Grapes Reduce Risks For Heart Disease

               
Grapes reduce risks for heart disease and diabetes 

Findings show grape consumption lowered blood pressure, improved heart function and reduced other risk factors for heart disease and metabolic syndrome

ANN ARBOR, Mich. - Could eating grapes slow what’s for many Americans a downhill sequence of high blood pressure and insulin resistance leading to heart disease and type 2 diabetes?

Scientists at the University of Michigan Health System are teasing out clues to the effect of grapes in reducing risk factors related to cardiovascular disease and metabolic syndrome. The effect is thought to be due to phytochemicals -- naturally occurring antioxidants – that grapes contain.

Findings from a new animal study will be presented today at the Experimental Biology convention in Anaheim, Calif., and show encouraging results of a grape-enriched diet preventing risk factors for metabolic syndrome, a condition affecting an estimated 50 million Americans and is often a precursor to type 2 diabetes.

Researchers studied the effect of regular table grapes (a blend of green, red and black grapes) that were mixed into a powdered form and integrated into the diets of laboratory rats as part of a high-fat, American style diet. All of the rats used were from a research breed that is prone to being overweight.

They performed many comparisons between the rats consuming a grape-enriched diet and the control rats receiving no grape powder. Researchers added calories and sugars to the control group to balance the extra calories and sugars gained from getting the grape powder.

After three months, the rats that received the grape-enriched diet had lower blood pressure, better heart function, and reduced indicators of inflammation in the heart and the blood than rats who received no grape powder. Rats also had lower triglycerides and improved glucose tolerance.

The effects were seen even though the grape-fed animals had no change in body weight.

In all, researchers say the study demonstrates that a grape-enriched diet can have broad effects on the development of heart disease and metabolic syndrome and the risk factors that go along with it.

“The possible reasoning behind the lessening of metabolic syndrome is that the phytochemicals were active in protecting the heart cells from the damaging effects of metabolic syndrome. In the rats, inflammation of the heart and heart function was maintained far better,” says Steven Bolling, M.D., heart surgeon at the U-M Cardiovascular Center and head of the U-M Cardioprotection Research Laboratory.

The researchers also looked for signs of inflammation, oxidative damage and other molecular indicators of cardiac stress. Again, the rats who consumed the grape powder had lower levels of these markers than rats who did not receive grapes.

There is no well-accepted way to diagnose metabolic syndrome which is really a cluster of characteristics: excess belly fat (for men, a waist measuring 40 inches or more and for women, a waist measuring 35 inches or more); high triglycerides which can lead to plague build-up in the artery walls; high blood pressure; reduced glucose tolerance; and elevated c-reactive protein, a marker for inflammation in the body.

Those with metabolic syndrome are at higher risk for cardiovascular disease and type 2 diabetes.

But the U-M study suggests that it may be possible that grape consumption can change the downhill sequence that leads to heart disease by prolonging the time between when symptoms begin to occur and a time of diagnosis.

“Reducing these risk factors may delay the onset of diabetes or heart disease, or lessen the severity of the diseases,” says E. Mitchell Seymour, Ph.D., lead researcher and manager of the U-M Cardioprotection Research Laboratory. “Ultimately it may lessen the health burden of these increasingly common conditions.”

Rats were fed the same weight of food each day, with powdered grapes making up 3 percent of the diet. Although the current study was supported in part by the California Table Grape Commission, which also supplied the grape powder, the researchers note that the commission played no role in the study’s design, conduct, analysis or preparation of the presentation. But because of differences in body weight, metabolic rate, lean body mass, daily calorie intake and other factors, U-M researchers cannot predict a cups a day equivalency for humans. The federal Dietary Guidelines for Americans recommends consuming 5 to 9 servings of fruits and vegetables a day.

Research on grapes and other fruits containing high levels of antioxidant phytochemicals continues to show promise. U-M will further its research this summer when it begins a clinical trial to test the impact of grape product consumption on heart risk factors.

“Although there’s not a particular direct correlation between this study and what humans should do, it’s very interesting to postulate that a diet higher in phytochemical-rich fruits, such as grapes, may benefit humans,” Bolling says.

