An insidious danger Silent strokes are nasty pieces of work. Most likely triggered by interruptions of blood flow in the brain, they destroy tiny clumps of brain cells — areas too small to cause the classic visible symptoms of stroke, such as slurred speech, blurred vision, and numbness or weakness on one side of the body.
In fact, the brain injury caused by silent strokes can be detected only by a brain scan. Yet silent strokes are far from innocuous. Over time their damage can accumulate and lead to memory lapses and other cognitive problems. Some research has also linked them to depression.
Silent strokes are surprisingly common. A
study published in June found that more than 10 percent of apparently healthy middle-aged adults had experienced at least one silent stroke. Other research suggests that almost 20 percent of older adults may be affected. The incidence increases with age.
A significant benefit For the Neurology study, more than 2,000 adults aged 65 and older underwent two brain scans five years apart to see if they had any of the tell-tale small brain lesions of a past silent stroke. Participants were also asked to fill out questionnaires about their fish consumption.
The study found that eating fish high in omega-3 fatty acids (such as tuna, salmon, mackerel, herring, sardines and anchovies) three or more times a week lowered the risk of silent stroke by almost 26 percent. Even once-a-week consumption of these types of fish was beneficial, reducing the risk by 13 percent.
Regular fish eaters in the study also had fewer changes in the white matter in their brains. (White matter is composed mostly of nerve fibers, called axons, which carry information between brain cells.) Like silent strokes, white matter abnormalities are associated with cognitive impairment and a higher risk of future full-blown strokes.
译文:
食用鱼肉怎样阻止大脑衰老？（二）
暗藏危机
静态中风是非常棘手的病症。大多数人病发可能是由于大脑血液输送被打断而引发的，输血的中断破坏了小块脑细胞——被破坏的区域太小以至于不会引发直观症状的传统中风，比如言语不清、视力模糊、以及半边人体的麻木感和虚弱感。
事实上，静态中风引起的大脑损害只能由大脑扫描检查出来。而静态中风却往往危害很大。随着时间的推移，对大脑的损害会积聚并导致记忆流失以及其他认知问题。一些研究也已经把它和抑郁联系了起来。
让人惊奇的是，静态中风非常普遍。一月份发表的一项研究发现超过10%的看似健康的中年人已经至少经历了一次静态中风。其他的研究表明大约20%的老年人可能会患上此病。机率随着年龄的上升而增加。
受益无穷
在这项神经病学的研究中，2000多名65岁以上老人在五年里分别进行了2次大脑扫描，目的是为了检查他们是否由于过去有过的静态中风而有任何所谓的大脑小部分损伤。参加者们也同样被要求填写一份关于他们食用鱼肉的调查问卷。
这项研究发现每周食用富含ω−3脂肪酸的鱼肉（比如金枪鱼、大马哈鱼、鲭鱼、鲱鱼、沙丁鱼和凤尾鱼）三次或者更多次可以降低26%的静态中风之风险。就算一周吃一次这些种类的鱼也非常有益，可以减少13%的患病风险。
研究中那些常常吃鱼肉的人在他们的脑白质中也很少有变化。（白质大多是由位于大脑细胞间携带信息的神经元组成的，神经元又被称为神经突轴。）像在静态中风中，脑白质的不正常是和认知损害联系在一起的，并且将来全身中风的风险也会很高。