一頓炸雞可以解決不開心了？日常生活中難免有壓力大的時候，遇到這種情況，很多人選擇吃一頓炸雞、炸薯條、炸串……這些食物真能讓人緩解壓力、釋放快樂嗎？錯了！
最近研究發現，經常吃這類食品並不會讓人真正放鬆和愉悅！相反，可能會增加負面情緒。
When we’re stressed out, many of us turn to junk food for solace. But new CU Boulder research suggests this strategy may backfire.
許多人在壓力大時會選擇用垃圾食品來安慰自己。但科羅拉多大學博爾德分校的一項新研究表明，這種策略可能適得其反。
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.
研究發現，動物實驗顯示，高脂肪飲食可能破壞體內的腸道菌群，並透過腸道和大腦之間的複雜通路，影響大腦中的化學物質，從而加劇焦慮。
“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.”
該研究的主要作者、科羅拉多大學博爾德分校綜合生理學教授克里斯托弗·羅瑞稱，“大家都知道高脂肪食物不健康，但我們往往只是從控制體重的角度出發。如果你明白它們還會以加劇焦慮的方式影響你的大腦，那麼其危害就更大了。”
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.
在之前的一項研究中，研究團隊發現，飼餵高脂肪飲食(主要由飽和脂肪組成)的大鼠表現出神經炎症和類似焦慮行為增加。
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.
儘管證據不一，但一些人類研究也表明，用更健康的飲食替代高脂肪、高糖、超加工飲食可以減少抑鬱和焦慮。
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.
為了更好地理解是什麼導致了脂肪焦慮的聯絡，研究團隊將處於“青春期”年齡段的大鼠分為兩組：其中一組大鼠連續9周被投餵約含11%脂肪的標準飲食，另一組則吃含45%脂肪的高脂肪飲食，這些脂肪主要是動物產品中的飽和脂肪。
Throughout the study, the researchers collected fecal samples and assessed the animals’ microbiome, or gut bacteria. After nine weeks, the animals underwent behavioral tests.
整個研究過程中，研究人員收集實驗鼠糞便樣本，評估它們的腸道細菌狀況。9周的飲食實驗後，這些實驗鼠接受了行為測試。
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.
結果顯示，與對照組相比，高脂飲食組的實驗鼠不僅體重增加，其腸道細菌多樣性也明顯較低。
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.
高脂肪飲食組還顯示，大鼠體內與神經遞質血清素的產生和訊號傳遞有關的三個基因表達（tph2, htr1a, slc6a4）水平較高，且在腦幹中縫背核的某一區域尤其明顯，該區域與壓力和焦慮有關。
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.
儘管血清素通常被認為是一種“讓人感覺良好的大腦化學物質”，羅瑞指出，當某些血清素神經元亞群被啟用時，可以在動物中引發類似焦慮的反應。值得注意的是，cDRD中tph2(或色氨酸羥化酶)的表達增加與人類的情緒障礙和自殺風險相關。
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.
羅瑞強調，並非所有的脂肪都是有害的，魚類、橄欖油、堅果和種子中的健康脂肪可以抗炎，對大腦有益。
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.
但對動物的研究表明，攝入以飽和脂肪為主的超高脂肪食物，尤其是在年輕的時候，既可以在短期內加劇焦慮，也可以使大腦在未來更容易產生焦慮。
編輯：董靜 陳丹妮 萬月英 李雪晴
來源：科羅拉多大學博爾德分校官網
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