THE TRILLIONS of bugs in a human gut digest complex carbohydrates into fatty acids that provide about 10% of an individual’s calories.(人类肠道中的数万亿微生物将复杂的碳水化合物消化成脂肪酸，这些脂肪酸提供个体约10%的卡路里。) They synthesise(合成) vitamins, notably(尤其，特别) K (which regulates(调节，控制) blood clotting) and various members of the B group. They help tune the immune system. They suppress the growth of pathogens(病原体). And they regulate production of signalling(信号传递的) molecules, such as serotonin(血清素), involved in sending messages from the gut to the brain.
人类肠道中的数万亿微生物将复杂的碳水化合物消化成脂肪酸，这些脂肪酸提供个体约10%的卡路里。它们合成维生素，尤其是K（调节血液凝固）和B族维生素的多种成员。它们帮助调节免疫系统，抑制病原体的生长，并调节信号分子的产生，如血清素，这些分子参与从肠道到大脑的信息传递。
Keeping your gut microbiome in tip-top condition(最佳状态) is thus wise. Maintaining a diverse mix of bacteria in it is widely thought a good way to do this. And, since different species have different appetites, diversity of diet makes sense(有道理，合理).
因此，保持肠道微生物组处于最佳状态是明智的。人们普遍认为，在其中维持多样化的细菌组合是做到这一点的好方法。而且，由于不同物种有不同的“胃口”，饮食多样化是有道理的。
In 2018 an American citizen-science(公民科学) project showed that people eating 30 types of plants a week had significantly(显著地) more diverse microbiomes than those eating fewer than ten. And work from Stanford University, published in 2021, confirmed that fermented(发酵的) foods such as kimchi(泡菜（韩国）) and sauerkraut(德国酸菜) diversify microbiomes, too. Some people, though, feel such off-the-peg(现成的，非定制的) advice is insufficient. They would prefer something bespoke(定制的，量身定做的).
2018年，一个美国公民科学项目表明，每周吃30种植物的人，其微生物组多样性显著高于每周吃不到10种的人。斯坦福大学2021年发表的研究也证实，泡菜和酸菜等发酵食品同样能使微生物组多样化。不过，有些人觉得这种现成的建议不够充分，他们更想要量身定制的东西。