ScienceDaily (July 6, 2010) — Everyone knows olive oil and a Mediterranean diet are associated with a lower risk for cardiovascular disease, but a new research report published in the July 2010 print issue of the FASEB Journal offers a surprising reason why: These foods change how genes associated with atherosclerosis function.
“Knowing which genes can be modulated by diet in a healthy way can help people select healthy diets,” said Maria Isabel Covas, D.Pharm., Ph.D., a researcher involved in the work from the Cardiovascular Risk and Nutrition Research Group at the Institut Municipal d’Investigacio Medica in Barcelona, Spain. “It is also a first step for future nutritional therapies with selected foods.”
Scientists worked with three groups of healthy volunteers. The first group consumed a traditional Mediterranean diet with virgin olive oil rich in polyphenols. The second group consumed a traditional Mediterranean diet with an olive oil low in polyphenols. The third group followed their habitual diet. After three months, the first group had a down-regulation in the expression of atherosclerosis-related genes in their peripheral blood mononuclear cells. Additionally, the olive oil polyphenols made a significant impact on the expression of genetic changes influencing coronary heart disease. Results also showed that the consumption of virgin olive oil in conjunction with a Mediterranean diet can positively impact lipid and DNA oxidation, insulin resistance, inflammation, carcinogenesis, and tumor suppression.
“This study is ground breaking because it shows that olive oil and a Mediterranean diet affect our bodies in a far more significant way than previously believed,” said Gerald Weissmann, M.D., Editor-in-Chief of the FASEB Journal. “Not only does this research offer more support for encouraging people to change their eating habits, it is an important first step toward identifying drug targets that affect how our genes express themselves.”
More Evidence Extra Virgin Olive Oil and Veggies Help the Heart
NEW YORK | Thu Dec 30, 2010 4:23pm EST
NEW YORK (Reuters Health) – It’s no secret that eating well is good for both body and mind, so it may not come as a surprise that a new study finds women who eat more olive oil and leafy vegetables such as salads and cooked spinach are significantly less likely to develop heart disease.
A group of Italian researchers found that women who ate at least 1 serving of leafy vegetables per day were more than 40 percent less likely to develop heart disease over an average of eight years, relative to women who ate two or fewer portions of those vegetables each week.
Women who downed at least 3 tablespoons of olive oil daily – such as in salad dressing – were also 40 percent less likely to be diagnosed with heart disease, compared to women who ate the least olive oil.
It’s not exactly clear why specifically leafy vegetables and olive oil may protect the heart, study author Dr. Domenico Palli of the Cancer Research and Prevention Institute in Florence told Reuters Health. “Probably the mechanisms responsible for the protective effect of plant-origin foods on cardiovascular diseases involve micronutrients such as folate, antioxidant vitamins and potassium, all present in green leafy vegetables.”
Folate reduces blood levels of homocysteine, Palli explained, which is thought to increase the risk of cardiovascular disease by damaging the inner lining of arteries. Other studies have shown people who eat more potassium have lower blood pressure, which can protect the cardiovascular system. Virgin olive oil may be particularly effective at lowering heart disease risk because of its high level of antioxidant plant compounds, he added.
This is not the first study to link olive oil or vegetables to good heart health. Most famously, the traditional Mediterranean diet — rich in vegetables and monounsaturated fats from olive oil and nuts, but low in saturated fat from meat and dairy — has been tied to a decreased risk of heart disease.
Mediterranean-style eating has also been credited with lowering risk for some cancers, diabetes, and, more recently, with slowing brain aging (See Reuters Health story of December 29, 2010).
Cardiovascular disease is a major killer, responsible for 30 percent of all deaths worldwide and the leading cause of death for both men and women in the U.S.
To look more closely at the role of foods in protecting against heart disease, Palli and colleagues reviewed dietary information collected from nearly 30,000 Italian women participating in a large national health study. Researchers followed the women, whose mean age was 50 at the beginning of the study, for an average of 8 years, noting who developed heart disease.
In that time, the women experienced 144 major heart disease-related events, such as heart attack or bypass surgery, the authors report in the American Journal of Clinical Nutrition.
Women who ate at least one daily serving (about two ounces) of leafy vegetables – such as raw lettuce or endives, or cooked vegetables like spinach or chard — had a 46 percent lower risk of developing heart disease than women who ate at most two portions per week.
Consuming at least an ounce of olive oil per day lowered their risk by 44 percent relative to women who consumed a half-ounce or less daily, the authors found.
The women’s intake of other types of vegetables, such as roots and cabbages, and their consumption of tomatoes or fruit did not seem to be linked to their risk for major heart events.
Both fruits and vegetables have been associated with heart benefits in past studies conducted elsewhere in Europe and in North America. The authors caution that the apparent lack of positive effect from high fruit consumption in their results may have something to do with a different attitude toward fruit in Italy. It is cheap, varied and easily available, so eating a lot of fruit is a widespread habit but it does not necessarily signal that the rest of someone’s diet is as healthy, the authors wrote.
Another issue with the study, Palli noted in an e-mail, is that women had to report how much they ate of various items, and some may not have remembered their diets accurately, or may have changed their eating habits during the study period. In addition, people sometimes over-estimate their healthy behaviors, believing they eat healthier than they really do.
SOURCE: link.reuters.com/dag34r American Journal of Clinical Nutrition, published online December 22, 2010.
Why Extra Virgin Olive Oil High in Oleic Acid is Beneficial to Health
Because of its high degree of resistance to attack by oxygen free radicals, higher levels of oleic acid in an olive oil help keep it fresher for longer, by preventing the formation of peroxidized (rancid) fats. And because your body will absorb any peroxidized fats that you consume and incorporate them into your cells, oleic acid’s superior resistance to free radical attack also protects your cell membranes, proteins, and DNA from being damaged, even as it protects the oil from spoiling.
Also, substituting oleic acid for saturated fatty acids in animal fats improves cholesterol balance,and research also suggests that oleic acid may also have more specific health benefits, such as the ability to help regulate healthy blood pressure by altering cellular signaling. For these and other reasons, the US FDA has approved the health claim that “Limited and not conclusive scientific evidence suggests that eating about 2 tablespoons (23 grams) of olive oil daily may reduce the risk of coronary heart disease due to the monounsaturated fat in olive oil.”