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So now we're back to talk a little bit about carbohydrates.
And this chapter really gets us into our first part
of nutrition science.
We're going to talk about different kinds
of carbohydrates and digestion, and also
some recommendations around carbohydrates.
And so let's start a little bit with some of our vocabulary
because again this is really important
to have a good foundation in vocabulary.
So carbohydrates are abbreviated as CHO.
And the reason for this is because their molecular makeup
is carbon, hydrogen, and oxygen.
And you'll see this in our notes for class.
It's so much easier for me to just write
CHO and I invite you to do that as well.
OK?
We want to break down this family of carbohydrates
into two separate areas.
We have simple carbohydrates, and these are really sugars.
What we're talking about here are fructose,
which is fruit sugar, things like lactose,
which is the sugar found in dairy products.
And there are a few here that we're
going to spend a little bit more time talking about.
And then complex carbohydrates, and you've probably
heard this term.
And there's this real push around nutrition
and how-- to encourage people to consume
more complex carbohydrates.
We'll unpack that a little bit and talk
about what those complex carbohydrates are
and the recommendations.
So for now I want you to appreciate
that within this framework of complex carbohydrates
we have starch and we have fiber.
And again, we'll talk more about this.
So this is just a foundation for us.
We want to take a step back now and look
at those simple carbohydrates.
I told you that they were sugars.
And we have a couple of monosaccharides
we're interested in.
And mono, meaning one, and then saccharide is sugar.
So if you see that word, don't panic.
It just means one sugar.
And there are three different ones
that we're primarily interested in for nutrition.
Glucose, which is really the sugar of the body.
So maybe you've heard this term when
we talk about someone who has a diabetic condition,
or someone that might be low blood sugar.
What we're talking about there is glucose.
Then we have fructose, and you might have a little hint here.
This is found in fruit, OK?
So it's found in bananas, it's found
in strawberries, cantaloupe, all of those fruits we enjoy.
Then we have the galactose.
And you're like, where does that come from, outer space?
I always have that joke, sorry.
But galactose is found complexed with glucose to make lactose.
You're never going to see galactose on its own in nature,
but it's still an important one of our monosaccharides
we want to talk about.
We then have three disaccharides.
And what we've done here to create
these disaccharides is we've taken monosaccharides
and we have just assorted them.
So you're going to find lactose, and this one
has one unit of glucose and one unit of galactose.
Then we have maltose.
And you might be scratching your head here,
thinking well, where have I seen maltose?
This is a sugar that's primarily used in food manufacturing.
So if you were to go down to the supermarket
and get a bag of chocolate chip cookies or something
like that, that have been produced in a factory,
you might see this as one of the ingredients there.
And I should also say that you may see other kinds of sugar,
maltodextrin, and all different kinds.
We aren't talking about those other sugars,
primarily because these are the sugars that are important to us
in nutrition and health.
So this is where we're going to focus.
And then we have sucrose.
And again, I could go down to the supermarket
and ask the person to bring me his finest bag of sucrose.
And what would he bring me?
Table sugar.
This could be white sugar, like we're
familiar with for our coffee or whatever, or brown sugar.
And with brown sugar all they've done
is taken that sucrose and added molasses to make it brown.
So that's the difference there.
I like this chart quite a bit because it really shows you
in a visual way of how these different monosaccharides
become disaccharides.
So you might put this on an index card
or find a way to study this so you understand which ones get
matched up to make the different disaccharides.
And this becomes important when we talk about digestion,
so that's why I'm encouraging you
to learn the different ones.
That really concludes the simple carbohydrates.
So now we get to move into the complex ones.
And within the complex carbohydrates
we have a few that we're going to talk about.
And again, there are different kinds of complex carbohydrates
but we're going to put them into some very discrete categories.
They're going to help us be able to name and talk about them.
So we have starches.
And starch is simply repeating units of glucose.
So I like to think about these different starch
units as a pearl necklace.
And each one of those little beads is a glucose unit.
We find starch in things like rice or bread or pasta.
And when we digest these it's very, very simple.
We break them apart and we have glucose available.
There are also branch starches, and these really just
have a different shape.
So you can see that this looks a little bit more like a tree.
And there are lots of different ways
that glucose is being built.
Then we can look at glycogen.
And so glycogen is different in that this is found in animals.
And you are an animal, I hate to break that to you.
So this is not just in beef or chicken.
This is also in humans.
This is the way that we store glucose or carbohydrates.
You're going to find glycogen in three places in the human body.
There's a little bit in your brain to help you think,
there's some in muscles.
There's actually quite a bit in your muscles.
And then there's a lot in your liver.
So this allows you to have quick energy.
And one of the things I really like about glycogen-- I
think it's a masterful design-- that this allows the fight
or flight response.
So if you think about, maybe you're out hiking
and you come across a bear.
Your body has this opportunity to either fight the bear
or run away.
And the way that we do that is that we use adrenaline,
this chemical that allows us to respond very instantly.
And you probably know what this feels
like when you have an adrenaline surge.
We're going to be able to mobilize all of these glucose
units from these terminal ends, we call it.
That's a very different than if we were composed of starch
and we had to break off each one in sequential rhythm.
This allows us to increase our blood sugar
dramatically and quickly.
So you'll find that in animals and in humans.
And then our last one that I want to talk about
is something called cellulose.
And you might be familiar with this
and say well, that's found in things like trees.
Well, we don't really very often eat trees.
Instead we eat other kinds of foods
that have cellulose in them.
For instance, celery has quite a bit.
And you see that in the strings of the celery.
You can chew it and chew it and chew it,
and it's hard to break down.
Humans cannot break this kind of molecule down.
Each one of these different units is held together with
something called a beta-1,4 bond.
That's not really that important to know that but you do want
to know that you can't break down fiber.
OK, this is a type of fiber.
There are other types.
There's hemicellulose and mucilages
and several other types.
