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This is Scientific American — 60-Second Science. I'm Christopher Intagliata.
Your nose may be the first place you think of as a source of mucus. But mucus is a major player in your gut, too. 'There's antimicrobial peptides and proteins that are present in there. Bacteria live in there and forage on the carbohydrates. And it's a lubricant, it helps sweep contents down the GI tract, without injuring the epithelial layer.'
Eric Martens, a microbiologist at the University of Michigan. He says farther down the GI tract, in the colon, the mucus builds a wall: a barrier against friendly bacteria, 'as well as pathogens that could be transiting through.' But here's the problem: your gut bacteria may chew right through that wall—if you skimp on fiber in your diet.
Martens and his team modeled that scenario in mice who'd been born free of microbes. They seeded the mice's guts with a human gut microbiome—then fed them a high-fiber diet: raw milled corn, whole wheat, whole soybeans and oats. 'It's about as raw of a diet as you can get.' The human equivalent: double our recommended daily intake of fiber. 'It's a lot of kale.'
That extreme high-fiber diet helped keep the mucus barrier intact. But in mice that had zero fiber—or the kind of soluble fiber typically added to processed foods—the fiber-eating members of the gut dwindled. Their absence opened up more real estate for mucus-munching bacteria, which boomed in number, and tore through the protective mucus wall—leaving intestinal cells open for microbial attack. The study is in the journal Cell.
The results suggest that 'the recent history of your diet could predispose how you react to an enteric pathogen.' And they're yet another endorsement of the magical properties of plant fiber. 'Eating natural vegetables, raw vegetables, cooked veggies, whole grains, is definitely good for you.' The good news is, the mice's gut bacteria bounced back within a day to a change in diet. So eat for the gut you want. Not the gut you have.
Thanks for listening for Scientific American — 60-Second Science Science. I'm Christopher Intagliata.
參考譯文
這里是科學美國人——60秒科學。我是克里斯托弗·因塔利亞塔。
對于粘液的來源，你想到的第一個地方可能就是鼻子。但是粘液也是腸道中的重要成分。“腸道中有抗菌肽和蛋白質。腸道中的細菌以碳水化合物為食。腸道中的粘液是一種潤滑劑，它可以幫助食物沿胃腸道滑下，而不損傷上皮層細胞。”
埃里克·馬頓斯是密歇根大學的微生物學家。他表示，在胃腸道下方，粘液在結腸處建造了一堵墻：這個屏障可以抵抗友善的細菌以及病原體通過。但是問題是：如果你的飲食中缺少膳食纖維，那腸道細菌也可能會穿過那堵墻。
馬斯頓和他的團隊用老鼠進行情況模擬，這些老鼠生來不含有任何微生物。他們在老鼠的腸道內植入人體腸道的微生物，然后給老鼠喂纖維含量高的飲食：生玉米碎、全麥、大豆和燕麥。“這基本上和人類食物的原料類似。”相當于人類的飲食：將攝入的纖維量翻倍。“這是大量的甘藍。”
纖維含量極高的飲食有助于保持粘液屏障的完整性。但是，老鼠體內沒有任何纖維，也沒有通常會添加到加工食品中的可溶性纖維，腸道中以纖維為食的細菌數量減少。纖維細菌的缺乏則為粘液細菌提供了更多場所，造成粘液細菌數量激增，然后通過保護的黏膜墻，導致腸道細胞易受到微生物的攻擊。該研究結果發表在《細胞》期刊上。
研究結果表明，“你最近的飲食可以反應出你如何應對腸道病菌。”它們也反應了植物纖維的神奇特性。“吃天然的蔬菜、生蔬菜、熟蔬菜、全谷物，絕對是對你有好處的。” 好消息是，老鼠的腸道細菌在改變飲食一天以后迅速恢復了活力。所以，要食用你的腸道告訴你要吃的食物，而不是你的直覺告訴你要吃的食物。
謝謝大家收聽科學美國人——60秒科學。我是克里斯托弗·因塔利亞塔。
重點講解：
1. skimp on 草率地做；馬馬虎虎地做；節儉使用；節省；
例句：Many families must skimp on their food and other necessities just to meet the monthly rent.
就為了交齊每月的租金，許多家庭不得不省吃儉用。
2. add to 添加；增加；摻加；
例句：The interest is added to your account every year.
利息每年都加到您的存款中。
3. open up （使）（機會、可能性等）出現；（使）產生；
例句：Night hiking opens up a new world to visitors.
夜游則讓游客置身一個全新世界。
4. react to （作出）反應；回應；
例句：They say children will react to what they see.
他們說孩子會對他們看到的做出反應。
