Background: Against the backdrop of rising global health awareness and population ageing, health‑preserving interventions encompassing traditional Chinese medicine (TCM) regimens, dietary therapeutics, and industrial‑produced dietary supplements have expanded rapidly. Public health decisions regarding these interventions are frequently guided by anecdotal experience rather than rigorous scientific evidence, potentially leading to resource waste and unrecognized health hazards. This narrative systematic review aims to appraise the evidence base for representative health‑preserving approaches, establish practical appraisal criteria, and generate evidence‑informed recommendations for clinical practice and public health.

Methods: Narrative systematic review methodology was adopted. Literature retrieval was performed across PubMed, Cochrane Library, and Embase. Representative interventions were grouped into three categories: TCM health‑preserving modalities, traditional nourishing foods, and modern dietary supplements. Evidence from randomised controlled trials (RCTs), individual‑participant‑data meta‑analyses (IPD‑MA), and systematic reviews was synthesised. Key methodological confounders including funding bias, sample‑size constraints, and population‑specific effect modification were addressed. Five core appraisal principles for health‑preserving interventions were formulated.

Results: Among TCM‑derived interventions, acupuncture demonstrates high‑grade evidence for chronic‑pain management, with favourable safety profiles under qualified practitioners. Berberine shows moderate‑level evidence for glycaemic regulation and may serve as an adjuvant metabolic intervention. Curcumin exhibits anti‑inflammatory potential in rheumatoid‑arthritis populations yet is substantially limited by poor oral bioavailability. Most compound herbal diets, constitution‑based conditioning, and seasonal tonification lack high‑quality human trial evidence and carry unquantified toxic‑drug‑interaction risks. For traditional nourishing foods, oral collagen supplementation shows disputed clinical benefits with prominent industry‑funding bias; high‑quality independent studies fail to confirm structural anti‑ageing skin effects. Edible bird’s‑nest delivers inferior nutritional value relative to conventional complete protein sources, with minimal human clinical validation. Chicken essence yields preliminary evidence for athletic recovery, yet evidence generalisability to the general population remains limited. Modern dietary supplements exhibit pronounced population‑dependent efficacy: omega‑3 fish‑oil confers cardiovascular benefits predominantly among patients with severe hypertriglyceridaemia rather than normolipidaemic healthy individuals. Vitamin‑D benefits manifest only in deficient populations. Probiotic efficacy is strictly strain‑specific. Routine multivitamin supplementation offers negligible primary‑prevention gains for chronic diseases among generally healthy adults; β‑carotene and vitamin‑E supplementation carry documented harms in select subgroups. Five appraisal principles are proposed: prioritising well‑conducted RCT evidence; valuing large‑sample multi‑centre studies; favouring high‑impact peer‑reviewed journals; scrutinising conflicts‑of‑interest and funding sources; and distinguishing therapeutic versus preventive effects and special versus general populations.

Conclusion: Health‑preserving interventions display heterogeneous evidence grades. Indiscriminate universal supplementation should be replaced by targeted, biomarker‑guided intervention strategies. Improving public evidence‑based health literacy is essential to mitigate misinformed health consumption. Future research should prioritise ethnic‑Chinese‑population‑specific data, standardised trial protocols for dietary supplements, and implementation frameworks translating evidence into public‑health practice.