Thursday, February 12, 2015

Fruits And Vegetables: Cardiovascular Benefits

Fruit consumption cuts cardiovascular disease risk by up to 40 percent

Daily fruit consumption cuts the risk of cardiovascular disease (CVD) by up to 40%, according to research presented at ESC Congress today by Dr Huaidong Du from Oxford, UK. The findings from the seven year follow-up study of nearly 0.5 million people in the China Kadoorie Biobank found that the more fruit people ate, the more their risk of CVD declined.

Dr Du said: "CVD, including ischaemic heart disease (IHD) and stroke, is the leading cause of death worldwide. Improving diet and lifestyle is critical for CVD risk reduction in the general population but the large majority of this evidence has come from western countries and hardly any from China."

She added: "China has a different pattern of CVD, with stroke as the main cause compared to western countries where IHD is more prevalent. Previous studies have combined ischaemic and haemorrhagic stroke probably due to the limited number of stroke cases in their datasets. Given their different physiology and risk factors, we have conducted the first large prospective study on the association of fruit with subtypes of stroke in Chinese adults from both rural and urban areas."

The current study included 451 681 participants with no history of CVD and not on anti-hypertensive treatment at baseline from the China Kadoorie Biobank(1) conducted in 10 different areas of China, 5 rural and 5 urban. Habitual consumption of fruit was recorded at baseline according to five categories: never, monthly, 1-3 days per week, 4-6 days per week, daily.

Over the seven year follow up period there were 19 300 cases of IHD and 19 689 strokes (14 688 ischaemic and 3562 haemorrhagic). Some 18% of participants consumed fruit daily and 6.3% never consumed fruit. The average amount of fruit eaten by the daily consumers was 1.5 portions (~150g) (2).

The researchers found that compared to people who never ate fruit, those who ate fruit daily cut their CVD risks by 25-40% (around 15% for IHD, around 25% for ischaemic stroke and 40% for haemorrhagic stroke). There was a dose response relationship between the frequency of fruit consumption and the risk of CVD (see figure).

Dr Du said: "Our data clearly shows that eating fresh fruit can reduce the risk of cardiovascular disease, including ischaemic heart disease and stroke (particularly haemorrhagic stroke). And not only that, the more fruit you eat the more your CVD risk goes down. It does suggest that eating more fruit is beneficial compared to less or no fruit."

The researchers also found that people who consumed fruit more often had significantly lower blood pressure (BP). Eating fruit daily was associated with 3.4/4.1 mmHg lower systolic/diastolic BP compared to those who never ate fruit. Dr Du said: "Our data shows that eating fresh fruit was associated with lower baseline BP. We also found that the beneficial effect of fruit on the risk of CVD was independent of its impact on baseline BP."

In a separate analysis, the researchers examined the association of fruit consumption with total mortality and CV mortality in more than 61 000 patients from the China Kadoorie Biobank who had CVD or hypertension at baseline. They found that compared to those who never ate fruit, daily consumers of fruit cut their overall risk of death by 32%. They also reduced their risks of dying from IHD by 27% and from stroke by around 40%.

Professor Zhengming Chen, the principal investigator of the China Kadoorie Biobank, said: "Patients with CVD and hypertension should also be encouraged to consume more fresh fruit. Many western populations have experienced a rapid decrease in CVD mortality during the past several decades, especially stroke mortality since the early 1950s, for reasons that are not yet fully explained. Improved access to fresh fruit may well have contributed importantly to that decline."

The researchers concluded: "Our results show the benefit of eating fruit in the healthy general population and in patients with CVD and hypertension. Fruit consumption is an effective way to cut CVD risk and should not only be regarded as 'might be useful'. Policies are needed to promote the availability, affordability and acceptability of fresh fruit through educational and regulatory measures."

Fruits and Veggies May Lower Stroke Risk

Regularly eating fruits and vegetables may reduce your stroke risk, according to a new review of worldwide research.

Stroke risk declined by 32 percent for every 200 grams of fruit consumed each day, and by 11 percent for every 200 grams of daily vegetables, according to the findings published in the journal Stroke.