Bolling says that people who want to lower their blood pressure, reduce their risk of diabetes or help with weakened hearts retain as much pumping power as possible should follow some tried-and-true advice to eat a healthy diet low in saturated fat, trans fat and cholesterol, achieve a desirable weight and increase physical activity.

New research shows grapes reduce risk for heart disease and diabetes


The millions of Americans with heart disease and type 2 diabetes didn't develop these diseases out of the blue. Their disorders are the result of a cascade of problems including high blood pressure, insulin resistance, abdominal fat and other symptoms of metabolic syndrome. Now University of Michigan (U-M) scientists say they've found something that could help put the brakes on this downward spiral of ill health. It's not a new drug but a delicious and easy lifestyle change: just eat grapes.

The U-M research findings, announced April 26th at the Experimental Biology convention held in Anaheim, California, showed grape consumption lowered blood pressure, improved heart function and reduced other risk factors for heart disease and metabolic syndrome, a condition affecting an estimated 50 million Americans that often leads to type 2 diabetes. The scientists stated the beneficial effects of grapes appear to be due to the rich supply of phytochemicals in the fruit.

The research team tested a mixture of green, red and black grapes on laboratory rats that are prone to being overweight. For three months, one group of the animals ate powdered grapes mixed into their regular feed, which was devised to imitate a typical high-fat, American style diet. A control group of similar rats received no grape powder in their food (which was supplemented so it had the same number of calories as the grape-added diet).

The results of the experiment showed the rats eating the grape-enriched diet had lower blood pressure, better heart function, and reduced indicators of inflammation in the heart and the blood than rats who received no grape powder. What's more, the grape eating rats had lower triglycerides and improved glucose tolerance even though there was no change in their body weight.

"The possible reasoning behind the lessening of metabolic syndrome is that the phytochemicals were active in protecting the heart cells from the damaging effects of metabolic syndrome," Steven Bolling, M.D., heart surgeon at the U-M Cardiovascular Center and head of the U-M Cardioprotection Research Laboratory, said in a statement to the media.

While this was an animal study, the scientists noted there's good reason to think eating grapes -- along with tried-and-true natural strategies such as eating little saturated fat, keeping weight under control and exercising regularly -- could have broad effects on the development of heart disease and metabolic syndrome in people.

"Reducing these risk factors may delay the onset of diabetes or heart disease, or lessen the severity of the diseases," said E. Mitchell Seymour, Ph.D., lead researcher and manager of the U-M Cardioprotection Research Laboratory. "Ultimately it may lessen the health burden of these increasingly common conditions."


Grapes And High Blood Pressure
How To Use Grape Seed Extract to Manage High Blood Pressure

Grapes have a long and storied history within the realm of healing, from the grape leaves that were once used to quell pain, inflammation and bleeding to the avowed healing properties of wine. In the more recent past, it has been discovered that many of the healing properties of grapes stem from the polyphenol content of their seeds. Polyphenols are powerful anti-oxidants that neutralize free radicals in your bloodstream. For more information on how free radicals and anti-oxidants work, see How To Understand Anti-Oxidants. Polyphenol antioxidants also naturally increase blood vessel dilation (vasodilation), which increases blood flow and decreases blood pressure. Grape seed extract is exactly what it sounds like--an extract produced from the seeds of grapes--with high levels of polyphenols, particularly one polyphenol known as proanthocyanidin that can lower blood pressure naturally.

Here's what you should know about how to use this extract to manage high blood pressure:
Grape seed extract is available in capsules, tablets, and tinctures. Look for products that are standardized to 95% OPC content. (OPC is an abbreviation for oligomeric proanthocyanidins, which are a class of flavonoid complexes.)
In its first human trial, grape seed extract performed well. In results reported in March, 2006, a University of California-Davis study showed that systolic blood pressure (the top number of a blood pressure reading) and diastolic blood pressure (the bottom number of a blood pressure reading) dropped an average of 12 and 8 points respectively, in male and female subjects with metabolic syndrome who took either a 150 or 300 milligram dose of of grape seed extract daily.

