Research carried out by the University of Otago has shown adults low in dietary vitamin C can enhance their feelings of vitality by consuming two kiwifruits a day for two weeks. The study emphasized the benefits of ingesting vitamin C through whole fruits such as the kiwifruit.
Observing effects were more evident than in a matched population consuming vitamin C mainly through a supplement tablet.
Whole Fruits and Vitamin C
Scientists from Otago’s Department of Psychology and the Center for Free Radical Research in Christchurch performed a placebo-controlled intervention to test whether enhancing vitamin C through whole fruit or tablets can improve feelings of vitality or zest for life.
As part of the study, 167 people between 18 to 35 years-old who had low baseline levels of vitamin C were randomly split into three groups: a kiwifruit group, an equivalent vitamin C tablet group, and a placebo-tablet group.
Every day for four weeks, participants were asked to eat two Sungold kiwifruit, which is incredibly high in vitamin C, or intake their tablet. Blood vitamin C level and questionnaire measures of mood, fatigue, and well-being were taken throughout the study on a bi-monthly basis.
Results showed that vitamin C levels in both the kiwifruit and vitamin C tablet group enhanced to normal within two weeks with no placebo effect. An important finding, though, was the additional benefits to vitality reported by the group consuming the fruit.
“Whole fruit had a broader range of benefits: lessening fatigue and improving mood and well-being across a wider number of people than we saw in the supplement group. The vitamin C tablet did decrease fatigue and improved well-being to some extent for individuals with consistently low vitamin C levels leading up to the intervention. Interestingly, the benefits from consuming kiwifruit emerged in just two weeks,” lead author Associate Professor Tamlin Conner explains.
Added Benefits of Vitamin C
Vitamin C has multiple functions in the body and brain and enhances the production of a number of hormones and neurotransmitters. Among these are adrenalin, serotonin, and oxytocin that manage stress levels, regulate mood, and foster feelings of well-being.
Co-investigator Professor Margreet Vissers says that although correlations between vitamin C and physical functioning are well-studied and known, this particular research establishes a role for vitamin C in mental functioning. The study also implies that whole fruit consumption promotes extra benefits to mental function.
Dr. Conner also says that by raising vitamin C levels by ingesting whole fruits like kiwifruit, people can benefit from other active ingredients that will improve more systems in the brain and body.
“For example, kiwifruit has numerous additional vitamins and minerals that support health and are also high in dietary fiber, which is beneficial to the gut. There are important links between the gut and the regulation of mood. This could account for why kiwifruit benefited mood more than vitamin C tablets,” Dr. Conner said.
The research, titled “KiwiC for Vitality: Results of a Randomized Placebo-Controlled Trial Testing the Effects of Kiwifruit or Vitamin C Tablets on Vitality in Adults with Low Vitamin C Levels,” has been published in the journal Nutrients.