Houston, Texas, USA : 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 U.S. 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. This understanding may have important downstream consequences for the primary prevention of cardiovascular disease,” said lead author Shafqat Ahmad, Ph.D., a research fellow at the Brigham and at the Harvard Chan School.
Randomized trials in Mediterranean countries and observational studies have previously linked a Mediterranean diet to reductions in cardiovascular disease, but the underlying mechanisms have been unclear. 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 max index (27.3 percent). The team also found connections to blood pressure, various forms of cholesterol, branch-chain amino acids and other biomarkers, but found that these accounted for less of the association between Mediterranean diet and risk reduction.
“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 multi-factorial way to this cardiovascular benefit that was seen over the long term.”
Citation : Shafqat Ahmad et al, Assessment of Risk Factors and Biomarkers Associated With Risk of Cardiovascular Disease Among Women Consuming a Mediterranean Diet, JAMA Network Open. DOI: 10.1001/jamanetworkopen.2018.5708
A second study found mediterranean-style diet may lower women’s stroke risk
Mediterranean-style diet may lower women’s stroke risk
Following a Mediterranean-style diet may reduce stroke risk in women over 40 but not in men—according to new research led by the University of East Anglia.
A new report, published today in the American Heart Association’s journal Stroke, reveals that a diet high in fish, fruit, vegetables, nuts and beans, and lower in meat and dairy, reduces stroke risk among white adults who are at high risk of cardiovascular disease.
The study is one of the largest and longest-running efforts to evaluate the potential benefits of the Mediterranean-style diet in lowering the risk of stroke.
It shows that the diet may be especially protective in women over 40 regardless of menopausal status or hormone replacement therapy.
Researchers from UEA, the University of Aberdeen and the University of Cambridge collaborated to study the intake of key components of a traditional Mediterranean-style diet including high intakes of fish, fruits and nuts, vegetables, cereal foods and potatoes and lower meat and dairy consumption.
Over a 17-year period, researchers examined the diets of more than 23,000 participants and compared stroke risk among four groups ranked highest to lowest by how closely they adhered to a Mediterranean style diet.
Study participants (23,232 white adults, aged between 40 and 77) were from the EPIC-Norfolk study, the UK Norfolk arm of the multi-centre European Prospective Investigation into Cancer study.
In participants who most closely followed a Mediterranean-style diet, the reduced onset of stroke was:
17 per cent in all adults;
22 per cent in women; and
6 per cent in men (which researchers said could have been due to chance).
Lead researcher Prof Ailsa Welch, from UEA’s Norwich Medical School, said: “This research shows us that following a Mediterranean-style diet rich in fish, fruits and nuts, vegetables and beans, and lower in meat and dairy, may reduce stroke risk for women over 40.
“But a healthy, balanced diet is important for everyone both young and old,” she added.
“It is unclear why we found differences between women and men, but it could be that components of the diet may influence men differently than women.
“We are also aware that different sub-types of stroke may differ between genders. Our study was too small to test for this, but both possibilities deserve further study in the future.”
There was also a 13 per cent overall reduced risk of stroke in participants already at high risk of cardiovascular disease across all four groups of the Mediterranean-diet scores. However, this was driven mainly by the associations in women who showed a 20 per cent reduced stroke risk. This benefit appeared to be extended to people in low risk group although the possibility of chance finding cannot be ruled out completely.
“Our findings provide clinicians and the public with information regarding the potential benefit of eating a Mediterranean-style diet for stroke prevention, regardless of cardiovascular risk,” said study co-author Prof Phyo Myint, from the University of Aberdeen.
Researchers used seven-day diet diaries, which had not been done before in such a large population. Seven-day diaries are more precise than food-frequency questionnaires and participants write down everything they eat and drink over the period of a week.
