Do kiwifruits improve mood?

Executive summary

* A paper has recently been published about a three-way intervention trial (involving 155 people) conducted in New Zealand. Participants needed to have low vitamin C levels.

* One third of the participants were given 250mg vitamin C daily, one third were given a placebo tablet, and the remaining third were given two SunGold® kiwifruit daily.

* The trial was not randomised, and this led to differences between the three groups, which needed to be adjusted for.

* The study claimed that kiwifruit could improve mood in as few as four days. After adjustment, there were no differences between vitamin C and placebo or kiwifruit and placebo.

* The researchers created a subset of people differently low in vitamin C and claimed results for these. We don't know if these data were adjusted. (Update - correspondence with the lead author confirmed that these data were not adjusted. There were therefore no results post adjustment).

* The NZ team have been involved in this research since 2017. The first claims for kiwifruit were made in 2020. This paper is more of the same.

* The authors reported no conflicts of interest. The study was funded by Zespri International Limited, which is the world's largest marketer of kiwifruit.