You don't break this down but instead
the bacteria in your gut breaks it down.
And that can have some different kinds
of consequences in terms of digestive health.
So again, we'll talk about this a little bit more.
So be sure that you're familiar with these different concepts.
Now we can move on to fiber and talk a little bit more
about what fiber is.
Because again, this is something we're hearing a lot about.
We want people to eat more fiber rich foods.
So what does that mean and what are the benefits
and what does it look like?
We can take that fiber again and break it
down a little bit more.
So we have soluble fibers, and soluble simply
means that it's going to dissolve in water.
So if you've ever cooked something like oatmeal
and maybe you left a little bit in the bowl or the pan.
And you go to wash it out and you'll
notice it's very slippery, maybe it's
a little sticky and kind of solid.
What's happened are those oatmeal fibers have blown up,
they've absorbed a whole bunch of water.
And that's what happens with these fibers.
They take up all of that extra water.
And that's some real benefits in terms of digestion.
These type of fibers tend to form something called gels,
and they tend to make food slippery.
And that has a real advantage in terms of digestion
because it helps move food through your system unimpeded.
And then we also see that there's
an opportunity here for that bacteria in your gut
to really use that fiber, that soluble fiber, and produce gas.
So for some people this is really quite bothersome.
But I will say that for people that consistently a high fiber
diet, they aren't bothered by gas.
So I really encourage you to add a little bit
of flavor to your diet every day if that's one of your goals,
as well as adding more water.
Because like I said, with that oatmeal example,
that soluble fiber is going to attract water.
So we want to make sure you have enough water in your system
and don't become dehydrated.
We find this particular type of fiber, the soluble fiber,
not only in oatmeal as I mentioned,
but also in other grains like barley.
You're also going to see it in fruits and vegetables.
Apples are a really good example.
Maybe you've made jelly sometime, or jam in the summer,
with strawberries or blackberries or something,
and you added pectin.
That's a soluble fiber, and it allows that jelly or that jam
to become very solid and gelatinous.
And so that's one of the benefits to this kind of fiber.
It's associated with a lower risk of chronic disease,
especially heart disease.
So if you go to the supermarket you're
going to see that different kinds of breakfast cereals
that have oats or barleys in them,
sometimes they'll have the little heart healthy symbol.
And that's letting you know that it's got soluble fiber
and it's really good for lowering
your risk of especially heart disease.
These also add a pleasing consistency to food.
They make them a little bit thicker and richer feeling,
especially something we call mouth feel.
You'll notice this especially with dairy products.
For instance, low fat yogurt sometimes is thin
and people don't really like it.
If you flip it over and look at the ingredients
you'll notice that maybe there's some kind of a modified food
starch on there, to give it that more fat feeling in your mouth.
Ice cream.
Again, I love ice cream.
If you read the ingredients you're
going to see something called carrageenan,
and that's a seaweed product that
adds thickness and richness to the ice cream,
especially for low fat ice creams.
That's particularly valuable for getting the consumer
to buy that product again.
Then we have insoluble fibers.
Now these are different because they don't dissolve in water.
So keep that in mind.
For instance, Metamucil.
Sometimes you see that advertised
or you might find it at the pharmacy.
People will add that to their diet to make sure
they're getting enough soluble fiber.
Well I could take celery and chop up that salary
and put it in a glass of water and stir it
until the cows come home.
It's never going to dissolve.
It doesn't do that.
But the advantage here, besides chronic disease
and so many other things, is that these are not
easily fermented by the bacteria in your gut.
So that's a little bit different.
Also, when we look at where these are found,
they're found in things like whole grains.
It's that outside of the whole grain.
So if you have an opportunity when
you're buy something like rice to go
for brown rice or a whole grain rice
versus the polished or white rice,
you're going to find a lot of benefit
in terms of insoluble fiber from the brown rice
or the whole grain.
That's why we're pushing that particular food
group or that type of food with people,
to make sure they're getting this kind of fiber
because you need to balance of insoluble and soluble.
And these particular types of fiber
retain their structure to some extent.
Now, I have a little caveat here because if we
were to take raw broccoli, and then steamed broccoli that's
cooked until it's done, and then broccoli that's
been cooked for hours, there is going
to be a fiber difference between these.
So for most people who are cooking food
until it's done but not over done,
they aren't going to lose significant amounts of fiber
and we really don't have to worry about it too much.
These also aid in digestion.
So I want you to get familiar with talking
about bowel habits and the whole digestive process
because all of it's important to our health.
When we look at soluble fibers, these
are the ones that dissolve, they tend
to increase the viscous nature of food and stool
as it moves through your body.
The insoluble fibers tend to add bulk and allow
that food product and the waste product
to be pushed through your digestive system.
So we need both of these kinds of fibers for proper digestion
and elimination.
Again, I really want to stress that your body does not
break down fiber.
Even if it's soluble fiber, you don't break it down.
You don't have that enzymatic capacity, we call it.
So again, it's the bacteria in your gut, which really feeds
into a discussion about why we want to have a healthy gut
and have all these bacteria.
You might choose a product like yogurt
that has natural live cultures.
That doesn't mean you're going to be more sophisticated
and like opera if you eat cultured food.
Instead it means that the bacteria in your gut
is going to be healthy.
Things like antibiotic use tend to kill that good bacteria,
and we need it for digestion.
So especially people that are on antibiotic therapy
need to have some yogurt or other kinds
of live cultures in their diet.
And then consider also that because we're not breaking down
those fibers, they pass through the body really undigested.
They're going to be chewed up and all that kind of thing
and they're going to be changed, but they
aren't really digested.
There is some conversation about whether or not
fiber provides energy.
The amount of fiber that you would
have to eat to get a significant amount of energy
or caloric value is way outside the normal human experience.
So for men, 38 grams of fiber day.
Women, 25.
You'd have to be eating 75, 80 grams of fiber a day
to actually have the amount of energy, somewhat significant.
