A Verdade Sobre a Carne!

Red meat is harmful? Does red meat increase the chance of a heart
attack? Can red meat cause cancer? And can red meat cause kidney problems and
also kidney stones? Hello, I am Dr. Thiago, and I am a urologist
here in São Paulo. These are claims that you will find out there,
especially from those who advocate reducing the consumption of red meat or even completely
removing it from the menu. But today, I will explain to you what we actually
have evidence for about all this and what you can take from this video for your life,
for your day-to-day, so that this information can be taken and applied in your daily life. This video is not related to any belief or
personal preference; therefore, it is information based on data. But before starting this video, comment below
if you have red meat included in your diet, if you usually eat meat, and if you don’t
eat it, why, the reason you have removed this food from your diet. Red meat is an important source of nutrients
for our body. It is one of the main sources of protein. It has proteins that we call high biological
value, meaning it contains amino acids that are essential for our health. In addition, it is also rich in iron, which
is heme iron, which is precisely the iron that is more easily absorbed by our body,
and it is also rich in vitamins B, zinc, selenium, nutrients that are important for our metabolism. The first major claim is that meat increases
the chance of cardiovascular events such as heart attacks and strokes, which is the cerebrovascular
accident or popularly known as a stroke. Where does this claim come from? Some observational studies, which are studies
where the researcher looks at ready-made data, usually from databases that exist mainly in
the United States and Europe, these researchers made a correlation between the consumption
of meat and these events, and they saw that these events were more frequent in patients
who had the habit of consuming more meat. What is the big problem with these studies? Since they are observational, there are thousands
of factors also present that the researcher may or may not know, so there are what we
call bias factors. That’s why these studies cannot create a cause-and-effect
relationship; they can indicate a relationship, but they cannot indicate cause and effect,
and that’s why they are not studies that we take much consideration for clinical practice
because the data can be biased, and these data may not demonstrate the reality due to
some factors that can confuse researchers when analyzing the data. Moreover, there was another major study published
in The New England Journal of Medicine, a major medical scientific journal, that compared
the Mediterranean diet with the normal diet. The Mediterranean diet is a diet rich in fruits,
vegetables, nuts, and it encourages moderate consumption of fish and poultry and low consumption
of red meat. Those who consumed this diet had a 30% reduction
in the chance of cardiovascular events when compared to those who consumed the normal
diet. Again, we cannot extrapolate these data exclusively
to the consumption of red meat because the diet is completely different. It differs not only in meat but in all other
factors: consumption of fruits, vegetables, fibers, micronutrients. There are a lot of factors that are different
here in these two groups, so we cannot say that this effect of reduction was solely due
to the consumption of red meat, okay? And then there was another large study. This study is a meta-analysis that takes analysis
from several other observational studies, which we call cohort studies, and this study
showed a 10% reduction in the relative risk for those who reduced meat consumption by
three servings per week. All these data have some big problems, in
addition to those biases that I told you that can confuse the researcher, and therefore
we cannot transpose these data to clinical practice. These studies, when we talk about absolute
risk, which I will demonstrate to you shortly, have little clinical relevance. So let’s assume that yes, there is no bias,
let’s assume that there is no bias, that these data are correct, that really reducing meat
consumption reduces by 10% the chance of you having a cardiovascular event such as a stroke
and heart attack. When we look at the absolute risk, for example,
this here is the table from the study itself, okay? I’m bringing here the table from the study
itself for you to understand that it talks here, look: cardiovascular mortality, which
is mortality from cardiovascular events, relative risk 0.9, okay? Translating this for you, a reduction of 10%
in relative risk. And then we will do the calculations of absolute
risks that the study itself did for us. It took here in a population that has 41 cardiovascular
events in 10 years for every 1000 people, okay? This risk reduction decreased four events;
instead of having 41, there would be 37. You see that when we transpose to absolute
risk, this reduction is very small. So I would reduce four events for every 1000
people for every 10 years, you see? That’s why when we look at the data, we need
to be very careful to define a clinical intervention or not. In addition, it says here, right, that the
data, uh, the degree of evidence is very low because the studies are only observational
and there is a great risk of bias, right? Therefore, we do not have data in the scientific
literature that support the interruption of red meat consumption in relation to cardiovascular
events. Whoever tells you this is pulling strings
to one side of the reduction of red meat consumption. We do not have this data in the literature
available to support this claim with regard to this exclusively. What I recommend, if you do not have a problem,
do not have any limiting belief, do not have any preference, maintain a moderate consumption
of red meat, okay? Because it is indeed very important as a source
of proteins, source of satiety, and sources of nutrients, okay? So this is for the cardiovascular issue. I want to move on now to the issue of cancer. There are some claims that say that red meat
is related to colon cancer, which is our large intestine. Where did this claim come from? We know that red meat, when subjected to high
temperatures, to cooking at high temperatures, can release what we call polycyclic aromatic