"Improving diet and lifestyle is critical for heart and stroke risk reduction in the general population," senior study author Dr. Yan Qu, director of the intensive care unit at Qingdao Municipal Hospital in China, said in a news release provided by the American Heart Association.

"In particular, a diet rich in fruits and vegetables is highly recommended because it meets micronutrient and macronutrient and fiber requirements without adding substantially to overall energy requirements," Qu added.

Stroke is the fourth leading cause of death in the United States and a major cause of disability. In China, stroke is the leading cause of death.

Boosting people's consumption of fruits and vegetables up to 600 grams a day could cut the rate of ischemic stroke (caused by a blood clot) by 19 percent worldwide, according to the World Health Organization.

Investigators analyzed 20 studies over the last 19 years that included more than 760,00 people and were conducted in the United States, Asia and Europe.

The lower risk was seen in strokes caused by a blood clot (ischemic) or bleeding (hemorrhagic) and was consistent among men and women and people of different ages.

Because of the way the study was designed, it can't show that fruits and vegetables are the cause of the decline in strokes, only that there is an association between frequent produce consumption and a lower risk of stroke.

Eating plenty of fruits and vegetables has also been linked to lower blood pressure, improved blood vessel function, as well as beneficial effects on body fat, waist size, cholesterol and inflammation, according to the review authors.

Eating vegetables lowers blood pressure

Consuming an amino acid commonly found in vegetable protein may be associated with lower blood pressure, researchers report in Circulation: Journal of the American Heart Association.

Researchers found that a 4.72 percent higher dietary intake of the amino acid glutamic acid as a percent of total dietary protein correlated with lower group average systolic blood pressure, lower by 1.5 to 3.0 millimeters of mercury (mm Hg). Group average diastolic blood pressure was lower by 1.0 to 1.6 mm Hg.

Systolic blood pressure is the force when the heart beats; diastolic pressure is the pressure when the heart rests between beats.

This average lower blood pressure seems small from an individual perspective. But, on a population scale, it represents a potentially important reduction, said Jeremiah Stamler, M.D., lead author of the study.

"It is estimated that reducing a population's average systolic blood pressure by 2 mm Hg could cut stroke death rates by 6 percent and reduce mortality from coronary heart disease by 4 percent," said Stamler, professor emeritus of the Department of Preventive Medicine in the Feinberg School of Medicine at Northwestern University in Chicago, Ill.

Based on American Heart Association 2009 statistics, 6 percent of stroke deaths would be more than 8,600 people and four percent of coronary heart deaths represents about 17,800 lives saved per year.

"High blood pressure is a major cardiovascular disease risk factor, and blood pressure tends to rise with age starting early in life so that the majority of the U.S. population age 35 and older is affected by pre-hypertension or hypertension," he said. "We have a massive public health problem, and trying to address it by the strategy that has prevailed for years — diagnosis and drug treatment — is inadequate. While clinically useful, it fails as a long-term approach for ending this massive problem."

The only long-term approach is to prevent pre-hypertension and hypertension by improved lifestyle behaviors, Stamler said. This includes maintaining a healthy body weight, having a fruit and vegetable-rich eating pattern and participating in regular physical activity. His previous study, INTERSALT, was instrumental in helping show that high-salt diets contribute to high blood pressure.

In the current study, researchers examined dietary amino acids, the building blocks of protein. Glutamic acid is the most common amino acid and accounts for almost a quarter (23 percent) of the protein in vegetable protein and almost one fifth (18 percent) of animal protein, Stamler said.

Researchers analyzed data from the International Study on Macro/Micronutrients and Blood Pressure (INTERMAP), on 4,680 people in 17 rural and urban populations in China, Japan, the United Kingdom and the United States. INTERMAP is a basic population study aiming to clarify the role of multiple nutrients in the etiology of unfavorable blood pressure patterns prevailing for most middle-aged and older individuals. Stamler and colleagues analyzed data from eight blood pressure tests, four diet recall surveys and two 24-hour urine collections for each participant.

"Although our research group and others earlier reported an association between higher consumption of vegetable protein and lower blood pressure, as far as we know this is the first paper on the relation of glutamic acid intake to blood pressure," said Ian J. Brown, Ph.D., co-author of the study and a research associate in the Department of Epidemiology and Public Health at Imperial College London.

