X-Message-Number: 26205
Date: Thu, 19 May 2005 20:55:06 -0700 (PDT)
From: Doug Skrecky <>
Subject: grapes as a health food

[Grapes or grape products can lower blood pressure, inhibit
atherosclerosis, inhibit cancer, and protect the heart from ischemic
damage. Consume at your risk.]

Biofactors. 2004;22(1-4):145-7.
Concord grape juice supplementation reduces blood pressure in
Korean hypertensive men: double-blind, placebo controlled
intervention trial.
    Many of the flavonoids found in grapes and grape products
such as juice or wine have been known to exert antioxidant,
anti-inflammatory, platelet inhibitory and arterial relaxing
effects either in vitro, in animal studies and in human trials.
This study was designed to test the effect of Concord grape
juice consumption on altering blood pressure in hypertensive
patients. Forty subjects were given 5.5 ml/kg body weight/day
of either Concord grape juice (CGJ) or a calorie-matched placebo
drink every day for 8 weeks. Blood pressure (BP) was measured on
weeks 0, 4 and 8. Compared to baseline, in the CGJ group systolic
BP was reduced on average by 7.2 mm Hg (p = 0.005) and diastolic
BP was reduced on average by 6.2 mm Hg (p = 0.001) at the end of
8 weeks. Comparable changes in the group getting the placebo
product were -3.5 mm Hg (NS) and -3.2 mm Hg (p = 0.05) Consuming
Concord grape juice, which is high in polyphenolic compounds, may
favorably affect BP in hypertensive individuals.

Publication Types:
J Med Food. 2005 Spring;8(1):41-6.
Comparison of the antioxidant activities of nine different fruits
in human plasma.
	Oxidative stress in humans is associated with damage to DNA,
proteins, and biological membranes. Oxidative stress, which often
arises as a result of an imbalance in the human antioxidant status,
has been implicated in aging and a number of human diseases such as
cancer, atherosclerosis, and rheumatoid arthritis. This study was
performed to test the hypothesis that the consumption of fruit
juices may improve antioxidant status in human plasma. Ten healthy
men 25-26 years old were recruited for the study. After overnight
fasting, study subjects were fed 150 mL of fruit juice, and blood
was collected at 0, 30, 60, 90, and 120 minutes after consumption.
After a 1-day wash-out period, subjects were fed with the next
sample of fruit juice until all nine juices (pear, apple, orange,
grape, peach, plum, kiwi, melon, and watermelon) had been evaluated.
All juices were prepared from pure fruits ground in a home-style
mixer. Dietary food records and anthropometric measurements were
used to evaluate the nutritional status of subjects. The antioxidant
activities of fruit juices were estimated by measuring antioxidant
status in the plasma using dichlorofluorescein (DCF) fluorescence.
Except for pear juice, eight kinds of juices exhibited potent
antioxidant effects in human plasma. Within 30 minutes after
consumption, orange, melon, grape, peach, plum, apple, and kiwi
juices already effectively suppressed reactive oxygen species
generation. This radical scavenging effect of fruit juices was
maintained for up to 90 minutes post-consumption, but the relative
DCF fluorescence had rebounded to near the initial levels at 2 hours
post-consumption in most samples tested. Interestingly, however,
grape juice continuously exerted persistent antioxidant activity
until 2 hours after supplementation. These results suggest that the
consumption of fruits or fruit juices may reduce damage from
oxidative stress, and that this effect may be a consequence of the
antioxidant activity of fruits in scavenging the reactive oxygen
species generated in human plasma. However, long-term studies with
more subjects are needed to provide additional supportive evidence
and better characterize the antioxidant properties of natural fruit
juices.

