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《美国医学会杂志》（Journal of the American Medical Association）的两篇研究文章进一步证明，某些长期生活习惯可能降低老年人智力减退的风险。

一位老年痴呆症患者（左）正在诊所接受治疗第一项研究对纽约的1,880位老年人进行了长期观察，结果发现地中海式饮食和体育锻炼均与罹患老年痴呆症的风险降低相关。哥伦比亚大学医学中心Taub阿尔茨海默氏症与老化脑部研究所（Taub Institute for Research on Alzheimer's Disease and the Aging Brain）公布的这项数据是一项大型老龄化研究项目的一部分。

第二项研究对法国的1,410名病人进行了较短期的观察，结果发现地中海式饮食和认知功能损害减缓之间有某种相关性。

第一篇研究文章的作者尼古拉斯·斯卡尔米斯（Nikolaos Scarmeas）生长于希腊雅典，他是吃鱼肉和蔬菜长大的。现在，这位神经学家建议更多人采用他母亲的烹饪食谱。这种传统饮食的特点是，除了摄入适量鱼肉和酒类，还食用大量蔬菜、豆类和谷类等食物，并佐以橄榄油。长期保持这种饮食习惯，可以使心血管系统更加健康。

哥伦比亚大学（Columbia University）的研究人员从1992年开始对老年病人进行追踪观察，每18个月检查一次，除了统计年龄、性别和受教育程度等控制因素外，检查内容还包括饮食、锻炼和精神健康情况。明尼苏达州罗切斯特市梅奥诊所（Mayo Clinic）阿尔茨海默氏症研究中心主任罗纳德·彼得森（Ronald Petersen）说，这是梳理出饮食和锻炼各自对预防老年痴呆症的作用的首批研究项目之一。研究表明，衰老不一定是消极的过程。彼得森并未参与该项研究。

这些研究只是观察结果，而非确定结论，但它们暗示了哪些因素可能降低罹患阿尔茨海默氏症或老年痴呆症的几率。在哥伦比亚大学的研究中，与那些没有严格坚持控制饮食或没有积极进行体育锻炼的人相比，最严格地坚持控制饮食的人把患阿尔茨海默氏症的风险降低了40%,而最积极进行体育锻炼的人把这一风险降低了33%.

在第二项研究中，法国研究人员发现，健康的饮食与减缓智力衰退有关，但他们未发现其与降低患老年痴呆症的风险之间有明显联系。

该领域的医生们谨慎地指出，这些发现并不表明它们之间存在因果关系，而是反映了保持健康生活方式的益处。"在70岁才突然停止吃麦当劳而开始吃抱子甘蓝时，这些益处不会马上显现，"明尼苏达州罗切斯特市梅奥诊所的神经学家戴维·克诺普曼（David Knopman）说道。他为发表于《美国医学会杂志》的这些研究文章撰写了按语，但没有参与其中任何一项研究。他的按语强调了研究中的混杂变量。他还写道，健康饮食和锻炼是诸多终身健康生活方式中的一部分。

阿尔茨海默氏症协会（Alzheimer's Association）的高级科学顾问扎文·哈恰图良（Zaven Khachaturian）同意这种观点。他说，这是一种有意思的见解，但我们现在需要将其转化为临床试验。哈恰图良曾担任美国国立卫生研究院（National Institutes of Health）阿尔茨海默氏症研究办公室主任。

这些发现公布前几周，一项新研究识别出一个基因，该基因可以帮助预测何人将罹患阿尔茨海默氏症（老年痴呆症的主要病因）及其患病年龄。这份报告在7月中旬召开的国际阿尔茨海默氏症会议上提交，它集中研究了围绕着ApoE基因的DNA.研究人员称，在发现结果得以证实前，还需要进行更多研究。

斯卡尔米斯博士说，目前他的研究有力地表明，分别来看，地中海式饮食和锻炼都有益于健康，但是将二者结合起来的效果更好。

他说："当结合饮食和锻炼时，患阿尔茨海默氏症的风险可相对降低约60%."