クランベリーの効能 尿路感染予防

 現地の果実が冬を通して保存でき、腐りかけの肉の風味を強化したので、ヨーロッパからの移住者は最初にクランベリーを感謝祭のテーブルに置いた。移住者は、ペミカン、クランベリーケーキ、ナッツ、それに乾燥したシカ肉や熊肉で、寒い冬を生き抜いてきたアメリカ先住民からベリーの台所での有用性を学んだ。
 両者ともまたクランベリーを熱、胃腸障害、腫れものの治療に使った。最近数十年で、科学者は、尿路感染や胃腸感染に対する作用、歯肉・心臓・ガンに対するクランベリーの効能を確認し、説明しはじめた。
 100年にわたり、女性たちはクランベリージュースが尿路感染を防止できると知っていて、酸味によると思われていたがそうではなかった。クランベリーの抗菌性の特性はproanthocyanidinsと呼ばれた一連の化合物による。10年前に、ハウエルの研究グループは化合物を分離し、どのように彼らが働くかを実演した。Proanthocyanidinsは大腸菌などの有害な細菌のまわりで「テフロン風の」コーティングを成形して結合する。伝染を妨げ、コーティングは、細菌が胃腸や尿道の壁に固着することを防止する。
 2001年のBMJに載った研究では、毎日クランベリージュースを飲む女性の尿路感染リスクは20%低かった。先月、Urology掲載の研究は、1日にグラス2杯のクランベリージュースが妊娠した女性の41%尿路感染の頻度を減らすとわかった。
 今年Nutritionに発表された研究で、毎日の1杯のクランベリージュースが子供のH. pylori感染を16%除去したことを示した。
 クランベリーにはビタミンA、E、C、鉄、カルシウム、カリウム、および抗酸化物が多く含まれる。
 コーネル大学のJie Sunによれば、クランベリーは試験管の中で肝臓と乳ガンの細胞成長を妨げるという。
 2006年にBritish Journal of Nutrition 掲載の研究で、1日1杯のクランベリージュースを飲むことで、肥満の人の善玉HDLコレステロールの値を8%増加させたことを示した。
 クランベリージュースが腎臓結石のリスクを増大させるという報告がいくつかある。
 ワーファリンの効果を薄めてしまうという報告もある。
 クランベリーは、収穫しやすいが、味は「ややほろ苦く」、クランベリー・ソースにするには相当の砂糖を必要とする。
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Cranberries -- good for what ails
Healthy fruit
http://www.latimes.com/features/health/la-he-nutrition24-2008nov24,0,2687173.story
Indians and settlers may have been on to something about the tart fruit's healing abilities.
By Elena Conis
November 24, 2008

画像Kathy Willens / Associated Press
A study published in the British Medical Journal in 2001 showed that women who drank a couple of ounces of cranberry juice daily for six months had a 20% lower risk of urinary tract infections.

European settlers first put cranberries on the Thanksgiving table because the local fruit lasted through winter and enhanced the flavor of gamy meat. The settlers had picked up on the berry's culinary potential from Native Americans, who survived cold winters by filling up on pemmican, a cake of cranberries, nuts and dried venison or bear meat.

Both groups also prescribed cranberries for fevers, gastrointestinal problems and dropsy -- a term used to describe any swelling or inflammation. Turns out, they were onto something. In the last few decades, scientists have begun to confirm and explain the cranberry's ability to fight infections of the urinary tract and gut and its potential to fight gum disease, heart disease and cancer.

"For over a hundred years, women have known that cranberry juice can prevent urinary tract infections," says Amy Howell, associate research scientist at the U.S. Department of Agriculture-supported Marucci Center for Blueberry and Cranberry Research at Rutgers University in Camden, N.J. "They thought it was due to acidity, but that's actually not the case."

Cranberry's antibacterial properties are due to a class of chemical compounds called proanthocyanidins. Ten years ago, Howell's research group isolated the compounds and demonstrated how they work: Proanthocyanidins bind to harmful bacteria such as E. coli, forming a "Teflon-like" coating around them. The coating prevents the bacteria from sticking to gastrointestinal and urinary tract walls, impeding infections.

The nonstick properties of proanthocyanidins may explain the results of several clinical trials that showed that cranberry juice can reduce the frequency of urinary tract infections.

