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 intake¹ 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 cognitive² functions into old age," Dr. A. Veronica Witte and colleagues from University of Munster wrote in the latest issue of Proceedings³ 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, helping⁴ 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 investigators⁵, 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 restriction⁶ 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."

来自德国建议的一项新的研究表明，在上了年纪的健康人当中，减少热量可能提高他们的记忆力。在这个研究中，研究员发现那些减少了自己接近百分之30的热量吸收的人在仅仅三个月之后就可以在标准的记忆测试中表现的比其他人好。

“我们的研究可以帮助形成一种新的策略，可以防治老年人的记忆力衰退，保持认知能力。”A.Veronica Witte教授和他在闵斯特大学的同事在国家科学研究院最新一期的公报上如此写道。

动物上的研究已经表明了，多吃低热量和多不饱和脂肪酸食物的日常饮食有利于大脑功能的发挥，能提高大老鼠的记忆力。

为了证明在人类中能否产生一样的效果，Witte的小组将50个平均年龄在60岁的从正常到超重的人分成了三组。一组限制了他们平时所消耗的热量的30%；第二组增加他们所消耗的不饱和脂肪酸的20%；而第三组，作为参照，不需要做任何改变。

根据这个调查，三个月后，热量受限制的那组在非文字记忆测试中得到了分数高出20%的可观结果。相比之下，在另外两组却没有明显的改变。

在这个调查中还注意到，在热量受限组，记忆力提升与身体里胰岛素减少和出现炎症的“生物标记”有关。这些改变在那些严格坚持热量限制饮食方式的人中最为明显。

“据我们所知，目前的结果提供了第一个试验证据，说明在人群中限制热量可以提高上了年纪的人的记忆能力。”Witt和他的同事如是说。

他们补充说:“这次研究的结果，有助于开发新的保护和治疗策略来保持晚年健康的认知能力。”