J Pharm Pharmacol. 2002 Nov;54(11):1515-20.
Antihypertensive, vasodilator and antioxidant effects of a vinifera
grape skin extract.
  Cumulative evidence suggests that moderate wine consumption exerts
a cardioprotective effect. We investigated the occurrence of an
antihypertensive effect of an alcohol-free hydroalcoholic grape
skin extract (GSE) obtained from skins of a vinifera grape (Vitis
labrusca) in experimental rodent hypertension models. The
vasodilator effect of GSE (polyphenols concentration 55.5 mg g(-1))
was also assessed in the isolated mesenteric vascular bed of Wistar
rats and the antioxidant effect was studied on lipid peroxidation of
hepatic microsomes. Oral administration of GSE significantly reduced
systolic, mean and diastolic arterial pressure in Wistar rats with
desoxycorticosterone acetate-salt and N(G)-nitro-L-arginine methyl
ester (L-NAME) induced experimental hypertension. In the rat
isolated mesenteric vascular bed pre-contracted with norepinephrine,
bolus injections of GSE induced endothelium-dependent vasodilatation
 that was substantially inhibited by L-NAME, but not by indometacin,
tetraethylammonium or glibenclamide. Lipid peroxidation of hepatic
microsomes estimated as malondialdehyde production was
concentration-dependently inhibited by GSE. In conclusion, the
antihypertensive effect of GSE might be owing to a combination of
vasodilator and antioxidant actions of GSE. These findings also
suggest that the beneficial effect of moderate red wine consumption
could be owing to an antihypertensive action induced by compounds
occurring in the skin of vinifera grapes.

Cancer Lett. 2005 May 5; [Epub ahead of print]
Purple grape juice inhibits 7,12-dimethylbenz[a]anthracene
(DMBA)-induced rat mammary tumorigenesis and in vivo DMBA-DNA
adduct formation.
There has been considerable interest in identifying specific foods
and phytochemicals that may have breast cancer preventive
properties. Concord grapes are rich in polyphenolic chemicals and
anthocyanin pigments that may have biological properties which
could suppress cancer such as having antioxidant, antiproliferative,
and proapoptotic actions. To determine the potential breast cancer
protective action of purple grape juice, we examined the effect of
grape juice consumption on the initiation stage of
7,12-dimethylbenz[a]anthracene (DMBA)-induced rat mammary
tumorigenesis and on the in vivo formation of rat mammary DNA
adducts in female Sprague-Dawley rats. Consumption of grape juice
significantly inhibited mammary tumor mass at termination and the
growth of tumors for the first 5 weeks of detectable tumor
development. Consumption of grape juice phenolics by rats also
significantly inhibited in vivo mammary DMBA-DNA adduct formation
by 34 and 56% for animals fed phenolics at 346 and 692mg/dL,
respectively, compared to controls. Mammary 8-oxo-deoxyguanosine
(8-oxo-dG) levels decreased by 25 and 37%, respectively, but the
differences were not statistically significant. Liver DMBA-DNA
adducts decreased by 10-30%, while 8-oxo-dG adducts remained
unchanged, following grape juice intake. Liver glutathione
S-transferase activity was significantly increased following grape
juice consumption, but only at the highest level of intake. In
addition, liver activities of catalase increased and xanthine oxidase
decreased significantly, but only at the highest grape juice dose.
Thus, these studies indicate that specific constituents or
combinations of phytochemicals in purple grape juice can block the
initiation stage of DMBA-induced rat mammary tumorigenesis. This
tumor inhibitory effect was associated with a suppression of mammary
DMBA-DNA adduct formation, which in part may be explained by
increased liver activity of the phase II metabolizing enzyme,
glutathione S-transferase. Mammary and liver 8-oxo-dG levels were
not significantly altered by grape juice consumption. Thus, grape
juice constituents appear to have benefit in decreasing
susceptibility of the rat mammary gland to the tumor-initiating
action of DMBA.

