Mediterranean diet associated with lower risk of death in cardiovascular disease patients
Adults who closely followed the
Mediterranean diet were 47 percent less likely to develop heart disease over a
10-year period compared to similar adults who did not closely follow the diet,
according to a study to be presented at the American College of Cardiology's
64th Annual Scientific Session in San Diego.
Among the study's participants,
adherence to the Mediterranean diet was more protective than physical activity.
The study, conducted in Greece, bolsters evidence from earlier studies pointing
to the diet's health benefits and is the first to track 10-year heart disease
risk in a general population. Most previous studies have focused on middle-aged
people.
"Our study shows that the
Mediterranean diet is a beneficial intervention for all types of people--in
both genders, in all age groups, and in both healthy people and those with
health conditions," said Ekavi Georgousopoulou, a Ph.D. candidate at
Harokopio University in Athens, Greece, who conducted the study along with
Demosthenes B. Panagiotakos, Ph.D., professor at Harokopio University. "It
also reveals that the Mediterranean diet has direct benefits for heart health,
in addition to its indirect benefits in managing diabetes, hypertension and
inflammation."
The study is based on data from a
representative sample of more than 2,500 Greek adults, ages 18 to 89, who
provided researchers with their health information each year from 2001 to 2012.
Participants also completed in-depth surveys about their medical records,
lifestyle and dietary habits at the start of the study, after five years and
after 10 years.
Overall, nearly 20 percent of the men
and 12 percent of the women who participated in the study developed or died
from heart disease, a suite of conditions that includes stroke, coronary heart
disease caused by the buildup of plaque in the heart's arteries, acute coronary
syndromes such as heart attack, and other diseases. Other studies have shown
Greeks and Americans have similar rates of heart disease and its risk factors.
The researchers scored participants'
diets on a scale from 1 to 55 based on their self-reported frequency and level
of intake for 11 food groups. Those who scored in the top-third in terms of
adherence to the Mediterranean diet, indicating they closely followed the diet,
were 47 percent less likely to develop heart disease over the 10-year follow-up
period as compared to participants who scored in the bottom-third, indicating
they did not closely follow the diet. Each one-point increase in the dietary
score was associated with a 3 percent drop in heart disease risk.
This difference was independent of
other heart disease risk factors including age, gender, family history,
education level, body mass index, smoking habits, hypertension, diabetes and
high cholesterol, all of which the researchers adjusted for in their analysis.
The analysis also confirmed results
of previous studies indicating that male gender, older age, diabetes and high
C-reactive protein levels, a measure of inflammation, are associated with an
increased risk for heart disease.
While there is no set Mediterranean
diet, it commonly emphasizes fresh fruits and vegetables, whole grains, beans,
nuts, fish, olive oil and even a glass of red wine. Earlier research has shown
that following the traditional Mediterranean diet is linked to weight loss,
reduced risk of diabetes, lower blood pressure and lower blood cholesterol
levels, in addition to reduced risk of heart disease.
"Because the Mediterranean diet
is based on food groups that are quite common or easy to find, people around
the world could easily adopt this dietary pattern and help protect themselves
against heart disease with very little cost," Georgousopoulou said.
Among study participants, women
tended to follow the Mediterranean diet more closely than did men. Despite the
fact that Greece is the cradle of the Mediterranean diet, urbanization has led
many Greeks to adopt a more Western diet over the past four decades, he said.
The study was limited to participants
living in and around Athens, Greece, so the sample does not necessarily reflect
the health conditions or dietary patterns of people in more rural areas or the
rest of the world. However, previous studies have also linked the Mediterranean
diet with reduced cardiovascular risks, including the Nurses' Health Study,
which included nearly 75,000 American nurses who were tracked over a 30-year
period. Additional studies in other adult populations would further advance
understanding of the diet's influence on heart disease risk.
“Prudent” diet (higher intake of fruits and vegetables; associated with a lower heart attack risk
The
typical Western diet — fried foods, salty snacks and meat — accounts for about
30 percent of heart attack risk across the world, according to a study of
dietary patterns in 52 countries reported in Circulation: Journal of the American Heart Association.
Researchers
identified three dietary patterns in the world:
•
Oriental: higher intake of tofu, soy and other sauces;
•
Prudent: higher intake of fruits and vegetables; and
•
Western: higher intake of fried foods, salty snacks, eggs and meat.
