According to the Center for Disease Control, over 700,000 Americans have a heart attack each year. Finding ways to reduce the risk of heart disease is a part of the nation's public health agenda. Every few
years, a flurry of new studies emerge to further our understanding of the
potential health benefits associated with eating (and living) the Mediterranean
way. I decided to spend this week writing about the Mediterranean diet. Before
I get going, I want to mention that I hate the word “diet.” It implies something
temporary in nature. When I talk about “diet,” I am referring to an eating plan; I
am talking about a way of life
Where does interest in the Mediterranean diet originate?
The health,
science, political and economic aspects of research and government have been aware
of and interested in the Mediterranean diet for decades (1). The
first formal epidemiological encounter with the Mediterranean diet dates back
to 1948 when the government of Greece and the Rockefeller Foundation worked
together to conduct a study to determine how to improve the living conditions
on Crete. This was a comprehensive project and the Rockefeller Foundation sent
an epidemiologist to Crete to lead the study. There were two main components of
the dietary arm of project. One part was a 7-day weighed food inventory
conducted at 128 homes. Another part of
the study involved obtaining 7-day diet records from more than 500 people. The results of this study revealed that the people of Crete ate a largely
plant-based diet that had a lot of nuts, olive oil, fruits, vegetables and
legumes, but did not eat a lot of red meat or refined sugar. It also showed that the people of Crete had a lower incidence of cardiovascular
disease.
In the 1950s,
a man named Ancel Keys became intrigued by the fact that people with access to
money living in United States also had access to plenty of food (1,2). In the
U.S., people with money and access to food also had higher rates of heart
disease and this phenomenon was not observed in some regions along the
Mediterranean Sea. He postulated that a combination of lifestyle and diet
impacted the risk of cardiovascular disease for the population as well as at
the individual level and that there were biological measures that related to
the risk of disease (i.e. cholesterol). This was a landmark study upon which our dietary guidelines were built. His research
group published the first of their results in the 1950s. He published a heart-healthy cookbook in 1959. The
dietary recommendations that Ancel Keys made in 1959 regarding diet, lifestyle
and heart health are remarkably similar to the Dietary Guidelines for Americans
that have been in place and slightly modified since 1990.
Resources:
1) Nestle, M. (1995). Mediterranean diets:
historical and research overview. AJCN.
61(suppl):1414S-20S.
2) Widmer R.J. Flammer AJ, Lerman LO, Lerman A. (2014) Mediterannean Diet, its components, and cardiovascular deisease. Am J Med. 10.1016/j.amjmed.2014.10.014. [Epub ahead of print].
The Mediterranean Diet in a Nutshell
The
Mediterranean diet is rooted in fresh fruits and vegetables, whole grains,
legumes, olive oil, nuts, and fish. Lifestyle factors that are
essential components of what we refer to as the “Mediterranean diet” include regular physical activity and sharing mealtime with friends and family. This
way of eating is a healthy and reasonable lifestyle approach that works for
many people in non-Mediterranean countries.
By Daniel Schwen (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
Make
fresh or minimally processed plant based foods the main course at every meal (this usually refers to 6 servings a day).
o fruits;
o vegetables;
o whole grains (breads, pastas, etc.);
o and/or legumes (lentils, beans, peas).
Use
olive oil in place of butter and margarine.
o Olive oil contains monounsaturated
fatty acids (MUFAs) that are heart-healthy. Select “extra virgin” or “virgin”
olive oil to get the most MUFAs from olive oil.
o Canola oil is also a good choice. It
is also a plant-derived oil that contains unsaturated fats.
o Butter contains saturated fat.
Margarine may contain trans saturated
fats. These fats are limited in the Mediterranean style of eating.
Enhance
the flavor of food with herbs and spices.
o Instead of seasoning with salt, the
flavor of food is enhanced by using herbs and spices.
o Herbs and spices not only add flavor,
but they also add very small amounts of beneficial phytochemicals (plant chemicals) to
the food you eat.
Eat
fish at least 2 times a week.
o Choose fatty fish like albacore tuna,
salmon, lake trout, mackerel, herring, etc. because these types of fish have a
type of polyunsaturated fat (PUFA) called omega-3 fatty acids. Omega-3 fatty
acids are heart-healthy.
Incorporate
lean proteins into your diet and use moderation.
o Lean protein refers to poultry, eggs,
low-fat or fat free dairy (yogurt, cheese, milk, etc.).
Limit
your intake of red meats and sweets to only a few times a month.
o Try fruit-based dessert options
Regular
physical activity is a part of daily life.
o 30 minutes per day 5-6 days a week of
moderate (lower intensity) activity or 20 minutes per day 3 times a week of
vigorous activity
Enjoy
meals with friends and family.
Consult with
a health care provider before starting a new exercise program. If you have a
medical condition like diabetes, heart disease, high blood pressure, or
anything else, it is important to discuss potential changes to your way of
eating with your health care provider before you make them.
Resources
- Academy of Nutrition and Dietetics. "Nutrition Q&A. What foods are included in the Mediterranean diet?" Accessed 12/15/2014.
- Christian Nordqvist (last update on September 10, 2014). "What is the Mediterranean diet? What are the benefits of the Mediterranean diet?" Medical News Today (MNT). Accessed 12/15/2014.
