The effect of asparagus stem consumption on health outcomes in adults: a systematic review.

Asparagus (Asparagus officinalis) contains bioactive compounds such as polyphenols and saponins, which have been shown to influence cognition, mood, sleep, stress and related biomarkers. However, the evidence from human studies has not been systematically synthesised. To address this, we conducted a systematic review evaluating the effects of asparagus-based products on cognitive, affective, sleep outcomes and related biomarkers in adults. A systematic search of PubMed, Scopus, Web of Science, PsycINFO, Google Scholar and Amino Up Ltd's website (up to April 2025) identified studies assessing asparagus supplementation in adults, following PRISMA guidelines (PROSPERO registration number: CRD42025636834). Human studies that employed randomised controlled trials or quasi-experimental designs and assessed the effects of orally administered asparagus-based products on cognition, mood, sleep or relevant biomarkers were included. Eighteen studies (thirteen randomised controlled trials and three pre-post-studies; 503 participants) were included. Cognitive improvements were observed in reaction time, accuracy and mental fatigue, while mood and stress-related outcomes showed reductions in anxiety and depressive symptoms. Sleep outcomes consistently demonstrated improvements in sleep quality and duration, while biomarker data showed effects on cortisol levels. Asparagus supplementation may offer modest benefits for cognition, mood and stress-related physiology, with particularly consistent effects on sleep quality. However, the magnitude of benefits varies by population, dose and duration, and the heterogeneity of interventions, small sample sizes and limited studies may constrain the generalisability of findings. Well-powered, long-term clinical trials are needed to determine optimal dosage, clarify mechanisms and assess efficacy across diverse populations.