The
Prudent diet was associated with a lower heart attack risk than the Oriental,
researchers said.
“The
objective of this study was to understand the modifiable risk factors of heart
attacks at a global level,” said Salim Yusuf, D.Phil., the study’s senior
author.
Previous
studies have reached similar conclusions about the Prudent and Western diet in
the United States and Europe. This study broadens those findings and identifies
a unique dietary pattern that researchers labeled “Oriental” (because of a
higher content of food items typical of an Oriental diet.) The dietary pattern
recommended by the American Heart Association is similar to the Prudent diet
described in this study.
“This
study indicates that the same relationships that are observed in Western
countries exist in different regions of the world,” said Yusuf, professor of
medicine at McMaster University and director of the Population Health Research
Institute at Hamilton Health Sciences in Ontario, Canada.
Researchers
analyzed the INTERHEART study, which documents the association of various risk
factors and the risk of heart attack in about 16,000 participants in 52
countries. Here, they analyzed 5,761 heart attack cases and compared them to
10,646 people without known heart disease (controls).
The
researchers created a dietary risk score questionnaire for heart attacks
patients, based on 19 food groups and adjusted it for dietary preferences for
each country. Trained medical personnel interviewed the heart attack patients
and the control group. The questionnaires included healthy food items (such as
fruits and vegetables) and unhealthy food items (such as fried foods and salty
snacks).
“A
simple dietary score, which included both good and bad foods with the higher
score indicating a worse diet, showed that 30 percent of the risk of heart
disease in a population could be related to poor diet,” said Romania Iqbal,
Ph.D., lead author of the study.
After
adjusting for known risk factors, researchers found:
•
People who consumed the Prudent diet of more fruits and vegetables had a 30
percent lower risk of heart attack compared to people who ate little or no
fruits and vegetables.
•
People who consumed the Western diet had a 35 percent greater risk of having a
heart attack compared to people who consumed little or no fried foods and meat.
•
The Oriental pattern showed no relationship with heart attack risk.
Researchers
said that while some components of the Oriental pattern may be protective,
others such as the higher sodium content of soy sauces, may increase
cardiovascular risk, neutralizing any relationship.
It’s
expensive and time-consuming to establish a large and long-term study examining
the relationship of diet and heart attack in every region of the world. So the
approach of this study is the only feasible way to examine the relationship to
diet and heart disease from multiple populations in a relatively short time at
an affordable cost, Yusuf said.
Data
from this study helped confirm that changes in dietary intake, including the
consumption of more fruits and vegetables, can help reduce the risk of having a
heart attack in populations worldwide, he said.
“At
the same time, an unhealthy dietary intake, assessed by a simple dietary risk
score, accounts for nearly one-third of the world population’s attributable
risk,” Yusuf said.
Mediterranean diet linked to improved CV function in
erectile dysfunction patients
Erectile dysfunction patients with poor diets
have more vascular and cardiac damage
The Mediterranean diet is linked to improved cardiovascular performance in patients with erectile dysfunction, according to research presented at EuroEcho-Imaging 2014 by Dr Athanasios Angelis from Greece. Patients with erectile dysfunction who had poor adherence to the Mediterranean diet had more vascular and cardiac damage.
EuroEcho-Imaging is the annual meeting of the European
Association of Cardiovascular Imaging (EACVI), a branch of the European Society
of Cardiology (ESC), and is held 3-6 December in Vienna, Austria.
Dr Angelis said: "Erectile dysfunction is not a symptom
of ageing, it is a bad sign from the body that something is wrong with the
vasculature. In 80% of cases erectile dysfunction is caused by vascular problems
and is a warning that patients are at increased risk of a heart attack or
stroke."
He added: "The Mediterranean diet is associated with
lower cardiovascular events and could be a way to help erectile dysfunction
patients lower their risk. We wanted to investigate whether patients with
erectile dysfunction who follow this diet have less vascular and cardiac
damage."
The study included 75 men with erectile dysfunction, aged 56
years on average, who attended the Department of Cardiology at Hippokration Hospital
in Athens, Greece. Adherence to the Mediterranean diet was assessed with the
Med-Diet Score1 which ranks patients as high (30-55), intermediate (21-29) or
low (0-20) according to consumption of cereals, fruit, vegetables, meat, fish,
dairy products, wine and olive oil.
