Sugary Soft Drinks Linked To Increased Risk Of Gout In Men

Daily Science Journal (Feb. 1, 2008) — Consumption of sugar sweetened soft drinks and fructose is strongly associated with an increased risk of gout in men, finds a study published by the British Medical Journal.

Gout is a joint disease which causes extreme pain and swelling. It is most common in men aged 40 and older. It is caused by excess uric acid in the blood (hyperuricaemia) which leads to uric acid crystals collecting around the joints.

In the United States, levels of gout have doubled over the last few decades, which coincided with a substantial increase in the consumption of soft drinks and fructose (a simple sugar and the only carbohydrate known to increase uric acid levels).

Conventional dietary recommendations for gout have focused on the restriction of purines (found in high levels in meat and meat products, especially liver and kidney) and alcohol but with no restriction of sugar sweetened soft drinks.

So researchers in the US and Canada examined the relation between intake of sugar sweetened soft drinks and fructose and the risk of gout.

They followed over 46,000 men aged 40 years and over with no history of gout. The men completed regular questionnaires on their intake of more than 130 foods and beverages, including sugar sweetened soft drinks and diet soft drinks, over a period of 12 years. Different types of fruits and fruit juices (high in natural fructose) were also assessed.

At the start of the study, and every two years thereafter, information on weight, regular use of medications and medical conditions were also recorded. Gout was diagnosed according to American College of Rheumatology criteria.

During 12 years of follow-up, the researchers documented 755 newly diagnosed cases of gout.

The risk of gout increased with increasing intake of sugar sweetened soft drinks. The risk was significantly increased with an intake level of 5-6 servings per week and the risk was 85% higher among men who consumed two or more servings of sugar-sweetened soft drinks per day compared to those who consumed less than one serving per month.

These associations were independent of other risk factors for gout such as body mass index, age, diuretic use, high blood pressure, alcohol intake, and dietary factors.

Diet soft drinks were not associated with the risk of gout.

Fruit juice and fructose rich fruits (apples and oranges) were associated with a higher risk of gout. However, the authors stress that this finding needs to be balanced against the benefit of fruit and vegetable intake to prevent other chronic disorders like high blood pressure, coronary heart disease, stroke and certain types of cancer.

In conclusion, our findings provide prospective evidence that consumption of sugar sweetened soft drinks and fructose is strongly associated with an increased risk of gout, say the authors. Furthermore, fructose rich fruits and fruit juices may also increase the risk. In contrast, diet soft drinks were not associated with the risk of gout.

Adapted from materials provided by BMJ-British Medical Journal, via EurekAlert!, a service of AAAS.

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Green Tea May Protect Bladder From Becoming Inflamed

Daily Science Journal (Jan 21, 2007) — Herbal agents could be used to treat inflammatory bladder diseases, according to a preliminary study that looked at the ability of green tea to protect bladder cells from inflammation. The University of Pittsburgh School of Medicine study, being presented at the annual meeting of the American Urological Association (AUA) in Anaheim, Calif., found that components of green tea protected bladder cells from damage in culture.

Green tea, reported to have many health benefits, is rich in powerful antioxidants that make it a possible remedy for many medical conditions. It is comprised of catechins -- plant metabolites that provide it with many anti-oxidative properties.

"We discovered that catechins found in green tea protected both normal and cancerous bladder cells from inflammation when we exposed the cells to hydrogen peroxide," said Michael B. Chancellor, M.D., professor of urology and gynecology at the University of Pittsburgh School of Medicine. "Although further studies are needed, these results indicate herbal supplements from green tea could be a treatment option for various bladder conditions that are caused by injury or inflammation."

In the study, normal and cancerous bladder cells were exposed to two major catechin components of green tea, epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), for 23 hours. Both significantly protected cell lines from exposure to hydrogen peroxide, which damages or kills cells. The concentrations of EGCG and ECG used in the study were at levels that may be achieved through dietary intake.

Approximately ten million American adults have problems controlling their bladders. Bladder disease affects both men and women and can include incontinence or interstitial cystitis, a chronic inflammatory condition that causes frequent, urgent and painful urination and pelvic discomfort.

Co-investigators of the study include Shelby Morrisroe, M.D., Christian Coyle, Ph.D., Brian Phillips, Ph.D., William de Groat, Ph.D., and Naoki Yoshimura, M.D., Ph.D., all with the University of Pittsburgh School of Medicine. The study is Abstract 299 in the AUA proceedings.

