文章将“肠道健康”从单纯关注活菌扩展到“后生元（postbiotics）”，即死菌、死菌碎片、微生物产物或其组合，并用多组数量级与比例支撑其潜在价值。每个人体内共生微生物以“万亿”计，主要集中在大肠；过去 20 年研究显示微生物多样性与健康相关，低多样性与“坏菌”比例更高与 2 型糖尿病、肥胖及神经退行性疾病（如帕金森、阿尔茨海默）相关。饮食端的最大可量化缺口是纤维：西方人群中约 90% 纤维摄入不足；纤维到达结肠后被发酵生成短链脂肪酸（SCFAs，如丙酸、丁酸、乙酸），支持肠屏障能量供给、血糖控制与抗炎。
对比益生元/益生菌/合生元（synbiotics）后，文本把“死菌有效”作为核心反直觉结论：益生菌补充剂常只含 1 种或少数菌种，且多因“合法且易培养”而非疗效而选，导致证据在多数情况下仍不足；而发酵食品菌种更丰富，更可能提升多样性。后生元证据来自对照研究的“安慰剂臂”意外效果：日本研究指出热灭活 Lactobacillus pentosus 可提升对普通感冒的免疫防护；后续研究显示多种死菌可改善儿童腹泻与咽痛；德国一项“大型研究”发现死的 Bifidobacterium bifidum 可缓解 IBS 症状。另有“一项小型研究”比较热处理酸菜与“活”酸菜，结论是两者缓解 IBS 的程度相近。
最被研究的后生元例子是 Akkermansia：其与更佳代谢健康、血糖控制与减重相关；比利时鲁汶大学 Patrice Cani 的研究称死的 Akkermansia 在小鼠与人类中具显著抗肥胖与抗糖尿病效应，且“死菌版本”比活菌更有效。机制假设包含群落产生的外多糖（exopolysaccharides）等结构：即便微生物死亡，这些结构仍可能降低炎症、保护肠屏障；动物研究还提示含外多糖的干燥粉末发酵食品可降血压、降胆固醇，甚至可能与抗癌保护相关。监管层面，活菌添加受严格限制，而死菌不可复制使限制负担下降，被视为功能性食品创新与研究扩展的窗口。
The article shifts “gut health” from a living-bacteria focus toward postbiotics—dead microbes, microbial fragments, microbial products, or combinations—and supports the idea with scale and prevalence figures. Each person hosts trillions of microbes, mostly in the large intestine; over the past 20 years, evidence has linked higher microbiome diversity with better health, while low diversity and more “bad” bacteria correlate with conditions including type 2 diabetes, obesity, and neurodegenerative disease. A major dietary gap is quantified as fiber deficiency: about 90% of people in the West fall short. Fiber reaches the colon and is fermented into short-chain fatty acids (SCFAs) such as propionate, butyrate, and acetate, which support gut lining energy, blood-glucose control, and reduced inflammation.
Against prebiotics/probiotics/synbiotics, the core numerical claim is that “dead” bacteria can still be active biologically. Probiotic supplements often contain one or a small handful of species, selected for legality and ease of culture rather than proven efficacy, which helps explain why benefits are often weak in disease prevention. Postbiotic evidence emerged when heat-inactivated microbes used as controls showed effects: Japanese work concluded a heat-inactivated Lactobacillus pentosus strain increased immune protection against the common cold; later studies reported dead bacteria helped children with diarrhoea and sore throats; a large German study found dead Bifidobacterium bifidum relieved IBS symptoms. A small study comparing heat-treated versus live sauerkraut found both eased IBS to a similar degree.
A leading postbiotic target is Akkermansia, associated with improved metabolic health, glucose control, and weight loss; Patrice Cani reported that dead Akkermansia showed significant anti-obesity and anti-diabetic effects in mice and humans and was more effective than the live form. Mechanistic hypotheses include community-produced exopolysaccharides that persist after microbial death and may reduce inflammation and protect the gut barrier; animal work suggests dried, powdered fermented foods containing these structures can lower blood pressure and cholesterol and may even help protect against cancer. Because live microbes are tightly regulated in foods and studies, the non-replicating nature of dead microbes reduces regulatory burden, positioning postbiotics as a likely functional-food mainstay.