Tea waste rich with extractable antioxidants
02/12/2005-
Tea waste is almost as rich in potent antioxidants, such as catechins, as the
new and expensive green tea leaves used by the supplements industry, according
to Iranian research to be published later this month in peer-reviewed journal
Food Chemistry.
The study, carried out by the Ferdowsi University of Mashhad, investigated three
extraction methods on different parts of the tea plant, and tea waste, and found
surprisingly high levels of antioxidants across all of the extracts.
Tea leaves that have already matured on the plant and the waste
that is left after fermenting black tea, “are often considered as
agricultural wastes”, said Dr Reza Farhoosh, the author of the study. But
they “could be used as potent natural antioxidative sources”. European
demand for tea extracts is currently surging, having reached 500 metric tonnes
by 2003. With tea prices at around $1.5 per kg, the possibility of cheaper raw
materials could shift the industry’s cost base. Green tea and green tea extracts
are currently produced from only the first two to four leaves of the tea plant
(Camellia sinensis). The other leaves are known as old tea leaves (OTL).
Fermenting the green tea leaves produces black tea, and obviously produces black
tea waste (BTW). The Iranian study reported high extraction yields of
polyphenols from OTL and BTW, including epigallocatechin gallate (EGCG), one of
the most widely researched polyphenols in green tea. Three different extraction
media were studied, using hot water, methanol or ethyl acetate. For both green
tea and black tea waste, the most efficient of the three methods was hot water
extraction, which delivered yields of 35 per cent for fresh green tea leaves and
a close-running 30 per cent for BTW. Extracts from green tea are now well
established as sources of polyphenols – containing a rich source of free radical
scavenging catechins. Recent data suggests these compounds play a beneficial
role in weight loss, cardiovascular and oral health, with some now emerging as
particularly powerful.
23/11/2005-
New research adds to mounting evidence that silicon delivered as
choline-stabilised orthosilicic acid (ch-OSAT) may boost the ability of calcium
and vitamin D to build bone mineral density (BMD) in osteoporosis and osteopenia
sufferers.
The latest study, led by Professor Tim Spector of St Thomas Hospital in London,
UK, builds on an earlier investigation indicating that the benefits of ch-OSA in
helping build and maintain bone lie in its regulation of bone mineralization,
which help trigger the deposition of calcium and phosphate, reducing the number
of bone-destroying cells (called osteoclasts) and increasing the number of
bone-building cells (osteoblasts). Spector and his team divided a group of
114 women, all of whom suffered from osteoporosis or osteopenia (bones that are
less dense than normal, giving the individual a higher risk of developing
osteoporosis), into four groups. Over a 12-month period the placebo group
received the standard recommended dose of calcium and vitamin D3 for osteopenia
and mild osteoporosis each day – that is, 1000mg and 800IU respectively.
The other three groups received the same calcium and vitamin D3 doses, but in
addition from Jarrow Formulas). The researchers measured the benefit of
the ch-OSA through markers of bone formation, such as Procollagen Type I
N-terminal Propeptide (PINP), Bone Specific Alkaline Phosphatase (BAP) and
Osteocalcin. Their findings were presented at the weekend at the conference of
the American Society of Bone and Mineral Research in Nashville, Tennessee.
Overall, they noted that the ch-OSA seemed to confer some additional benefit to
Ca/Vit D3 supplementation. The effect was particularly pronounced in the PINP,
the most sensitive bone formation marker. In the groups receiving six and 12mg
of silicon, the improvements were “significant”. Interestingly, there
appeared to be no significant effect on spinal BMD, but significant changes in
femoral BMD were noted in a subgroup of women with a low femur T-score at the
start of the study. This finding was consistent with earlier animal studies.