hydrocarbons, an ugly and long name that you do not need to know. I’m here explaining to you, and this substance,
which we will abbreviate as PAH, could be related to colon cancer, which is the large
intestine. When we again look at the data in the literature,
we see that observational studies again, those that look only at data retrospectively where
the researcher has some variables that he can measure, uh, seems to have a relationship,
but when you do a controlled study where the researcher takes a… what we call a randomized
double-blind clinical trial, which is the best scientific study for us to be able to
define cause and consequence, these results were not demonstrated in the more controlled
studies, so this same risk factor was not identified. There is a classification from the International
Cancer Society that classified red meat as being in group 2A, which means probably carcinogenic. This is because there are not enough data
to affirm that red meat causes colon cancer, okay? When we talk about diet, the bias factors
are many. For example, a person who is concerned about
eating less red meat for their health is concerned about their health. This person tends to go to the doctor more
often, tends to eat better, tends to not smoke, tends to have healthier life habits, and this
in itself is already a bias that can interfere with the final result of these observational
studies. That’s why when we talk about cause and consequence
with regard to food, it’s very difficult for us to do a study that controls all these variables. Therefore, here returns my previous recommendation:
we do not have data in the literature available to support the claim that red meat causes
colon cancer, okay? What I recommend regarding this, if you have
no restrictions, maintain moderate consumption of red meat, okay? And regarding the kidney, Doctor, can red
meat cause kidney problems? Those who have kidney problems, who have kidney
stones, should they avoid consuming red meat? Here I need to separate two people: those
who have chronic kidney disease, that is, those who already have a renal function problem. Understand chronic kidney disease as the functioning
of the kidney, not kidney stones, not renal calculus, we will talk about kidney stones
later. Patients who already have chronic kidney disease
should limit not only meat consumption but protein consumption because, yes, there is
a worsening, an acceleration of the loss of renal function if you consume excess protein,
okay? What is this recommendation? From 0.6 grams per kilogram of weight to 0.8
grams per kilogram of weight of protein, not meat. That’s why patients who have chronic kidney
disease, who are already in this phase where the kidney is already losing function for
any reason—high blood pressure, diabetes, renal diseases that can cause problems in
the kidney—should maintain nutritional monitoring so that the nutritionist can do this calculation
for you because protein deficiency is also detrimental. You should not have a protein deficiency because
otherwise, you will start to lose muscle from your body, and this is extremely harmful to
your health, okay? For patients who do not have chronic kidney
disease, protein consumption does not damage the kidney. What damages the kidney are diseases that
hurt the kidney—high blood pressure, diabetes, renal problems, nephritis, and even kidney
stones, depending on the situation. Now speaking specifically of patients who
have kidney stones, when we look at the data for patients who have renal calculus, there
is also a lot of controversy about this issue of protein from red meat with the formation
of kidney stones. To summarize and for you to understand this
and take it to your life, what we recommend is not to exceed 1.5 grams per kilogram of
protein, okay? Again, it’s protein, not meat, you understand? Pay attention here: if you weigh 70 kg, you
will be able to eat around 100 grams of protein per day. That’s quite a bit. A 100-gram steak of red meat has around 20
to 25 grams. So if you do the math, it’s almost 1 kg of
meat. That’s why if you also have kidney stones,
it’s important that the nutritionist does this calculation for you, and also regarding
red meat, there is no strong evidence to support it very much. Therefore, what I recommend to my patients
is you can consume red meat, just don’t consume it every day. Have a preference for replacing red meat with
white meat, fish, eggs, milk protein because these are also very important sources of protein
and will make you balance your diet, okay? In summary, then, to wrap up this video: red
meat, there is no data in the literature to justify that it causes cancer, that it causes
heart attacks, that it causes kidney stones. Maintain moderate consumption, and here is
what I always say on this channel: if you follow me here, if you’ve seen my videos,
I say maintain a balance. Dietary balance is extremely important. Obviously, that 60-65-year-old patient who
eats 5 kg, 1 kg of meat at the barbecue on the weekend, drinks 10 liters of beer, and
smokes will have a much greater chance of having problems than that person who eats
a balanced diet with high consumption of fruits, vegetables, and is making sure that their
body has access to nutrients that person with an unbalanced diet will not have, okay? So don’t look for hacks, don’t look for shortcuts. Red meat is a very important source
of proteins; it is a very important source of various nutrients for our body, mainly
iron, and it
is not as villainous as some people spread out
there. This is what we have from data in the medical
literature today; these are the best works that I brought here for you so that you can
pass on this data so
that you can consume meat peacefully without a guilty conscience. Therefore, you can indeed maintain moderate
consumption of red meat and maintain a balanced diet. Again, if
you do not want to consume it due to beliefs or values, there is no problem at all, but
be careful not to be in deficit of some proteins, okay? If you have any doubts, leave them in the comments. Comment here what you thought of this video,
share this video with someone you believe will need this information. This
is very important so that we can continue growing and making these videos
for you. Subscribe to the channel, like this video. I am Dr. Thiago, and until the next video.