Sophia Dimou

Sophia Dimou
Sophia Dimou

Κυριακή 1 Ιουνίου 2014

Fibers from grains are better than fibers from vegetables and fruits

Grains are better than vegetables and fruit!

In this portion, we're going to look at
the effect of Dietary Fiber and how it
pertains to heart disease risk.
Dietary fiber is the plant matter that is
indigestible in human body.
And we classify fibers as being either
soluble or insoluble.
While there's definitely benefits to both
soluble and insoluble fiber, if you had
to choose one over the other, it would be
soluble fiber that's most associated with
reduced heart disease risk.
Viscous soluble fibers modestly help to
lower LDL cholesterol levels, so that's
the mechanism by which they're related to
heart disease risk.
Soluble fibers occur in conjunction with
diets that are low in saturated fat and
trans fat and cholesterol.
So you already know about the benefits of
cutting out or cutting down on those
components of your diet.
Here's something that you can add more to
your diet.
Soluble fiber dissolves in water, it
forms a gel like substance.
Well, many grains, and whole grains, do
contain, both soluble and insoluble
fiber.
Oats have the highest proportion of
soluble fiber of any grain.
Other good sources of soluble fiber
include foods like oatmeal, oat bran,
beans, peas, rice bran, barley, citrus
fruits, strawberries, and apple pulp.
Sometimes, people ask you know, should I
eat more soluble or more insoluble fiber,
and to be honest most people for that
they are just splitting hairs.
You should focus on eating more foods
that contain naturally occurring sources
of fiber and you will naturally be
getting both more soluble and more
insoluble fiber but for the sake of heart
disease we are going to focus today on
soluble fiber.
How does soluble fiber impact your heart
health? Soluble fiber helps to improve
hyperlipidemia through the combined
effects of the following 3 things.
Soluble fiber helps to delay gastric
emptying.
When you eat a food containing soluble
fiber, it takes your body a longer time
to digest that food than it would if it
didn't have the soluble fiber in it.
It helps to increase the excretion of
bile acids.
And to reduce, the hepatic synthesis of
cholesterol, which I'll explain in a
moment.
Let's look at the gastric emptying
component.
Soluble fiber works, to help reduce heart
disease, by the mechanism, of reducing
gastric emptying, in the following way.
Soluble fibers take longer to digest.
And this plays a role on satiety and
weight control.
We know that if you feel full, well, we,
we surmise that if you feel full, you're
going to eat less.
If you eat less, you're going to weigh
less.
If you have a healthy weight, you're
going to be at lower risk for heart
disease.
There's also the potential that the
gastric emptying component may have a
beneficial effect on insulin sensitivity.
And insulin sensitivity is linked to
heart disease risk.
The second mechanism by which soluble
fiber works is to increase the excretion
of bile acids.
Soluble fiber binds with bile acids in
your small intestine, and helps remove it
from the body.
This reduces the rate of bile acid
recycling.
The loss of bile acids in your stool
stimulates your liver to increase its
uptake from the circulation and to
replenish your supply.
The result is that your serum total and
LDL cholesterol levels drop down.
But, it's important to note that your HDL
and triglyceride levels are generally
unaffected.
The third potential mechanism by which
soluble fiber helps to impact heart
health is by decreasing your liver's
synthesis of cholesterol.
Some soluble fibers belong to a class of
compounds called oligosaccharides.
These oligosaccharides are fermented in
the lower portion of your gut into short
chained fatty acids, and.
Acids.
These short chained fatty acids enter
your circulatory system.
And maybe inhibit, or basically tell your
liver to make less cholesterol.
So perhaps you've heard that cholesterol
comes both internally and externally.
It can come from the foods, if you eat
animal foods in your diet.
But your body can also make it.
and perhaps, the more planned foods, with
soluble fiber that you make,actually in
turn is helping to reduce the amount of
cholesterol that your liver is making
inside of you.Insoluble fibers, to some
degree do play a role on heart help as
well.They promote motility in your gut
and increase your stool bulk.They also,
They're also linked to lower rates of
cardiovascular disease.
All be it, less so then soluble fiber.
They help promote satiety which is linked
to a healthy weight.
They may help lower your blood pressure
or your risk of blood clots and they may
help lower inflammation as well.
So, all of those things do positively
impact your heart health.
What's the bottom line here? You should
work on eating more sources of fiber from
things like fruits, vegetables, whole
grains, and legumes, and not really worry
exactly about how much soluble or
insoluble fiber you're getting.
A lot of foods, for example an apple, or
a half a cup of dried oatmeal, has f
grams of fiber.
Two of those are soluble And two are
insoluble.
You get the heart healthy benefits from
the combination of the soluble, you get a
little bit more of the gut health
benefits from the insoluble.
At the end of the day, both of those are
good things.
So the recommendation is to increase the
amount of fiber that you get from foods.
Note that these proposed mechanisms have
