NEW YORK – Cutting calories may improve memory among healthy elderly men and women, a new study from Germany hints. In the study, researchers found that people who cut their calorie intake by approximately 30 percent performed better on standard memory tests after just three months.
"Our study may help to generate novel prevention strategies to maintain cognitive functions into old age," Dr. A. Veronica Witte and colleagues from University of Munster wrote in the latest issue of Proceedings of the National Academy of Sciences.
Animal studies have shown that diets low in calories and rich in unsaturated fatty acids - the kind found in olive oil and fish - are beneficial for brain function, helping to improve memory in aging rats.
To see whether the same effects can be induced in humans, Witte's team divided 50 normal- to overweight individuals whose average age was 60 years into three groups. One group restricted by up to 30 percent the amount of calories they consumed; a second group increased their consumption of unsaturated fatty acids by up to 20 percent; and a third group, serving as the control group, made no changes.
According to the investigators, the calorie-restricted group saw a significant 20 percent average increase in verbal memory scores after 3 months. In contrast, no significant changes in memory performance emerged in the two other groups.
The investigators also noticed that memory improvements in the calorie-restricted group correlated with decreases in insulin levels and "biomarkers" of inflammation in the body, and that these changes were most pronounced in those individuals who stuck closest to the prescribed calorie-restricted diet.
"To our knowledge, the current results provide the first experimental evidence in humans that caloric restriction improves memory in the elderly," Witte and colleagues note.
The results of this study, they add, "may help to develop new prevention and treatment strategies for maintaining cognitive health into old age."
译文:
研究表明——吃的少，记得多
据纽约报道——德国一项新研究暗示，减少卡路里的摄入可使健康的中老年人的记忆力有所提高。在该研究中，调查者发现那些在三个月内减少大约30%的卡路里摄入的人们在记忆测试中比其他人的表现要好得多。
A·维罗妮卡·维特医生和她来自蒙斯特大学的同事们在最新的一期国家科学院学报中写道：“我们的研究也许会产生一些全新的预防老年人认知功能退化的新方法。“
动物研究也已经表明低卡路里含量并且富含不饱和脂肪酸（即在橄榄油和鱼类中发现的脂肪酸）的饮食非常有益于大脑功能，能够帮助衰老的老鼠提高记忆力。
为了了解这样的作用是否也对人类同样有效，维特的团队将平均年龄为60岁，体型从中等到肥胖的五十名测试者分为三组。一组是执行减少30%卡路里摄入的饮食，第二组则是增加20%的不饱和脂肪酸的摄入量，第三组则作为对比组，对饮食习惯不作任何调整。
根据调查者的数据，限制卡路里摄入的一组在三个月后在非文字记忆的测试中有了非常明显的平均20%的提高。而对比之下，在另外两组中则没有出现什么很大的变化。
调查者同样也注意到限制卡路里摄入的这一组，他们的记忆力提高是和胰岛素的水平降低和体内炎症的身体表征有着互相关联，并且这些变化大多都是显现在那些严格按照卡路里限制的饮食进食的人身上。
维特和她的同事提到，“根据我们的知识，现有的结果提供了第一项在人类身上的实验证据，也就是卡路里的限制摄入能够提高老年人的记忆力。”
对于这项研究结果，他们还说，“这也许能够帮助寻找出一种新的预防和治疗老年人认知记忆方面的方法。”