So don't think that this is providing energy for you
either.
The bacteria also, just to bring you back
into that conversation, with the soluble and insoluble fiber,
the bacteria is what ferments and processes this.
The soluble more than the insoluble.
So again, not something that your body is equipped to do.
And like I said, it produces gas in some people.
Fiber recommendations.
So this is where really the rubber
meets the road because we know what the fiber is
and how to classify but how much do we need a day?
So I've already said that men need to have 38,
and I'm here using the average adult male, 19 to 50.
38 grams a day.
And then women, 25 grams.
I really like this recommendation for children
right here.
We have their age plus five grams of fiber per day.
And I think most parents, even if they can't remember
some elaborate formula for figuring out fiber requirements
for their children, know how old their child is and can add five
to it.
So learn this recommendation so that if you're
talking to parents in any setting, whether it's
at a basketball game and you're talking about fiber,
or a cocktail party, or if you're working in health care,
this is a really, really good easy formula to remember.
And these other ones, just know which group you're in and then
when we look at dietary intake later,
of course you're going to be able to judge where you are.
Some other recommendations we have around fiber
aren't just about the amount of fiber in the day, right?
That's important.
We also want to look at overall carbohydrate intake.
So the Committee on Dietary Intakes,
so we have this Dietary Reference Intake.
This big book called the DRIs.
And the recommendation there is that most adults in the US
are getting between 45% and 65% of their calories
from carbohydrates.
This doesn't mean that I get to have all of those calories
from simple sugars.
It means that that's about carbohydrate recommendations.
So this might just give you an idea about the health
or the appropriateness of low carbohydrate
or no carbohydrate diets.
And there are many reasons that we
don't want to have those kind of dietary approaches.
One of them is that our body doesn't want to run on fat.
If you look at the way that the human body is built
and the way that we derive energy from food,
we rely on carbohydrates.
We also use fat but we have to have carbohydrates.
So a low carbohydrate diet is not
nearly as dangerous as a no carbohydrate diet.
So someone that's relying on protein and fat
for the majority of their energy runs the risk
of putting their body into something
we call a ketotic state, and that's incredibly dangerous.
There's more in the book that you can read about this
but it's really undesirable.
But the thing I will mention about this
is that if you talk to someone who
has been a low carbohydrate or no carbohydrate diet,
they're going to tell you it's effective.
And the unfortunate thing is, it is effective.
People lose eight, 10, 15 pounds in a week, the first week.
And the reason that happens is that when
[INAUDIBLE] going to store them in muscles and in liver
and a little bit in our brain, you also have to store water.
So when people go on a no carb diet or low carb
diet what they're actually doing is
using that remaining carbohydrate they've stored
and shedding all of the water that was stored with it.
So of course they're going to lose a lot of weight.
It's all water weight.
And then they stay on this diet for a while.
And even people that love bacon and cheese and fat
can't stay on that diet forever.
They go back to eating carbs, they gain the weight back.
And in the meantime they have heart disease
and high cholesterol.
So not a good lifestyle choice.
There's no shortcuts to health, really.
We also have to look back at what
we talked about in the beginning part of our course,
about the caloric value of carbohydrates.
They're worth four calories per gram.
Fats are worth nine.
So right there should be a big clue
about whether it's carbohydrates that
are the problem for Americans or fat.
It's really-- you need both of them,
but in appropriate amounts.
Our body, if we are having a low carbohydrate
or no carbohydrate diet, we do have the ability
to take protein and convert it into glucose.
It's very metabolically expensive,
which means that the calories that I get from turning protein
into glucose are minimal.
And I'm going to use more calories of protein
that I actually yield in terms of carbohydrate or glucose.
So someone that's already very compromised, maybe
a patient that isn't eating for some reason, they have
on anorexia nervosa or their anorexic, meaning they've
just stop eating.
This isn't going to be appropriate,
they're going to start catabolizing large muscle
groups and protein stores, and we
don't want that to happen with a patient that's
already compromised.
The other thing is, and I'm not sure
that this is really a valid reason in nutrition
but just smart economics, is that no carb or low carb diets
are very expensive because you're eating protein
and you're eating fat.
And you could choose very cheap meats
but the cheaper the meat, the more fat in it.
And it's not the right kind of fat.
So again, I would be very, very cautious
of diets, any particular diet that's
asking you to cut out an entire class of nutrients.
So if we were to shift our thinking and I gave you a diet
and I told you never drink water again, you'd say,
this is silly, don't do that.
The same thing can be extended to a carbohydrate free diet.
It's not appropriate and it's not safe,
and people have died on these diets.
So we want to figure out ways to eat
the appropriate kinds of carbohydrates.
I do have on one other slide in our textbook
that I think might be helpful to you
to look at some of the benefits of different kinds of fiber.
So we can look at soluble fiber, where it's found,
some of the actions in the body, and then also the benefits.
And we can do that as well with insoluble fibers.
So take a look at that.
I'm also going to unpack those benefits a little bit more.
And we're going to talk particularly
about heart disease risk and some of the benefits
that we see with different kinds of diets and carbohydrate
and fiber choices.
So one of the things that is most helpful to people,
if they are at all at risk or think
they might be at risk of heart disease,
maybe they have a family history or maybe high cholesterol,
is the fact that fiber rich foods
help reduce serum or blood cholesterol levels,
which then in turn lowers your risk of heart disease.
As well there are some other kind
of characteristics around fiber rich diets.
So if you think about foods that are high in fiber,
you might think about broccoli and apples, whole grains,
different kinds of vegetables.
They are very, very low in saturated fat.
The only saturated fat they have would be the stuff
that you add.
So if you cook broccoli and put cheese sauce and butter on it,
that's where your saturated fat comes from.
They have no trans fat.
Trans fat naturally only occurs in two places,
and carbohydrates isn't one of them.