not been proven from supplemental sources
of fiber.
So you can't eat a crappy diet and then
turn around and eat a lot of soluble and
insoluble fiber supplements, and think
that you're going to get the same
benefits.
You have to focus on the foods.
In the United States, the Food and Drug
Administration has approved the following
health claim.
Now, at first glance, it looks like a
mouthful, and it is, but we're going to
break it down piece by piece.
The approved health claim says, that
diets that are low in saturated fat and
cholesterol and rich in fruits,
vegetables, and grain products that
contain some types of fiber, and
in-particular soluble fiber may reduce
the risk of heart disease, a disease that
is associated with many factors, okay so
there's not just one thing you can pick
out of your diet and say that is going
to.
Heart disease in me.
But the important components here are
reducing your saturated fat, increasing
your soluble fiber.
And keeping in mind that diet is really
just one component of heart disease.
You gotta cut back or cut out the
smoking, you need to exercise more.
there are some other lifestyle.
Components in there.
But when you're looking at diet, go down
on your fat.
Go up on your fiber.
What sort of foods have fiber in them?
Fruits, vegetables, whole grains,
legumes, nuts and seeds.
But, many of the foods that are typical,
or are large components of the western
diet are actually quite low in fiber.
Take a look at these.
Think about your own diet.
In the last 24 hours have you consumed
dairy foods? Meat and poultry, eggs, any
sort of beverage, unless it's 100% fruit
juice which doesn't even have a lot of
fiber, most beverages have no fiber, oils
and fats have no fiber as well.
You might notice that these food contain
protein.
But so do most of these foods.
Again, working on the focus to reduce our
animal products, and increase our plant
products, not only helps to improve the
fat profile of our diet, but we also can
get all of the protein that we need.
Not to mention you get a lot more fiber,
when you're eating, from this side, of
the food list.
How much fiber a day do we need, well,
there are all sorts of different
recommendations, but in the United
States, the Institute of Medicine
recommends that for males, if 50 or
younger, they should have 38 grams of
fiber, 51 or older, 30 grams of fiber;
females under age 50, 25 grams, and those
over, 21 grams.
Why do males generally have higher fiber
needs than do females? Well there seems
to be a link between the amount of fiber
that individuals eat and their risk for
colon cancer.
There's a lot of conflicting data in the
literature, but for the most part, males
are at a higher risk for developing colon
cancer.
And as a result, their fiber intake needs
are higher.
Not to mention, that men, usually have
higher calorie needs, so as a proportion
of their calories, you would see that the
total grams of fiber goes up.
Since there's all sorts of different
recommendations, we'll kind of pick a
target in the middle, which is 30 grams
of fiber a day.
And most of us would be well-served to
eat 30 grams of fiber a day.
The average American actually only eats
15 grams a day.
How can you get 30 grams a day? And how
can you get twice as much as the typical
American eats? Well, let's take a look at
this meal plan.
Let's say, for breakfast, you have an egg
with a slice of whole wheat toast, and a
pear.
You get 8 grams of fiber there.
At lunch, you do a cup of lentil soup.
Some brown rice, and a couple boiled
greens for another 15 grams.
At snack time, you go for yogurt, which
doesn't have any fiber, but if you add a
cup of berries to that, you get 6 grams
of fiber.
At dinner, a small portion of chicken
breast because there's no fiber in meat,
a 1/2 cup of soba noodles, and a cup of
carrots gives you another 4 grams.
And then after dinner, you're hungry
again for that ice cream.
No fiber in there.
But if you add up your whole day, you see
you got 33 grams of fiber.
The key is that every time you eat you
want to have 4, 5 or 6 grams of fiber.
If you do that and you eat 3, 4 or 5
times a day, 4 or 5 more so, you're going
to be able to meet those 30 gram Per day.
Usually you can't just sit down and eat
30 grams of fiber in one meal.
But if you focus on having whole grains,
fruits and vegetables or legumes at every
meal and snack you can easily get to that
30 gramm recommendation.
What does the research say about the role
and the relationship between fiber and
heart disease.
One of the best known studies, is a
Harvard study from 1986, that looked at
almost 44,000 male health professionals,
who were aged 40-75 years old, and didn't
have any heart disease or diabetes.
They completed a detailed, 131 item
questionnaire, that looked at and
analized the total amount of dietary
fiber they were eating.
Eating from food.
They were followed at the 6 year period
and there was an inverse association to
be found between the amount of fiber that
they took in and their risk for heart
attack.
What the researchers found was that a
high total dietary fiber intake was
linked to a 40% lower risk of coronary
heart disease.
And, furthermore, the researchers found
that yes, while fruits and vegetables
were important, that cereal fiber, from
grains, was particularly beneficial.
If you're interested in learning more
about the role of dietary fiber, in heart
disease, I recommend that you check out
these three resources.