Vascular function was assessed by measuring two aspects of
atherosclerosis, namely atheromatosis and arteriosclerosis. Atheromatosis
refers to the development of atheroma (plaque), a fatty deposit in the intima
(inner lining) of the artery, and was measured by the intima-media thickness
(IMT) of the common carotid artery. Arteriosclerosis refers to the stiffening
of the arteries and was evaluated with carotid-femoral pulse wave velocity
(PWV). Heart involvement was based on diastolic function and left ventricular
mass.
The researchers found that a lower Med-Diet Score correlated
with significantly worse vascular and heart function. These patients had
greater IMT and aortic stiffness as well as higher left ventricular mass and
more profound diastolic dysfunction.
Dr Angelis said: "Patients with erectile dysfunction
who had unhealthy diets had more vascular and cardiac damage than those who
followed the Mediterranean diet. Previous studies have shown that patients with
erectile dysfunction have vascular damage but we found that the heart is also
damaged. This may help to further explain why these patients are more prone to
cardiovascular events. The formation of atheroma, the stiffening of the
arteries, and the poor functioning of the heart can eventually lead to a
cardiac event."
He added: "Our findings suggest that adopting the
Mediterranean diet can improve the cardiovascular risk profile of patients with
erectile dysfunction and may reduce their chances of having a heart attack or
stroke. This needs to be tested in a larger study."
The Mediterranean diet is characterised by daily consumption
of fruit, vegetables, unrefined cereals and pasta, olive oil and nuts. Dairy
products are eaten in modest amounts, in the form of yogurt and cheese. Consumption
of meat is low, with red meat once a week and poultry once a week considered a
healthy level. A modest amount of wine can be consumed, and refined sugar
should be avoided in favour of natural desserts like fruit.
Dr Angelis said: "Really simple changes in our diet may
help a lot, for example using olive oil which contains monounsaturated fat. If
someone doesn't have the money to buy some of the foods they can substitute
them with others, for example nuts are a good source of monounsaturated fat.
Sometimes it's difficult to adopt something if you consider that it's part of a
prescription, but the Mediterranean diet is not a prescription, it's a
lifestyle. It's about having an awareness of what foods are healthy or
unhealthy."
He concluded: "Patients who have erectile dysfunction
and don't adhere to the Mediterranean diet have vascular and cardiac damage and
are at increased risk of heart attack and stroke. Our findings suggest that
adopting a healthy diet can reduce that risk. We also advise patients to stop
smoking, exercise and ensure that they have healthy levels of blood pressure
and lipids."
Diets high in fruit, vegetables, whole
grains and nuts among factors to lower first-time stroke risk
American Heart
Association/American Stroke Association guideline
Eating
Mediterranean or DASH-style diets, regularly engaging in physical activity and
keeping your blood pressure under control can lower your risk of a first-time
stroke, according to updated AHA/ASA guideline published in the American Heart
Association's journal Stroke.
"We
have a huge opportunity to improve how we prevent new strokes, because risk
factors that can be changed or controlled — especially high blood pressure —
account for 90 percent of strokes," said James Meschia, M.D., lead author
of the study and professor and chairman of neurology at the Mayo Clinic in
Jacksonville, Florida.
The
updated guidelines recommend these tips to lower risk:
- Eat a Mediterranean
or DASH-style diet, supplemented with nuts.
- Monitor high blood pressure
at home with a cuff device.
- Keep
pre-hypertension from becoming high blood pressure by making lifestyle
changes such as getting more physical activity, eating a healthy diet and
managing your weight.
- Reduce the amount of
sodium in your diet; sodium is found mostly in salt.
- Visit your
healthcare provider annually for blood pressure evaluation.
- If your medication
to lower blood pressure doesn't work or has bad side effects, talk to your
healthcare provider about finding a combination of drugs that work for
you.
- Don't smoke. Smoking
and taking oral birth control pills can significantly increase your stroke
risk. If you're a woman who experiences migraines with aura, smoking
raises your risk of stroke even more than in the general population.
- Mediterranean-style
or DASH-style diets are similar in their emphasis on fruits, vegetables,
whole grains, legumes, nuts, seeds, poultry and fish. Both are limited in
red meat and foods containing saturated fats, which are mostly found in
animal-based products such as meat, butter, cheese and full-fat dairy.
- Mediterranean-style
diets are generally low in dairy products and DASH-style diets emphasize
low-fat dairy products.
- Avoiding secondhand
smoke also lowers stroke and heart attack risks, according to the
guidelines.