It is found a little bit in milk,
but when we think about fiber rich foods
milk probably shouldn't come to mind.
And then the only place we're going to find cholesterol
in our diet are in animal derived foods, so cheese
and meats and things like this.
So that is right there a huge advantage.
Many people who are at risk of heart disease
or are developing heart disease are best
advised to watch saturated and trans fat intake very closely.
Also, when you look at those foods
again that are rich in fiber, again fruits and vegetables
and whole grains, you're going to find
that they have certain qualities.
So the proteins that are found in legumes and beans
are really very, very good choices for people.
Most people, when they choose protein,
don't stay within protein allowances.
For instance, a serving size of a piece of beef,
it's only three ounces, the size of a deck of cards.
If you go out to eat and they brought you a deck of cards,
you be appalled.
Yet that is an appropriate serving size.
So we vastly overconsume animal proteins.
And vegetable proteins, a couple of days a week,
would be a really good choice.
So it's not just about what we're
adding but it's about what we're removing from the diet
when we rely on some of these other foods.
And then of course phytochemicals.
And phytochemicals, that word phyto refers to plants.
So I can take broccoli.
I could distill it down to all of the vitamins and minerals
and put it in a pill and give it to you.
But there's a real opportunity when you actually
eat real food because you're getting things
that I can't quantify and put into a pill.
These are the phytochemicals.
These are all of those benefits that
make real food so much more important than a pill.
And they've done studies on this in case
you doubt the veracity of my argument, where they have
taken a person's entire micronutrient needs, so
their vitamins and minerals, and put them into a pill
and given them the pill.
These people don't do well.
And they're really unhappy because we enjoy eating.
Their digestion is all messed up.
So relying on supplements for all of those
different chemicals, especially the vitamins and minerals
in food, is not an appropriate choice.
We'll talk about that more later.
Now I mentioned that one of the things that we
see as a direct benefit of having a high fiber
diet or a fiber rich diet is an opportunity
to bring down serum cholesterol levels.
We have a big fancy name for this.
It's called enterohepatic recycling.
Now that name isn't really that important
but there are a couple things I want to talk about with this.
So I have a schematic here, a little diagram
of how this works.
And although we've talked about bile yet,
it's important for our conversation
since we have to start somewhere.
Bile is made by your liver and is stored your gallbladder.
And what bile does is it helps you digest fats.
So when we have a meal, we've eaten something
and it's made its way into our small intestines,
the gallbladder sends a little bit of this bile
into the small intestines to help us digest the fat.
If we have a fiber rich diet and we
have food in our small intestines
that has fiber in it, it acts like a tumbleweed.
And it captures little bits of that bile.
And it can't get out of there.
Normally that bile is going to be recycled,
and we see that bile is being reabsorbed.
And it's going to be going back up to the liver
and reused to make more bile.
So the bile is cholesterol, it's made out of cholesterol
in your liver.
If we actually can trap some of that cholesterol or the bile,
that's the same thing basically, in the tumbleweed
and it gets excreted from the body,
we're going to be very effective at bringing down
those serum levels of cholesterol.
The other thing that happens, and I
don't have a slide for this, is that I've
mentioned that this fiber acts as a tumbleweed.
Let's say that I've had a piece of whole wheat bread
and I put some butter on it.
Within that tumbleweed of fiber and butter,
that tumbleweed is really going to trap the butter
so that my body can't absorb it.
So some of that fat is actually going
to be excreted from the body unabsorbed.
So that's just another benefit, and eventually that mechanism
of trapping the fat is going to help
you reduce serum cholesterol.
So this is enterohepatic recycling.
It's not important to know that big fancy name
but to know the benefit we receive.
Another disease that's of critical importance
to many Americans is diabetes.
We see type 2 diabetes being at really epidemic levels.
We used to call this adult onset diabetes.
That name is a thing of the past.
We're seeing teenagers with this particular disease, or even
prediabetes.
So we want to prevent this in people and help manage it.
And I will say that if you know someone with type 2 diabetes,
it is the number one reversible chronic disease.
So we do have an opportunity for someone who is type 2 diabetic,
and I'm not saying it's easy.
It requires a great deal of change in lifestyle and diet.
But it is possible to reverse that diabetic situation.
So when we look at some of the benefits of a fiber
rich diet in relation to preventing or managing
diabetes, we see glucose control.
So if you think about foods that are rich in fiber,
the example I like to use here is a glass of orange juice.
If you were to squeeze a glass of orange juice
it might take four oranges, right,
and you get this nice glass of juice.
Would you ever sit down and eat four oranges?
Probably not.
Because one of the things that happens
when you eat this orange, all that fiber
modulates your blood glucose control.
If I were to have just a glass of orange juice,
basically all I'm getting is all the sugar and water
out of the fruit and my blood sugar
goes up very dramatically and very high.
So you see people on this roller coaster
when they're choosing foods that are not fiber rich.
Their blood sugar spikes, then their insulin
has to have a corresponding spike,
and so they end up on this roller coaster.
And it not only affects your pancreas, which is really
being asked to do a lot of work, but it affects you emotionally.
We see people on this roller coaster.
They're very buoyant and happy, and then they're
really low and dragging and irritable.
So there are a lot of benefits right there,
not just about diabetes, but also just mood
and how you feel throughout your day.
Then we also see that those fibers--
so when we have the fiber rich meal-- it's
going to trap some of those different nutrients
and we see a delay in the passage of food
through the system.
And this is pretty important because it's
going to delay the return of hunger.
And also the fact that, just like
we were talking about with our blood sugar curve,
because it's trapping nutrients that sugar is slowly released
over time as the food is being digested.
Another extraordinarily important benefit.
Also when we look at that another one of those
benefits we see with modulating blood sugar levels
is that we often see people having to have less medication.
And less medication, less intervention, less side effects
and complications.
All right, weight management.
I invite you here to think about if you've
had for breakfast something like Rice Krispies.
