中英文稿

數(shù)萬億細菌、病毒和真菌 生活在我們身上及體內(nèi)，?和它們保持良好平衡的關(guān)系?是對我們有利的。?它們一起形成腸道微生物群，?這是一個豐富的生態(tài)系統(tǒng)， 在我們的身體中發(fā)揮各種作用。?腸道細菌可以分解 體內(nèi)無法消化的食物，?產(chǎn)生重要的營養(yǎng)物質(zhì)，?調(diào)節(jié)免疫系統(tǒng)，?防止有害細菌。?我們目前還無法明確?健康的腸道需要哪些有益細菌，?但我們確切地知道， 對于健康的微生物群來說，?擁有多種細菌非常重要。?影響微生物群的因素有很多，?包括環(huán)境、?藥品，如抗生素，?以及我們是否生于剖腹產(chǎn)。

?飲食也漸漸變成了 影響腸道健康的?主要因素之一。?雖然無法控制所有因素，?但我們可以通過關(guān)注飲食?來控制體內(nèi)微生物群的平衡。?來自水果、蔬菜、堅果、豆類 和全谷類食物的膳食纖維?是腸道菌群最好的補給。?當(dāng)細菌分解纖維時，?它們會產(chǎn)生短鏈脂肪酸， 滋養(yǎng)腸道屏障，?改善免疫功能，?幫助預(yù)防炎癥， 從而降低癌癥風(fēng)險。?攝入的纖維越多，?腸道中消化纖維的細菌就越多。?在最近的一項研究中，?科學(xué)家們將南非農(nóng)村人 長期食用的高纖維飲食，?換成非洲裔美國人的高脂多肉飲食。?改用高脂肪、低纖維的 西式飲食僅僅兩周后，?非洲農(nóng)村人實驗組出現(xiàn)結(jié)腸炎癥增加、?丁酸鹽減少的現(xiàn)象。?這種短鏈脂肪酸， 可以降低患結(jié)腸癌的風(fēng)險。?與此同時，改用高纖維、 低脂肪飲食的實驗組?則出現(xiàn)相反的結(jié)果。?

當(dāng)我們攝入低纖維加工食品時， 腸道細菌出現(xiàn)了什么問題呢？?對于腸道細菌來說， 纖維越少意味著補給越少，?致使腸道細菌挨餓，直至死亡。?這會使細菌多樣性減少，?并產(chǎn)生饑餓細菌。?事實上，有些細菌甚至 開始吃黏液層。?特定的食物也會影響腸道細菌。?在最近的一項微生物組研究中，?科學(xué)家發(fā)現(xiàn)水果、?蔬菜、?茶、?咖啡、?紅酒、?以及黑巧克力?都可以增加細菌多樣性。?這些食物含有多酚，?一種天然抗氧化劑。?另一方面，?乳脂含量高的食物，?如全脂牛奶，加糖的蘇打水?則會使細菌多樣性降低。?

如何烹制食物也很重要。?最低限度加工的新鮮食品 通常含有更多纖維，?可以提供更多營養(yǎng)。?所以清蒸的，?淡炒的，?或生的蔬菜?通常比油炸菜品更有益。?還有一些食物制作方法， 可以切實地將有益細菌，?也稱為益生菌，引入腸道。?發(fā)酵的食物中含有大量有益的益生菌，?如乳酸桿菌?和雙歧桿菌。?在制冷工藝發(fā)明之前，?本來是作為一種保存食物的方式。?發(fā)酵這種傳統(tǒng)工藝 一直廣泛流傳于全世界。?韓國泡菜、?德國酸菜、?印尼豆豉?和紅茶菌等食物?為我們的飲食提供了多樣性和活力。

?酸奶是另一種可以為腸道 帶來有益菌的發(fā)酵食品，?但這并不意味著所有的 酸奶對我們都是有益的。?那些糖分較多、 細菌較少的品牌?可能對我們沒有好處。?這些只是一般指導(dǎo)原則。?要徹底了解食物與我們體內(nèi) 微生物群之間的相互作用，?還需要很多研究。?我們看到了正向相關(guān)性，?但腸道內(nèi)部很難進行直接觀察。?例如，我們目前還不知道?是這些食物直接 改變了細菌多樣性，?還是發(fā)生了更加復(fù)雜的過程。?僅僅是剛開始研究腸道世界內(nèi)部，?我們就已經(jīng)初窺微生物 對消化系統(tǒng)健康的重要性。?好消息是我們可以 調(diào)動腸道里的細菌。?補充纖維、?多吃新鮮和發(fā)酵食品，?剩下的事情放心交給腸道， 它會讓你變得強壯。