In this section, we're going to look at
the effect of dietary fiber on blood sugar
control. What does the research say about
the role of fiber in helping to prevent
diabetes? Well we've got two different
studies to look at. And they're two
different studies that followed
individuals who had taken a detailed
dietary questionnaire at the beginning of
the study, from which the researchers
could figure out what their usual intake
of total and then specific sources of
dietary fiber were. They looked at the
glycemic index, as well as the glycemic
load. That was for the females. In the
male study that was done in the 1997, the
participants were giving a semi-validated
food frequency questionnaire. And what
that means is they were just asked to
select, for example, fruits. How often do
you eat apples? Once a day, once a week,
once a month, two times a month, etc. All
of the people in both of these studies had
no heart disease, no cancer, and no
diabetes at their time of entry into this
study. The results from the study were
that those who reported eating the most
fiber from grains, and that was about 8
grams a day, has a 30% lower risk of
developing diabetes than those who ate the
least amount of fiber from grains, and
that's three grams of fiber per day. It's
not that there was anything wrong about
fiber from legumes or fruits and
vegetables, but this particular study
found results that pertained just to
cereal grains. In another study done in
2007, 15,000 men and women, age 35 to 65
were followed for an average of 7 years.
They were also given a questionnaire that
asked detailed questions about their
dietary fiber intake.
The results from this study showed that
those who ate the most cereal fiber, an
average of 16.6 grams per day, had 27%
lower risk of type 2 diabetes than those
who ate the least amount of cereal fiber.
There was no relationship to be found
between total fiber intake or other fibers
from fruits, vegetables and diabetes risk.
And what unfortunately happens, is,
sometimes with studies like this is that
the lay media will take the results, and
skew them to say, look, fruits and
vegetables do absolutely nothing to help
prevent diabetes, but that's really not
the case. We know that there's nothing
harmful about eating more fruits and
vegetables. If you increase your total
fiber across the board, including cereal
fibers, it looks like that would help to
prevent against diabetes. But even if an
isolated study doesn't show that increased
fiber from fruits, vegetables, and legumes
reduces diabetes risk, it's important to
note, that it doesn't increase the risk,
so there's really no reason not to include
these foods in our diets. As far as
dietary fiber recommendations go, the
recommendation is 14 grams per 1000
calories. This is just one of many
recommendations that works out to about 28
grams a day. A good rule of thumb is that
as an average adult, you should be aiming
to eat somewhere around 30 grams of fiber
a day. If you do include grains in your
diet, as you should in a well-balanced
diet, about half of them should come from
whole grains. What is the effect of fiber
on blood sugar in people who have
diabetes? Well, we know that fiber works
in your favor in a number of ways. First
and foremost, fiber-containing foods slow
the absorption of carbohydrate. If you eat
a food that has fiber in it, it will take
you longer to digest it than a comparable
food that doesn't have fiber. This slow
digestion and absorption of carbohydrate,
leads to a less market increase in your
blood sugar. That, in turn, reduces the
demand on insulin. There is also, in
addition to those blood sugar effects,
there's a satitating effect of fiber.
Eating fiber contain foods makes you feel
fuller for longer. If you feel fuller for
longer, the notion is that you're not
going to go over eat the next time you go
to eat at that is what in turn is linked
to having a healthier weight, getting to a
healthier weight, or being able to
maintain that healthy weight. Let's take a
look at 2 different breakfasts. As a
dietician, I so metimes hear people
complain, you know, I don't like to eat
breakfast, I actually feel hungrier after
I eat breakfast. Follow up with the
question, well, what did you eat for
breakfast? Let's say, they had the
breakfast on the left. This is a white
bagel. It's a refined bread product with
jelly on it. It's a carbohydrate with more
carbohydrate on it. There's no protein,
there's no fat, and there's no fiber. If a
person eats that for breakfast, that's
about, maybe three or four hundred
calories, depending upon how much jelly
they use, and how bid the bagel is.
They're going to feel full, for a short
period of time, but because it's just
carbohydrate, their body's going to
process that sugar very quickly, it's
going to exit the stomach, and yeah, that
person's going to feel pretty hungry in a
relatively short period of time after
eating that breakfast, because that
breakfast is just carb. The breakfast on
the right features a half of a whole wheat
bagel with peanut butter on it. The whole
wheat bagel has fiber, the peanut butter
has fat, and some protein, and hopefully
not too much added sugar. This breakfast
might also be three or 400 calories,
depending upon the serving size of the
bread or the peanut butter. But the person
who eats that three or 400 calorie
breakfast is going to feel fuller for
longer than the person who had the white
bread with the jelly on it. Again, it's
the effect of the fiber, the protein, and