The writing committee reviewed existing guidelines, randomized
clinical trials and some observational studies.
"Talking about stroke prevention is worthwhile,"
Meschia said. "In many instances, stroke isn't fatal, but it leads to
years of physical, emotional and mental impairment that could be avoided."
Mediterranean-style diets
most successful in lowering CV risk
A study published in The American Journal of Medicine reveals that a whole diet
approach, which focuses on increased intake of fruits, vegetables, nuts, and
fish, has more evidence for reducing cardiovascular risk than strategies that
focus exclusively on reduced dietary fat. This new study explains that while
strictly low-fat diets have the ability to lower cholesterol, they are not as conclusive
in reducing cardiac deaths. By analyzing major diet and heart disease studies
conducted over the last several decades, investigators found that participants
directed to adopt a whole diet approach instead of limiting fat intake had a
greater reduction in cardiovascular death and non-fatal myocardial infarction.
Early investigations of the relationship
between food and heart disease linked high levels of serum cholesterol to
increased intake of saturated fat, and subsequently, an increased rate of
coronary heart disease. This led to the American Heart Association's
recommendation to limit fat intake to less than 30% of daily calories,
saturated fat to 10%, and cholesterol to less than 300 mg per day.
"Nearly all clinical trials in the
1960s, 70s and 80s compared usual diets to those characterized by low total
fat, low saturated fat, low dietary cholesterol, and increased polyunsaturated
fats," says study co-author James E. Dalen, MD, MPH, Weil Foundation, and
University of Arizona College of Medicine. "These diets did reduce
cholesterol levels. However they did not reduce the incidence of myocardial
infarction or coronary heart disease deaths."
Carefully analyzing studies and trials
from 1957 to the present, investigators found that the whole diet approach, and
specifically Mediterranean-style diets, are effective in preventing heart
disease, even though they may not lower total serum or LDL cholesterol. The
Mediterranean-style diet is low in animal products and saturated fat, and
encourages intake of monounsaturated fats found in nuts and olive oil. In
particular, the diet emphasizes consumption of vegetables, fruit, legumes,
whole grains, and fish.
"The potency of combining individual
cardioprotective foods is substantial – and perhaps even stronger than many of
the medications and procedures that have been the focus of modern
cardiology," explains co-author Stephen Devries, MD, FACC, Gaples
Institute for Integrative Cardiology (Deerfield, IL) and Division of
Cardiology, Northwestern University (Chicago, IL). "Results from trials
emphasizing dietary fat reduction were a disappointment, prompting subsequent
studies incorporating a whole diet approach with a more nuanced recommendation
for fat intake."
Based on the data from several
influential studies, which are reviewed in the article, Dalen and Devries
concluded that emphasizing certain food groups, while encouraging people to
decrease others, is more cardioprotective and overall better at preventing
heart disease than a blanket low-fat diet. Encouraging the consumption of olive
oil over butter and cream, while increasing the amount of vegetables, fruits,
whole grains, nuts, and fish promises to be more effective.
"The last fifty years of
epidemiology and clinical trials have established a clear link between diet,
atherosclerosis, and cardiovascular events," concludes Dr. Dalen.
"Nutritional interventions have proven that a 'whole diet' approach with
equal attention to what is consumed as well as what is excluded is more
effective in preventing cardiovascular disease than low fat, low cholesterol
diets."
Mediterranean Diet Helps Cut Risk of Heart
Attack, Stroke
Results of the PREDIMED study, aimed at
assessing the efficacy of the Mediterranean diet in the primary prevention of
cardiovascular diseases, have been published in The New England Journal of Medicine. They show that the
Mediterranean diet supplemented with extra-virgin olive oil or tree nuts
reduces by 30 percent the risk of suffering a cardiovascular death, a
myocardial infarction or a stroke.
The study has been coordinated by the
researcher Ramon Estruch, from the Faculty of Medicine of the UB and the
Hospital Clínic -- affiliated centres with the health campus of the UB, HUBc --
and has had the collaboration of the professor Rosa M. Lamuela and her team
from the Natural Antioxidant Research Group of the Faculty of Pharmacy --
located at the campus of international excellence BKC -- which determined the
biomarkers of Mediterranean diet consumption.
The research is part of the project PREDIMED,
a multicentre trial carried out between 2003 and 2011 to study the effects of
the Mediterranean diet on the primary prevention of cardiovascular diseases.
