On a cool, sunny morning last week, I was sitting at the bar in PayN’Take, a local joint in downtown Flagstaff, constructing the basic skeleton of this article. As I fueled my thoughts with a routine cup of joe, I had the pleasure of meeting an inquisitive and seemingly balanced local woman. We got to talking, as women do, about metabolism and other related topics, diet being one of them. The pinnacle of the conversation came when she mentioned how surprised she was at her ability to stay lean as she aged – how she hasn’t had to suffer the declination in metabolism that many of her friends have commonly experienced. As the conversation continued to unravel, many loose ends connected, both satisfying her choices and solidifying my belief in the associated science.
Tess is Greek, her family heritage stemming from a rich yet non-affluent background. She has continued to consume a balance of foods she’s familiar with culturally, her diet consisting of full-fat yogurts and nuts, minimally processed foods and small amounts of meat protein. Her physiological response to these choices has flourished. Of course, with modern science comes modification (less sugar, and reduction in allergenic foods as necessary for individualization), but as she eluded to, the traditional components seemed to work for both her ancestors and her current family.
Sound familiar? Many of us “in-the-know” have probably heard something about the Mediterranean Diet, and that “something” being most likely positive. In March, I had the opportunity to present some research at the American Heart Association’s 2016 Epidemiological/Lifestyle Scientific Sessions, held this year in Phoenix. The conference consisted of researchers all over the U.S. discussing the effects of diet, physical activity and lifestyle behavior on cardiovascular health.
One of the keynote lectures was delivered by Dr. Ramon Estruch, a professor at the Barcelona University School of Medicine in Barcelona, Spain. His discussion focused on the effects of a Mediterranean-style diet on cardiovascular health – something popular magazines have often referred to as “good for your waistline.” Although, in the U.S., we usually use body image instead of health as a reason to alter our eating habits and exercise, those popular magazines are correct. In fact, the AHA recommends it as the diet and lifestyle most likely to provide a favorable decrease in risk for cardiovascular disease (CVD), the leading cause of death in the U.S.
The selection of foods comprising the Mediterranean diet are based on the cultural regions of southern Italy, Crete and other parts of Greece during the 1960’s. The diet consists of:
- High intake of: Fruits and vegetables, whole grains, nuts, olive oil
- Moderate consumption of fish, poultry and wine (consumed with meals, discussed later)
- Small amounts of dairy, red meats, and sweets
- Lifestyle incorporating physical activity
Dr. Estruch was the primary investigator for one of the largest clinical trials ever to be held, with Spain investing a total of 6.8 million euros (~$7.5 million U.S.) to fund the study. He and his colleagues examined the preventative effects of a Mediterranean-style diet on the health of individuals with a high-risk for developing cardiovascular disease. The PREDIMED trial (Primary Prevention of Cardiovascular Disease with a Mediterranean Diet), published in The New England Journal of Medicine, included 7,447 men and women, ages 55-80, with no initial diagnosis of CVD.
They were followed from 2003 to 2010, and assigned to three groups based on diet: a traditional low-fat diet, a Mediterranean diet supplemented with nuts (walnuts, almonds and hazelnuts), or a Mediterranean diet supplemented with extra-virgin olive oil (EVOO; 4 tbs per day). In order to better isolate the effects of the diet alone, calorie restriction and physical activity alterations were not recommended . The trial concluded that following a Mediterranean-style diet may result in a 30% decrease in risk for stroke and CVD (click on the figure below to enlarge the results).
Estruch is not the only investigator to reach such conclusions. In 2013, Dr.’s Nagila Damasceno and Aleix Sala-Vila, also of the Hospital Clínic, Barcelona, Spain, conducted an analysis using a subset of subjects from the PREDIMED trial, looking at the effects of the Mediterranean diet on body composition and cholesterol. After one year of adhering the diet, the investigators found:
- The Mediterranean diet supplemented with extra nuts caused significantly favorable changes in waist circumference (a decrease of 5 cm, or roughly 2 inches), and favorable changes in LDL (bad cholesterol)
- The Mediterranean diet supplemented with EVOO provided significant increases in HDL (good cholesterol)
Dr. Monica Domenech and her team in Barcelona, using yet another subset of the PREDIMED trial subjects, found that those consuming both the nut- and EVOO-supplemented Mediterranean diets had a 24-hour decrease in blood pressure, as well as fasting glucose levels.
In 2002, Dr.’s Frank Hu and Walter Willett of Harvard’s School of Public Health and Medical School, respectively, selected 147 previously conducted dietary investigations to see which factors served best for preventing the onset of CVD. The selected studies included the Nurses’ Health Study, which contains 14 years worth of dietary information on more than 80,082 nurses. They examined the nutritional/behavioral constituents of each study, including carbohydrate content, cholesterol, fiber, dietary habits, trans fat and omega-3 fatty acid content. Their conclusion?
“Substantial evidence indicates that diets using non-hydrogenated unsaturated fats as the predominant form of dietary fat, whole grains as the main form of carbohydrates, an abundance of fruits and vegetables, and adequate omega-3 fatty acids can offer significant protection against CHD. Such diets, together with regular physical activity, avoidance of smoking, and maintenance of a healthy body weight, may prevent the majority of cardiovascular disease in Western populations.”
Investigators of the Lyon Diet Heart Study reached similar results, recommending the consumption of whole grains, green and root vegetables, replacing red meats with poultry and fish, plus daily consumption of fruits.
