The use of kiwi fruit (Actinidia deliciosa) for supporting or treating insomnia is primarily supported by emerging scientific evidence rather than traditional use. Several small clinical studies have investigated the potential of kiwi fruit in improving sleep quality. The most frequently cited study is a 2011 trial conducted in Taiwan, where 24 adults with sleep disturbances consumed two kiwifruits one hour before bedtime for four weeks. Results indicated significant improvements in sleep onset, duration, and efficiency, as measured by sleep diaries and standardized sleep quality questionnaires (Lin et al., Asia Pac J Clin Nutr. 2011). Other studies have suggested that the sleep-promoting effects of kiwi may be attributed to its high content of antioxidants (like vitamin C and E), serotonin, and folate, all of which are implicated in sleep regulation and mood stabilization.

However, the available evidence is limited by small sample sizes, lack of large randomized controlled trials, and relatively short study durations. The mechanism is not fully understood, though kiwi's serotonin content is a plausible contributing factor. While the preliminary findings are promising, more rigorous and larger-scale research is needed to confirm the efficacy and clarify the mechanisms. There is no strong record of kiwi being used in traditional medicine for sleep, so the current rationale is mainly scientific and recent. Therefore, the overall evidence rating is moderate to low (2/5).