The study was funded by the Carlos III Health Institute by means of the
cooperative research thematic network (RETIC RD06/0045) and the CIBER of
Physiopathology of Obesity and Nutrition (CIBERobn).
A total of 7,447 people with major
cardiovascular risk factors participated in the study. They were divided into
three dietary intervention groups: a Mediterranean diet supplemented with
extra-virgin olive oil, a Mediterranean diet supplemented with nuts (walnuts,
almonds, hazelnuts), and a low-fat diet (animal and vegetable). A dietician
visited the patients every three months and they attended dietary training
group sessions, in which they received detailed information about the
Mediterranean and the low-fat diet, and the food included in each one.
Moreover, they were provided with shopping lists, menus and recipes adapted to
each type of diet and each season of the year.
During the study, those participants who
followed any of the two types of Mediterranean diet received freely
extra-virgin olive oil (one litre per week), and nuts (30 grams per day; 15
grams of walnuts, 7.5 grams of almonds and 7.5 grams of hazelnuts).
After five years, it has been proved that
participants who followed any of the two types of Mediterranean diet showed a
substantial reduction in the risk of suffering a cardiovascular death, a
myocardial infarction or a stroke.
According to the researchers, the results
of PREDIMED study are relevant as they prove that a high-vegetable fat diet is
healthier at a cardiovascular level than a low-fat diet. The authors state that
the study has been controversial as it provides new data to reject the idea
that it is necessary to reduce fats in order to improve cardiovascular health.
Mediterranean Diet:
Ingredients for a Heart-Healthy Eating Approach
In countries bordering the Mediterranean
Sea, heart disease is less common than in the United States. Researchers
believe that foods common to the area are a major reason for this difference.
Eating generous amounts of fruits and
vegetables and whole grains. In most Mediterranean countries, fruits and
vegetables are part of every meal. They are naturally low in fat and sodium and
have no cholesterol. Many are loaded with antioxidants, which may help prevent
cholesterol buildup in the arteries.
Breads, pastas and rice are typically
made from whole grains instead of grains that have been refined and lost some
nutritional value. Whole grains provide an excellent source of fiber and
contain a variety of vitamins and minerals. Certain types of dietary fiber also
can help reduce blood cholesterol levels and may lower the overall risk of
heart disease.
Getting most fats from healthy sources.
Olive oil is the primary fat used in Mediterranean cooking. This type of
monounsaturated fat can help reduce low-density lipoprotein (LDL, or “bad”)
cholesterol levels when used in place of unhealthy saturated fats or trans
fats. Other healthy fats in the Mediterranean diet include polyunsaturated fats
and omega-3 fatty acids, which can be found in vegetable oils, nuts and fish.
Omega-3 fatty acids are considered especially beneficial because they can lower
triglycerides, a type of blood fat; improve the health of blood vessels; and
protect against death from sudden heart attack.
Consuming very little red meat and eating
generous amounts of legumes. Red meat isn’t a big part of the Mediterranean
diet. Legumes, a class of vegetables that includes beans, peas and lentils --
offer a source of protein that’s typically low in fat and contains no
cholesterol.
Drink wine, in moderation. Some research
has shown that a light intake of alcohol is associated with a reduced risk of
heart disease. In the Mediterranean, the alcoholic beverage consumed most is
wine, which may offer slightly greater heart health benefits than other forms
of alcohol. For women (and men over age 65), the recommendation is no more than
one glass, or 5 ounces, of wine daily. For men under age 65, it’s no more than
two glasses, or 10 ounces, daily.
Other aspects of the Mediterranean diet
include dining on fish or shellfish as least twice a week; lesser amounts of
dairy products, such as cheese and yogurt; incorporating small portions of nuts
and seeds daily; eating sweets only on occasion; using herbs and spices instead
of salt to flavor food; getting plenty of physical activity; and eating meals
with family and friends.
The Mediterranean diet may be best known
as a heart-healthy eating plan, but some studies suggest that it may also
reduce the risk of diabetes, certain cancers, obesity and Alzheimer’s disease.
Mediterranean diet helps men lower bad
cholesterol
A heart-healthy diet helped men at high
risk for heart disease reduce their bad cholesterol, regardless of whether they
lost weight, in a study presented at the American Heart Association’s
Arteriosclerosis, Thrombosis and Vascular Biology 2013 Scientific Sessions.