Eduardo Sanchez, chief medical officer for prevention at the American Heart Association, who was not part of this study, said: “The American Heart Association recommends a heart-healthy and brain-healthy dietary pattern that includes a variety of fruits and vegetables, whole grains, low-fat dairy products, fish, poultry, beans, non-tropical vegetable oils and nuts and limits saturated fat, trans fat, sodium, red meat, sweets and sugar-sweetened beverages; this dietary pattern reduces risk factors and risk for heart disease and stroke.
“This study provides more evidence that supports AHA’s recommendation.”
Citation : ‘The Mediterranean Diet Reduces Risk of Incident Stroke in a Population with Varying Cardiovascular Disease Risk Profiles’ is published in the journal Stroke.
A third study found that Mediterranean-style diets is linked to better brain function in older adults.
Mediterranean-style diets linked to better brain function in older adults
Eating foods included in two healthy diets—the Mediterranean or the MIND diet—is linked to a lower risk for memory difficulties in older adults, according to a study published in the Journal of the American Geriatrics Society.
The Mediterranean diet is rich in fruits, vegetables, whole grains, beans, potatoes, nuts, olive oil and fish. Processed foods, fried and fast foods, snack foods, red meat, poultry and whole-fat dairy foods are infrequently eaten on the Mediterranean diet.
The MIND diet is a version of the Mediterranean diet that includes 15 types of foods. Ten are considered “brain-healthy:” green leafy vegetables, other vegetables, nuts, berries, beans, whole grains, seafood, poultry, olive oil, and wine. Five are considered unhealthy: red meat, butter and stick margarine, cheese, pastries, sweets and fried/fast foods.
Researchers examined information from 5,907 older adults who participated in the Health and Retirement Study. The participants filled out questionnaires about their eating habits. Researchers then measured the participants’ cognitive abilities—mostly on their memory and attention skills.
The researchers compared the diets of participants to their performance on the cognitive tests. They found that older people who ate Mediterranean and MIND-style diets scored significantly better on the cognitive function tests than those who ate less healthy diets. In fact, older people who ate a Mediterranean-style diet had 35% lower risk of scoring poorly on cognitive tests. Even those who ate a moderate Mediterranean-style diet had 15% lower risk of doing poorly on cognitive tests. The researchers noted similar results for people who ate MIND-style diets.
This study suggests that eating Mediterranean and MIND-style diets is linked to better overall cognitive function in older adults, said the researchers. What’s more, older adults who followed these healthy diets had lower risks for having cognitive impairment in later life, noted the researchers.
Citation : Claire T. McEvoy et al, Neuroprotective Diets Are Associated with Better Cognitive Function: The Health and Retirement Study, Journal of the American Geriatrics Society. DOI: 10.1111/jgs.14922
A fourth study found that mediterranean diet may help preserve cognitive function.
Mediterranean diet may help preserve cognitive function
Eating right may help protect brain health in old age, a group of new studies show. The research was scheduled for presentation at the annual Alzheimer’s Association International Conference, held from July 16 to 20 in London.
In particular, the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet lowered people’s risk of dementia, two studies concluded. The MIND diet is a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diets, both of which were originally designed to help improve heart health. Seniors who carefully followed the MIND diet had a 35 percent lower risk of declining cognitive function as they aged. Even people who only moderately adhered to a MIND diet reduced their risk of cognitive decline between 18 to 24 percent.
The other two studies presented at the Alzheimer’s Association meeting also focused on the cognitive effects of nutrition: A Swedish study of 2,223 people found that those eating a healthy diet called the Nordic Prudent Dietary Pattern over six years had better cognitive status. This diet calls for people to limit their intake of root vegetables (potatoes, carrots), refined grains, butter and margarine, sugary foods, and fruit juice.
A Columbia University-led study of 330 people with a mean age of 80 found that people following a dietary pattern that encourages inflammation exhibited poorer executive function. Magnetic resonance imaging revealed that they also had a smaller total volume of brain gray matter. This pattern of eating involved high intake of cholesterol, beta-carotene, and lutein, and low intake of omega-3 fatty acids, calcium, folate, and vitamins.