Hypertension and Nutrition

Hypertension and Nutrition

November 9, 2019 1 By Bertrand Dibbert


High blood pressure, which is also known
as hypertension, is a serious health condition that causes complications
throughout the body from heart attacks and headaches to eye and kidney damage. Let’s review what blood pressure is and then how diet is related. Blood pressure is
actually the pressure that blood exerts on an artery wall. I’m going to draw here schematic of an artery. We think about blood flowing through this. When the heart is
beating, it will actually have a higher amount of pressure going up against
those artery walls. Then when that heart is at rest, there is a smaller
amount of pressure. So when get your blood pressure taken, with that
cuff around your arm, they are measuring that difference between when that heart
is beating, and they’ll call that pressure the systolic pressure. And then
when that heart is at rest, and they call that the diastolic. The unit being
used here for that measurement is millimeters of mercury (mmHg). Now when they report it, they’ll give the systolic over the diastolic. So, you will get a blood
pressure of 120 over 80. If we are above that, we have hypertension. They have
stages of that. Stage one is when you have a blood pressure of 130 to 139 of a
systolic and 80 to up to 90 for diastolic. This stage one is considered the level
of which when lifestyle can still make a difference and get your blood pressure
back down to normal levels. It still has negative consequences, so we want to reduce it. But it is not so severe that they’re going to force
medication on that individual. Once you have a blood pressure with
systolic above 140 or above 90 for the diastolic, you really need to take
medication to get it back down. If we look at the incidence… how much do we
have this in the U.S. population…here is data reported by the National Health and
Nutrition Examination Survey. They look at the overall incidence of
hypertension. It is about 30 percent of adults in United States, so about one
in three individuals have pre or hypertension,
stage one and stage two and beyond. Look at the difference between the sexes. There is not a huge difference between them, but this data is a little bit
misleading because it is for everyone and in reality men tend to get it at an
earlier age but we women catch up when we get into our 50’s and 60’s. Looking
at age, we can see the difference and what is happening here. For all you young
students out there, less than 10% of people before the age of 40 have
hypertension. By the time you are over 60 years of age, 65 percent, or two out of three people,
have hypertension. When we take a look at race, what you can see there is that the
the group of individuals who have the highest incidence are going to be those
of non-Hispanic black heritage. Not only do they have a higher percent
overall, but they tend to get it earlier in life and to have more severe
consequences. If that is your heritage, you are going to get your blood pressure
checked and you are going to maintain medical care around that. So, these are
incidences and we are looking at risk factors associated with development, but
these are risk factors we cannot change. But lifestyle can also make a difference and part of that is diet so let’s take a look at what we can do to lower our risk.
Lifestyle changes that can help reduce blood pressure include the usual
suspects of maintaining a healthy weight and being physically active. Both of
those have been shown to be able to reduce blood pressure by about three to
seven mmHg each and then, of course, having a healthy diet. Research
linking diet with blood pressure has looked at many different variables, some
of them foods, some of them nutrients. Foods have include coffee, tea, soybeans
fish oil, chocolate, alcohol and then all kinds of different nutrients. Sometimes it
can actually seem overwhelming. But sodium is the one that probably has had
the most research and probably is the most impactful so we are going to review
that. Then we are going to take a look at the dietary recommendations associated
with blood pressure. They actually have a specific dietary recommendation
called the Dietary Approach to Stop Hypertension which tries to incorporate
as much as that research as possible. First,we need to understand how sodium
is regulated. It is not regulated at the GI (gastrointestinal) tract. If you consume more sodium or
salt, you are going to absorb it. Rather, sodium is going to be regulated at
the kidneys. If we are healthy individuals, we will generally be it at
equilibrium. That means if we consume more salt or sodium, w are going to excrete more sodium, and vice versa; we consume less, we excrete less. But there are some individuals we call salt or sodium sensitive. For those individuals,
their kidneys are less efficient at removing excess sodium and
therefore, they may experience hypertension when they have a higher
sodium intake. This graph really demonstrates that. Let’s take a look
at what this graph is showing. It is looking at changes in systolic blood
pressure here at the top and the diastolic blood pressure on the bottom
part. Coming across the right of this, we are looking at changes in
urinary sodium, which is the first line – variables, and also the change
in the grams of salt in the day. Now what this represents is the amount removed
from the diet so it looks odd because it is going up in numbers where the
amount that is coming out in the sodium but what that is again is the amount of
salt they removed from the diet. To understand the numbers, the average intake of salt was about 9 to 12 grams a day. Let’s compare that to sodium. So, 9 to 12
grams of salt equals about 3,500 to 5,000 milligrams of sodium. Recall the Dietary Guidelines is recommending we keep that to less
than 2300 milligrams. So, this group of individual
has definitely above the dietary guidelines. As they were taking out the
salt, you can see what was happening to their blood pressure. We have two groups
here. They were looking at healthy individuals and individuals who have
high blood pressure. For both the systolic and diastolic, we can see that
for those individuals who had hypertension their blood pressure
was being impacted more. When they took out more sodium their blood pressure was dropping more. For those individuals who were healthy
though, it did not have a big impact… a slight impact, but not dramatic. So again, those individuals if they had more sodium in their diet, they actually just
excreted more. it was those individuals who were sodium or salt sensitive that
had the bigger impact. Now it’s estimated that between 30 – 40% of
the general population are salt or sodium sensitive. It is not easy though to
identify an individual, specific individual, that is likely to have that. We do know that certain certain population groups will have a higher incidence. In fact individuals who are hypertensive probably 50 to 70 % of them will have be salt sensitive. Other population groups include
individuals who are obese, individuals who have diabetes and individuals with black
or African-American heritage. So now we understand for those individuals who are
salt or sodium sensitive if you reduce the salt and sodium in your diet you
will have a lower blood pressure. Let’s take a look at the DASH diet
remember – stands for the Dietary Approach to Stop Hypertension.
It doesn’t just look at sodium. It also takes a look at those other nutrients. Things like potassium, calcium, magnesium, protein and fiber. All of the ones we need to increase in our diet, not just the reduction in
sodium. It is very similar to MyPlate but it’s a little bit richer in those grains,
it’s going to be low fats, also include those nuts and seeds that
research has shown to be helpful. So lifestyle change can help reduce one’s
risk for hypertension, especially for those individuals in that
prehypertension values, that are just modestly above high blood pressure
levels and we can get it back down to normal and help reduce our risk for chronic
disease.