How a high-fat diet can make you anxious
高脂肪饮食是如何让你焦虑的
When we’re stressed out, many of us turn to junk food for solace. But new CU Boulder research suggests this strategy may backfire.
许多人在压力大时会选择用垃圾食品来安慰自己。但科罗拉多大学博尔德分校的一项新研究表明，这种策略可能适得其反。
The study found that in animals, a high-fat diet disrupts resident gut bacteria, alters behavior and, through a complex pathway connecting the gut to the brain, influences brain chemicals in ways that fuel anxiety.
研究发现，动物实验显示，高脂肪饮食可能破坏体内的肠道菌群，并通过肠道和大脑之间的复杂通路，影响大脑中的化学物质，从而加剧焦虑。
“Everyone knows that these are not healthy foods, but we tend to think about them strictly in terms of a little weight gain,” said lead author Christopher Lowry, a professor of integrative physiology at CU Boulder. “If you understand that they also impact your brain in a way that can promote anxiety, that makes the stakes even higher.”
该研究的主要作者、科罗拉多大学博尔德分校综合生理学教授克里斯托弗·罗瑞称，“大家都知道高脂肪食物不健康，但我们往往只是从控制体重的角度出发。如果你明白它们还会以加剧焦虑的方式影响你的大脑，那么其危害就更大了。”
In a previous study, the team found that rats fed a high-fat diet consisting primarily of saturated fat showed increases in neuroinflammation and anxiety-like behavior.
在之前的一项研究中，研究团队发现，饲喂高脂肪饮食(主要由饱和脂肪组成)的大鼠表现出神经炎症和类似焦虑行为增加。
While evidence is mixed, some human studies have also shown that replacing a high-fat, high-sugar, ultra-processed diet with a healthier one can reduce depression and anxiety.
尽管证据不一，但一些人类研究也表明，用更健康的饮食替代高脂肪、高糖、超加工饮食可以减少抑郁和焦虑。
To better understand what may be driving the fat-anxiety connection, Lowry’s team divided male adolescent rats into two groups: Half got a standard diet of about 11% fat for nine weeks; the others got a high-fat diet of 45% fat, consisting mostly of saturated fat from animal products.
为了更好地理解是什么导致了脂肪焦虑的联系，研究团队将处于“青春期”年龄段的大鼠分为两组：其中一组大鼠连续9周被投喂约含11%脂肪的标准饮食，另一组则吃含45%脂肪的高脂肪饮食，这些脂肪主要是动物产品中的饱和脂肪。
Throughout the study, the researchers collected fecal samples and assessed the animals’ microbiome, or gut bacteria. After nine weeks, the animals underwent behavioral tests.
整个研究过程中，研究人员收集实验鼠粪便样本，评估它们的肠道细菌状况。9周的饮食实验后，这些实验鼠接受了行为测试。
When compared to the control group, the group eating a high-fat diet, not surprisingly, gained weight. But the animals also showed significantly less diversity of gut bacteria.
结果显示，与对照组相比，高脂饮食组的实验鼠不仅体重增加，其肠道细菌多样性也明显较低。
The high-fat diet group also showed higher expression of three genes (tph2, htr1a, and slc6a4) involved in production and signaling of the neurotransmitter serotonin—particularly in a region of the brainstem known as the dorsal raphe nucleus cDRD, which is associated with stress and anxiety.
高脂肪饮食组还显示，大鼠体内与神经递质血清素的产生和信号传递有关的三个基因表达（tph2, htr1a, slc6a4）水平较高，且在脑干中缝背核的某一区域尤其明显，该区域与压力和焦虑有关。
While serotonin is often billed as a “feel-good brain chemical,” Lowry notes that certain subsets of serotonin neurons can, when activated, prompt anxiety-like responses in animals. Notably, heightened expression of tph2, or tryptophan hydroxylase, in the cDRD has been associated with mood disorders and suicide risk in humans.
尽管血清素通常被认为是一种“让人感觉良好的大脑化学物质”，罗瑞指出，当某些血清素神经元亚群被激活时，可以在动物中引发类似焦虑的反应。值得注意的是，cDRD中tph2(或色氨酸羟化酶)的表达增加与人类的情绪障碍和自杀风险相关。
Lowry stresses that not all fats are bad, and that healthy fats like those found in fish, olive oil, nuts and seeds can be anti-inflammatory and good for the brain.
罗瑞强调，并非所有的脂肪都是有害的，鱼类、橄榄油、坚果和种子中的健康脂肪可以抗炎，对大脑有益。
But his research in animals suggests that exposure to an ultra-high-fat diet consisting of predominantly saturated fats, particularly at a young age, could both boost anxiety in the short-term and prime the brain to be more prone to it in the future.
但对动物的研究表明，摄入以饱和脂肪为主的超高脂肪食物，尤其是在年轻的时候，既可以在短期内加剧焦虑，也可以使大脑在未来更容易产生焦虑。
苏格拉底有一句名言：我知我无知。说的是，当你认识到的东西越多就越发现自己无知。苏格拉底认为，人对于客观世界的认识是有限的，且不可能完全认识客观世界，并且不应对客观世界刨根究底。神对于世界的规划自有安排，若人一意孤行地探索世界和自然的奥秘，则最终将亵渎甚至触怒神明。正因为人对神所构建的世界不可能实现完全认知，因此那些宣称自己能够认识和改造世界的人，本身便是无知的代言。尽管苏格拉底的关于“ 我知我无知”的观念的解读，在现在看来有失客观科学。但至少苏格拉底告诫人们，人的认知是有限的，现有的知识甚至可能存在错误和疏漏。因此，无论任何时代，我们都必须对自己的无知加以认识并通过不懈的开拓，去更新甚至颠覆固有的知识结构。我们在求学之路上也要报以我知我不知的心态，才能走得更远、终有所成。最后，祝愿每一位考研学子都能顺利上岸！