The 19 24- to 62-year-old men in the
study had metabolic syndrome, which refers to three or more significant risk
factors for heart disease and stroke. The risk factors included in this study
were high waist circumference, high blood pressure, high levels of
triglycerides and fasting glucose and low levels of high density lipoprotein or
HDL “good” cholesterol.
For five weeks, the men followed a
standard North American diet which is high in fats, carbohydrates, refined
sugar and red meat. For a second five weeks, they ate a Mediterranean-style
diet, which is high in fruits, vegetables and whole grains, and low in red
meat. It also includes olive oil and moderate wine drinking.
The men then went on a 20-week
weight-loss regime, then another five weeks of Mediterranean eating.
Regardless of whether patients lost
weight, following the Mediterranean-style diet resulted in a 9 percent decrease
in levels of low density lipoprotein (LDL) known as “bad” cholesterol.
Similarly, blood concentrations of the protein part of the lipoprotein, called
apolipoproteinB, dropped 9 percent after eating Mediterranean-style.
Apolipoprotein plays an important role in lipid transport and metabolism.
“The Mediterranean-style diet, or
MedDiet, may be recommended for effective management of the metabolic syndrome
and its related risk of cardiovascular disease,” said Caroline Richard, M.Sc.,
study lead author and a registered dietician and Ph.D. candidate in nutrition.
Healthy diet may help prevent recurrent
heart attacks, strokes
If you have cardiovascular disease, a
heart-healthy diet may help protect you from recurrent heart attacks and
strokes, according to new research (December, 2012) in the American Heart
Association journal Circulation.
"At times, patients don't think they
need to follow a healthy diet since their medications have already lowered
their blood pressure and cholesterol — that is wrong," said Mahshid
Dehghan, Ph.D., study author and a nutritionist at the Population Health
Research Institute, McMaster University in Hamilton, Ontario, Canada.
"Dietary modification has benefits in addition to those seen with aspirin,
angiotensin modulators, lipid-lowering agents and beta blockers."
For the study, 31,546 adults (average age
66.5) with cardiovascular disease or end organ damage were asked how often they
consumed milk, vegetables, fruits, grains, fish, meat and poultry in the past
12 months. They were also asked about lifestyle choices such as alcohol
consumption, smoking and exercise. Total scores were determined by daily
fruits, vegetables, grains and milk consumed and the ratio of fish to meats
consumed.
During a follow-up of nearly five years,
participants experienced 5,190 cardiovascular events.
Researchers found those who ate a
heart-healthy diet had a:
35 percent reduction in risk for
cardiovascular death;
14 percent reduction in risk for new
heart attacks;
28 percent reduction in risk for
congestive heart failure; and
19 percent reduction in risk for stroke.
Food habits in different regions of the
world varied considerably; however, a healthy diet was associated with
prevention of recurrent cardiovascular disease throughout the world in
countries with different economic levels, Dehghan said.
A diet rich in vegetables and fruits with
a higher ratio of fish to meats appeared to be more beneficial for preventing
heart disease than for preventing cancer, fractures or injury.
"Physicians should advise their
high-risk patients to improve their diet and eat more vegetables, fruits,
grains and fish," Dehghan said. "This could substantially reduce
cardiovascular recurrence beyond drug therapy alone and save lives
globally."
Study Affirms ‘Mediterranean Diet’ Improves
Heart Health
A team of Johns Hopkins researchers has
uncovered further evidence of the benefits of a balanced diet that replaces
white bread and pasta carbohydrates with unsaturated fat from avocados, olive
oil and nuts — foods typical of the so-called “Mediterranean diet.”
In a report prepared for the American
Heart Association’s scientific sessions in Orlando (November, 2011) , the Johns
Hopkins investigators say swapping out certain foods can improve heart health
in those at risk for cardiovascular disease, even if the dietary changes aren’t
coupled with weight loss.
“The introduction of the right kind of
fat into a healthy diet is another tool to reduce the risk of future heart
disease,” says Meghana Gadgil, M.D., M.P.H., a postdoctoral fellow in the
Division of General Internal Medicine at the Johns Hopkins University School of
Medicine who presented the research.
Gadgil and her colleagues analyzed data
from the OmniHeart Trial, which studied the cardiovascular effects of three
different balanced diets on 164 people with mild hypertension but no diabetes.