Common sources of vegetable protein include beans, whole grains — including whole grain rice, pasta, breads and cereals — and soy products such as tofu. Durum wheat, which is used to make pasta, is also a good source of vegetable protein.

Stamler noted that there are no data on the possible effects of glutamic acid supplements and emphasized the importance of "improved habitual food intake for the prevention and control of hypertension, not popping pills."

Stamler said the INTERMAP Study may help explain on a molecular level why the Dieatary Approaches to Stop Hypertension (DASH) diet lowers blood pressure. The DASH eating pattern, developed by the U.S. National Institutes of Health, is rich in fruits, vegetables and low-fat and nonfat dairy products as well as whole grains, lean poultry, nuts and beans. The pattern is recommended by the American Heart Association and the National Heart, Lung, and Blood Institute, the key sponsor of the INTERMAP study.

"The DASH eating pattern resembles the Mediterranean eating style for the 21st century, including reduced salt intake," Stamler noted. "Multiple modifications supply multiple nutrients helpful for the prevention and control of high blood pressure, including glutamic acid.

Although the current study examined just one element in the dietary mix, amino acids, Stamler said there's no one "magic bullet."

Eating fruits and vegetables linked to healthier arteries later in life

Women who ate a diet high in fresh fruits and vegetables as young adults were much less likely to have plaque build-up in their arteries 20 years later compared with those who consumed lower amounts of these foods, according to research presented at the American College of Cardiology's 63rd Annual Scientific Session. This new finding reinforces the importance of developing healthy eating habits early in life.

Previous studies have found that middle-aged adults whose diet consists of a high proportion of fruits and vegetables are less likely to have a heart attack or stroke, but the relationship between fruit and vegetable consumption during young adulthood and heart disease later in life was less clear. To study this concept, researchers evaluated the association between dietary intake of fruits and vegetables in young adults and the presence of coronary artery calcification (CAC) 20 years later. CAC scores, which were obtained using a CT scan, provide a direct estimate of the amount of plaque in the coronary arteries.

"It's an important question because lifestyle behaviors, such as a heart healthy diet, are the foundation of cardiovascular prevention and we need to know what dietary components are most important," said Michael D. Miedema, M.D., M.P.H., a cardiologist at the Minneapolis Heart Institute, and the lead investigator of the study.

Specifically, women who reported consuming the most fruits and vegetables (eight to nine servings a day for a 2,000-calorie diet) in their 20s were 40 percent less likely to have calcified plaque in their arteries in their 40s compared with those who ate the least amount (three to four servings a day) during the same time period. This association persisted even after researchers accounted for other lifestyle behaviors, as well as for their current-day diets, further demonstrating the role dietary patterns at younger ages may play.

"These findings confirm the concept that plaque development is a lifelong process, and that process can be slowed down with a healthy diet at a young age," Miedema said. "This is often when dietary habits are established, so there is value in knowing how the choices we make in early life have lifelong benefits."

Surprisingly, the same benefit did not hold true for men, which warrants further investigation.

"Several other studies have also suggested that a diet high in fruits and vegetables is less protective in men, but we do not have a good biological reason for this lack of association," Miedema said, adding that the study had less power to evaluate men (62.7 percent were female vs. 37.3 percent male).

The study included 2,508 participants from the ongoing government-sponsored Coronary Artery Risk Development in Young Adults (CARDIA) study, which is evaluating how heart disease develops throughout adulthood. CARDIA began in the mid-1980s with a group of men and women 18-30 years of age and has collected extensive data on medical, socioeconomic, psychosocial and behavioral characteristics.

At the start of CARDIA (1985-1986), women and men were asked about their consumption of different fruits and vegetables and the number of servings they had eaten in the past month using a semi-quantitative interview food-frequency questionnaire. Researchers then calculated the average number of servings of fruits and vegetables per day and adjusted them to a 2,000-calorie diet. People were divided into three groups based on self-reported fruit and vegetable intake: high, moderate and low. CAC was measured at year 20 (2005-2006) using electron-beam computed tomography. The average age at baseline and the 20-year follow-up was 25 and 45 years, respectively.

