Grapes And 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.

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

Grape Juice & Blood Pressure

Grapes have been used for thousands of years to successfully reduce inflammation, stop bleeding and treat eye infections. Most of grapes' benefits are due to their high content of antioxidants called polyphenols. Evidence indicates that drinking grape juice might reduce blood pressure, a risk factor for heart disease.
High Blood Pressure

Although blood pressure fluctuates throughout the day, chronically high blood pressure can damage arteries leading to your heart, causing a decrease in oxygen-rich blood flow. This increases your risk for kidney problems, heart disease and stroke. Since hypertension has no symptoms, it's often referred to as the silent killer, according to the Mayo Clinic. Consuming grape juice as part of your daily diet might help improve blood pressure levels.

Hypertensives

Concord grape juice might reduce blood pressure in hypertensives, according to a study conducted by researchers from Kyunghee University in South Korea. Participants consumed 5.5 ml of Concord grape juice per kilogram of body weight or a placebo daily for eight weeks. Scientists discovered that those in the Concord grape juice group experienced decreases in blood pressure compared with those in the placebo group, according to research published in the 2004 issue of "Biofactors."
Elevated Blood Pressure

Similar results were also seen in another study performed by researchers from the Nutrition and Metabolism Research Unit at Radiant Research. Scientists discovered that men with elevated blood pressure consuming 12 oz. of Concord grape juice per day for 12 weeks experienced a significant reduction in blood pressure compared with those ingesting a placebo, according to Nutra-Ingredients.

Glutathione

High blood pressure can damage the heart and reduce levels of glutathione, a powerful antioxidant that protects the heart from damage. According to Science Daily, grape polyphenols turn on genes that elevate glutathione levels in the heart, which decreases the damage caused by high blood pressure. Further research is necessary.

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 Hypertension

Resource links provided by NLM:
MedlinePlus related topics: High Blood Pressure
U.S. FDA Resources
Further study details as provided by Boston University:
Primary Outcome Measures:
Blood pressure measured by 24-hour recorder [ Time Frame: 8 weeks ] [ Designated as safety issue: No ]

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)


135 grapes a day could help lower blood pressure and minimise risk of heart attack

Grapes helped lower blood pressure and improve heart function in lab rats fed an otherwise salty diet, U.S. researchers have said.

The findings, published in the Journal of Gerontology: Biological Sciences, may help people with high blood pressure, they said.

'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,' said Mitchell Seymour of the Cardioprotection Research Laboratory at the University of Michigan.


In a study sponsored in part by California grape producers, Seymour and colleagues examined the effects of ordinary grapes on rats that develop high blood pressure when fed a salty diet.

Some of the rats ate a diet containing a powder from red, green and purple table grapes and a high-salt diet. Others were fed the grape powder and a low-salt diet. The powder, which contained the same nutrients in fresh grapes, allowed the scientists to measure the rats' intake carefully.


After 18 weeks, the rats that ate the grape-enriched diet had lower blood pressure, better heart function, reduced inflammation throughout their bodies, and fewer signs of heart muscle damage than rats that ate a salty diet but no grapes.

'The inevitable downhill sequence to hypertension and heart failure was changed by the addition of grape powder to a high-salt diet,' Dr. Steven Bolling of the University of Michigan, who heads up the lab, said in a statement.

Bolling said he thinks flavonoids, beneficial chemicals found in grapes, green tea, cocoa and and tomatoes, could be having an effect on blood pressure. Flavonoids have been shown in other studies to have heart-health benefits.

Food producers are keen to show the health benefits of their products. Studies sponsored by chocolate makers, almond and walnut producers have shown various heart benefits, including reducing inflammation in blood vessels and lowering the risk of heart attacks and stroke.

Grape powder comprised about three percent of the rats' diet. For humans, that would be about nine servings of grapes a day. One serving is about 15 grapes.

The California Table Grape Commission provided financial support for the study and supplied the grape powder. Other sponsors included the National Heart, Lung and Blood Institute, part of the National Institutes of Health.

High blood pressure, also known as hypertension, can lead to heart attack, heart failure, stroke and kidney failure.




Grapes good for men's heart health




Consuming grapes may help protect heart health in people with metabolic syndrome, a new study has revealed.