The researchers compared the body’s ability to regulate blood sugar and
maintain healthy insulin levels while on a carbohydrate-rich diet, a
protein-rich diet and a diet rich in unsaturated fats. People whose bodies fail
to effectively use insulin usually develop type 2 diabetes, which is a major
risk factor for heart disease.
The researchers found that a generally
balanced diet higher in unsaturated fats such as those in avocados, olive oil
and nuts improves insulin use significantly more than a diet high in
carbohydrates, particularly such refined carbs as white bread and pasta. The
preferred diet is very similar to the Mediterranean diet, inspired by the foods
of southern Italy and Greece and emphasizing healthy fats, fruits and
vegetables.
Each participant in the study was fed
each of the three diets for six weeks in a row, with two to four weeks off in
between. Blood samples were collected after fasting periods in weeks four and
six of each diet, and used to monitor insulin and glucose levels. The study was
designed to keep participants at their starting weights. “A lot of studies have
looked at how the body becomes better at using insulin when you lose weight,”
Gadgil says. “We kept the weight stable so we could isolate the effects of the
macronutrients. What we found is that you can begin to see a beneficial impact
on heart health even before weight loss.”
Mediterranean
Diet: Ingredients for a Heart-Healthy Eating Approach
In countries bordering the Mediterranean
Sea, heart disease is less common than in the United States. Researchers
believe that foods common to Greece and southern Italy are a major reason for
this difference.
The February, 2010 issue of Mayo Clinic Women’s HealthSource covers
key components of the Mediterranean diet as well as reasons why this approach
is beneficial to heart health. Key components include:
Eating generous amounts of fruits and
vegetables and whole grains. In most Mediterranean countries, fruits and
vegetables are part of every meal. They are naturally low in fat and sodium and
have no cholesterol. Many are loaded with antioxidants, which may help prevent
cholesterol buildup in the arteries.
Breads, pastas and rice are typically
made from whole grains instead of grains that have been refined and lost some
nutritional value. Whole grains provide an excellent source of fiber and contain
a variety of vitamins and minerals. Certain types of dietary fiber also can
help reduce blood cholesterol levels and may lower the overall risk of heart
disease.
Getting most fats from healthy sources.
Olive oil is the primary fat used in Mediterranean cooking. This type of
monounsaturated fat can help reduce low-density lipoprotein (LDL, or “bad”)
cholesterol levels when used in place of unhealthy saturated fats or trans
fats. Other healthy fats in the Mediterranean diet include polyunsaturated fats
and omega-3 fatty acids, which can be found in vegetable oils, nuts and fish.
Omega-3 fatty acids are considered especially beneficial because they can lower
triglycerides, a type of blood fat; improve the health of blood vessels; and
protect against death from sudden heart attack.
Consuming very little red meat and eating
generous amounts of legumes. Red meat isn’t a big part of the Mediterranean
diet. Legumes, a class of vegetables that includes beans, peas and lentils --
offer a source of protein that’s typically low in fat and contains no
cholesterol.
Drink wine, in moderation. Some research
has shown that a light intake of alcohol is associated with a reduced risk of
heart disease. In the Mediterranean, the alcoholic beverage consumed most is
wine, which may offer slightly greater heart health benefits than other forms
of alcohol. For women (and men over age 65), the recommendation is no more than
one glass, or 5 ounces, of wine daily. For men under age 65, it’s no more than
two glasses, or 10 ounces, daily.
Other aspects of the Mediterranean diet
include dining on fish or shellfish as least twice a week; lesser amounts of
dairy products, such as cheese and yogurt; incorporating small portions of nuts
and seeds daily; eating sweets only on occasion; using herbs and spices instead
of salt to flavor food; getting plenty of physical activity; and eating meals
with family and friends.
The Mediterranean diet may be best known
as a heart-healthy eating plan, but some studies suggest that it may also
reduce the risk of diabetes, certain cancers, obesity and Alzheimer’s disease.
Mediterranean-style diet improves heart
function
A study of twins shows that even with
genes that put them at higher risk of cardiovascular disease, eating a
Mediterranean-style diet can improve heart function, according to research
reported in Circulation: Cardiovascular
Quality and Outcomes, an American Heart Association journal.
Using data from the Emory Twins Heart
Study, researchers found that men eating a Mediterranean-style diet had greater
heart rate variability (HRV) than those eating a Western-type diet. Heart rate
variability refers to variation in the time interval between heart beats during
everyday life – reduced HRV is a risk factor for coronary artery disease and
sudden death.