I know if I have Rice Krispies I'm hungry like, half
an hour later, but if I actually have
a bowl of hearty oatmeal or a high fiber cereal,
I really stay full a lot longer.
And really that's an opportunity for weight management.
Because if I have eaten my 200 calories of cereal
and I'm hungry immediately, I might actually
eat more energy than I need.
But if I've had my 200 calories of a fiber rich cereal,
I'm going to delay hunger and not
be encouraged to eat more energy than I need.
So consider that pretty strenuously.
If you're looking to reduce your body weight,
fiber is an important part of weight control overall.
Then we see that the types of foods
that are high in fiber or these complex carbohydrates
are naturally low in fat, we've already talked about that.
But they don't have added sugars, also,
which is another source of extra energy that we don't need.
And if you think about, for instance, maybe I went down
and I got a coffee, one of those fancy coffee drinks,
one of those in the blender.
That's a tremendous amount of fat and sugar and calories.
Those have anywhere from between 900 and 110 calories in them,
and I'm drinking.
I don't feel full after I've had it.
For that same amount of calories I
could have anywhere from 11 to 13 cups of strawberries.
Now I probably wouldn't feel good if I sat down
and had that many strawberries, but if you
think about how long you're going
to stay full from eating strawberries or any other kind
of fiber rich food, it's very different than drinking
calories.
And this is something that Walter Willett at Harvard says,
that we've gotten into a habit of drinking calories.
We have to be very, very cautious about that
because those calories that we get from beverages
don't increase feelings of satiety.
Satiety is the feeling of fullness or satisfaction
after eating.
So if I drink a whole bunch of calories,
I'm not going to fell full the same way
if I actually eat them.
So again, that's that orange juice
versus eating actual fruit example.
OK, so those are soluble fibers also swell.
So think about something like rice cakes.
One of the reasons a lot of people like those rice cakes
is because they have that and a glass or two of water
and they feel really full because it absorbs the water
and keeps them feeling satisfied for longer.
And of the benefits don't stop there.
So we're going to have a somewhat frank discussion
of your bowels here.
So digestive tract health.
So if we have a high fiber diet this
is going to increase our opportunities
to keep those tissues, those very sensitive tissues,
healthy.
And it does it in a number of different ways.
But we want to make sure-- and this
is where a conversation about bowel movements is necessary.
People will say to me, how often should I go to the bathroom?
How many times should I have a bowel movement?
For some people it's once a day, twice a day.
For some people it's once every other day.
We know that once a week or once every two weeks is not healthy.
Fiber is an important part of this,
so when I hear people saying they have issues
with constipation and hemorrhoids
and not being on a regular bowel movement schedule,
it's an opportunity to talk about fiber because they
may be having a diet that just doesn't have enough fiber
or they're not having enough fluids with their diet.
So those different kinds of fibers
that we've talked about enlarge stool and it also makes it
slippery so it allows the passage
throughout the digestive system.
So we want to avoid constipation because constipation really
increases opportunities for straining.
And when people strain to have a bowel movement
we see other kinds of issues creep up.
So hemorrhoids is a big one, and a hemorrhoid is basically
just a vericose vein of the ***.
These can become terribly painful.
They can bleed, they can rupture, require surgery.
Best to avoid that kind of problem.
Fiber can be very helpful.
Also we see that fiber can reduce
our risk of appendicitis.
And so the appendicitis is really
a vestigial organ, something that we don't really need,
but it sits there and causes problems for us sometimes.
So if we have a high fiber diet it
speeds the transit of waste products
and allows less of an opportunity for an infection
to occur.
Also, I have a slide that I'm going to show you about this,
but I want to talk about something called
diverticulosis.
So I want you to appreciate the ending up that word, -osis.
-Osis is really a state of having a disease.
So you can think of all kinds of diseases that end in -osis.
That's very different than -itis.
And you'll hear that ending, diverticulitis, as well.
-Itis refers to an acute situation, inflammation,
swelling, things like this.
So we can avoid diverticulosis and diverticulitis
with a high fiber diet.
So here I just want to show you a picture of your colon.
And this may not be something you've ever seen.
I encourage you to think about your digestive tract
as a tube or a pipe.
And when people are straining to have a bowel movement
because they're constipated, what happens
is that these delicate walls of muscle have to respond,
and you're putting a lot of pressure on them.
And you can see these little bubbles.
They're kind of like these little pouches,
and we call them diverticula.
And these form where that muscle has been strained.
And you can see one here, a very nice little cross section, what
will happen is different kinds of material
will get stuck in here.
And it can cause pain, it can cause bleeding
and inflammation, and this whole region
of your digestive tract, really your whole digestive tract
is highly vascular, which means that there's
a lot of blood flow.
So people can lose a significant amount of blood
from their colon when they're in a diverticulitis situation,
when they have inflammation and an acute situation.
So this can be avoided.
I will say that recent surveys have
shown that 80 percent of people have
the formation of this diverticula.
It comes from straining, it comes from a low diet.
We want to avoid that.
So it's about getting the message about a high fiber diet
early in life.
So children, young people, everyone needs fiber,
up through the life cycle.
Older folks need it as well.
So a few more comments about your colon.
So I want to talk about colon cancer, colorectal cancer.
This is something that's kind of a tricky situation
because a lot of people will ignore symptoms
because they find embarrassing or something like that.
Not too many people want to talk about their bowel habits
at all, and especially not with a physician.
But there are things we can do to lower our risk
and be a little bit more comfortable about what's
normal.
So one of things that fiber will do
is it acts a little bit as a scrub
brush for your large intestines.
And there are all of those cells, the cells that
line your large intestine epithelial
layer, those last two to three days.
And if you think about it, they're
in a really caustic environment, right?
They're being assaulted with waste products
all the time, waste products they contain carcinogens,
all kinds of things that your body just doesn't want.