Ann N Y Acad Sci. 2002 May;957:302-7.
Reduction of myocardial ischemia reperfusion injury with regular
consumption of grapes.
Recently several polyphenolic antioxidants derived from grape
seeds and skins have been implicated in cardioprotection. This
study was undertaken to determine if the grapes were equally
cardioprotective. Sprague Dawley male rats were given (orally)
standardized grape extract (SGE) for a period of three weeks.
Time-matched control experiments were performed by feeding the
animals 45 microg/100 of glucose plus 45 microg/100 g fructose
per day for three weeks. After 30 days, rats were sacrificed,
hearts excised and perfused via working-mode. Hearts were made
ischemic for 30 min followed by two hours of reperfusion. At
100 mg/kg and at 200 mg/kg, SGE provided significant
cardioprotection as evidenced by improved post-ischemic
ventricular recovery and reduced amount of myocardial infarction.
No cardioprotection was apparent when rats were given grape
samples at a dose of 50 mg/100 g/day. In vitro studies
demonstrated that the SGE could directly scavenge superoxide
and hydroxyl radicals which are formed in the ischemic
reperfused myocardium. The results demonstrate that the heats
of the rats fed SGE reduced myocardial ischemia reperfusion
injury by functioning as in vivo antioxidant.

J Nutr. 2000 Jan;130(1):53-6.
Grape juice, but not orange juice or grapefruit juice, inhibits
human platelet aggregation.
Coronary artery disease is responsible for much mortality and
morbidity around the world. Platelets are involved in
atherosclerotic disease development and the reduction of
platelet activity by medications reduces the incidence and
severity of disease. Red wine and grapes contain polyphenolic
compounds, including flavonoids, which can reduce platelet
aggregation and have been associated with lower rates of
cardiovascular disease. Citrus fruits contain different classes
of polyphenolics that may not share the same properties. This
study evaluated whether commercial grape, orange and grapefruit
juices, taken daily, reduce ex vivo platelet activity. In a
randomized cross-over design, ten healthy human subjects
(ages 26-58 y, five of each gender) drank 5-7.5 mL/(kg. d) of
purple grape juice, orange juice or grapefruit juice for 7-10
d each. Platelet aggregation (whole blood impedance aggregometry,
Chronolog Model #590) at baseline was compared to results after
consumption of each juice. Drinking purple grape juice for one
week reduced the whole blood platelet aggregation response to
1 mg/L of collagen by 77% (from 17.9 +/- 2.3 to 4.0 +/- 6.8 ohms,
P = 0.0002). Orange juice and grapefruit juice had no effect on
platelet aggregation. The purple grape juice had approximately
three times the total polyphenolic concentration of the citrus
juices and was a potent platelet inhibitor in healthy subjects
while the citrus juices showed no effect. The platelet
inhibitory effect of the flavonoids in grape juice may decrease
the risk of coronary thrombosis and myocardial infarction.

J Agric Food Chem. 2004 Aug 11;52(16):5297-302
Phenolics from commercialized grape extracts prevent early
atherosclerotic lesions in hamsters by mechanisms other than
antioxidant effect.
The aim of this study was to evaluate the antiatherosclerotic
effect of commercially available phenolic-rich extracts from
grape seeds (ExGrape seeds, EGS; grape seed extract, GSE) and
marc (ExGrape total, EGT) in cholesterol-fed hamsters and to
investigate possible operating mechanisms. These extracts fed
at a moderate dose mimicking two glasses of red wine per meal
reduced plasma cholesterol (-11% on average) but did not affect
plasma antioxidant capacity of hamsters. The extracts prevented
the development of aortic atherosclerosis by 68% (EGS), 63% (EGT),
and 34% (GSE). Elsewhere, in an ex vivo experiment using rat
aortic rings, EGS (7 microg/mL) induced 77% endothelium-dependent
relaxation, whereas EGT and GSE (30 microg/mL) induced 84 and 72%,
respectively. These results suggests that phenolic extracts from
grape seeds and marc are beneficial in inhibiting atherosclerosis
by indirect mechanism(s).

Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=26205