「科學60秒」（60-Second Science）是全球最著名的科學英文廣播，由《科學美國人》出品，網羅全球最新奇的科學發現，用過山車式的飛快語速，將其濃縮在60秒的播音之中。收聽「科學60秒」，既能知新，又可練耳。
在訂閱號主頁點擊「聽廣播」可獲取「科學60秒」推送目錄，141009及之前的內容可通過回復日期代碼獲取音頻和中英文對照腳本，141009之後的內容可直接點擊連結到包含音頻的頁面。
Drugged Gut Microbiome Cuts Heart Risk in Mice
給腸道細菌吃藥能降低小鼠的心臟病風險
撰文/播音 克里斯多福·因塔利亞塔（Christopher Intagliata）
翻譯 Meatle
審校 邰倫玥
The microbes in our gut play a big role in helping us digest our food. But as they break down nutrients, they also generate secondary compounds that can influence our health. Take carnitine, or lecithin—substances found in red meat. When your gut microbes break them down, the bugs excrete the waste product trimethylamine, TMA. Which your liver enzymes convert to trimethylamine-N-oxide, TMAO, a substance that ups the risk of heart disease.
我們消化道中的微生物在消化食物方面起著重要的作用。然而在它們分解食物的同時，也產生了一些影響我們健康的副產物。舉個例子，當腸胃細菌分解紅肉中常見的肉毒鹼或卵磷脂時，這些微生物會排洩出三甲胺(TMA)。三甲胺在肝臟的酶的作用下，轉化為可以增加心臟疾病風險的物質——氧化三甲胺(TMAO)。
But this effect isn't limited to red-meat eaters. "We're constantly feeding our gut microbes these compounds. Even in the most ardent vegetarian or vegan it happens." Stanley Hazen, a physician in preventive cardiology at Cleveland Clinic. "Every time you eat, even when you eat a pickle or a cucumber or a pure piece of lettuce, once you eat something, your gallbladder contracts and squirts some bile into the intestines to try to help digest the food." And even bile, he says, has compounds, like lecithin, that gut microbes digest into TMA.
然而這種影響並不局限於紅肉愛好者。「我們持續不斷地用這些化合物餵養腸胃微生物。甚至嚴格的素食者也不例外。」克利夫蘭診所的預防心臟病學醫師，斯坦利·哈森（Stanley Hazen）說到。「只要你吃了東西，即使吃下的是泡菜、黃瓜或只是一片生菜，膽囊就會收縮，擠出一些膽汁進入到腸道以協助消化。」而膽汁也含有卵磷脂這類的化合物，被腸道細菌轉化為TMA。
So why not block the gut microbes from making TMA in the first place? Hazen and his colleagues found a substance that does just that. It's a kind of butanol called DMB, and it's found in extra-virgin olive oil, grapeseed oil, and some red wines and balsamic vinegars. When mice ate DMB, the compound blocked the gut bacteria from producing TMA—which in turn prevented clogged arteries in the animals.
那為何不在源頭上阻止細菌產生這些物質？哈森與他的同事發現了一種具有此功效的物質。這是一種被稱為DMB的丁醇類物質。這種物質可以在特級初榨橄欖油、葡萄籽油、紅酒或義大利香脂醋中找到。當小鼠攝入了DMB後，DMB會阻止腸道細菌生成TMA，換句話說，DMB可以預防小鼠的心肌梗塞。
"I kind of like to think of this as a statin for microbes. When we take a statin, or something that blocks cholesterol synthesis in our body cells, we're not killing the cell, we're just preventing the body from making cholesterol. In an analogous way, this is preventing the microbe from making TMA, and that therefore in the host reduces TMAO levels and is reducing diet-induced atherosclerosis." The study is in the journal Cell. [Zeneng Wang et al, Non-lethal Inhibition of Gut Microbial Trimethylamine Production for the Treatment of Atherosclerosis]
「我認為這是一種對微生物起效的斯達汀。當我們吃下了斯達汀，或是其他抑制細胞中的膽固醇生成的物質，我們並沒有殺死這些細胞，只是阻止了膽固醇的生成。類似地，DMB阻止微生物產生TMA，而這樣會在源頭上減少TMAO的水平，並且減少食源性的動脈粥樣硬化。」這項研究被刊登在Cell上。
As for whether this finding explains the heart-healthy benefits of the Mediterranean diet for humans? "We haven't studied the Mediterranean diet. But you can start connecting the dots. And I think that is an area where future studies need to go." Until then, no harm in a little olive oil—especially if you’re putting it on a nutritious salad.
這項發現是否解釋了為何地中海式飲食會對人類心臟健康有益？雖然研究人員尚未對地中海飲食展開研究，但是你可以朝這個方向聯想。同時這將是後續研究的方向。在更加深入的研究之前，吃點兒橄欖油應該沒啥害處，尤其是加在營養滿滿的沙拉裡時。
點擊閱讀原文，或在環球科學ScientificAmerican微信訂閱號主頁點擊「聽廣播」可獲取「科學60秒」推送目錄，141009及之前的內容可通過回復日期代碼獲取音頻和中英文對照腳本，141009之後的內容可直接點擊連結到包含音頻的頁面。