For example, a study published in the British Medical Journal in 2001 showed that women who drank a couple of ounces of cranberry juice daily for six months had a 20% lower risk of urinary tract infections, compared with women in a control group. A study published in the Canadian Journal of Urology in 2002 showed that just 20% of women who drank three glasses of cranberry juice daily for a year experienced urinary tract infection symptoms, compared with 32% of women who drank a placebo.

And last month, a study in the journal Urology found that two glasses of cranberry juice a day reduced the frequency of urinary tract infections by 41% among pregnant women.

Proanthocyanidins also appear to keep the bacterium H. pylori, which causes ulcers, from sticking to the linings of the stomach and intestines. A 2005 study of 189 adults with H. pylori infections in the journal Helicobacter, showed that two glasses of cranberry juice daily for three months reduced the degree of infections, compared with those who drank a placebo.

And a study in the journal Nutrition this year showed that a daily glass of cranberry juice eliminated H. pylori infections in 16% of infected children; a placebo eliminated only 1.5%.

Other research suggests that the compounds could keep plaque-forming bacteria at bay. In lab experiments, cranberry proanthocyanidins stopped oral streptococci and other bacteria from sticking to surfaces. But researchers warn against using the juice as a mouthwash because of its sugar content and acidity.

Cranberries are high in vitamins A, E and C, iron, calcium, potassium and antioxidants. The last may explain the fruit's possible anti-cancer and anti-heart-disease effects. Cranberry impedes the growth of liver and breast cancer cells in lab dishes, says Jie Sun, a scientist at General Mills who previously researched the fruit's anti-cancer effects at Cornell University.

And in 2006, Canadian researchers published suggestive findings in the British Journal of Nutrition showing that drinking a glass of cranberry juice a day increased concentrations of good HDL cholesterol by 8% in overweight men. (The study was funded by the Canadian Cranberry Growers Coalition.)

But the tart red berries may not be for everyone. Gorging on too many or guzzling too much juice can result in an upset stomach or diarrhea. A couple of reports indicate that cranberry juice may increase the risk of kidney stones in people prone to them. And there's conflicting evidence that cranberries may interfere with blood thinning drugs, such as warfarin.

The common cranberry's benefits still seem to outweigh its drawbacks, but despite this, most Americans limit their consumption to a single day of the year. The reason for this may have been best summed up by writer and naturalist Henry David Thoreau more than 150 years ago: Cranberries, he wrote, were easy to harvest, but their taste was "a little bitterish."

Given the amount of sugar in most cranberry sauce recipes, most Americans, it seems, would agree.

Conis is a freelance writer.

health@latimes.com

-------------------------------------------------
Cranberries May Help Prevent Urinary Tract Infections
Their high acid content inhibits bacterial growth, experts say
-- Robert Preidt
http://health.msn.com/health-topics/alternative-medicine/articlepage.aspx?cp-documentid=100227310

Their high acid content inhibits bacterial growth, experts say.

THURSDAY, Nov. 27 (HealthDay News) -- Make sure to put plenty of cranberry sauce on your plate this Thanksgiving, because it may help protect you against urinary tract infections (UTIs), according to the American Urological Association.

The high acid content in cranberries, which have long been used as a home remedy for simple UTIs, help inhibit bacterial growth along the urinary tract, the AUA said.

UTIs occur when bacteria enter the urinary tract and multiply in the urethra, causing the lining of the urethra to become red and irritated. Left unchecked, bacteria from an infection in the urethra can move deeper into the urinary tract to the bladder and kidneys. Kidney infections are dangerous and can lead to life-threatening conditions such as bacteremia (bacteria in the bloodstream) if not treated.

Each year in the United States, UTIs account for more than eight million doctor visits. UTI symptoms include painful urination, cloudy urine, a stronger urine odor than normal, or blood in the urine (hematuria). People with these symptoms should see their doctor.

The AUA also said that hematuria may also be caused by a more serious problem in the urinary tract, and anyone who notices blood in their urine should seek prompt medical attention.

While cranberries are beneficial, they may not help everyone. Other ways to prevent UTIs include proper hydration and judicious use of antibiotics prescribed by a doctor. Don't delay or refrain from urinating, and don't rush when you're urinating. That's because your risk of UTIs can be higher if you retain urine and don't completely empty your bladder, the AUA said.

More information

The U.S. National Institute of Diabetes and Digestive and Kidney Diseases has more about urinary tract infections.
SOURCE: American Urological Association, news release, Nov. 24, 2008

Copyright © 2008 ScoutNews, LLC. All rights reserved.

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