Some interesting and important takeaways:
- Healthy Fats. Many studies have shown us the negative effects trans fats have on our body – they raise LDL and lower HDL cholesterol, add to insulin resistance, increasing risk for atherosclerosis and heart disease. This is why the FDA elected to remove them from processed foods. On the flip side, omega-3 and omega-9 (oleic) fatty acids have been touted for their anti-inflammatory effects and improvements in lipid profile, lowering the risk for CVD. Consuming fish twice per week has been associated with a 30% decrease in CVD risk in women. EVOO contains several beneficial compounds in addition to unsaturated, healthy fats, such as polyphenols and vitamin-E tocopherols, both of which promote decreases in inflammation and aid in the prevention of heart disease. Many studies also support the positive effects that nuts have on lowering LDL cholesterol values and decreasing abdominal fat.
- Alcohol (what about that French paradox?) Aside from his role as a dietary expert, Dr. Estruch is also a Member of the Advisory Board of the European Foundation for Alcohol Research (ERAB). (see our article on “The Health Benefits of Beer” for more). He, along with several colleagues, have suggested that the moderate consumption of wine and beer with food increases the antioxidant abilities of the body, positively affects cholesterol (alcohol increases HDL), and lowers the risk for heart disease. According to the investigators of a study published in the journal Nutrients, polyphenols found in hops, as well as other synergistic compounds in beer, may provide anti-carcinogenic, estrogenic and antiviral effects.
- Whole, fresh foods. Carbohydrates – to eat or not to eat, how much, yadda yadda (we will have an article on this)? The consumption of whole, complex carbohydrates, such as oats, barley, rye, and vegetables and fruits, has been shown to lead to a better insulin profile and increased intake of antioxidants. The soluble fiber contained in these foods slows digestion, regulates the insulin response to glucose released after digestion, and improves lipid profile. We also know that foods with a lower glycemic index and overall lower glycemic load have positive effects on insulin resistance, and are associated with a lower risk for developing CVD.
According to Estruch/PREDIMED trial,
“Salient components of the Mediterranean diet reportedly associated with better survival include moderate consumption of ethanol (mostly from wine), low consumption of meat and meat products, and high consumption of vegetables, fruits, nuts, legumes, fish, and olive oil. Perhaps there is a synergy among the nutrient-rich foods included in the Mediterranean diet that fosters favorable changes in intermediate pathways of cardiometabolic risk, such as blood lipids, insulin sensitivity, resistance to oxidation, inflammation, and vasoreactivity.”
Arranz, S., Chiva-Blanch, G., Valderas-Martínez, P., Medina-Remón, A., Lamuela-Raventós, R. M., & Estruch, R. (2012). Wine, beer, alcohol and polyphenols on cardiovascular disease and cancer. Nutrients, 4(7), 759-781.
Damasceno, N. R., Sala-Vila, A., Cofán, M., Pérez-Heras, A. M., Fitó, M., Ruiz-Gutiérrez, V., … & Ros, E. (2013). Mediterranean diet supplemented with nuts reduces waist circumference and shifts lipoprotein subfractions to a less atherogenic pattern in subjects at high cardiovascular risk.Atherosclerosis, 230(2), 347-353.
Doménech, M., Roman, P., Lapetra, J., de la Corte, F. J. G., Sala-Vila, A., de la Torre, R., … & Toledo, E. (2014). Mediterranean Diet Reduces 24-Hour Ambulatory Blood Pressure, Blood Glucose, and Lipids One-Year Randomiz
Estruch, R., Martínez-González, M. A., Corella, D., Salas-Salvadó, J., Ruiz-Gutiérrez, V., Covas, M. I., … & Arós, F. (2006). Effects of a Mediterranean-style diet on cardiovascular risk factors: a randomized trial. Annals of internal medicine, 145(1), 1-11.
Estruch, R., Ros, E., Salas-Salvadó, J., Covas, M. I., Corella, D., Arós, F., … & Lamuela-Raventos, R. M. (2013). Primary prevention of cardiovascular disease with a Mediterranean diet. New england journal of medicine,368(14), 1279-1290.
Hu, F. B., & Willett, W. C. (2002). Optimal diets for prevention of coronary heart disease. Jama, 288(20), 2569-2578.
Kris-Etherton, P., Eckel, R. H., Howard, B. V., Jeor, S. S., & Bazzarre, T. L. (2001). Lyon Diet Heart Study Benefits of a Mediterranean-Style, National Cholesterol Education Program/American Heart Association Step I Dietary Pattern on Cardiovascular Disease. Circulation, 103(13), 1823-1825.
Park, A. (2013, Feb). It’s the olive oil: Mediterranean diet lowers risk of heart attack and stroke. TIME. Retrieved from http://healthland.time.com/2013/02/25/its-the-olive-oil-mediterranean-diet-lowers-risk-of-heart-attack-and-stroke/
Sofi, F., Cesari, F., Abbate, R., Gensini, G. F., & Casini, A. (2008). Adherence to Mediterranean diet and health status: meta-analysis. Bmj, 337, a1344.
The mediterranean diet reduces by 30% the heart attack and stroke risk. (2013, Feb). Hopsital clinic of barcelona. Retreived from http://blog.hospitalclinic.org/en/2013/02/la-dieta-mediterrania-pot-reduir-un-30-el-risc-dinfart-i-ictus/