阿尔茨海默病试验研究发现高蛋白饮食使模型小鼠大脑缩小
转自丁香园动态版
ScienceDaily (Oct. 21, 2009) — One of the many reasons to pick a low-calorie, low-fat diet rich in vegetables, fruits, and fish is that a host of epidemiological studies have suggested that such a diet may delay the onset or slow the progression of Alzheimer's disease (AD). Now a study published in BioMed Central's open access journal Molecular Neurodegeneration tests the effects of several diets, head-to-head, for their effects on AD pathology in a mouse model of the disease. Although the researchers were focused on triggers for brain plaque formation, they also found that, unexpectedly, a high protein diet apparently led to a smaller brain.
ScienceDaily（09年10月21日） ----流行病学研究建议选择富含蔬菜，水果和鱼类的低热量低脂肪饮食，因为这样的饮食习惯可能会延迟AD发病或延缓病程发展。目前分子神经退行性疾病杂志的一项研究对几种饮食对AD的影响，尤其是对模型小鼠在AD病理学上的影响进行了试验。虽然研究人员主要目的在于研究导致斑块形成的因素，但他们意外的发现高蛋白饮食可显著缩小大脑。
A research team from the US, Canada, and the UK tested four differing menus on transgenic mouse model of AD, which express a mutant form of the human amyloid precursor protein (APP). APP's role in the brain is not fully understood; however it is of great interest to AD researchers because the body uses it to generate the amyloid plaques typical of Alzheimer's. These mice were fed either
来自美国，加拿大和英国的研究小组测试了四种不同的饮食对APP（淀粉样前体蛋白）转基因AD模型小鼠的影响，APP的作用目前尚不完全明确，机体通过利用APP生成典型的阿尔茨海默病淀粉样蛋白斑块，因此它仍引起了研究者的极大关注。
试验中模型小鼠被喂食四类饮食
a regular diet,
a high fat/low carbohydrate custom diet,
a high protein/low carb version or
a high carbohydrate/low fat option.
The researchers then looked at the brain and body weight of the mice, as well as plaque build up and differences in the structure of several brain regions that are involved in the memory defect underlying AD.
正常饮食
高脂肪/低碳水化合物饮食
高蛋白/低碳水化合物饮食
高碳水化合物/低脂肪饮食
而后研究人员对小鼠大脑和身体重量，以及在几个与AD记忆缺陷有关的区域的斑块形成情况和结构差异进行了分析。
Unexpectedly, mice fed a high protein/low carbohydrate diet had brains five percent lighter that all the others, and regions of their hippocampus were less developed. This result was a surprise, and, until researchers test this effect on non-transgenic mice, it is unclear whether the loss of brain mass is associated with AD-type plaque. But some studies in the published literature led the authors to put forward a tentative theory that a high protein diet may leave neurones more vulnerable to AD plaque. Mice on a high fat diet had raised levels of plaque proteins, but this had no effect on plaque burden.
结果意外发现，喂食高蛋白质/低碳水化合物饮食的小鼠与其他组相比大脑重量减轻了百分之五，而且海马区发育不良。这个结果令人吃惊，在研究人员对非转基因小鼠进行测试之前，还不能确定大脑的质量损失是否与AD淀粉斑块有关。但据文献报道，已有一些作者提出一个假说----高蛋白饮食可能会使神经元更易受到淀粉斑块的损害。高脂饮食的小鼠的淀粉蛋白水平虽然上升，但对斑块数量没有造成明显影响。
Aside from transgenic mice, the pressing question is whether these data have implications for the human brain. "Given the previously reported association of high protein diet with aging-related neurotoxicity, one wonders whether particular diets, if ingested at particular ages, might increase susceptibility to incidence or progression of AD," says lead author, Sam Gandy, a professor at The Mount Sinai School of Medicine in New York City and a neurologist at the James J Peters Veterans Affairs Medical Center in the Bronx NY. The only way to know for sure would require prospective randomised double blind clinical diet trials. According to Gandy, "This would be a challenging undertaking but potentially worthwhile. If there is a real chance that the ravages of AD might be slowed or avoided through healthy eating.
除了要考虑转基因的因素，另一个疑问是，这些数据对人类大脑是否有应用价值。之前曾有高蛋白饮食与和老龄化神经毒性有关的报道，不禁令人怀疑，如果在特定的年龄摄入某些特别的饮食是否可能会增加AD发病的敏感性或是加快病程的发展。论文主要作者，Sam Gandy表示，开展随机双盲临床试验是必需的，这是一项艰巨的任务，但如果真的有可能通过饮食可以减缓或避免AD，也是值得的。
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