Researchers observed a reduction in key risk factors for heart disease in men with metabolic syndrome: reduced blood pressure, improved blood flow and reduced inflammation. Natural components found in grapes, known as polyphenols, are thought to be responsible for these beneficial effects.



he randomized, placebo-controlled, crossover study, led by principal investigator Dr. Maria Luz Fernandez and Jacqueline Barona, a PhD student in Dr. Fernandez' lab at the Department of Nutritional Sciences of the University of Connecticut, recruited men between 30 and 70 years of age with metabolic syndrome.

The study is believed to be the first to look at the impact of grapes on metabolic syndrome.

Metabolic syndrome is a cluster of conditions that occur together - increased blood pressure, a high blood sugar level, excess body fat around the waist or low HDL (the good cholesterol) and increased blood triglycerides - significantly increasing the risk for heart disease, stroke and diabetes.

Metabolic syndrome is a major public health concern, and is on the rise in the U.S.

In this study, participants were randomly assigned to consume grapes, in the form of a freeze-dried whole grape powder, or a placebo powder, for four weeks.

Then, following a 3-week "washout" period where neither grapes nor placebo were consumed, individuals were allocated to the alternate treatment.

This powerful study design allowed investigators to compare the response of each individual to consumption of both the placebo and grapes.

The study results showed that for each of the study's subjects, grape consumption resulted in significant decreases in blood pressure, improved blood flow (greater vasodilation), and decreases in a compound associated with inflammation.

"These results suggest that consuming grapes can improve important risk factors associated with heart disease, in a population that is already at higher risk," Fernandez said.

"This further supports the accumulating evidence that grapes can positively influence heart health, and extends it to men with metabolic syndrome," Fernandez added.

The study was recently published in the Journal of Nutrition.




Grapes May Protect Heart




New research from the US on laboratory rats suggests that eating grapes could help to fight high blood pressure resulting from a salty diet and could also reduce other cardiovascular risks and heart muscle damage. The effect is thought to be due to the high level of flavonoids in grapes.

The study was led by researchers from the University of Michigan Cardiovascular Center in Ann Arbor, and is published in the October issue of the Journal of Gerontology: Biological Sciences.

For the study, the researchers investigated the effect of dried grape powder made from regular table grapes (a mix of green, red and black varieties) when mixed in the diet of laboratory rats that had been bred to develop high blood pressure when fed on a salty diet (the Dahl Salt-Sensitive or Dahl- SS rat model).

The 60 rats were in five groups depending on how much salt was in their diet: high salt or low salt, whether they also had the grape powder, and whether they were given a mild dose of a common blood pressure drug (the vasodilator hydralazine).

Thus the five groups were: (1) low salt only, (2) low salt plus grape powder, (3) high salt only, (4) high salt plus grape powder, and (5) high salt plus vasodilator hydralazine.

The results showed that:
After 18 weeks, compared to their counterparts on diets without grape powder, the rats that had the grape powder had lower blood pressure, better heart function, reduced inflammation in their bodies, and less heart muscle damage.

The rats that had the blood pressure medication and high salt diet also had lower blood pressure, but their heart damage was greater than in the grape powder fed groups.
The study was part of Mitchell Seymour's doctoral research in nutrition science at Michigan State University. Seymour, who manages the U-M Cardioprotection Research Laboratory under the supervision of U-M heart surgeon Dr Steven Bolling, said that the findings explained their theory that there was something special about grapes, beyond the simple blood-pressure reducing effect we already expect from diets rich in fruit and vegetables.

Bolling, who is also professor of cardiac surgery at the U-M Medical School said that the animals in the study were not unlike millions of Americans who develop heart failure because of many years of diet-related high blood pressure.

"The inevitable downhill sequence to hypertension and heart failure was changed by the addition of grape powder to a high-salt diet," said Bolling.

Although grapes have many natural compounds that could be responsible for this effect, the researchers think in this case it is the flavonoids, either by affecting cells directly or via their antioxidant properties.

"These flavonoids are rich in all parts of the grape - skin, flesh and seed, all of which were in our powder," said Bolling.

Other studies have already suggested that flavonoids may reduce other potentially harmful molecular and cellular body processes.

Bolling said they were not about to tell patients to stop taking their blood pressure medication and eat only grapes. However, people who want to lower their blood pressure should cut down on the amount of salt in their diet.

"There is, as we now know, a great variability, perhaps genetic even, in sensitivity to salt and causing hypertension," said Bolling.

"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," he added.