The study is funded by the Fishbein Family CURE-IC Program.

Adapted from materials provided by University of Pittsburgh Schools of the Health Sciences, via EurekAlert!, a service of AAAS.

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Green Tea And EGCG May Help Prevent Autoimmune Diseases, Cup Of Green Tea To Keep The Bacteria Away

Daily Science Journal (Jan. 16, 2008) — Green tea may help protect against autoimmune disease, Medical College of Georgia researchers say.

Dr Stephen Hsu and colleagues found that green tea may help protect against autoimmune disease. (Credit: Image courtesy of Medical College of Georgia)

Researchers studied an animal model for type I diabetes and primary Sjogren’s Syndrome, which damages the glands that produce tears and saliva.

They found significantly less salivary gland damage in a group treated with green tea extract, suggesting a reduction of the Sjogren’s symptom commonly referred to as dry mouth. Dry mouth can also be caused by certain drugs, radiation and other diseases.

Approximately 30 percent of elderly Americans suffer from degrees of dry mouth, says Dr. Stephen Hsu, a researcher in the MCG School of Dentistry and lead investigator on the study. Only 5 percent of the elderly in China, where green tea is widely consumed, suffer from the problem.

“Since it is an autoimmune disease, Sjogren’s Syndrome causes the body to attack itself and produce extra antibodies that mistakenly target the salivary and lacrimal glands,” he says. There is no cure or prevention for Sjogren’s Syndrome.

Researchers studied the salivary glands of the water-consuming group and a green tea extract-consuming group to look for inflammation and the number of lymphocytes, a type of white blood cells that gather at sites of inflammation to fend off foreign cells.

The group treated with green tea had significantly fewer lymphocytes, Dr. Hsu says. Their blood also showed lower levels of autoantibodies, protein weapons produced when the immune system attacks itself, he says.

Researchers already know that one component of green tea – EGCG – helps suppress inflammation, according to Dr. Hsu. "So, we suspected that green tea would suppress the inflammatory response of this disease. Those treated with the green tea extract beginning at three weeks, showed significantly less damage to those glands over time.”

Researchers also suspect that the EGCG in green tea can turn on the body’s defense system against TNF-alpha – a group of proteins and molecules involved in systemic inflammation. TNF-alpha, which is produced by white blood cells, can reach out to target and kill cells.

“The salivary gland cells treated with EGCG had much fewer signs of cell death caused by TNF-alpha,” Dr. Hsu says. “We don’t yet know exactly how EGCG makes that happen. That will require further study. In some ways, this study gives us more questions than answers.”

These results, published in a recent issue of Autoimmunity, reinforced findings of a 2005 study showing a similar phenomenon in a Petrie dish, Dr. Hsu says. Further study could help determine green tea’s protective role in other autoimmune diseases, including lupus, psoriasis, scleroderma and rheumatoid arthritis, he says.

Adapted from materials provided by Medical College of Georgia.

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Cup Of Green Tea To Keep The Bacteria Away

Beneficial effects of green tea have been known for millenia, particularly in Asian cultures. An ancient Chinese proverb says: "Better to be deprived of food for three days, than tea for one". A cup of green tea contains up to 200 mg of catechins, whose biological activity has been mainly attributed to its antioxidant activity. Efficiency of green tea extract in oral hygiene has been known for centuries and this gave researchers a clue that antibacterial activity might be involved.

Now researchers from the National institute of Chemistry in Ljubljana, Slovenia discovered that the main ingredients of green tea are able to perform other tricks. They found out that green tea catechins inhibit essential bacterial enzyme DNA gyrase, which is the target of several existing clinically used drugs. By the use of NMR spectroscopy, researchers from Slovenia have now pinpointed the ATP-binding site of DNA gyrase as target of EGCG, the most abundant catechin from the green tea extract. Up to now several compounds targeted against the ATP-binding site of bacteria gyrase have been known but couldn't be used as drugs due to their side effects on mammalian cells.

Lead researcher Roman Jerala, the head of the Laboratory of Biotechnology at NIC explains: "We can anticipate to avoid the problem of toxicity using the compounds based on the green tea catechins, which have centuries of established safety record in the human diet."

This finding may be used to develop even more potent antibacterial compounds. Results were recently published in the Journal of Medicinal Chemistry.

Adapted from materials provided by National Institute Of Chemistry, Slovenia.