If we have a high fiber diet all of those cells
get sloughed off like a big loofah
so any of the damaged cells are going
to be removed, before they can actually go rogue and get
"mavericky" and grow out of proportion
and create tumors and things like this.
So high fiber diet reduces your risk of colon cancer
I will say that a super, super high fiber
diet is not necessarily a benefit.
So we see people having a high fiber
diet of 70 or 80 grams of fiber a day, two or three times
our recommendation.
That actually increases your risk of colon cancer
because it's so abrasive on those tissues.
So 38 grams for men, 25 for women.
That's completely appropriate.
If you go over by five or maybe even 10, not a problem.
But we don't really want you having 75 grams of fiber a day.
The other thing that happens is that those fibers can also
help to reduce the pH of the intestines.
And this has some different benefits
in terms of slowing cellular growth, especially
for cancer cells.
So that's an important mechanism as well.
All right, so now we want to look
at digestion of carbohydrates.
So far we've covered a whole bunch of information
about different terms, broken down
that whole big umbrella of carbohydrates,
and we've talked about benefits of fiber.
Now we want to figure out how we digest these things.
Keep in mind, we're not digesting fiber.
We're digesting other kinds of carbohydrates, sugars
and starches.
So in order for us to be able to do this,
this whole process is going to start and the mouth.
You have something in your saliva called salivary amylase
and if you look at that word, amylase, at the end it has,
a-s-e.
When you see that ending, dollars to doughnuts it's
going to be an enzyme.
Not always, but for the vast majority of words
you're going to see in nutrition or in science,
it indicates an enzyme.
So you say, well what is an enzyme?
Well, an enzyme simply is a chemical,
it's a protein manufactured in your body.
And we also have other kinds of enzymes we can put into people.
But the idea is that it's going to take big things
and break them down into smaller things.
So I invite you to think back to our pearl necklace of starch,
all those little beads of glucose.
We can take an enzyme and we can start
to break those off so that we have individual glucose units.
That's what an enzyme does.
We have this one that I referred to
in our mouth, the salivary amylase,
and this is the first action we have on carbohydrates.
So if we take a bite of potato or a saltine cracker
or something like this, that enzyme in our saliva
starts to break down those bonds in the starch
and free up or liberalize those glucose units.
So this is in our spit, and what's
going to happen is that we're going to chew up that food
and it's going to go down into our stomach.
Now in our stomach, it's a very caustic environment.
The pH is like two, which makes it very, very acidic.
It's like battery acid, it's a primordial location.
And it's not going to really allow
for there to be much digestion of carbohydrates.
We're going to talk about a few different kinds of nutrients
that are digested in the stomach.
Carbohydrates is not one of them.
So really, this is kind of a holding area for the food
that you've eaten.
There's lots of things that happen in the stomach
but digestion isn't one of them.
As food passes out of the stomach
into the small intestines through that pyloric sphincter,
we're going to see the vast majority
of our digestion happening here.
And we know this.
The small intestines are the site
of all kinds of digestive action.
Carbohydrates is no different.
And they are different kinds of enzymes
that are being produced.
The pancreas is a primary manufacturing plant
for enzymes.
And I want to show you a picture.
I like this picture, I think it's very helpful.
We have a girl and what she's done
is she's eaten some kind of a carbohydrate rich meal.
We see the food has made its way.
And now it's here in the small intestines.
And if I can walk in front here I'm
going to show you, when we see this little picture here,
we're kind of looking at a cross section
of the small intestines.
This is area we refer to as the lumen, or that opening
in the pipe, where all the food is going to be.
And here we have the epithelial layer,
which is the lining of the small intestines.
And then we have more of that structural component,
so this is going to be blood flow.
Because again, the intestines is highly vascular.
And this is an important highway, so to speak,
for moving different kinds of nutrients around the body.
They're transported in blood.
So we have these little fragments of carbohydrates
and you can see they have these little bonds,
these little green like arrow type things in between.
The enzymes that reside in the lumen,
these pancreatic enzymes, are going
to come along and break those bonds,
to free up those different carbohydrates or sugars.
Then they're going to pass in through this epithelial layer
right here and then go into the blood, where they're
transported around the body.
This is very, very easy for some types
of these monosaccharides we've talked about.
Glucose, that's naturally found in the blood, not a problem.
The galactose, that one is going to be a little bit different.
And then also the fructose.
So those are going to require a little bit more action.
Especially I want to talk about fructose.
Because when we look at fructose,
it's a five carbon sugar.
And the chemistry isn't really that important.
But what we do see is that fructose
has to be converted into glucose for our body to use it.
And the same thing happens with the galactose,
which is part of that complex making up lactose or milk
sugars.
So here, these two types of monosaccharides,
have to have the liver involved to convert them to glucose
which is usable.
The other products here, all of these free glucose units,
can go right into the blood and be used by the body, especially
the muscles.
We see the muscles using a lot of glucose.
And almost every single cell in your body
has a receptor for glucose, and uses glucose.
Now we have opportunities then, when
we look at what happens after we have digested a meal.
So we've gotten all of this glucose
and it's come into our bloodstream.
We have to be able to store some of it and use some of it.
If I'm exercising I'm going to be able to use a lot of it
right away to keep up my blood sugar
so that I'm actually efficient at exercising.
But there's usually a surplus that we don't need at the time.
Or if we're not exercising we may need very little of it
at that time.
So we need to store some of it.
And this is where pancreatic hormones become involved.
We've talked about enzymes that are produced by the pancreas
but now we want to look at hormones.
You've probably heard of insulin, and this the first one
that we're going to talk about.
Insulin is produced when blood sugar levels are very high.
It helps to clear that blood sugar and move it into cells.
And I told you that it's stored in your liver,
and it's stored in your muscles, and a little bit in your brain.
So insulin's job is to come along and move the glucose out
of the blood and put it into muscles for storage.
Or into your liver for storage.