"This study suggests that combined therapy of ch-OSA plus Ca/Vit
D3 is a safe, well tolerated treatment that has a potentially beneficial effect
on bone turnover, especially bone collagen, and possibly femoral BMD, compared
to Ca/Vit D3 alone,"
concluded the researchers. The study was supported by a grant from the UK’s
National Osteoporosis Society. A spokeswoman for the charity said:
“We are especially interested in this work as it demonstrates
potential benefits to people with osteoporosis.
Korean research touts fermented cabbage as a possible cure
By
KAREN HERZOG
Posted: Nov. 3, 2005
While President Bush scrambles to ward off an avian flu pandemic, the world's
largest sauerkraut producer, tucked amid the glacial lakebeds of rural
Wisconsin, is sitting atop a bumper crop of one possible preventative. That's
right: Sauerkraut. An international buzz is surrounding the unassuming,
fermented cruciferous vegetable that costs 89 cents per 14.5-ounce can.
Scientists at Seoul National University in South Korea fed an extract of kimchi,
a spicy Korean variant of sauerkraut, to 13 chickens infected with avian flu,
and a week later, 11 of the birds started to recover, according to a report by
the BBC Network. In case everyone is going out to buy sauerkraut, I want to
point out that most commercial sauerkraut is HEATED to pasteurize the product
and presumably make it salfe. But this sterilization process kills all the
beneficial bacteria. The kimchee used in the promising study was not heated.
Real kimchee is not cooked or heated. It is made with raw cabbage and then
fermented. Also, real kimchee has lots of cayenne and garlic in it. So yes,
sauerkraut is a miracle food in a lot of ways. But if you buy it, make sure it's
raw and not pasteurized. The only place you can buy sauerkraut like this is in a
health food store. And even there, you have to read the labels to make sure it's
raw.
10/11/2005-
Taking high doses of B vitamins may help reduce the risk of a second stroke
and heart attacks, according to a new analysis.
The B vitamin group, including folic acid, B6, and B12, reduce the amount of the
amino acid homocysteine in the blood. High levels of this substance have been
linked to heart disease. But a previous study by the Vitamin Intervention for
Stroke Prevention (VISP) group based in Canada and the US suggested that taking
a combination of B9, B6 and B12 did not reduce recurrent stroke and cardiac
events. However work carried out since then suggested to the team that their
initial trial included patients who were not likely to benefit from the
treatment. In a new analysis they excluded patients with low and very high
B12 levels at baseline. These were likely to have B12 malabsorption or to be
taking B12 supplements outside the study. Patients with significant renal
impairment were also excluded as they were unlikely to respond to vitamin
therapy. In the remaining 2155 patients, high-dose vitamin supplements reduced
recurrent stroke, death and heart disease by 21 per cent compared with those
taking low-dose vitamins, they report in the 1 November issue of Stroke
Stroke (vol 36, p2404). When they subdivided patients by baseline levels of
vitamin B12, thus identifying those with difficulties absorbing the vitamin, the
differences between the low-dose and high-dose groups became greater. The
authors suggest that given the fortification of flour with folate, the response
to vitamin therapy for lowering homocysteine largely depends on B12 levels of
heart patients. Higher doses of B12 could be required to reduce homocysteine,
and thus to reduce stroke and heart attack.
23/09/2005-
Researchers in Spain have developed an aloe vera gel that can be used as an
edible coating to prolong the quality and safety of fresh produce.
The gel, which scientists claim does not appear to affect food taste or
appearance, could soon provide a safe, natural and
environmentally-friendly alternative to conventional synthetic preservatives
that are currently applied to produce after harvesting.
20/10/2005- Antioxidants in red wine appear to have positive effects on the arteries of people with heart disease, according to a Greek study.
A team from Harokopio
University in Athens found that both red wine, and wine that had the alcohol
removed, reduced artery stiffness in 15 subjects with coronary artery disease.
This condition - defined stiff arteries - raises blood pressure and puts
patients at risk for heart attack.
Because the effects were observed with non-alcoholic wine, the researchers
attributed these effects to antioxidants in the red wine.
