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Study shows Mediterranean diet associated with better cognitive function in older adults

Adapted from an article for Medical Express by Fayeza Ahmed, September 11, 2019

Adherence to a Mediterranean diet has been associated with less cognitive decline over five years in older adults in the United States, according to a new study led by University of Maine and the University of South Australia researchers.

The study, conducted by researchers Alexandra Wade, Merrill Elias, and Karen Murphy and published in the journal Nutritional Neuroscience, examined the relationship between Mediterranean diet adherence and cognitive function in a sample of older adults in the Maine-Syracuse Longitudinal Study (MSLS).

MSLS, a study of aging, hypertension, cardiovascular disease, and cognitive function, was launched in 1974 by Elias. It has obtained longitudinal data from young adulthood to the elder years for 1,000 individuals, and cross-sectional data for more than 2,400 individuals initially recruited from central New York and followed throughout the U.S.

The Mediterranean diet has been associated with a range of health benefits. However, the majority of Mediterranean diet studies have been conducted in Mediterranean populations, and findings from non-Mediterranean populations are mixed.

Wade and colleagues found that participants who reported consuming a higher intake of foods associated with a Mediterranean diet, including olive oil, fruits, vegetables, legumes, fish, whole grains, and red wine, experienced moderately lower rates of cognitive decline in visual spatial organization and memory, attention and global cognitive function over a five-year period.

Causal relations cannot be inferred as the study was observational, according to the researchers. However, the findings indicate that adherence to a Mediterranean diet may be capable of delaying age and disease-related cognitive decline, one of the leading risk factors of dementia.

Future studies must examine possible associations between Mediterranean diet, such as biological factors or general good health as a positive influence on cognitive function, the researchers say.

The research reflects a longtime collaboration between researchers at the University of South Australia and the University of Maine.

Reference: Wade AT, Elias MF, Murphy KJ. Adherence to a Mediterranean diet is associated with cognitive function in an older non-Mediterranean sample: findings from the Maine-Syracuse Longitudinal Study. Nutritional Neuroscience. 2019; doi: 10.1080/1028415X.2019.1655201.

Vegetables’ health benefits increase when cooked with extra virgin olive oil

Adapted from an article from the University of Barcelona, June 13, 2019 

Cooking the vegetables in sofrito (the traditional Spanish sauté of garlic, onion, and tomato) with extra virgin olive oil increases the absorption and release of the bioactive compounds in the vegetables, according to a study conducted by a research team from the Faculty of Pharmacy and Food Sciences at the University of Barcelona (UB), from the Physiopathology of Obesity and Nutrition Networking Biomedical Research Centre (CIBERobn), and the Diabetes and Associated Metabolic Diseases Networking Biomedical Research (CIBERDEM), led by Rosa M. Lamuela-Raventós. These results, published in the scientific journal Molecules, allow for insight into the mechanisms by which gastronomy could play a relevant role in the health-improving effects of the Mediterranean diet.

The Mediterranean diet, which involves a high consumption of phytochemicals from vegetables, fruits, and legumes, has been correlated to health-improving effects in cardiovascular and metabolic health. This correlation has largely been established by findings from the extensive PREDIMED study, a multicenter clinical trial carried out from 2003 to 2011 with more than 7,000 participants.

However, the healthful effects of the Mediterranean diet have been challenging to reproduce in non- Mediterranean populations—possibly, according to the researchers, because of differences in cooking techniques. With this study, researchers have attempted to assess whether the Mediterranean gastronomy imputes its health benefits not only via its food components but also via the way those foods are cooked.

The objective of the study was to assess the effect of the extra virgin olive oil on bioactive compounds in tomato, onion, and garlic—the traditional ingredients in sofrito, one of the key cooking techniques in the Mediterranean diet. According to the researchers, this sauce has forty different phenolic compounds and a high amount of carotenoids, and its consumption is associated with an improvement of the cardiovascular risk parameters and insulin sensitivity.

“The main result of the study is that cooking vegetables with extra virgin olive oil [allows] the bioactive compounds, such as carotenoids and polyphenols, that are present in vegetables we find in sofrito to move to the olive oil, which enables the absorption and bioactivity of these compounds,” says Lamuela -Raventós, director of the Institute for Research on Nutrition and Food Safety (INSA-UB).

The study also identified a new property of olive oil. Previous researchers had noted that the combination of olive oil and onion produces isomers of certain carotenoids. These isomers are more bioavailable and have a higher antioxidant content. This study found that olive oil facilitates this process not only with carotenoids but also with polyphenols, which are transferred from the vegetables to the oil.

These results could explain earlier findings by this research group that the presence of olive oil increases the anti-inflammatory effects of sofrito. “We saw that this increase can occur due to the migration of bioactive compounds (carotenoids and polyphenols) from the tomato, onion, and garlic to the oil during the cooking process, which [improves] the absorption of these compounds,” concludes José Fernando Rinaldi de Alvarenga, INSA-UB member and lead author of the paper.

