Kiwi is one of the foods recommended to facilitate intestinal transit in case of constipation due to its fiber content and it is also one of the fruits that contains the most vitamin C, since the consumption of a medium-sized kiwi provides around 85% of the recommended daily amount of this vitamin.
Now, in addition to its benefits for the intestine, advantages for the brain are added, according to the findings of a new study carried out by researchers at the University of Otago (New Zealand) which reveals that including kiwi in the daily diet promotes a good mood and can improve vitality and emotional well-being in just four days. The findings have been published in The British Journal of Nutrition.
Professor Tamlin Conner, psychologist and co-author of the work, said the findings provide a tangible and accessible way for people to protect their mental health. “It’s great for people to know that small changes to their diet, like adding kiwis, could make a difference in how they feel every day.” Conner’s work examines “modifiable lifestyle habits that improve or impede well-being,” or, in other words, the small, manageable things humans can do to be happy and healthy.
Vitamin C intake has been associated with better mood, vitality, well-being and less likelihood of experiencing depressive symptoms, while a deficiency of this micronutrient has been linked to a greater risk of suffering from depression and cognitive impairment. However, Conner said research on how quickly improvements in mood occurred after introducing vitamin C supplements or whole food sources was limited.
The impact of nutrients on mental health
The authors of the new study attempted to prove this by designing an eight-week dietary intervention for 155 adults with vitamin C deficiency. They divided the participants into groups to receive either a vitamin C supplement, a placebo, or two kiwis. These people reported on their vitality, mood, well-being, quality and quantity of sleep, and physical activity through smartphone surveys.
The researchers found that kiwi supplementation improved vitality and mood within four days, peaking around 14-16 days after starting intake and experiencing improvement from day 14. Vitamin C, on the other hand , marginally improved mood until day 12.
Kiwi supplementation improved vitality and mood within four days, peaking around 14-16 days after starting intake
Lead author Dr Ben Fletcher, who carried out the research as part of his PhD at Otago, said understanding the nuances of when and how these effects occurred in day-to-day life contributed to knowledge of the potential benefits of the foods and supplements rich in vitamin C for mental health.
“This helps us see that what we eat can have a relatively quick impact on how we feel,” he says. “Our participants had relatively good mental health to begin with, so they had little room for improvement, but they still reported benefits from the kiwi or vitamin C interventions.”
Fletcher adds that while vitamin C supplements produced some improvements, the study highlights the potential synergistic effects of eating whole foods like kiwi. “We encourage a holistic approach to nutrition and wellness, incorporating various nutrient-dense foods into your diet.”
As well as the direct implications for people seeking to improve their mental wellbeing, Professor Conner says the study introduces a novel methodology into nutritional research. “Using intensive smartphone surveys offers real-time understanding of daily changes in mood-related outcomes,” she concludes.