The
double-blind, cross-over study, reported in the September issue of the
American Journal of Hypertension (vol 18, issue 9, pp1161-7), also showed
that after consuming either 250ml of regular or dealcoholized red wine, patients
saw a significant decrease in central systolic blood pressure, the top reading
of the blood pressure. Central systolic blood pressure fell 7.4 mm Hg and 5.4 mm
Hg after consumption of red wine and non-alcoholic red wine, respectively. The
mechanisms for the reduction of arterial stiffness are not well understood
10/11/2005-
Plant chemicals in olive oil, rather than the fatty acids, may be responsible
for the good heart health widely observed in Mediterranean populations, say
Spanish researchers.
In a study on blood vessel function in human volunteers, they found that a
polyphenol-rich olive oil caused a significant improvement but there was little
effect after subjects consumed an oil that had many of the phenols removed.
Healthy blood vessels ensure proper blood flow around the body whereas unhealthy
vessels can eventually lead to blockages with implications for the heart.
The
work by a team from the Reina Sofia University Hospital in Córdoba is one of a
growing number of investigations going on around the world to better understand
why olive oil protects the heart. Several epidemiological studies have linked
high consumption of olive oil, a key ingredient in the traditional Mediterranean
diet, to lower incidence of heart disease in many south European countries. But
only in recent years have researchers begun to investigate how the plant oil
exerts these beneficial effects. Identifying a mechanism for a food’s health
effect is key to confirming its healthy properties and gaining scientific
credibility for its consumption as a health food. The work on olive oil is
complex however as it contains hundreds of potentially active compounds, many of
which are not well-known. Moreover with numerous varieties of oil available,
studies cannot be easily compared. Yet there have been some recent
breakthroughs. In September, US scientists identified a previously unknown
chemical, which they called oleocanthal, that has a strong anti-inflammatory
action.
They compared its action on COX enzymes to that of drugs like the common painkiller ibuprofen.
The new research, to be published in the 15 November issue of the Journal of the American College of Cardiology (vol 46, pp 1864-1868), is also important as it is the first to show a direct benefit of an olive oil with high content in phenolic compounds on endothelial function in humans, according to the authors. Phenols are a large group of compounds that include flavonoids such as anthocyanins and quercetin, phenolic acids like ellagic acid, fibres such as lignans and vitamins. Many of these have antioxidant, anti-inflammatory and anti-clotting properties, all of which are known to benefit cardiovascular health. The Spanish scientists looked particularly at the response of the endothelium, or inner lining, of small blood vessels in the fingers of subjects to sudden changes in blood flow, which were produced by inflating and then deflating a blood pressure cuff. Poor responsiveness to this sort of blood flow test is considered an early warning sign of cardiovascular disease. Previous studies have linked high-fat meals to poor endothelial function lasting for several hours after eating. So the team designed a study on a relatively high-fat meal - 60g of white bread with 40ml of olive oil. The subjects, 21 adults with high cholesterol levels, were randomized to receive either an olive oil high in phenolic compounds (400 parts per million) or the same brand of oil that had been processed to remove most of the phenolic compounds (80 parts per million remaining). Then they crossed over and repeated the study to consume the other oil. Consumption of the polyphenol-rich breakfast was associated with an improvement in endothelial function, as well as a greater increase in concentrations of nitric oxide, report the researchers. "Virgin olive oil is more than fat because it is a real juice with other healthy micronutrients," said author author Dr Francisco Pérez Jiménez. "We think, looking at our results, that the reduction in oxidative stress and the increase in the nitric oxide bioavailability are behind the observed improvement in ischaemic reactive hyperemia," he said. But he cautioned that further studies in "appropriate populations, or with a large sample size, are required to definitively establish the in vivo antioxidant properties of these components in relation to cardiovascular disease outcomes."
Moreover, the scientist noted that not all olive oils have a high phenolic content. But the results add up to the evidence to support increasing consumption of olive oil as way of preventing progression of atherosclerosis.