The UC Davis research team recently is currently doing another human trial of grape seed extract using pre-hypertension subjects with a systolic blood pressure of 120-139 mmHg and a diastolic blood pressure of 80-89 mmHg. In animal studies, grape seed extract has reduced blood pressure in pre-hypertensive subjects.
A study reported in the Journal of Hypertension found that grape seed polyphenols in combination with Vitamin C increased both systolic and diastolic blood pressure. This study suggests caution in combining Vitamin C supplements with grape seed extract.
Grape seed extract is considered safe. However, because herbs and dietary supplements are not strictly regulated by the U.S. food and Drug Administration, it is difficult to verify the purity and strength of products claiming to contain the extract. Also remember that the extract may interact with other herbs, supplements, or medications. For example, it increase the risk of bleeding. Grape seed extract should only be used with the guidance of a qualified health care professional.
And while this might seem obvious....if you are allergic to grapes, odds are that you are allergic to grape seed extract and should not take it to reduce high blood pressure or for any other reasons.

In addition to its ability to manage and control blood pressure, grape seed extract has some additional benefits:
Grape seed extract may also protect against cardiovascular disease by restoring impaired endothelial function and by protecting against the oxidation of low-density lipoprotein (LDL) or the "bad" cholesterol.

Animal studies have suggested that topical grape seed extract promotes antitumor activity. Test tube studies suggest that it inhibits human lung cancer, breast cancer, and gastric adenocarcinoma cells. Human trials of the extract's cancer-fighting properties have not yet been conducted.

Some animal studies suggest that procyanidins from grape seed may promote hair growth. Expect a human trial soon.

Remember that grape seed extract is not a panacea. If you do decide to use it to manage high blood pressure, you still need to follow your doctor's lifestyle, medication and dietary recommendations for controlling your blood pressure.


Blood Pressure Lowering Effects of Grape Juice
Purpose

Recent studies suggest that a diet rich in fruit and vegetables can lower blood pressure, and a number of lines of evidence suggest that grape products may have such an effect. The purpose of this study is to determine whether consuming grape juice lowers blood pressure in individuals with pre-hypertension or stage I hypertension.


Condition Intervention
Hypertension Dietary Supplement: Concord Grape Juice

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Efficacy Study
Intervention Model: Crossover Assignment
Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor)
Primary Purpose: Treatment
Official Title: Effect of Concord Grape Juice on Blood Pressure and Vascular Function in Subjects With Pre-Hypertension and Stage 1 HypertensionResource links provided by NLM:

MedlinePlus related topics: High Blood Pressure
U.S. FDA Resources

Further study details as provided by Boston University:


Secondary Outcome Measures:
Pulse wave velocity [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
Pulse amplitude tonometry [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
Blood pressure during mental tasks [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]
Estimated Enrollment: 60
Study Start Date: March 2006
Study Completion Date: May 2009
Intervention Details:
Dietary Supplement: Concord Grape Juice
Approximately 16 oz of grape juice or placebo
Detailed Description:

Elevated blood pressure (BP) is among the most common and important risk factors for atherosclerosis. A number of non-pharmacological therapies have successfully been applied to prevent the development of elevated BP or reduce elevated BP. For example the DASH Study showed that a diet rich in fruits, vegetables and low fat dairy products, and reduced in saturated fat, total fat and cholesterol, substantially lowered blood pressure in normotensive and hypertensive individuals.

Within the past three years a number of small clinical trials have suggested suggest that drinking purple grape juice for a period of 6-12 weeks may lower blood pressure individuals with elevated blood pressure. Other clinical trials have shown that Concord grape juice improves the function of the vascular endothelium, possibly providing an explanation for the beneficial effect. However, there is a need for a prospective, controlled study to determine whether grape juice has a beneficial effect on blood pressure.

The present study will compare the effect of drinking Concord purple grape juice (7 ml/kg or about 16 oz/day for a 70 kg person) and the effect of calorie-matched placebo on 24-hour ambulatory blood pressure, blood pressure reactivity, and vascular function in men and women in the category of "pre-hypertension" (defined as blood pressure greater than 120/80, but less than 149/89 mmHg and Stage 1 hypertension (defined as blood pressure greater than 140/90, but less than 160/100). This study will specifically recruit patients with systolic blood pressure of 130-159 mmHg or diastolic blood pressure of 85-99 mmHg. The study will be double blind and have a crossover design with the order of treatment randomized (grape juice first or placebo first). A dietician will provide all subjects with formal instruction in a low salt diet, which is the current recommended initial therapy for patients with Stage 1 hypertension.

