研究：每日五蔬果 健康好身體

British nutritionists threw down the gauntlet to dietary guidelines in April by declaring seven daily portions of fresh fruit and vegetables, rather than the recommended five, were the key to health.

But a new foray into the arena of sound eating says the famous five-a-day recommendation made by the UN's World Health Organisation (WHO) in 2003 should be fine.

Researchers in China and the United States trawled through 16 published investigations into diet and health involving more than 830,000 participants, who were followed for periods ranging from four and a half years to 26 years.

Every additional daily serving of fruit and vegetables reduced the average risk of premature death from all causes by five percent, the scientists found.

Over the period of the studies, 56,000 of the participants died, researchers said.

In the case of death from a heart attack or a stroke, each additional serving curbed risk by four percent.

But there was no evidence of an additional fall in risk beyond five portions, according to the review, published online Tuesday by the British Medical Journal (BMJ).

"We found a threshold of around five servings a day of fruit and vegetables, after which the risk of death did not reduce further," said the investigators, led by Frank Hu of the Harvard School of Public Health in Boston, Massachusetts.

High consumption of fruit and veg did not translate into a significant reduction in the risk of death from cancer, the study also found.

In addition to advising patients about the virtues of healthy eating, doctors should also push home the message about risks from obesity, inactivity, smoking and excessive drinking, said the paper.

In April, researchers at University College London found that eating seven daily portions or more could reduce the risk of cancer by 25 percent and of heart disease by 31 percent, compared to people who consumed less than one portion a day.

The study was based on the eating habits of more than 65,000 people in England between 2001 and 2008.

The London researchers admitted to being surprised by what they found and cautioned the results may not be applicable to other countries.

Britain has one of the highest rates of heart disease in Europe, a fact blamed in part on a diet high in fat and sugar.

The WHO guidelines are based on the equivalent of five 80-gram (three-ounce) portions. One portion is roughly equivalent to a medium-sized apple, a bowl of mixed salad or three dessert spoonfuls of raw, cooked, canned or frozen vegetables.

英國(guó)營(yíng)養(yǎng)學(xué)家在四月份向既定的食譜指南發(fā)起挑戰(zhàn)，宣稱保持身體健康的關(guān)鍵是每日七種蔬果搭配而不是以往推薦的五種蔬果。

但是一項(xiàng)新的關(guān)于健康飲食的調(diào)查顯示，聯(lián)合國(guó)世界衛(wèi)生組織((WHO))在2003年推薦的著名的每日五蔬果搭配是合理的。

中國(guó)和美國(guó)的研究者搜索了16種已經(jīng)出版的飲食和健康調(diào)查，涉及到超過(guò)83萬(wàn)的參與者，這些人參與并接受了從4年半到26年不等的跟蹤調(diào)查。

科學(xué)家們發(fā)現(xiàn)，每日每多攝入一份蔬菜和水果，由各種因素引起的早死亡率就會(huì)降低5%。

研究者稱，有5.6萬(wàn)參與者在這項(xiàng)研究進(jìn)行的過(guò)程中去世。

在那些死于心臟病和中風(fēng)的病例中，每天多吃一種蔬果，疾病的威脅就降低4%。

但是根據(jù)英國(guó)醫(yī)學(xué)雜志(BMJ)周二在網(wǎng)上發(fā)表的評(píng)論，仍然沒(méi)有證據(jù)能表明多增加一種可以比五種的搭配更能降低死亡率。

“我們發(fā)現(xiàn)一天五蔬果是一個(gè)臨界值，在此基礎(chǔ)上增加再多的份量對(duì)降低死亡風(fēng)險(xiǎn)也無(wú)濟(jì)于事。”位于馬薩諸塞，波士頓的哈佛大學(xué)公共衛(wèi)生學(xué)院的弗蘭克•胡(Frank Hu)所領(lǐng)導(dǎo)的研究團(tuán)隊(duì)稱。

研究也發(fā)現(xiàn)，多攝入蔬菜和水果并不代表就能顯著降低患癌死亡的風(fēng)險(xiǎn)。

這篇論文提到，除了建議病人健康飲食外，醫(yī)生也應(yīng)該盡量告誡他們?cè)诩彝ド钪袘?yīng)注意肥胖，缺少鍛煉，吸煙以及過(guò)度酗酒對(duì)身體帶來(lái)的風(fēng)險(xiǎn)。

在四月份，英國(guó)倫敦大學(xué)學(xué)院(University College London)的研究者們發(fā)現(xiàn)，一天攝入七種蔬果或以上份量的人同那些一天攝入量少于一種的人相比，患癌癥的風(fēng)險(xiǎn)降低25%，患心臟病的風(fēng)險(xiǎn)降低31%。

這項(xiàng)研究是依據(jù)2001年到2008年間英國(guó)6.5萬(wàn)多人的飲食習(xí)慣而得出的。

倫敦的研究者們承認(rèn)他們對(duì)自己的發(fā)現(xiàn)感到十分驚喜，同時(shí)謹(jǐn)慎地提醒這項(xiàng)結(jié)果可能并不適用于其它國(guó)家。

英國(guó)是歐洲心臟病發(fā)生率最高的國(guó)家，部分原因應(yīng)歸咎于含過(guò)多脂肪和糖分的飲食習(xí)慣。

世界衛(wèi)生組織以5份80克(3盎司)的攝入量為指南。每一份差不多相當(dāng)于一個(gè)中等大小的蘋果，一碗什錦沙拉或是三個(gè)甜點(diǎn)勺那么多生的、熟的、罐裝的或速凍的蔬菜。