Trillions of bacteria, viruses, and fungi live on or inside of us,?and maintaining a good, balanced relationship with them?is to our advantage.?Together, they form the gut microbiome,?a rich ecosystem that performs a variety of functions in our bodies.?The bacteria in our guts can break down food the body can't digest,?produce important nutrients,?regulate the immune system,?and protect against harmful germs.?We don't yet have the blueprint?for exactly which good bacteria a robust gut needs,?but we do know that it's important for a healthy microbiome?to have a variety of bacterial species.?Many factors affect our microbiomes,?including our environment,?medications like antibiotics,?and even whether we were delivered by C-section or not.?Diet, too, is emerging as one of the leading influences?on the health of our guts.?And while we can't control all these factors,?we can manipulate the balance of our microbes?by paying attention to what we eat.?Dietary fiber from foods like fruits, vegetables, nuts, legumes, and whole grains?is the best fuel for gut bacteria.?When bacteria digest fiber,?they produce short chain fatty acids that nourish the gut barrier,?improve immune function,?and can help prevent inflammation, which reduces the risk of cancer.?And the more fiber you ingest,?the more fiber-digesting bacteria colonize your gut.In a recent study, scientists exchanged the regular high-fiber dietsof a group of rural South Africans?with the high-fat, meat-heavy diets of a group of African-Americans.?After just two weeks on the high-fat, low-fiber, Western-style diet,?the rural African group showed increased inflammation of the colon,as well as a decrease of butyrate.?That's a short chain fatty acid thought to lower risk of colon cancer.?Meanwhile, the group that switched to a high-fiber, low-fat diet?had the opposite result.?So what goes wrong with our gut bacteria when we eat low-fiber processed foods??Lower fiber means less fuel for the gut bacteria,?essentially starving them until they die off.?This results in less diversity?and hungry bacteria.?In fact, some can even start to feed on the mucus lining.?We also know that specific foods can affect gut bacteria.?In one recent microbiome study,?scientists found that fruits,?vegetables,?tea,?coffee,?red wine,?and dark chocolate?were correlated with increased bacterial diversity.?These foods contain polyphenols,?which are naturally occurring antioxidant compounds.?On the other hand,?foods high in dairy fat,?like whole milk, and sugar-sweetened sodas?were correlated with decreased diversity.?How food is prepared also matters.?Minimally processed, fresh foods generally have more fiber?and provide better fuel.?So lightly steamed,?sautéed,?or raw vegetables?are typically more beneficial than fried dishes.?There are also ways of preparing food that can actually introduce good bacteria,?also known as probiotics, into your gut.?Fermented foods are teeming with helpful probiotic bacteria,?like lactobacillus?and bifidobacteria.?Originally used as a way of preserving foods?before the invention of refrigeration,?fermentation remains a traditional practice all over the world.?Foods like kimchi,?sauerkraut,?tempeh,?and kombucha?provide variety and vitality to our diets.?Yogurt is another fermented food that can introduce helpful bacteria into our guts.?That doesn't necessarily mean that all yogurt is good for us, though.?Brands with too much sugar and not enough bacteria?may not actually help.?These are just general guidelines.?More research is needed before we fully understand?exactly how any of these foods interact with our microbiomes.?We see positive correlations,?but the insides of our guts are difficult places to make direct observations.?For instance, we don't currently know?whether these foods are directly responsible for the changes in diversity,?or if something more complicated is happening.?While we're only beginning to explore the vast wilderness inside our guts,?we already have a glimpse of how crucial our microbiomes are for digestive health.?The great news is we have the power to fire up the bacteria in our bellies.?Fill up on fibers,?fresh and fermented foods,?and you can trust your gut to keep you going strong.