So keep that in mind.
Then we have something called glucagon.
And this might be less familiar to people
because we have this whole national conversation
about diabetes and insulin.
We don't talk about it's corresponding agent,
which is glucagon.
And glucagon has an opposite job of insulin.
So if you haven't eaten for a while
and your blood sugar levels are really low,
the pancreas is going to make glucagon.
And the glucagon sends out this signal to your liver
and to your muscles that you need
to increase the levels of blood sugar,
so it's going to liberalize that stored glucose, which
is stored in the form of glycogen.
Now I want to back pedal to one thing I said.
I said that the glucagon is going
to liberalize, or kind of allow you
to access the sugar stored in your muscle.
That's only going to happen if you're exercising.
The only way to take the glycogen or the glucose out
of muscle is to exercise.
You can free it up from your liver without a problem,
but it has to be accessed through exercise if you're
going to take it out of muscles.
And the reason for this is really your own protection.
It's a fight or flight response.
So that if I was fighting that bear when I'm hiking,
I'm going to be able to respond.
If we were to go the opposite direction
and take it out of our muscles before our liver,
that wouldn't put me in a very good situation
because if I confront the bear I'm
not going to be able to respond.
So there's always going to be some in your muscles
and we never take it out of our brain.
It's always there, even if you're
starving, because your brain has to think.
Your body is going to shut down other systems
before it does that.
So make sure that you know these two hormones.
You want to know insulin and its job, when it's produced,
and what it does.
And then also glucagon.
All right, so now I want to just mention,
I talked about that fight or flight response.
Epinephrine, or adrenaline, can do the same thing as insulin.
It's going to free up stored glycogen or store glucose.
That's that fight or flight response.
It's quick energy.
So now we understand how food is digested,
what happens to those carbohydrates
as we break them down in the system.
Let's look at what can go wrong I mentioned insulin and this is
really the thing we've most often associate
with diabetic conditions, that something's gone wrong
with insulin production.
So I want to talk about diabetes just a little bit.
The true name of diabetes is diabetes mellitus,
and within this whole umbrella of diabetes
we can break it down into different types.
But what we're talking about is that there's
some kind of a abnormality with blood sugar levels.
Whether it's type 1 or type 2 it doesn't matter.
We're seeing the same kind of issue.
And the prevalence is vastly increasing.
Prevalence means the number of people in our population
that are dealing with this disease.
I told you earlier that it used to be called adult onset.
We're seeing so many children with this,
and it's really predicted to become an epidemic in the US
in the next 20 to 30 years.
It is also the number one cause of preventable blindness
in the US.
In the world it's Vitamin A deficiency.
In pol US it's diabetes.
There are so many other kinds of complications that we see.
Amputations, and maybe you know someone
that's been in this situation.
Definitely we see different kinds of issues
crop up during pregnancy when people are diabetic.
Also heart disease, kidney disease, and premature death,
and then also increased risk of other kinds
of causes of death related to your immune system.
Generally speaking, if I go back up to premature death,
being diabetic on average reduces
your life span by about a decade.
So there are some significant reasons for us
to talk about this.
Type 1 diabetes, this is not the one
we're dealing with overall as the huge health
concern in the US.
It does occur, and what's happening here
is that the pancreas for some reason is making no insulin.
And is often detected in childhood.
There's different kinds of symptoms
that people might experience.
In terms of prevalence in the US,
it's really a small percentage of the cases of diabetes
we're seeing.
And it happens for lots of different reasons.
There's some speculation that it could be a toxin, sometimes
a virus, people say that there's a genetic link,
that it happens for autoimmune disorder
reasons, viral infections.
So we don't really understand and there's
reason to believe that some cases are
blamed on each one of these causes.
Type 2 diabetes is really where we
want to spend the vast majority of our time talking about this.
And what's happening is that the pancreas is actually
making insulin, and very often it's
making tremendous amounts of insulin.
But the body is not responding the way it should.
So again, remember that a hormone
is a messenger, and insulin a hormone.
So the insulin is sending out this message
to all of your cells, hey, I want
you to take some of that glucose out of the blood.
Well, for people that are producing a tremendous amount
of insulin, because maybe they're
having a very simple carbohydrate diet
and they're on that roller coaster of high blood sugar
and insulin, it's really exhausting.
And so all the muscles start to say, and the liver says,
you know what, I see this insulin all the time,
it doesn't mean anything to me.
I'm not going to react.
Eventually what will happen is that those cells
don't respond at all.
And we see people over time really wearing out
their pancreas, and the pancreas gets exhausted.
It says, I'm making all this insulin
and nothing's happening.
I'm just going to give up.
So we see people over time becoming type 1 diabetics.
Evidence seems to indicate that it's
about 10 years after someone has been diagnosed with type 2
diabetes that they actually become a type I diabetic.
Not in every situation, obviously we
want people to manage the condition,
we want people to hopefully reverse it
through diet and exercise.
But that doesn't happen in all situations.
So with type 2 diabetes, again, the prevalence has gone way up.
And I want you to be familiar with this term, insulin
resistance, because that's really what's happening here
is the body's producing the insulin
but it's not having really any effect.
And so blood sugar levels remain incredibly high,
which is very damaging to tissues.
OK so I want you to continue to read a little bit more
about diabetes in the book.
But there are some things that we
can talk about that might be important for us
in terms of preventing or managing the condition.
So when we look at a lifestyle that's going to help people
manage the condition, staying at a normal body weight.
And I will say that just because someone
is overweight or at a high BMI, does not mean
they have diabetes.
That alone is not an indicator or a predictor
of diabetic conditions.
It's just one of those things that
adds more fuel to the fire.
So if we can get people to stay at an appropriate body weight
it's going to be very helpful for managing the condition.
A diet that's high in all of those good foods
that we should be eating, right, fruit and vegetables, and fish,
and poultry, natural foods, whole foods, in their
un-messed around with state.