Reference: de Alvarenga JF et al. Using extra virgin olive oil to cook vegetables enhances polyphenol and carotenoid extractability: a study applying the sofrito technique. Molecules. 2019;24(8): DOI: 10.3390/molecules24081555.

Diet including olive oil may reduce blood-clotting risk in healthy obese adults

Adapted from an article by the American Heart Association, March, 7, 2019

In a group of healthy obese adults, eating olive oil at least once a week was associated with less platelet activity in the blood, which may reduce the tendency of blood to clot and block blood flow. These findings are according to preliminary research presented at the American Heart Association’s Epidemiology and Prevention/Lifestyle and Cardiometabolic Health Scientific Sessions 2019, a premier global exchange of the latest advances in population-based cardiovascular science for researchers and clinicians.

Platelets are blood cell fragments that stick together and form clumps and clots when they are activated. They contribute to the buildup of artery-clogging plaque, known as atherosclerosis, the condition that underlies most heart attacks and strokes, according to lead study author Sean P. Heffron, MD, MS, MSc, assistant professor at NYU School of Medicine and the NYU Center for the Prevention of Cardiovascular Disease in New York, New York.

Using food frequency surveys, researchers determined how often 63 obese, nonsmoking, nondiabetic study participants ate olive oil. The participants’ average age was 32.2 years and their average body mass index (BMI) was 44.1. Obesity is defined as having a body mass index (BMI)—a ratio of body weight to height—over 30.

Researchers found that those who ate olive oil at least once a week had lower platelet activation than participants who ate olive oil less often, and that the lowest levels of platelet aggregation were observed among those who ate olive oil more frequently.

“People who are obese are at increased risk of having a heart attack, stroke, or other cardiovascular event, even if they don’t have diabetes or other obesity-associated conditions. Our study suggests that choosing to eat olive oil may have the potential to help modify that risk, potentially lowering an obese person’s threat of having a heart attack or stroke,” Heffron said. “To our knowledge, this is the first study to assess the effects of dietary composition, olive oil specifically, on platelet function in obese patients,” said co-author Ruina Zhang, BS, an NYU medical student.

Some limitations of the study are that it relied on questionnaires completed by the participants; it measured how often they ate olive oil, but not how much olive oil they ate; and because it was observational, the study could not prove that eating olive oil will reduce platelet activation in obese adults.

Researchers Explore What’s Behind Mediterranean Diet and Lower Cardiovascular Risk

Brigham and Women’s Hospital, December 7, 2018 

A new study by investigators from Brigham and Women’s Hospital, Harvard Medical School, and the Harvard T.H. Chan School of Public Health offers insights from a cohort study of women in the US who reported consuming a Mediterranean-type diet.

Researchers found a 25 percent reduction in the risk of cardiovascular disease among study participants who consumed a diet rich in plants and olive oil and low in meats and sweets. The team also explored why and how a Mediterranean diet might mitigate risk of heart disease and stroke by examining a panel of 40 biomarkers, representing new and established biological contributors to heart disease. The team’s results are published in JAMA Network Open.

“Our study has a strong public health message that modest changes in known cardiovascular disease risk factors, particularly those relating to inflammation, glucose metabolism, and insulin resistance, contribute to the long-term benefit of a Mediterranean diet on cardiovascular disease risk,” said lead author Shafqat Ahmad, PhD, a research fellow at the Brigham and at the Harvard Chan School.

The current research draws on data from more than 25,000 female health professionals who participated in the Women’s Health Study. Participants completed food intake questionnaires about diet, provided blood samples for measuring the biomarkers, and were followed for up to 12 years. The primary outcomes analyzed in the study were incidences of cardiovascular disease, defined as first events of heart attack, stroke, coronary arterial revascularization, and cardiovascular death.

The team categorized study participants as having a low, middle, or upper Mediterranean diet intake. They found that 428 (4.2 percent) of the women in the low group experienced a cardiovascular event, compared to 356 (3.8 percent) in the middle group, and 246 (3.8 percent) in the upper group, representing a relative risk reduction of 23 percent and 28 percent, respectively, a benefit that is similar in magnitude to statins or other preventive medications.

The team saw changes in signals of inflammation (accounting for 29 percent of the cardiovascular disease risk reduction), glucose metabolism and insulin resistance (27.9 percent), and body mass index (27.3 percent).

“While prior studies have shown benefit for the Mediterranean diet on reducing cardiovascular events and improving cardiovascular risk factors, it has been a ‘black box,’ regarding the extent to which improvements in known and novel risk factors contribute to these effects,” said corresponding author Samia Mora, MD, MHS, a cardiovascular medicine specialist at the Brigham and Harvard Medical School. “In this large study, we found that modest differences in biomarkers contributed in a multifactorial way to this cardiovascular benefit that was seen over the long term.”

Reference: Ahmad S, Moorthy MV, Demler OV, et al. Assessment of risk factors and biomarkers associated with risk of cardiovascular disease among women consuming a Mediterranean diet. JAMA Netw Open. 2018;1(8):e185708.