"CAC scoring is currently the best predictor we have for future heart attacks," Miedema said. Calcium build-up in the walls of the coronary arteries is an early sign of heart disease, and the presence of CAC substantially raises an individual's risk for a future heart attack.

In their analysis, researchers controlled for smoking, exercise, consumption of red meat, sugar-sweetened beverages and other dietary and cardiovascular risk factors that correlate with atherosclerosis. Participants with extreme high or low caloric intake/day or those missing CAC scores were excluded from the analysis.

The current findings are in line with the 2011 U.S. Department of Agriculture Dietary Guidelines that advise Americans to fill half of their plates with colorful fruits and vegetables at each meal or snack. Based on these recommendations, adults who consume a 2,000-calorie a day diet should be consuming 2.5 cups of vegetables and two cups of fruit a day – a big jump from what the average American usually gets from their diet, according to government figures.

Fruits and vegetables are packed with vitamins, minerals, fiber, antioxidants and other things that are known to promote good health. Plant-based diets in general have also been linked to greater longevity, less cancer, lower cholesterol, lower blood pressure and healthier body weight.

Miedema emphasized that more studies are needed to further define the relationship between fruits, vegetables and cardiovascular disease in men and women, in addition to determining the best ways to increase compliance with a diet high in fruits and vegetables in the U.S. population.

Vegetables, fruits reduce stroke risk in women
Swedish women who ate an antioxidant-rich diet had fewer strokes regardless of whether they had a previous history of cardiovascular disease, in a study reported 2011 in Stroke: Journal of the American Heart Association.

"Eating antioxidant-rich foods may reduce your risk of stroke by inhibiting oxidative stress and inflammation," said Susanne Rautiainen, M.Sc., the study's first author and Ph.D. student at the Karolinska Institutet in Sweden. "This means people should eat more foods such as fruits and vegetables that contribute to total antioxidant capacity."

Oxidative stress is an imbalance between the production of cell-damaging free radicals and the body's ability to neutralize them. It leads to inflammation, blood vessel damage and stiffening.

Antioxidants such as vitamins C and E, carotenoids and flavonoids can inhibit oxidative stress and inflammation by scavenging the free radicals. Antioxidants, especially flavonoids, may also help improve endothelial function and reduce blood clotting, blood pressure and inflammation.

"In this study, we took into account all the antioxidants present in the diet, including thousands of compounds, in doses obtained from a usual diet," Rautiainen said. Researchers collected dietary data through a food-frequency questionnaire. They used a standard database to determine participants' total antioxidant capacity (TAC), which measures the free radical reducing capacity of all antioxidants in the diet and considers synergistic effects between substances.

Researchers categorized the women according to their TAC levels — five groups without a history of cardiovascular disease and four with previous cardiovascular disease.

For women with no history of cardiovascular disease who had the highest TAC, fruits and vegetables contributed about 50 percent of TAC. Other contributors were whole grains (18 percent), tea (16 percent) and chocolate (5 percent).

The study found:

- Higher TAC was related to lower stroke rates in women without cardiovascular disease.
- Women without cardiovascular disease with the highest levels of dietary TAC had a statistically significant 17 percent lower risk of total stroke compared to those in the lowest quintile.
- Women with history of cardiovascular disease in the highest three quartiles of dietary TAC had a statistically significant 46 percent to 57 percent lower risk of hemorrhagic stroke compared with those in the lowest quartile.

"Women with a high antioxidant intake may be more health conscious and have the sort of healthy behaviors that may have influenced our results," Rautiainen said. "However, the observed inverse association between dietary TAC and stroke persisted after adjustments for potential confounders related to healthy behavior such as smoking, physical activity and education."

For the study, researchers used the Swedish Mammography Cohort to identify 31,035 heart disease-free women and 5,680 women with a history of heart disease in two counties. The women were 49-83 years old.

Researchers tracked the cardiovascular disease-free women an average 11.5 years and the women with cardiovascular disease 9.6 years, from September 1997 through the date of first stroke, death or Dec. 31, 2009, whichever came first.

