Dementia Studies Find Diet, Exercise Matter

    Two studies published in this week's Journal of the American Medical Association add to evidence that long-term lifestyle habits may reduce the risk of mental decline in old age.

    The first study, a long-term look at 1,880 elderly people in New York City, found that a Mediterranean-type diet and physical activity each were linked to less risk for Alzheimer's disease. The Taub Institute for Research on Alzheimer's Disease and the Aging Brain at Columbia University Medical Center released the data as part of a larger research project on aging.

    The second study, a shorter-term observation of 1,410 patients in France, found some correlation between a Mediterranean-type diet and slower cognitive damage.

    Nikolaos Scarmeas, the author of the first study, grew up eating fish and vegetables in Athens, Greece. Now the neurologist suggests more people take up his mother's cooking. Marked by high consumption of foods such as vegetables, legumes and cereals, served with olive oil, in addition to moderate fish and alcohol intake, the traditional diet has long conferred better cardiovascular health.

    Starting in 1992, researchers at Columbia University monitored elderly patients every 18 months for diet, exercise and mental health, in addition to a number of controls including age, sex and education. 'This is one of the first studies to tease apart the independent contributions of diet and exercise for dementia prevention,' says Ronald Petersen, director of the Alzheimer's Disease Research Center at the Mayo Clinic in Rochester, Minn., who was not involved in the research. 'It suggests that aging need not be a passive process.'

    These studies are observational and not definitive, but they hint at what might reduce the chances of Alzheimer's or dementia. In the Columbia research, those who adhered most closely to the diet reduced their risk for Alzheimer's by 40%, while those with the highest physical activity decreased their risk 33%, compared with people who didn't adhere closely to the diet or weren't physically active.

    In the second study, French researchers found the healthy diet to be associated with slower mental decline, but they didn't discover a strong link with a reduction in dementia.

    Doctors in the field are careful to note that none of these findings demonstrate a causal relationship, but instead reflect the advantages of a continual healthy lifestyle. 'The benefits don't just occur at age 70 when you suddenly stop eating McDonald's and start eating Brussels sprouts,' says David Knopman, a neurologist at the Mayo Clinic in Rochester, Minn., who wrote the editorial accompanying the studies in JAMA and wasn't involved in either study. His editorial highlights confounding variables in the studies. 'Healthy diet and exercise is part of a package of lifelong healthy living.'

    Zaven Khachaturian, a senior science adviser to the Alzheimer's Association, agrees. 'This offers interesting insight but we need to turn it now into clinical trials,' says the former director of the Office of Alzheimer's Disease Research at the National Institutes of Health.

    These findings arrive a few weeks after new research identified a gene that could help predict who will develop Alzheimer's -- the leading cause of dementia -- and at what age. The report, given in mid-July at the International Conference on Alzheimer's Disease, concentrated on DNA surrounding the ApoE gene. Researchers say more studies are needed before the findings can be confirmed.

    For now, Dr. Scarmeas says his studies strongly suggest that a Mediterranean diet and exercise both confer independent and positive health benefits. But together, they are even better.

    'The relative risk reduction for Alzheimer's is about 60% when you combine the diet and exercise,' he says.

    最近刊登于《美國醫學會雜志》（Journal of the American Medical Association）的兩篇研究文章進一步證明，某些長期生活習慣可能降低老年人智力減退的風險。

    一位老年癡呆癥患者（左）正在診所接受治療第一項研究對紐約的1,880位老年人進行了長期觀察，結果發現地中海式飲食和體育鍛煉均與罹患老年癡呆癥的風險降低相關。哥倫比亞大學醫學中心Taub阿爾茨海默氏癥與老化腦部研究所（Taub Institute for Research on Alzheimer's Disease and the Aging Brain）公布的這項數據是一項大型老齡化研究項目的一部分。

    第二項研究對法國的1,410名病人進行了較短期的觀察，結果發現地中海式飲食和認知功能損害減緩之間有某種相關性。

    第一篇研究文章的作者尼古拉斯·斯卡爾米斯（Nikolaos Scarmeas）生長于希臘雅典，他是吃魚肉和蔬菜長大的。現在，這位神經學家建議更多人采用他母親的烹飪食譜。這種傳統飲食的特點是，除了攝入適量魚肉和酒類，還食用大量蔬菜、豆類和谷類等食物，并佐以橄欖油。長期保持這種飲食習慣，可以使心血管系統更加健康。

    哥倫比亞大學（Columbia University）的研究人員從1992年開始對老年病人進行追蹤觀察，每18個月檢查一次，除了統計年齡、性別和受教育程度等控制因素外，檢查內容還包括飲食、鍛煉和精神健康情況。明尼蘇達州羅切斯特市梅奧診所（Mayo Clinic）阿爾茨海默氏癥研究中心主任羅納德·彼得森（Ronald Petersen）說，這是梳理出飲食和鍛煉各自對預防老年癡呆癥的作用的首批研究項目之一。研究表明，衰老不一定是消極的過程。彼得森并未參與該項研究。

    這些研究只是觀察結果，而非確定結論，但它們暗示了哪些因素可能降低罹患阿爾茨海默氏癥或老年癡呆癥的幾率。在哥倫比亞大學的研究中，與那些沒有嚴格堅持控制飲食或沒有積極進行體育鍛煉的人相比，最嚴格地堅持控制飲食的人把患阿爾茨海默氏癥的風險降低了40%,而最積極進行體育鍛煉的人把這一風險降低了33%.

    在第二項研究中，法國研究人員發現，健康的飲食與減緩智力衰退有關，但他們未發現其與降低患老年癡呆癥的風險之間有明顯聯系。

    該領域的醫生們謹慎地指出，這些發現并不表明它們之間存在因果關系，而是反映了保持健康生活方式的益處。"在70歲才突然停止吃麥當勞而開始吃抱子甘藍時，這些益處不會馬上顯現，"明尼蘇達州羅切斯特市梅奧診所的神經學家戴維·克諾普曼（David Knopman）說道。他為發表于《美國醫學會雜志》的這些研究文章撰寫了按語，但沒有參與其中任何一項研究。他的按語強調了研究中的混雜變量。他還寫道，健康飲食和鍛煉是諸多終身健康生活方式中的一部分。

    阿爾茨海默氏癥協會（Alzheimer's Association）的高級科學顧問扎文·哈恰圖良（Zaven Khachaturian）同意這種觀點。他說，這是一種有意思的見解，但我們現在需要將其轉化為臨床試驗。哈恰圖良曾擔任美國國立衛生研究院（National Institutes of Health）阿爾茨海默氏癥研究辦公室主任。

    這些發現公布前幾周，一項新研究識別出一個基因，該基因可以幫助預測何人將罹患阿爾茨海默氏癥（老年癡呆癥的主要病因）及其患病年齡。這份報告在7月中旬召開的國際阿爾茨海默氏癥會議上提交，它集中研究了圍繞著ApoE基因的DNA.研究人員稱，在發現結果得以證實前，還需要進行更多研究。

    斯卡爾米斯博士說，目前他的研究有力地表明，分別來看，地中海式飲食和鍛煉都有益于健康，但是將二者結合起來的效果更好。

    他說："當結合飲食和鍛煉時，患阿爾茨海默氏癥的風險可相對降低約60%."