorful diet.
Eating a high fruit and vegetable diet may have protective
and preventative health effects, especially in relation
to chronic or aging related diseases.
And in terms, it could have a vast benefit in terms
of overall human health maintenance.
So, again, I encourage you to
up the colorfulness of your diet.
And I want to thank you for having me out tonight,
and if you have any questions, I will try to answer them now
or go and do some more research and get back to you.
So, thank you.
[audience applauding]