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Consumption Of Green Tea Associated With Reduced Mortality In Japanese Adults, Drinking Tea Associated With Lower Risk Of Ovarian Cancer

Daily Science Journal (Sep. 13, 2007) — Adults in Japan who consumed higher amounts of green tea had a lower risk of death due to all causes and due to cardiovascular disease, according to a study in the September 13 issue of JAMA. But there was no link between green tea consumption and a reduced risk of death due to cancer.

Tea is the most consumed beverage in the world aside from water. Three billion kilograms of tea are produced each year worldwide, according to background information in the article. Because of the high rates of tea consumption in the global population, even small effects in humans could have large implications for public health. Among teas, green tea polyphenols have been extensively studied as cardiovascular disease (CVD) and cancer chemopreventive agents. Although substantial evidence from in vitro and animal studies indicates that green tea preparations may impede CVD and carcinogenic processes, the possible protective role of green tea consumption against these diseases in humans remains unclear.

Shinichi Kuriyama, M.D., Ph.D., of the Tohoku University School of Public Policy, Sendai, Japan, and colleagues examined the association between green tea consumption and mortality (death rate) due to all causes, CVD, and cancer within a large population. The study, initiated in 1994, included 40,530 adults (age 40 to 79 years) in northeastern Japan, where green tea is widely consumed. Within this region, 80 percent of the population drinks green tea and more than half of them consume 3 or more cups and day. The participants, who had no history of stroke, coronary heart disease, or cancer at baseline, were followed for up to 11 years (1995-2005) for all-cause death and for up to 7 years (1995-2001) for cause-specific death.

Over 11 years of follow-up, 4,209 participants died, and over 7 years of follow-up, 892 participants died of cardiovascular disease and 1,134 participants died of cancer. The researchers found that green tea consumption was inversely associated with death due to all causes and due to cardiovascular disease. Compared with participants who consumed less than 1 cup/d of green tea, those who consumed 5 or more cups/d had a risk of all-cause mortality and CVD mortality that was 16 percent lower (during 11 years of follow-up) and 26 percent lower (during 7 years of follow-up), respectively.

These inverse associations of all-cause and CVD mortality were stronger among women, although the inverse association for green tea consumption was observed in both sexes. In women, compared with those who consumed less than 1 cup/d of green tea, those who consumed 5 or more cups/d had a 31 percent lower risk of CVD death.

The researchers found there no significant association between green tea consumption and death from cancer. There were weak or neutral relationships between black tea or oolong tea and mortality.

"Clinical trials are ultimately necessary to confirm the protective effect of green tea on mortality," the authors write.

This study was supported by a Health Sciences Research Grant for Health Services, Ministry of Health, Labour, and Welfare, Japan.

Adapted from materials provided by JAMA and Archives Journals, via EurekAlert!, a service of AAAS.

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Drinking Tea Associated With Lower Risk Of Ovarian Cancer

Women who drank at least two cups of tea a day had a lower risk of ovarian cancer than those who did not drink tea, according to a study in the December 12/26 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Evidence from laboratory studies indicates that green and black tea preparations may protect against various cancers. But few epidemiological studies have examined the relationship specifically between tea consumption and the risk of ovarian cancer, according to background information in the article.

Susanna C. Larsson, M.Sc., and Alicja Wolk, D.M.Sc., of the National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden, prospectively examined the association between tea consumption and the risk of ovarian cancer in 61,057 women, aged 40 to 76, who were participants in the population-based Swedish Mammography Cohort. Participants completed a validated 67-item food frequency questionnaire at enrollment between 1987 and 1990, and were followed for cancer incidence through December 2004. At baseline, 68 percent of the participants reported drinking tea (mainly black tea) at least once per month. During an average follow-up of 15.1 years, 301 women were diagnosed as having invasive epithelial ovarian cancer.

"We observed a 46 percent lower risk of ovarian cancer in women who drank two or more cups of tea per day compared with non-drinkers," the authors report. "Each additional cup of tea per day was associated with an 18 percent lower risk of ovarian cancer."

Women who drank less than one cup of tea per day had an 18 percent lower risk of ovarian cancer than non-drinkers. The risk was 24 percent lower for women who drank one cup of tea per day.

"This association does not depend on lower coffee consumption among women with high tea consumption; coffee is not associated with ovarian cancer risk in this cohort," the authors write.

"In summary, our results from a large population-based cohort of Swedish women suggest that tea consumption may lower the risk of ovarian cancer," the authors conclude. "Because prospective data on this relationship are scarce, our findings need confirmation by future studies."

(Arch Intern Med. 2005;165:2683-2686. Available pre-embargo to the media at www.jamamedia.org.)