After a 1-week run-in period, subjects will consume each beverage for 8 weeks with a 4-week rest period between treatments. Blood pressure will be measured before and after each treatment period using a 24-hour ambulatory blood pressure recording. After each treatment period, we will measure changes in blood pressure induced by psychological challenge (mental arithmetic and computer tasks) and by the cold pressor test. In order to gain insight into the potential mechanisms of benefit, we will also examine the effects of beverage consumption on endothelial function, stiffness of the central aorta, fasting glucose and insulin, body weight, and markers of systemic inflammation, including CD40 ligand and C-reactive protein. Finally, we will store plasma samples for future investigation of other potential effects of grape juice on the cardiovascular system.

We hypothesize that Concord grape juice will have favorable effects on blood pressure compared to placebo.


Eligibility
Ages Eligible for Study: 21 Years to 75 Years
Genders Eligible for Study: Both
Accepts Healthy Volunteers: Yes

Criteria

Inclusion Criteria:
Adult males and females
Body Mass Index (BMI) of less than 35.0 kg/m2
Systolic blood pressure (130-159 mmHg) and/or diastolic blood pressure (85-99 mm Hg) on two screening visits
Subject must be judged to be in good health on the basis of medical history; 5. Subject must not be taking any antihypertensive medications for at least one month prior to the Screening Visit

Exclusion Criteria:

History of clinically defined coronary artery disease, peripheral artery disease, stroke, active gastrointestinal ulcers, renal, or hepatic disease;
History of bleeding disorders or malabsorption syndromes;
Taking drugs for regulating hemostasis, including stable-dose aspirin;
History of active cancer
Females who are pregnant or planning to become pregnant
Use of weight-loss drugs (including over-the-counter and dietary supplements)
Diagnosed diabetes mellitus
Subjects who consume a vegetarian diet
Recent history (within the past 6 months) of alcohol or substance abuse.
Laboratory values outside the following ranges: serum potassium (3.5-5.1 mg/dl), creatinine (0.5-1.3 mg/dl), hematocrit (36-50%), white blood count (4.0-11.0 K/ul), platelet count (150-400 k/ul)

Red grapes 'are wonder cure for high blood pressure and cholesterol'

Red grapes are more than just the source for the world’s finest wine - the fruits themselves are a wonder cure against heart attacks, according to new research.

And while a glass of wine is a recognised part of a healthy Mediterranean-style diet, it seems the bits of the grape thrown away to make the tipple could be even healthier.

Researchers made a cocktail extracted from the most fibre-rich parts of the grape such as the skin and seeds which are the waste byproduct in vineyards.

Tests on human volunteers found the extract was extremely rich in both fibre and antioxidants which reduce the risks of cardiovascular disease - the world’s biggest killer.

Most other superfoods for the heart, like the plant extract psyllium or healthy oats for instance, are usually good for either fibre or antioxidants rather than both together.

But the tests at Madrid University using a concoction called Grape Antioxidant Dietary Fibre (GADF) was high in both potentially lifesaving ingredients.

Over a 16 week period, adding the extract to the volunteers’ regular diet ‘significantly’ reduced their ‘Lipid Profile’ - the range of tests to determine a patient’s risk of heart disease.

This included reducing blood pressure by up to five per cent and cholesterol by up to 14 per cent among the volunteers, said the research.

A Mediterranean-style diet including components like red wine, olive oil and tomatoes has long been considered healthier than other Western diets rich in deep fried and fast food.

The research suggests the grape extract would make such a diet up to 50 per cent even more effective in reducing the risks of heart attacks.

Cardiovascular disease is the biggest cause of death in the Western World accounting for up to 50 per cent of all natural mortalities.

The extract, if turned into a health supplement, could be particularly useful for those who suffer from high blood pressure or high cholesterol, said the researchers.

The results are published in the journal Nutrition today/Wed after 34 non-smoking adults were tested with the GADF extract over 16 weeks.

While that was going on, a further nine students from the university who were not given the extract were also monitored so they could be compared to the first group.