And whole grains, of course, because we
know that a lot of people are consuming grain products,
this is the foundation of our diet in a lot of ways.
We want to make sure 50% of your grains per day
are whole grains.
Then also exercise, and the value of this cannot be
understated.
Exercise allows you to remove that stored glucose
from your muscles.
That's the only way we're going to be able to do it.
And then your body can put more glucose in there.
So you end up having this reservoir of glucose
in your muscles, you empty it, you can fill it back up,
and empty it again.
Exercise is one of the best ways to manage diabetic conditions.
And then restrict alcohol.
And you may say well, why would you do that?
Well, a couple of reasons.
One is that alcohol is empty calories.
And then also, when people of alcohol on board
they make very different decisions about food.
So you have a couple of beers on board
and suddenly you're ordering a pizza, right,
or you're doing something else that you wouldn't
have done if you hadn't had alcohol on board.
So if we can restrict this or take it out of the equation,
that's a great idea.
And also alcohol is very high in sugars,
which can raise that blood sugar dramatically.
And then of course don't smoke, but no one should smoke.
OK, so some warning signs of diabetes,
and there are a lot of them.
A couple of new vocabulary words for you in this list,
polydipsia, which means excessive thirst,
and polyuria, excessive urination.
So if you like vocabulary I encourage
you to think about those.
There are lots of other ones.
Now some people may have a couple of these symptoms
and be diagnosed, some people may have all of them.
It varies from individual to individual.
But these are common symptoms and warnings signs that we see.
We're going to talk a little bit about managing diabetes.
But now looking specifically at the diet,
I've already talked about whole foods, and fish,
and vegetables, and fruits, and whole grains.
But we want to make sure they we're
getting adequate nutrients, meeting our needs for vitamins
and minerals.
And then also recommendations around fiber
because that's going to keep us full,
delay the return of hunger.
Not have a whole lot of added sugar.
Sugar is in almost everything, yogurts, barbecue sauce,
salad dressings, everywhere.
It is so hard to control that but if we're
eating whole foods, they aren't going to have added sugar,
they're just naturally the whole food.
So that can be appropriate.
Also, control the amount of total carbohydrates for someone
that has diabetes.
So when we look at a food label a lot of people
will focus on the amount of sugars in the product.
That's important, but that's not what you want to look at.
You want to look at total carbohydrate.
OK, so label reading is very important but make sure
you're focusing on the right part.
Then we want to also look at the fat in people's diet
because there is a link between diabetes and heart disease.
So this is an opportunity for us to also examine
good fats and bad fats in the diet.
Our bad fats are saturated and trans fat,
and the good ones are monounsaturated
and polyunsaturated.
So that's why we want to focus, and then
also making sure that we're not exceeding
total fat recommendations.
Protein is also important, but most Americans
eat vastly more animal protein and protein in general
than they need.
So we're going to talk, when when we get to the protein
chapter, about how to judge whether or not
we're getting too much or the right amount.
But for now, keep in mind that protein, more is not
necessarily desirable.
The appropriate amount is all we need.
I just wanted to spend a really quick minute
touching on a couple of other things
that I think are important because we
hear them talked about a lot.
So glycemic load, or glycemic index diets.
What we're looking at here, glycemic index
refers to the amount that a particular food
will increase your blood sugar.
And these are all standard against white bread,
for instance, and glucose.
So we have this long continuum for all these different foods,
and obviously glucose, having a straight shot of glucose,
is going to increase your blood glucose levels dramatically.
Other foods have a slightly less extreme effect.
So down here I've got tomato juice and yogurt
and peanuts and things like that.
This can be important for someone
who's trying to manage their blood sugar levels,
so if they know the glycemic index of the food
they might be able to judge how it's
going to affect their blood sugar levels.
But this varies considerably from individual
to individual, and even within a particular food.
So a banana is not just a banana.
It's about the amount of ripeness,
so a ripe banana has a whole lot more sugar than a green banana.
And then also what I pair it with.
So if I have that banana and put peanut butter on it,
the glycemic index or the glycemic load of that meal
goes way down.
And most people don't just eat one food.
We tend to combine foods, so this can be good
and it can be bad.
Most useful for people who maybe have diabetes or someone trying
to reduce their body weight or for an athlete.
Some athletes might want to choose high glycemic index
foods to bring up their blood sugar
if they're in a hypoglycemic state, where
they have low blood sugar.
Which is the next topic I just want to touch on briefly
is hypoglycemia.
Hypo, you've probably heard that term, it means below.
So think about a hypodermic needle, it goes under the skin.
As opposed to hyper, which means above or high.
So hypoglycemia refers to someone with low blood sugar
and this has all kinds of symptoms that are generally
fairly uncomfortable for people.
Fatigue and irritability, weakness.
We see this in athletes who maybe have exercised
a little bit longer than they should,
or people have had too much insulin.
Maybe they're diabetic, there are lots of reasons.
And some people just predisposed to hypoglycemia.
So anxiety, sweating, hunger, there's all kinds of symptoms.
If this is something that you're experiencing
you're going to want to pay attention to it
and maybe change your meal planning a little bit
so that your spacing is a little different.
The other thing that can happen, and we
see this with children who may be a little bit hypoglycemic,
is they have a hard time learning.
So this is something directly affects you.
So if you have not eaten since the night before, you get up,
don't have any breakfast, go to class,
your intellectual capacity and your cognitive ability
is compromised because your blood sugar may be pretty low.
So this is importance of breakfast again.
So we want to make sure that kids and adults are well
fed in the morning.
Breakfast is really the most important meal of the day,
get you started on the right foot.
So that's been a whirlwind tour of carbohydrates.
We've talked about different types of carbohydrates.
We've talked about digestion.
We've talked about the benefits of fiber.
And also some particular disease or concerns
around carbohydrates, namely type 2 diabetes.
All right, see you next time.