Researchers identified 1,322 strokes among cardiovascular disease-free women and 1,007 strokes among women with a history of cardiovascular disease from the Swedish Hospital Discharge Registry.

"To the best of our knowledge, no study has assessed the relation between dietary TAC and stroke risk in participants with a previous history of cardiovascular disease," Rautiainen said. "Further studies are needed to assess the link between dietary TAC and stroke risk in men and in people in other countries, but we think our results are applicable."

Eating More Fruit and Vegetables Is Linked to a Lower Risk of Dying from Ischemic Heart Disease

A European study investigating the links between diet and disease has found that people who consume more fruit and vegetables have a lower risk of dying from ischaemic heart disease -- the most common form of heart disease and one of the leading causes of death in Europe. However, the authors point out that a higher fruit and vegetable intake occurs among people with other healthy eating habits and lifestyles, and that these factors could also be associated with the lower risk of dying from IHD.

The study was published online on January 19, 2011 in the European Heart Journal.

Data analysed from the European Prospective Investigation into Cancer and Nutrition (EPIC) Heart study has shown that people who ate at least eight portions of fruit and vegetables a day had a 22% lower risk of dying from IHD than did those who consumed fewer than three portions a day. A portion weighed 80 grams, equal to a small banana, a medium apple, or a small carrot.

Dr Francesca Crowe of the Cancer Epidemiology Unit at the University of Oxford, UK, and the first author of the paper by the EPIC study collaborators, said: "This study involved over 300,000 people in eight different European countries, with 1,636 deaths from IHD. It shows a 4% reduced risk of dying from IHD for each additional portion of fruit and vegetables consumed above the lowest intake of two portions. In other words, the risk of a fatal IHD for someone eating five portions of fruit and vegetables a day would be 4% lower compared to someone consuming four portions a day, and so on up to eight portions or more."

Ischaemic heart disease (IHD) is characterised by reduced blood supply to the heart; people suffering from it can develop angina, chest pains and have a heart attack.

The EPIC study started in 1992 and recruited participants from a total of ten European countries until 2000. For the analysis of IHD deaths, data from eight countries for people aged between 40 and 85 were used. Participants answered questions about their diet at the time of entry to the study and other questions about health, socio-economic status and life-style, such as smoking, drinking and exercise habits. They were followed-up for an average of nearly eight and a half years.

The researchers found that the average intake of fruit and vegetables was five portions a day; people in Greece, Italy and Spain ate more, and those in Sweden ate less.

When analysing the data, the researchers made allowances for confounding factors such as differences in lifestyles and eating habits. However, the study could be limited by errors in measuring correctly people's fruit and vegetable intake as well as other aspects of their diet. In addition, the study had a higher proportion of women, which might not be generalisable to the wider European population.

Dr Crowe said: "The main message from this analysis is that, in this study, people who consume more fruits and vegetables have lower risk of dying from IHD. However, we need to be cautious in our interpretation of the results because we are unsure whether the association between fruit and vegetable intake and risk of IHD is due to some other component of diet or lifestyle.

"If we could understand, by means of well-designed intervention studies, the biological mechanisms that could underlie the association between fruits and vegetables and IHD, this might help to determine whether or not the relation between fruit and vegetables with IHD risk is causal."

In an accompanying editorial, Professor Sir Michael Marmot, director of the University College London (UCL) International Institute for Society and Health, head of the UCL Department of Epidemiology and Public Health, and chairman of the Commission on Social Determinants of Health, writes that it is difficult to reach firm conclusions about causation from results that show a 22% lower risk of dying from IHD (an odds ration of 0.78) in people who eat eight portions of fruit and vegetables a day.

He continues: "Such an odds ratio is, however, of huge practical importance. Cardiovascular disease is the most common cause of death. A reduction of 22% is huge. But... this reduction in mortality comes with consumption of eight portions a day, or 640g. Such a high consumption was found in only 18% of the men and women in these eight cohorts. There would need to be big shift in dietary patterns to achieve this healthy consumption of eight portions a day. It is worth trying to move in that direction. Reductions in cancers of several sites, in blood pressure and stroke, would add to this reduction in fatal CHD. Moving to a diet that emphasises fruit and vegetables is of great importance to public health."

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