the fat. So breakfast is a very important
meal, but it's also important to take into
consideration what are you eating for
breakfast. If it's just carb, you're not
doing yourself any favors. Add carb, plus
a little bit of fiber, protein, and fat in
order to keep yourself and your blood
sugar stable and keep yourself full. There
are a number of different positive effects
that fibers can have on your blood
glucose. The types of fiber that have been
shown to be the most effective or most
beneficial for blood sugar management are
the fibers that come from things like
gums, beta-glucans, p syllium, resistant
starches and pectins. What manufacturers
love to do is pick a part data like this
and go and add these types of fiber to
other types of food that were'nt
traditionally high in fiber especially in
the united states we see a lot of incident
of this, the adding of plant fibers to
different foods that were traditionally
low in fiber, things like yogurt, or ice
cream sandwiches. The takeaway message
from data that shows that these are
effective types of fiber at maintaining
good blood sugar control, is not that we
should go eat them in highly processed and
packaged foods, but rather, we should look
for foods that are naturally occuring
sources of these, including fruits,
vegetables, legumes, and oats. A lot of
times with these resistant starches, and
the added fibers, if you have to add them
into foods, to increase the fiber content,
manufacturers also have to proportionally
increase the amount of sugar and salt to
mask the taste of the displeasing fiber.
So what's the point of having a high fiber
food, if you have to go and add a whole
bunch of salt and sugar to make it taste
good? Instead, stick to the naturally
occurring sources of these fiber, to get
the best benefits. I mentioned that the 28
grams per 2,000 calories is one way in
which we estimate fiber needs, but I also
want to point out that in the US the
institute of medicine recommends these
guidelines based on age. The older you
get, you tend to eat less calories, so the
number of grams of fiber you need goes
down. And recall that men will always have
higher fiber needs than will females of a
similar age because of their increased
risk for colon cancer. So we know that
fibers are important in helping to prevent
or delay the onset of diabetes, but what
does the research indicate for people who
already have diabetes? In 2000 there was a
very small study that was published that
looked at 13 individuals who had type 2
diabetes. These people were randomized
into a group to follow one of two
different diets. They could either be in
the group where they had a moderate fiber
intake, which was 24 grams. That's pretty
good, considering most people only eat 15
grams of fiber. There's 8 grams of soluble
fiber, and 16 grams of insoluble fiber.
The other group was a very high fiber
group. They were encouraged, and they did
eat 50 grams of fiber a day, 25 soluble
and 25 insoluble. Now you can image that a
study like this is of course going to have
a very small sample size, because that's a
very expensive study to conduct. The
researchers had to closely monitor all of
the foods that the people ate for the
period of the study. In this case, after
the 6th week, and keep in mind none of
these foods were fortified, they were all
naturally occuring sources of fiber. After
6 weeks, the high fiber diet group had a
mean preprandial glucose level, that means
before you eat meals, that was 13 points
lower than those who didn't have the very,
very high fiber diets. Their total
cholesterol also went down, as did
triglycerides, and the very low
cholesterol levels. The key to this study
is that 24 grams is a lot of fiber, but 50
grams of fiber is way more than the
standard recommendation. So some
individuals use research like this to
advocate for an even much higher fiber
diet than the general therapeutic
practices. 24 grams is good but in some
cases, it might look like 50 grams of
naturally occurring fiber is even better
for helping to control blood sugar in
people who have type 2 diabetes. A couple
tips for increasing fiber, you can't just
go from 24 grams in one day to 50 in the
next. If you do you, you might experience
some unpleasant GI side effects. Very
quickly increasing the amount of dietary
fiber that you eat can lead to gas,
bloating, constipation, and diarrhea. Two
tips, go slow when you increase your
fiber. Bump it up by just a few grams per
day. You also want to make sure that
you're drinking enough water. And for
every, for the extra fiber that you're
adding to your diet, try to make sure that
you're getting at least 6 to 8 gl asses of
water a day. What happens is, your fiber,
if you don't have enough water, sits as an
undigestible mass in your colon. You need
a lot of water, and that fiber soaks up
the water, which will help to float the
stool out of your colon. If you're not
careful and you increase your fiber too
quickly, you can actually end up having
the opposite of the desired effect, which
is that very high fiber content without
enough water can lead to constipation. If
you're interested in learning more, I
would advise you to check out this
Fiber-o-meter from Web MD. It's a fun and
easy tool to help track the amount of
fiber in the foods that you're eating. See
if you're getting somewhere close to that
30 grams per day. Some of you might even
be getting closer to 50.

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