Editor's Note: This work was supported by research grants from the Swedish Cancer Foundation and the Swedish Research Council/Longitudinal Studies, Stockholm, Sweden.


Adapted from materials provided by JAMA and Archives Journals, via EurekAlert!, a service of AAAS.

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New Skin-healing Chemicals, Green Tea And The 'Asian Paradox'

Daily Science Journal (Aug. 30, 2007) — Researchers have made synthetic lipids called pseudoceramides that are involved in skin cell growth and could be used in treating skin diseases in which skin cells grow abnormally.

Ceramides are lipids found in the outermost skin layer called the stratum corneum, which is made of dead skin cells and mainly serves as a physical barrier. Ceramides' main biological function is to control how skin cells grow and differentiate -- a process through which skin cells become specialized.

Scientists have created in the laboratory synthetic ceramides, called pseudoceramides, to treat skin diseases such as atopic dermatitis, a form of eczema characterized by red, flaky and very itchy skin; psoriasis, a disease that causes red scaly patches on the skin; and glucocorticoid-induced epidermal atrophy, in which the skin shrinks due to skin cell loss.

Jeung-Hoon Lee and colleagues have developed a new series of pseudoceramides and examined their effects on skin cells. They found that three pseudoceramides called K6PC-4, K6PC-5, and K6PC-9 significantly increased the amount of proteins produced when skin cells differentiate. These results were obtained both on cultured skin cells and on a reconstituted epidermis. K6PC-4, K6PC-5, and K6PC-9 may be used to treat skin diseases arising from abnormal growth of skin cells, the scientists concluded.

Article: "Novel synthetic ceramide derivatives increase intracellular calcium levels and promote epidermal keratinocyte differentiation," by Yoo Bin Kwon, Chang Deok Kim, Jong-Kyung Youm, Hyung Sub Gwak, Byeong Deog Park, Seung Hun Lee, Saewha Jeon, Bo Joong Kim, Young-Joon Seo, Jang-Kyu Park, and Jeung-Hoon Lee

Adapted from materials provided by American Society for Biochemistry and Molecular Biology, via EurekAlert!, a service of AAAS.

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Green Tea And The 'Asian Paradox'

There is a lower incidence of cardiovascular disease and cancer in Asia where people smoke heavily, which may be accounted for by high consumption of tea, particularly green tea, according to a review article published by a Yale School of Medicine researcher.

"We do not yet have a full explanation for the 'Asian paradox,' which refers to the very low incidence of both heart disease and cancer in Asia, even though consumption of cigarettes is greater than in most other countries," said Bauer Sumpio, M.D., professor and Chief of Vascular Surgery in the Department of Surgery. "But we now have some theories."

Sumpio, the lead author of the review in the Journal of the American College of Surgeons, said he and his colleagues reviewed more than 100 experimental and clinical studies about green tea in writing the article.

He said one theory is that the average 1.2 liters of green tea consumed daily by many people in Asia offers the anti-oxidant protective effects of the polyphenolic EGCG. EGCG may prevent LDL oxidation, which has been shown to play a key role in the pathophysiology of arteriosclerosis. EGCG also reduces the amount of platelet aggregation, regulates lipids, and promotes proliferation and migration of smooth muscle cells, which are all factors in reducing cardiovascular disease, he said.

Sumpio said other reports show that EGCG prevents growth of certain tumors. Tea, according to studies, also can improve gastrointestinal function, alcohol metabolism, kidney, liver and pancreatic function, protect skin and eyes and alleviate arthritis. Tea has been used in managing and preventing allergies, diabetes, bacterial and viral infections, cavities, reduce or cure diseases with an inflammatory component and improve neurologic and psychological health.

"More studies are necessary to fully elucidate and better understand green tea's method of action, particularly at the cellular level," Sumpio said. "The evidence is strong that green tea consumption is a useful dietary habit to lower the risk for, as well as treat, a number of chronic diseases. Certainly, however, smoking cessation is the best way to prevent cardiovascular disease and cancer."

Reference: Journal of the American College of Surgeons 202: 813-825 (May 2006)

Adapted from materials provided by Yale University.

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Green Tea Holds Promise As New Treatment For Inflammatory Skin Diseases, Tea Extracts Help Treat Damaged Skin In Cancer Patients

Daily Science Journal (Aug. 7, 2007) — Green tea could hold promise as a new treatment for skin disorders such as psoriasis and dandruff, Medical College of Georgia researchers say.