- Mayo Clinic Staff (last update on June 14, 2013). "Mediterranean diet: A heart-healthy eating plan." Mayo Clinic. Accessed 12/15/2014.
The Mediterranean Diet & Heart Health
Scientists like to know how things work. In nutrition, we like to know
how dietary components impact biological function. Unfortunately, it is complicated.
Let’s say you eat an apple. Is it a red or green apple? This matters because the
pigment of the skin contains phytochemicals (plant chemicals) so red apples
have different phytochemicals than green ones. Not better or worse,
just different. Apples also contain vitamins, fiber, water, carbohydrates, a little
bit of protein and some minerals. You take a bite of the apple. You chew it and then swallow. It enters your stomach and small intestine where you digest and absorb it. You absorb nutrients and
phytochemicals into your body. Scientists continue to learn about how phytonutrients function in the body. Many are involved in initiating cell signaling processes that lead to other functions like reducing inflammation. The carbohydrate portion of the apple helps to fuel your cells. You can use the amino acids released from the protein to make other proteins in your body. The microbiota (the microorganisms that live in
your intestines) may make use of some of the components of the apple. The fibrous
parts of the apple move on through to your colon and eventually get excreted. This can all happen after eating an apple because all of the components are ingested at one time and work
together both in your food and in your body. This complex interaction gets lost
when you take a supplement.
It is possible that the complex interaction between the different components of the Mediterranean diet get lost when the diet and lifestyle is picked apart and taken out of context. To prepare for this post, I read some review and primary research articles (I reference a recent review article throughout this post). In general, individual healthful effects of fruits and vegetables, fish, olive oil, whole grains, nuts, physical activity and red wine (in moderation) are identified, however, different studies find different results. This may be because researchers look at different outcome measures, because of other differences in study design, or it may be because taking one constituent out of context modifies the effect of its interaction with the other dietary and lifestyle components that are part of the Mediterranean diet.
Diets rich in olive oil and
fatty fish provide MUFAs and PUFAs. These fatty acids may reduce inflammation in the body, decrease the
amount of oxidative damage, and reduce the risk of blood clotting. Extra virgin
and virgin olive oil contain MUFAs which have been shown to reduce LDL
cholesterol, reduce blood clotting, decrease reactive oxygen species (which can cause oxidative damage). Fatty fish contain omega-3 PUFAs
which improves lipid profiles (reduce LDL cholesterol) and improve blood pressure
(1, 2). Canola oil is another source of PUFA that is also heart-healthy. It has
been shown to reduce triglycerides and lower blood pressure when used instead
of saturated fat (2).
Fruits and vegetables contain
vitamins, phytochemicals and fiber. Diets
that are high in fruits and vegetables may improve cholesterol levels and reduce
the presence of reactive oxygen species. People who eat more fruits and
vegetables tend to eat them in place of other foods. Eating more fruits and
vegetables is associated with a decreased risk for cardiovascular disease. It
may also be associated with lower blood pressure and lower body mass index (1).
The maximum benefits of the Mediterranean diet are associated with 6 servings
or more per day of fruits and vegetables, but a moderately reduced risk of
cardiovascular disease has been, in some observational studies, detected with
3-5 servings per day (2).
Whole grains provide fiber and
phytochemicals. Eating whole grains is associated with better health and a reduced risk
of heart disease. Whole grains provide fiber. Fiber facilitates removal of waste
from the colon and also reduces the absorption of some types of dietary
compounds, like dietary cholesterol. Diets that meet the fiber recommendation
(25 grams/day women and 35 grams/day men) tend to be associated with less
overall inflammation, healthier blood pressure, and improved cholesterol.
Nuts and legumes are an
important part of the Mediterranean diet.
Nuts contain unsaturated fats and are high in calories (they provide 9
kcals/gram). Because they are both a healthful choice but calorically rich, it is
recommended that you eat them with awareness and substitute them for another
food such as a food that contains saturated fat. Eating nuts is associated with
reduced risk of cardiovascular disease, improved lipid profiles and better
blood pressure (1). Legumes are a staple in the Mediterranean diet, however it
is unclear how they work in the body to improve health (1).
 |
"Broad-beans-after-cooking". Licensed under Public Domain via Wikimedia Commons
(Fava beans)
The health benefits of drinking
red wine, in moderation. Drinking red wine may improve cholesterol, lower blood pressure and reduce the risk of
cardiovascular disease (1,2). Moderate alcohol consumption of wine means one 5-oz glass of
wine per day for women and men over 65 and two 5-oz glasses of
wine per day for men (2). Phytochemicals present in the skin of red grapes (i.e.
resveratrol) are believed to be responsible for the health benefits of red
wine. It is possible to achieve similar benefits with red grape juice, but it
is important to select juice that is low in added sugar.
If you are concerned about heart disease, have a pre-existing health condition, or a family history of heart disease, it is important that you discuss your
concerns with your health care provider before starting a new eating plan and/or exercise program
Resources:
1) Widmer R.J. Flammer AJ, Lerman LO, Lerman A. (2014) Mediterannean Diet, its components, and cardiovascular deisease. Am J Med. 10.1016/j.amjmed.2014.10.014. [Epub ahead of print].
2) Mayo Clinic Staff (last update on June 14, 2013). "Mediterranean diet: A heart-healthy eating plan." Mayo Clinic. Accessed 12/15/2014.
