研究:高盐饮食会让你的身体很难抵抗感染
研究:高盐饮食会让你的身体很难抵抗感染
There are several risks associated with a high-salt diet, including high blood pressure, heart attack and stroke — but a new study reveals that a compromised immune system should be added to that list.
高盐饮食会带来多种风险，包括高血压、心脏病和中风，但一项新的研究表明，免疫系统受损也应列入其中。
To mitigate the well-documented health risks associated with a high-salt diet, the World Health Organization recommends adults cap their salt intake to about one teaspoon, or 5 grams, per day — an amount equivalent to about two Big Macs.
为了减少高盐饮食对健康的危害，世界卫生组织建议成年人每天的盐摄入量控制在一茶匙左右，即5克，相当于两个巨无霸。
Unfortunately, as the Food and Drug Administration points out, Americans consume on average some 8.5g of salt each day — almost double the WHO’s recommendation — which partially explains why the US suffers such high rates of hypertension, a major contributing factor to cardiovascular and metabolic diseases.
不幸的是，正如美国食品和药物管理局指出的，美国人平均每天摄入8.5克盐——几乎是世界卫生组织建议的两倍——这部分解释了为什么美国高血压发病率如此之高，而高血压是导致心血管和代谢疾病的主要因素。
Now, German researchers at the University of Bonn believe that too much salt could also weaken our immune system — particularly our defenses against bacterial infections.
现在，德国波恩大学的研究人员认为，过多的盐也会削弱我们的免疫系统，尤其是我们对细菌感染的防御能力。
“We examined volunteers who consumed 6 grams of salt in addition to their daily intake,” says Prof. Dr. Christian Kurts, whose study was published Wednesday in the journal Science Translational Medicine. “This is roughly the amount contained in two fast food meals, i.e. two burgers and two portions of french fries.”
“我们调查了那些每天摄入6克盐的志愿者，”克里斯蒂安·库尔茨(Christian Kurts)教授说，他的研究周三发表在《科学转化医学》(Science Translational Medicine)杂志上。“这大概是两份快餐所含的量，即两份汉堡和两份薯条。
Kurts says their research “prove[s] for the first time that excessive salt intake also significantly weakens an important arm of the immune system.” Yet, these findings contradict prior studies which have shown that a high-salt diet was effective in healing infections caused by certain skin parasites in laboratory animals. Thus, many scientists had previously concluded that sodium chloride could have immune-boosting qualities.
库尔茨说，他们的研究“首次证明了过量的盐摄入也会显著削弱免疫系统的一个重要分支。”然而，这些发现与先前的研究相矛盾，之前的研究表明，高盐饮食对治愈实验动物中某些皮肤寄生虫引起的感染是有效的。因此，许多科学家先前已经得出结论，氯化钠可能具有增强免疫力的性质。
“Our results show that this generalization is not accurate,” says Dr. Katarzyna Jobin, lead author of the current study. They explain that the skin functions as a salt reservoir for the body, which lends a hand in the elimination of certain skin diseases. But inside the body, salt concentration is meant to remain constant — save the kidneys, which bear the brunt of high salt intake. This latest study discovered that, as the kidneys filter blood, the presence of salt prompts glucocorticoids, a type of hormone, to build up in the body, which impairs a common type of bacteria-busting immune cell called granulocytes.
“我们的结果表明，这种概括是不准确的，”卡塔兹纳·乔宾博士说，他是目前这项研究的主要作者。他们解释说，皮肤是身体的盐库，有助于消除某些皮肤病。但是在体内，盐的浓度应该保持不变——除了肾脏，肾脏承受着高盐摄入的冲击。这项最新研究发现，当肾脏过滤血液时，盐的存在会促使糖皮质激素(一种激素)在体内积聚，而糖皮质激素会损害一种常见的破坏细菌的免疫细胞，即粒细胞。
“We were able to show this in mice with a listeria infection,” explains Dr. Jobin. “We had previously put some of them on a high-salt diet. In the spleen and liver of these animals we counted 100 to 1,000 times the number of disease-causing pathogens.” Urinary tract infections, the study finds, also healed much more slowly.
“我们能够在感染李斯特菌的老鼠身上证明这一点，”Jobin博士解释道。“我们之前曾让其中一些人吃高盐食物。在这些动物的脾脏和肝脏中，我们发现了100到1000倍的致病菌。研究发现，尿路感染的愈合速度也慢得多。
After just one week on the high-salt regimen, blood samples from test subjects showed that human granulocytes were already failing to cope with bacterial intruders. They also showed increased glucocorticoid levels — which scientists anticipated would have an impact on the immune system, as glucocorticoid cortisones are already used to suppress inflammation (caused by an immune response) in medical settings.
在高盐饮食仅一周后，来自测试对象的血液样本显示，人类粒细胞已经无法应对细菌入侵。它们还显示出糖皮质激素水平升高——科学家们预计这将对免疫系统产生影响，因为在医学领域，糖皮质激素已经被用来抑制炎症(由免疫反应引起)。