“This means that the autonomic system
controlling someone’s heart rate works better in people who eat a diet similar
to a Mediterranean diet,” said Jun Dai, M.D., Ph.D., study author and assistant
professor of nutrition and epidemiology at Indiana University in Bloomington.
Eating a Mediterranean-style diet — one
characterized by low saturated fats and high in fish, fruits, vegetables,
legumes, nuts, olive oil, cereals and moderate alcohol consumption — reduces a
person’s heart disease risk. But until now, the way the diet helps reduce the
risk of coronary disease remains unknown.
Dai and her colleagues analyzed dietary
data obtained from a food frequency questionnaire and cardiac data results from
276 identical and fraternal male twins. They scored each participant on how
closely his food intake correlated with the Mediterranean diet; the higher the
score, the greater the similarity to a Mediterranean-style diet.
To measure HRV, participants had their
heart’s electrical activity continuously measured and recorded with a Holter
Monitor, a portable, battery operated electrocardiogram device.
Using twins allowed team members to
assess the influence of the diet on HRV while controlling for genetic and other
familial influence.
Among the study’s key findings:
- Measurements of HRV showed that the
higher a person’s diet score, the more variable the heart beat-to-beat time
interval — 10 percent to 58 percent (depending on the HRV measure considered)
for men in the top Mediterranean diet score quarter compared to those in the
lowest quarter; this equates to a 9 percent to 14 percent reduction in
heart-related death.
- Genetic influence on HRV frequency
ranged from 20 percent – 95 percent, depending on the HRV measure considered.
-
The study cannot be generalized to women or
other ethnic groups because 94 percent of participants were non-Hispanic white
males.
Mediterranean diet = lower
heart disease
A
review of previously published studies suggests that vegetable and nut intake
and a Mediterranean dietary pattern appear to be associated with a lower risk
for heart disease, according to a report published in the April 13, 2009 issue
of Archives of Internal Medicine, one
of the JAMA/Archives journals. However, intake of trans-fatty acids and foods
with a high glycemic index may be harmful to heart health.
"The
relationship between dietary factors and coronary heart disease has been a
major focus of health research for almost half a century," the authors
write as background information in the article. Although "a wealth of
literature" has been published on the topic, "the strength of the
evidence supporting valid associations has not been evaluated systematically in
a single investigation."
Andrew
Mente, Ph.D., of the Population Health Research Institute, and colleagues
conducted a systematic search for articles investigating dietary factors in
relation to heart disease published between 1950 and June 2007. A total of 146
prospective cohort studies (looking back on the habits of a particular group of
individuals) and 43 randomized controlled trials (where participants are
randomly assigned to a dietary intervention or a control group) were identified
and included in the systematic review.
When the researchers pooled the study
results and applied a predefined algorithm, "we identified strong evidence
of a causal relationship for protective factors, including intake of
vegetables, nuts and monounsaturated fatty acids and Mediterranean, prudent and
high-quality dietary patterns, and harmful factors, including intake of
trans–fatty acids and foods with a high glycemic index or load and a western
dietary pattern," they write. "Among these dietary exposures,
however, only a Mediterranean dietary pattern has been studied in randomized
controlled trials and significantly associated with coronary heart
disease."
In
addition, modest relationships were found supporting a causal relationship
between intake of several other foods and vitamins and heart disease risk,
including fish, omega-3 fatty acids from marine sources, folate, whole grains,
alcohol, fruits, fiber and dietary vitamins E and C and beta carotene. Weak
evidence also supported causal relationships between vitamin E and ascorbic
acid supplements, saturated and polyunsaturated fatty acids and total fats,
alpha-linoleic acid, meat, eggs and milk.
"The
modest or weak evidence of these dietary exposures is mostly consistent with
the findings of randomized controlled trials, although randomized controlled
trials have yet to be conducted for several factors," the authors write.
"Taken together, these findings support a causal relationship between only
a few dietary exposures and coronary heart disease, whereas the evidence for
most individual nutrients or foods is too modest to be conclusive."
"Although
investigations of dietary components may help to shed light on mechanisms
behind the benefits of dietary patterns, it is unlikely that modifying the
intake of a few nutrients or foods would substantially influence coronary
outcomes," they conclude. "Our findings support the strategy of
investigating dietary patterns in cohort studies and randomized controlled
trials for common and complex chronic diseases such as coronary heart
disease."
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