Those given GADF saw ‘significantly reduced total cholesterol’, particularly LDL, the type known as ‘bad cholesterol’ which can lead to heart problems in later life.

The reduction in both cholesterol and blood pressure was much bigger than the effects caused by other high fibre products on the market, they said.

Researcher Jara Perez Jimenez said: ‘GADF showed significant reducing effects in lipid profile and blood pressure.

‘The effects appear to be higher than the ones caused by other dietary fibres, such as oat fibre or psyllium, probably due to the combined effect of dietary fibre and antioxidants.’

Grapes May Fight High Blood Pressure


A hardy helping of grapes may fight high blood pressure and heart disease if you eat a salty diet, a new University of Michigan study shows.

Because black, green, and red grapes contain high levels of naturally occurring antioxidants, the fruits may reduce hypertension that can lead to heart failure, shows the study, published in the October issue of the Journal of Gerontology: Biological Sciences.

Scientists including Mitchell Seymour, MS, report that flavonoids -- found in abundance in the skin, flesh, and seeds of grapes -- may be the substances that provide the beneficial effects they found in their study of laboratory rats.

Grapes and High Blood Pressure

The researchers studied the effects of regular table grapes -- a blend of green, red, and black fruits -- that were fed to rats in powdered form.

After 18 weeks, rats that ate the grape-enriched powder had lower blood pressure, better heart function, and reduced inflammation throughout their bodies than comparable rodents that didn't receive the mixture. Rats on salty diets plus hydralazine, a blood pressure medicine, had lower blood pressure, but their hearts weren't as protected from damage as the animals fed grapes.

"These findings support our theory that something within the grapes themselves has a direct impact on cardiovascular risk, beyond the simple blood-pressure-lowering impact that we already know can come from a diet rich in fruits and vegetables," says Seymour, who manages the University of Michigan Cardioprotection Research Laboratory.

Steven Bolling, MD, who heads the program, says the rats in the study were in a similar situation as millions of Americans who have high blood pressure related to their diets and who develop heart failure because of prolonged hypertension.

"The inevitable downhill sequence to hypertension and heart failure was changed by the addition of grape powder to a high-salt diet," Bolling says. "Although there are many natural compounds in the grape powder itself that may have an effect, the things that we think are having an effect against the hypertension may be the flavonoids, either by direct antioxidant effects, by indirect effects on cell function, or both."

Such naturally occurring substances already have been shown to reduce other potentially harmful molecular and cellular activity, the researchers say in a news release.

The study notes that grapes and other fruits high in antioxidant phytochemials show promise, as does research on the impact of red wine on heart health.

Still, the best advice for people with blood pressure problems is to cut down on the amount of salt they get, Bolling says.

"There is, as we know, a great variability, perhaps genetic even, in sensitivity to salt causing hypertension," he says. "Some people are very sensitive to salt intake, some are only moderately so, and there are perhaps some people who are salt resistant. But in general we say, 'Stay away from excess salt.'"

Grape-Enriched Diet

The researchers studied several groups of rats and assigned each group of 12 to various combinations of salty foods, grape powder, and hydralazine. All the rodents were fed the same weight of food daily, with powdered grapes making up 3% of the diet for the animals that received grapes as part of either a low-salt or high-salt diet. Rats receiving hydralazine lapped it up in their water supply.

After looking at various factors, including molecular indicators of cardiac stress, the researchers still found that the rats in the high-salt grape and high-salt hydralazine groups developed high blood pressure over time but had lower systolic blood pressures than the high-salt rats deprived of grape powder.

"Though it's true that your mom told you to eat all your fruits and your vegetables, and that we are learning a lot about what fruits, including grapes, can do ... we would not directly tell patients to throw all their pills away and just eat grapes," Bolling says.

The researchers say the study suggests that a grape-enriched diet can have broad effects on hypertension, but that more work is needed to see if the beneficial effects will apply to humans.

They write that the findings "may have particular importance to our aging population, which has reduced intake of both fruit and vegetables."

According to recent data, only 35% of women and 39% of men over age 60 consumed two servings of fruits per day, and only 6% of both women and men met the goal of three servings daily of vegetables.

The study was funded in part by the California Table Grape Commission, but the authors note that the commission had no involvement in study design, data analysis, or manuscript preparation.