Dr Hsu says, "There are no cures for autoimmune diseases. But it is possible that this is a non-toxic way to regulate them. We need further study -- on humans -- to determine the full effects." (Credit: Medical College of Georgia)

Researchers studied an animal model for inflammatory skin diseases, which are often characterized by patches of dry, red, flaky skin caused by the inflammation and overproduction of skin cells. Those treated with green tea showed slower growth of skin cells and the presence of a gene that regulates the cells' life cycles.

"Psoriasis, an autoimmune disease, causes the skin to become thicker because the growth of skin cells is out of control," says Dr. Stephen Hsu, an oral biologist in the MCG School of Dentistry and lead investigator on the study published in the Aug. 18 edition of Experimental Dermatology. "In psoriasis, immune cells, which usually protect against infection, instead trigger the release of cytokines, which causes inflammation and the overproduction of skin cells."

Other autoimmune diseases with similar side effects include lupus, which can lead to skin lesions, and dandruff.

Green tea, already shown to suppress inflammation, helps by regulating the expression of Caspase-14, a protein in genes that regulates the life cycle of a skin cell.

"That marker guides cells by telling them when to differentiate, die off and form a skin barrier," Dr. Hsu says. "In people with psoriasis, that process is interrupted and the skin cells don't die before more are created and the resulting lesions form."

Animal models treated with green tea also showed reduced levels of proliferating cell nuclear antigen, a gene expressed when skin cells multiply. In psoriasis, the gene is over-expressed and speeds production of skin cells.

"Before treatment, the antigen, PCNA, was present in all layers of the skin," Dr. Hsu says. "Typically, PCNA is only found in the basal layer, the innermost layer where skin cells continually divide and new cells push the older ones to the skin surface, where they eventually slough off. After being treated with green tea, the animal models showed near-normal levels of PCNA in only the basal layers."

This research is important because some treatments for psoriasis and dandruff can have dangerous side effects, he says.

"The traditional treatment of ultraviolet light and medication, while it can control the lesions and be used long term, may cause squamous cell carcinoma – the second most common form of skin cancer," Dr. Hsu says. "Some of the most effective anti-dandruff shampoos also have carcinogens in them. While the U.S. Food and Drug Administration allows that in small amounts, the bottom line is that we don't know the long-term effects of using those products continuously."

Green tea, which is plant-derived, may be an alternative, he says. But scientists must work to overcome some barriers with the treatment.

The chemicals in green tea are so active that they are oxidized too quickly when mixed with other ingredients. They also dissolve in water, which cannot penetrate the skin's barrier.

Researchers are looking for a balanced formula that can dissolve in fats, which can permeate the skin, Dr. Hsu says.

Adapted from materials provided by Medical College of Georgia.

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Tea Extracts Help Treat Damaged Skin In Cancer Patients

Tea extracts work as an effective treatment for patients who suffer from damaged skin following radiation treatment for cancer. Researchers show that this might partly be due to the anti-inflammatory properties of tea.

In a study published in the open access journal BMC Medicine, researchers show that tea acts at the cellular level, by inhibiting inflammatory pathways, to reduce inflammation. They also show that tea extracts reduce the duration of radiation-induced skin damage by up to 10 days in patients who received radiation treatment.

Frank Pajonk, from the University of California in Los Angeles, USA, and colleagues from the University of Freiburg, Germany, studied the effects of green tea and black tea extracts on patients who had been treated with radiotherapy, which can damage the skin. The authors then analysed the effects of the same tea extracts on human and mouse white blood cells in culture.

Pajonk et al. find that tea extracts reduce the duration of skin toxicity following radiotherapy by 5 to 10 days. Green tea extracts are more effective than black tea extracts in some patients. Pajonk et al. also show that tea extracts reduce the release of pro-inflammatory cytokines, such as IL-1beta, IL-6, IL-8, TNFalpha and PGE2, in human white blood cells in culture, with green tea having higher anti-inflammatory properties than black tea. Both black tea and green tea inhibit one major inflammatory pathway in mouse white blood cells.

Pajonk et al. add that tea's high content of polyphenols is likely to be responsible for its high anti-inflammatory activity, but that other pathways are probably involved in its clinical effectiveness.

Adapted from materials provided by BioMed Central, via EurekAlert!, a service of AAAS.

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New Process Boosts Levels Of Heart-healthy Compounds In Cocoa Powder, (Add On- Cocoa, But Not Tea, May Lower Blood Pressure)

Daily Science Journal (Jun 10, 2007) — Scientists in Spain are reporting development of a new process to make cocoa powder with higher amounts of the healthful chemical compounds linked to chocolate's beneficial effects. The study is scheduled for publication in the May 30 issue of ACS' Journal of Agricultural and Food Chemistry.

Cocoa beans -- the source of chocolate -- in a cacao pod. (Credit: Photo by Keith Weller; courtesy of USDA/Agricultural Research Service)

Juan Carlos Espin de Gea and colleagues report that the new cocoa powder contains levels of some flavonoids 8 times higher than conventional cocoa. They achieved the higher flavonoid content by omitting the traditional fermentation and roasting steps used in the processing of cocoa beans. Those steps destroy some flavonoids, which are natural antioxidants.

Researchers used the flavonoid-enriched cocoa powder in a clinical trial to determine whether the compounds were bioavailable — in a form that humans can absorb. In the trial, six healthy volunteers consumed a milk drink made with flavonoid-enriched cocoa. The same volunteers later drank chocolate milk made from traditional cocoa. Blood and urine tests established the bioavailability of flavonoids in the enriched-milk drink, showing that people do absorb higher levels of the compounds.

Based on the results, researchers suggest further clinical trials on the health benefits of flavonoid-enriched cocoa powder.

Adapted from materials provided by American Chemical Society, via EurekAlert!, a service of AAAS.

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Cocoa, But Not Tea, May Lower Blood Pressure

Foods rich in cocoa appear to reduce blood pressure but drinking tea may not, according to an analysis of previously published research in the April 9 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Current guidelines advise individuals with hypertension (high blood pressure) to eat more fruits and vegetables, according to background information in the article. Compounds known as polyphenols or flavonoids in fruits and vegetables are thought to contribute to their beneficial effects on blood pressure and cardiovascular risk. "Tea and cocoa products account for the major proportion of total polyphenol intake in Western countries," the authors write. "However, cocoa and tea are currently not implemented in cardioprotective or anti-hypertensive dietary advice, although both have been associated with lower incidences of cardiovascular events."

Dirk Taubert, M.D., Ph.D., and colleagues at the University Hospital of Cologne, Germany, conducted a meta-analysis of 10 previously published trials, five of cocoa's effects on blood pressure and five involving tea. All results were published between 1966 and 2006, involved at least 10 adults and lasted a minimum of seven days. The studies were either randomized trials, in which some participants were randomly assigned to cocoa or tea groups and some to control groups, or used a crossover design, in which participants' blood pressure was assessed before and after consuming cocoa products or tea.

The five cocoa studies involved 173 participants, including 87 assigned to consume cocoa and 86 controls, 34 percent of whom had hypertension (high blood pressure). They were followed for a median (middle) duration of two weeks. Four of the five trials reported a reduction in both systolic (the top number, when the heart contracts) and diastolic (the bottom number, when the heart relaxes) blood pressure. Compared with those who were not consuming cocoa, systolic blood pressure was an average of 4.7 millimeters of mercury lower and diastolic blood pressure was an average of 2.8 millimeters of mercury lower.

The effects are comparable to those achieved with blood pressure-lowering medications, the authors note. "At the population level, a reduction of 4 to 5 millimeters of mercury in systolic blood pressure and 2 to 3 millimeters of mercury in diastolic blood pressure would be expected to substantially reduce the risk of stroke (by about 20 percent), coronary heart disease (by 10 percent) and all-cause mortality (by 8 percent)," they write.

Of the 343 individuals in the five tea studies, 171 drank tea and 172 served as controls, for a median duration of four weeks. Drinking tea was not associated with a reduction in blood pressure in any of the trials.

Tea and cocoa are both rich in polyphenols, but while black and green tea contain more compounds known as flavan-3-ols, cocoa contains more of another type of polyphenol, procyanids. "This suggests that the different plant phenols must be differentiated with respect to their blood pressure-lowering potential and thus cardiovascular disease prevention, supposing that the tea phenols are less active than cocoa phenols," the authors write.

The findings do not indicate a widespread recommendation for higher cocoa intake to decrease blood pressure, but it appears reasonable to substitute phenol-rich cocoa products such as dark chocolate for other high-calorie or high-fat desserts or dairy products, they continue. "We believe that any dietary advice must account for the high sugar, fat and calorie intake with most cocoa products," the authors conclude. "Rationally applied, cocoa products might be considered part of dietary approaches to lower hypertension risk."

Adapted from materials provided by JAMA and Archives Journals.

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